1257428 (1) 九、發明說明 【發明所屬之技術領域】 本發明是關於用溫度已加熱處理到金屬的轉態點溫度 附近之惰性氣體來進行之乾式的恆溫保持熱處理系統之應 用，且是關於在這系統的前部和後部，備有前室、預冷卻 室、冷卻室等的相關處理室，既全面又效率良好連續進行 金屬的熱處理之連繪式金屬熱處理系統。另外，本發明是 ^ 關於將表面已滲碳處理過的製品（以下稱爲工件），投入 到近年開發之可保持恆溫的氣體冷卻爐中，不用鹽浴而是 經過前述工件的剛好麻田散鐵（martensite)轉態點之上 的溫度之恆溫保持，進行成爲常溫以下的溫度的氣體淬火 • ’且能進行鹽浴所達不到之高度、高品質的溫度滓火之渗 碳氣體淬火方法。 【先前技術】 Φ 金屬的淬火方法，已知有將預熱到淬火開始溫度之工 件一口氣冷卻到吊溫’之後進fj回火之〜'般捽火之外，還 有俗稱爲恆溫熱處理法，依S曲線（T、T、τ曲線）所設 定的中間溫度，經一定時間保持恆溫，之後急速冷卻到室 溫之沃氏體回火法（austemper )、麻氏體回火法 （ martempe〇 、麻氏體萍火法（n-rquench)等。日本專利 特開2〇〇〇 — 1 293 6 1號公報中（鋼製或者鑄鐵製零組件的 熱處理方法），記載有將工件加熱到麻田散鐵（ m a r t e n s i t e )轉態溫度’接者急速冷卻_麻田营女釣^ ( (2) 1257428 martensite )轉態開始點進行淬火，直到部分轉態爲變靭 鐵（bainite )才用鹽浴保持恆溫，之後冷卻至室溫，再接 著進行瞬間淬火，就能明顯改善零組件的尺寸穩定性。 過去，恆溫保持之熱處理是用鹽浴來進行（參考社團 法人日本熱處理技術協會編輯，熱處理技術便覽，2000 年8月30日發行，ρ·144〜147(鹽浴熱處理））。淬火 是用 150〜550 °C的低溫用，570〜950 °C的中溫用， φ 1 〇 〇 〇〜13 ο 〇 °c的高溫用之鹽浴。鹽浴材則是依溫度來使用 KN02 或 KN〇3、及 NaCL、及 LiCl 或是 KC1。 用鹽浴之金屬的熱處理無法從真空爐或氣相爐等的預 ^ 熱爐取出工件就一口氣冷卻到所要的溫度，而進行種種的 • 措施（參考社團法人日本熱處理技術協會編輯，熱處理 技術便覽，2000年8月30日發行，ρ· 769〜773(鹽浴爐 ))〇 例如：在真空爐內配置高溫的鹽浴，在暫時把鹽附著 φ 在表面的狀態下取出工件，再在施加防銹披覆過後的狀態 下，依序移動到溫度很低的鹽浴，最後在於中間溫度的鹽 浴中保持恆溫。鹽浴間的移動是用鏈滑車等來進行。以高 溫工件和高溫熱浴爲對象的作業必須既熟練又極小心進行 〇 此外，也有俗稱爲連續式，在預熱爐的下方配置沃氏 體回·火法處理用的鹽浴，將從預熱爐所排出的小工件移至 鹽浴，用輸送帶依序來使工件移動的例子。其缺點是對處 理品有很多限制而只能用在沃氏體回火法等。 -6- (3) 1257428 也有俗稱爲多目的式，以批次托盤式自 熱爐和鹽冷卻槽連接起來全自動進行沃氏體 例子。但是這種方式仍然要大規模使用鹽浴 鹽浴因不管用任何的使用方法仍是將工 內來進行冷卻或是恆溫保持，必要有浸入和 段’因而本身在處理上就會受到很多的限制 氏體回火法，急速冷卻到2 0 0 °C後迅速升溫 φ 行恆溫保持，之後冷卻到常溫之繁瑣的製程 鹽浴’又必要有相對鹽浴來移送工件之手段 型化而製品成本增加的原因。 另外’近年因使用鹽浴而造成環境污染 行工件冷卻時，特別是當進行淬火時，已逐 冷卻而改用N 2氣體或A r氣體來進行冷卻、 曰本專利特開平5 — 6 6 0 9 0號公報所記載的 要在在耐壓性的爐本體內收納工件後加熱到 • 接著就進行冷卻，因而要能夠在前述爐本體 的惰性氣體，利用渦輪鼓風機的作動使該氣 迅速將前述處理品冷卻。這真空爐設有對設 件進行除熱、1次預熱、2次預熱、到淬火 仕了頁熱温度的筒溫保持等一連串的加熱處理 工件經過一連串的預熱處理，接著就能將5 吹入、冷卻，並進行淬火處理。該爐也稱爲! 不過’過去的可氣體淬火的噴流爐，可 的工件急速冷卻到常溫，且可以進行常溫的 動搬運，將預 回火法處理的 〇 件浸漬在鹽浴 拉起工件的手 。如同升溫沃 到 2 5 (TC並進 必要有複數個 ’成爲裝置大 的問題，當進 漸避開用鹽來 淬火。例如： 真空爐，爲了 1000〜1200 〇C 內導入5 Bar 體循環，比較 定在內部的工 溫度的預熱、 之加熱手段。 Bar的\ ν2氣體 賁流爐。 以將預熱過後 淬火處理，但 - 7- (4) 1257428 因用直接配置在循環路中的水冷管以水冷 的冷卻的關係，所以用來保持恆溫的中間 無法進行，因而沃氏體回火法、麻氏體回 火法等必須要進行恆溫保持的熱處理則無 也有用上述噴流爐嘗試沃斯回火法的 。這情況，將控制裝置的目標溫度設定在 此處是以使一定時間保持恆溫的方式來指 I 流爐依照指令，氣體溫度比目標溫度還低 的加熱器作動，比目標溫度還高時則加熱 之間，藉由鼓風機來循環的氣體流隨時經 冷卻。因而上路噴流路高到5 0〜1 0 0 °C、侣 現大幅的溫度變化，以致於不堪使用。即 無法控制恆溫保持。另外，因惰性氣體的 以還會有部分、局部發生過度冷卻的問題 是只使惰性氣體的導入溫度上升就可以。 Φ 日本專利特開平3 — 2 5 3 5 1 2號公報中 冷卻的沃氏體回火法處理方法），記載有 開2 000 — 1 293 6 1號公報中所記載的包含 理不用鹽浴而改用惰性氣體來進行的方法 請專利範圍所記載，沃氏體回火法處理是 3 0 0〜5 00 °C的惰性氣體後保持一定時間。 日本專利特開平3 — 2 5 3 5 1 2號公報中 裝置，設有收納9 0 0 °C加熱工件之高壓室: 體之儲備氣槽’而兩者之間用配管相連接 來進行氣體本身 溫度的恒溫保持 火法、麻氏體淬 法進行。 恆溫淬火的例子 恆溫保持溫度， 令。因而上述噴 時則工件加熱用 器停止作動。這 由水冷裝置進行 5到100°c就會出 是過去的噴流爐 導入爲常溫，所 。儘管如此並不 (高溫高壓氣體 上述日本專利特 恆溫保持之熱處 。即是如同該申 對加熱工件噴吹 的第1圖所示之 及存放高壓N2氣 。在儲備氣槽之 -8- (5) 1257428 輸入側的配管，組裝具有控制閥和壓縮機的電路和具有控 制閥和耐熱風扇的電路之並聯電路。 适裝置因在工件開始冷卻時，由儲備氣槽導入 3 00〜5 0 0 °C的N2氣體並對工件噴吹，所以不會發生過度冷 卻的問題。之後利用耐熱風扇的作動，循環流經由儲備氣 槽還流到配管，工件則被恆溫控制在3 00〜5 00°C。 但是對於小型數Kg的工件也許可能，不過50、1〇〇 0 Kg以上的一般淬火裝置，因工件的放熱熱量龐大而必須 將配管尺寸設爲例如：直徑3 0 cm等，且各機器類不堪於 5 00 °C以上的高溫。儲備氣槽只是在剛開始導入3 00〜5 0 0°C 的惰性氣體而已並無其他的意義。特別是一般淬火裝置在 實用上並不適用。 曰本專利特開平3 一 2 5 3 5丨2號公報中的第2圖係只在 剛開始供應來自儲備氣槽的N 2氣體，用來形成冷卻風的 氣體則是在於局壓容器內進行循環，而壓力容器內，配置 • 有循環路、用來形成循環流的耐熱性風扇、及將循環氣體 冷卻到3 0 0〜5 0 0 °C的冷卻器。 但是雖然是只在循環路中配置有冷卻器的構造卻沒有 具體述說，不過考慮到冷卻中的冷煤溫度爲與循環氣體溫 度平衡的3 00〜5 00 t，這點就會造成裝置過度大型，至少 疋：無法成爲泛用置。右是把冷卻器的冷煤溫度設爲 3 〇 0〜5 0 〇 °C則必要有圖以外的熱控制裝置，若是熱容量很 大則要相g大型的裝置’結果是無法實施。例如：必須有 將3 00〜5 0 0 °C的冷煤儲存在裝置外之油槽、及調節該油槽 (6) 1257428 溫度的冷卻油和加熱用加熱器之以及耐熱用的循環幫浦等 ，變爲超過爐體以上的大小’配置在熱處理工廠內本身就 不容易。 另外，日本專利特開平3 — 2 5 3 5 1 2號公報中的第1圖 和第2圖所示之可恆溫保持的裝置’只有工件重量很輕、 工件的熱容量很小，且熱父換設備變很大也能接受之實驗 設備等才能實施，不過由於是加上恆溫保持至之後的冷卻 φ 爲止在1個爐內進行之裝置，因而會有效率不良且不適於 大量生產的問題點。另外’恆溫保持、冷卻分別都需要時 間，因而1個工件進行熱處理就至少要6〜8小時。再則， 因用來保持恆溫的繁瑣之裝置構成的關係，會有預熱或是 冷卻的方式受到限制，且無法實現效率良好又效果很高的 熱處理方法等的缺陷。 另外，過去的滲碳淬火方法，例如：在日本專利特開 平5 — 22244 5號公報、特開平6 — 1 229 1 9號公報中已有記 ❿載。 日本專利特開平5 - 22244 5號公報中所示之滲碳淬火 方法，其特徵爲：將加熱工件浸漬在已保持在內部剛好麻 田散鐵轉態點之上的溫度（400〜4 5 0 t )之第1熱浴後， 之後再浸漬在表面剛好麻田散鐵轉態點之上的溫度（ 2 0 0〜2 5 (TC )之熱浴，之後進行冷卻。這種方法是鑒於在 於滲碳處理過之工件的內部與表面之麻田散鐵轉態點溫度 有很大的不同’使兩轉態的時間點一致而促使內部非滲碳 部分的轉態達到均一性。此處的第1和第2熱浴係用硝酸 - 10- (7) 1257428 鉀和硝酸石碳等的鹽浴。 曰本專利特開平6 - 1 2 2 9 1 9號公報所示之滲碳淬火方 法，鑒於工件內部與表面的麻田散鐵轉態點溫度有很大的 不同，而急速冷卻（例如2 0 0 °C /秒以上）到剛好表面麻 田散鐵轉態點之上的溫度，也就是冷卻到麻淬火點（23 0 。(：）。有關急速冷卻的方法並未作說明，不過這種的冷卻 仍然不得不依靠鹽浴等的熱浴，還必須考慮到攪拌、噴吹 等，且受限於薄的工件。 過去，這種滲碳工件係用鹽浴進行恆溫保持，接著進 行淬火處理。因而進行處理來使齒輪、花鍵軸、有鍵槽的 滲碳零組件等之尺寸精度提高。不過由於都用鹽浴來進行 恆溫保持的處理，因而不只設備大型，作業環境劣化，且 其實施不容易，還有條件變更就必須變更設備，不容易依 照工鍵來變更條件，結果是不容易適用於各種工件。 【發明內容】 本發明是鑒於上述過去的技術，其目的是提供將能夠 用惰性氣體來保持恆溫進行熱處理之乾式恆溫保持熱處理 系統實用化，且在其前部和後部備有前室、加熱室、冷卻 室等的相關處理室，而能夠更有效率且高品質進行金屬熱 處理之連繪式金屬熱處理系統。 本發明的另外目的，是用備有近年本發明者等所開發 的在1 0 0〜5 0 0 °C的任意中間溫度都可保持恆溫的恆溫保持 室之氣體冷卻爐，以任意的冷卻形式將滲碳處理過後的工 -11 - (8) 1257428 件冷卻處理，因而不用鹽浴仍容易進行高品質的滲碳淬火 〇 爲了解決上述課題，本發明的備有恆溫保持室之連續 式金屬熱處理系統，其特徵爲： 具備有在於將所投入的加熱工件調節到金屬轉態點溫 度的恆溫氣體環境中保持恆溫之恆溫保持室， 在前述恆溫保持室的前部，設有將前述工件加熱到淬 φ 火溫度之加熱室，在後部，則設有將恆溫保持過後的工件 急速冷卻到常溫以下的溫度之氣體冷卻室，經由可開閉的 門裝置來連續連接各室，並且將工件連續流動到各室，在 各室中施加獨立的熱處理。 因在恆溫保持g的前部，設有加熱室，所以將加熱過 後的工件送到恆溫保持室，在恆溫保持室中冷卻到恆溫保 持的溫度並能保持恆溫。又因在恆溫保持室的後部，設有 氣體冷卻室，所以能將恆溫保持過後的工件送往氣體冷卻 φ 室並急速冷卻到所要的溫度。冷卻室的構成並沒有受到限 制，沒有冷卻到例如：室溫仍能進行急速冷卻到負溫度的 急冷處理。加熱、恆溫保持接著在各室中進行冷卻，所以 配合最大所要時間的生產節拍時間nh連續輸送，就能進 行有效率的熱處理。 如申請專利範圍第1項之恆溫保持室，其中在前述恆 溫保持室，附屬有將從該室的一部分所吸引的氣體再度往 內部送出之循環路，該循環路分歧出2個吸引端被’其中 一方的分歧管維持原樣，而在另一方的分歧管’配置有用 -12- (9) 1257428 常溫冷煤適度將氣體冷卻到大幅低於前述恆溫保持的溫度 之溫度之冷卻器，在兩分歧管的合流點的更後方’配置有 氣體循環用的風扇，兩分歧管都中介設有用來控制流量的 閥， 爲了要讓前述合流點後面的溫度成爲前述恆溫保持的 溫度，而設有調節前述閥的張開度之控制器。 這恆溫保持室其構成極簡單，即使工件熱容量很大也 ϋ 能對應於臨時變動。冷卻器可用20〜50°C程度的冷煤設成 水冷或是空冷。用與現在已實用化的噴流爐同樣的水冷管 最爲實用化。 恆溫保持室具有循環路，吸引端被分歧出2個’其中 一方的分歧管維持原樣，而在另一方的分歧管，配置有用 常溫冷煤之冷卻器’在兩分歧管的合流點的更後方’配置 有氣體循環用的風扇’兩分歧管都設有用來控制流量之有* 如蝶形閥的閥’爲了要讓前述合流點後面的溫度成爲前^ φ 恆溫保持的溫度（200〜5 0 0 °C )而設有調節各閥的張開度 之控制器。因此，風扇的溫度不致於比恆溫保持的溫度更 高。投入工件可以是剛加熱後的8 2 0〜1 2 5 0 0 °C的工件’也 可以是已預冷到恆溫保持的溫度的工件。投入到恆溫保字寺 室的工件朝應該冷卻的方向’所以功能上沒有必要在循胃 路中設置加熱器。只不過最初供應熱氣體時在管內的冷谷P 防止或恆溫保持格外需要長時間的情況’因也有成爲® ^ 保持的溫度以下的可能性’所以也可以附屬有小容量的力口 熱器。 -13- (10) 1257428 開始進行恆溫保持則調節閥的張開度 體的溫度隨時維持在恆溫保持的溫度。因 件中使任意的熱量放出，且流量也能自由 量來計算，工件重量爲5 0 0〜1 0 0 0 K g則圓 爲3 0〜5 0 c m程度。 加熱室、恆溫保持室、氣體冷卻室的 比較能自由設定，在將工件從加熱室送至 φ 時，將之前的工件從恆溫保持室送到氣體 連續的處理。 在前述恆溫保持室與前述加熱室之間 對加熱工件噴吹冷溫氣體而將加熱工件急 持的溫度之預冷卻室。預冷卻室送入例如 將工件急速冷卻到恆溫保持的溫度。可以 下角度急遽化。 依據其特徵爲：具備有在將所投入的 φ 金屬轉態點溫度的恆溫氣體環境中保持恆 9 在前述恆溫保持室的前部，設有將前 火溫度之加熱室，在後部，則設有將恆溫 急速冷卻到常溫以下的溫度之氣體冷卻室 門裝置來連續連接各室，並且將工件連續 各室中施加獨立的熱處理之備有恆溫保持 熱處理系統，連續連接加熱室、恆溫保持 ，並能連續依序移送工件。因能自由設計 ，循環路中之氣 此，能從加熱工 調節。由所要熱 形循環路的直徑 各生產節拍時間 恆溫保持室的同 冷卻室就能進行 ，也可以配置有 速冷卻到恆溫保 :N2氣體就可以 將冷卻曲線的降 加熱工件調節到 溫之恆溫保持室 述工件加熱到淬 保持過後的工件 ，經由可開閉的 移送到各室，在 室之連續式金屬 室、氣體冷卻室 各室，所以各構 -14- (11) 1257428 成和全體構成爲簡單的構成。又因依各室的最大所要時間 所決定之生產節拍時間依序移送工件，所以能有效率進行 熱處理。因能在冷卻中途進行恆溫保持，所以提咼零組件 的尺寸穩定性。因是乾式又不用鹽浴，所以環境改善，並 能進行既安全又衛生的作業。更因恆溫保持室和前部的加 熱室、後部的氣體冷卻室之構成沒有受限制，所以設計上 有闻自由度又應用上能局度控制而達到更加提尚熱處理品 Φ 質。 依據其特徵爲：在前述恆溫保持室，附屬有把從該室 的一部分所吸引的氣體再度往內部送出之循環路，該循環 路分歧出2個吸引端，其中一方的分歧管維持原樣，而在 另一方的分歧管，配置有用常溫冷煤適度將氣體冷卻到犬 幅低於前述恆溫保持的溫度之溫度之冷卻器，在兩分歧管 的合流點的更後方，配置有氣體循環用的風扇，兩分歧管 都中介設有用來控制流量的閥， # 爲了要讓前述合流點後面的溫度成爲前述恆溫保持的 溫度’而設有調節前述閥的張開度之控制器的備有恆溫保 持室之連續式金屬熱處理系統，因極簡單構成恆溫保持室 ，所以能構成有高實用性且是既小型又低價的系統。循環 路有必要但儲備氣槽或大型的熱交換設備則都不需要。常 溫冷煤因能用水或空氣，所以裝置構成格外簡單且具實用 性。 另外，因在後部備有冷卻室，所以恆溫保持室不需要 冷卻到室溫或是更低的溫度之手段，只要能進行恆溫保持 -15- (12) 1257428 即可，系統的構成簡單。 依據其特徵爲：在前述恆溫保持室與前述加 ，配置有對加熱工件噴吹冷溫氣體而用來將加熱 冷卻到恆溫保持的溫度爲止之預冷卻室之連續式 理系統，因單是依序移送控制即可，所以各室控 不會發生控制差錯。 依據其特徵爲：在前述恆溫保持室與前述加 n ，配置有對加熱工件噴吹冷溫氣體而用來將加熱 冷卻到恆溫保持的溫度爲止之預冷卻室之連續式 理系統，預冷卻室和恆溫保持室在1個生產節拍 行處理，就能將加快恆溫保持室之冷卻曲線的降_ 預冷卻和氣體冷卻（主冷卻），因不同的工 時進行，所以將主冷卻時所用的惰性氣體2度用 ，因而也能達到惰性氣體的有效利用。 另外，用來解決上述課題之本發明的滲碳氣 φ 法，是將已滲碳處理過的工件投入到可恆溫保持 卻爐中，經過前述工件的表面剛好麻田散鐵轉態 溫度之恆溫保持，進行成爲常溫以下的溫度的氣 滲碳氣體淬火方法，其特徵爲： 藉由前述氣體冷卻爐之冷卻氣體的氣壓、風 目標溫度的變更等進行控制要素的變更來使冷卻 溫保持的溫度爲止之冷卻速度變更，管理前述工 和表面的到達麻田散鐵轉態點時刻，而調節恆溫 制目標溫度。在前述氣體冷卻爐中，具有能依控 熱室之間 工件急速 金屬熱處 制單純而 熱室之間 工件急速 金屬熱處 時間內進 F速度。 件能夠同 在預冷卻 體淬火方 的氣體冷 點之上的 體淬火之 量、控制 到前述恆 件的內部 保持的控 制目標溫 -16- (13) 1257428 度將投入工件保持恆溫之恆溫保持室， 且在前述恆溫保持室，附屬有把從該室的一部分所口及 引的氣體再度往內部送出之循環路，該循環路分歧出2個 吸引端，其中一方的分歧管維持原樣，而在另一方的分歧 管，配置有用常溫冷煤適度將氣體冷卻到大幅低於前述恆 溫保持的溫度之溫度之冷卻器，在兩分歧管的合流點的更 後方，配置有氣體循環用的風扇，兩分歧管都中介設有用 來控制流量的閥， 爲了要讓前述合流點後面的溫度成爲前述恆溫保持的 溫度，而設有調節前述閥的張開度之控制器。 本發明者等已開發之氣體冷卻爐的例子，例如有：國 際公開 W003/080876 A1(熱氣體淬火裝置和熱氣體熱 處理系統）的例子。這國際公開 W 0 0 3 / 0 8 0 8 7 6 記載有 將循環爐分歧成第1 (高溫用）和第2 (低溫用）的2個 流路，調節兩流路所備有之控制窗的張開度並且控制前述 φ 第1和第2流路的終端位置所具備之混流器流出溫度之基 本型的熱氣體淬火裝置等。依據這熱氣體淬火裝置，經設 定任意的控制目標溫度，將加熱工件投入到爐中，就能冷 卻到100〜5 0 0 °C之間所任意設定的控制目標溫度並保持恆 溫。之後也能夠藉由相同的爐或是與這爐連接之另外的氣 體急速冷卻室’氣體急速冷卻到常溫以下的溫度。 因此，本發明是經由恆溫氣體冷卻爐的氣壓、風量、 控制目標溫度等進行控制要素的變更，而調節恆溫保持的 控制目標溫度，且管理前述工件的內部及表面之到達麻田 -17- (14) 1257428 政鐵轉悲點的各個時刻。適當的淬火方法，也是參考設定 過去例子所記載之第1和第2熱浴的2段目標溫度或使表 面和內部的麻田散鐵轉態開始同時行進的例子。 控制目標溫度的變更只變更電氣控制器的設定溫度即 可。也可以在冷卻中途或室恆溫保持的中途進行變更。能 土 5 C以下的控制，例如：誤差2〜3它的控制。特別是因恆 溫保持的溫度設爲表面剛好轉態點之上溫度的溫度，所以 # 使這溫度上下變動係意味著可微妙調節工件表面附近的麻 田散鐵轉態。因氣體壓可在1〜7 Bar間進行調節，所以也 可以調節噴吹氣體的氣體密度，並使冷卻速度變化。因風 量爲直接噴吹到工件表面的氣體分子密度，所以也可以因 而使冷卻速度變化。氣體壓、風量都可以在恆溫保持的中 途變化。 工件的表面位置並不是實際表面而是其代表位置，最 好是參考表面更深 0 · 2〜0 · 5 m m深度的一個位置。這位置 φ 即也可以是滲碳部分的中心位置。例如：工件爲齒輪時， 內部及在離表面0.2〜0.5 mm之間所設定的參考位置之麻 田散鐵轉態點分別設成4 0 0 °C、2 5 0 °C，相對於實際表面麻 田散鐵轉態點2 00 °C而將控制目標溫度設定爲220〜23 0 °C ’在這範圍內使控制目標溫度變化時，可以相對到達內部 的轉態點時刻來大幅前後調節參考位置的到達轉態點時間 等。 前述氣體冷卻爐具有恆溫保持室以及氣體急速冷卻室 來作爲氣體冷卻室，前述恆溫保持室係先低後高來取得控 -18- (15) 1257428 制目標溫度，可以依照最終表面剛好麻田散鐵轉態點溫度 之上的溫度保持恆溫。若爲這樣，用比表面麻田散鐵轉態 點溫度更低的溫度，用例如：1 5 0 °C的氣體來加快冷卻速 度，而能進行不會牽扯到TTT曲線圖（S曲線）的鼻頭（ η 〇 s e )之冷卻，且能緩和內部和表面的溫度差。 另外，前述氣體冷卻爐具有預冷卻室和恆溫保持室以 及氣體冷卻是來作爲氣體冷卻室，前述工件的表面溫度能 φ 在預冷卻室中冷卻到恆溫保持的溫度附近爲止，接著在恆 溫保持室中進行恆溫保持。 若爲這樣，能在預冷卻室中形成較快速的冷卻，而能 進行不會牽扯到TTT曲線圖的鼻頭（nose )之冷卻，且能 緩和內部和表面的溫度差。 如以上所述，依據本發明，用可依照任意的中間溫度 保持恆溫的氣體冷卻爐，進行直到滲碳處理過後的工件保 持恆溫爲止的冷卻，變更控制目標溫度、氣體壓、風量等 φ 的控制要素而變更冷卻速度，不用鹽浴仍能容易設定任意 的冷卻形態，又能簡單地進行少有畸變且是高品質的熱處 理。由於是氣體冷卻所以作業環境也大幅改善° 可以進行恆溫保持的氣體冷卻爐，若是用將循環路分 歧成第1 (高溫用）、第2 (低溫用）的2流路’經調節 各別所設置之控制窗的張開度，而將兩流路之接合點的溫 度調整成控制目標溫度的形式之氣體冷卻爐’則能依照 ± 5 t以下的控制溫度來進行控制，又能任意設定控制目 標溫度。氣體壓、風量也能自由變更。這兩控制要素能夠 -19- (16) 1257428 在冷卻和恆溫保持的中途進行變更，且控制目標溫 口又定成2段、3段的複數個段。不必要更換鹽浴經 度變更的開關操作就能簡單地實施。 若是將工件的表面更深0.2〜0.5 mm深度的一 設爲參考位置，管理內部和表面的溫度達到轉態點 W1 Μ ’則能g周節工件表面和內部的到達麻田散鐵轉 刻’又能進行少有畸變且是高品質的滲碳淬火。 【實施方式】 以下’參照附圖來說明用來實施本發明的形態 圖爲表不把前室、加熱室、恆溫保持室、冷溫氣體 串聯起來所形成之連續式金屬熱處理系統1之側面 。第2圖爲表示第丨圖之循環路2的側面圖中有關 分沿著F2 — F2線之剖面圖。第3圖爲表示擴大第 循環路2部分之俯視圖。第4圖爲第1圖〜第3圖 φ 系統1之控制說明圖。 第1圖中，本發明的用來實施之連續式金屬熱 統1，以備有循環路2的恆溫保持室3爲核心，在 有加熱室4，在後部備有冷溫冷卻室5。在加熱室 部配置有前室6，全體上是依前室6、加熱室6、恆 室3、冷溫冷卻室5的順序，依序移送工件W並進 理之構成。爲了要移送工件W而設有輸送滾筒R。 加熱室4包括有單是將工件W加熱之真空加 1青況、及對加熱工件W進行滲碳處理之滲碳加熱 度能夠 目標溫 個位置 溫度的 態點時 。第1 冷卻室 剖面圖 爐體部 1圖的 所示的 處理系 前部備 4的前 溫保持 行熱處 熱爐的 爐的情 -20- (17) 1257428 況。滲碳加熱爐的情況，除了設有加熱器，還設有丙院氣 體等或滴劑的注入裝置、或燃燒排出這裝置的排出氣體之 輔助設備。也可以將其他的滲碳加熱爐所滲碳處理過後的 工件W再加熱而進行滲碳淬火。 前室6係爲了將工件w供應到加熱室4而以常壓或 是負壓來保持工件W ’在前方有對應負壓用的門裝置7。 加熱室4係在真空狀態下將工件w加熱到8 2 0〜〗2 5 0 • °C，在前方後方，具有各別的門裝置8、9且具有加熱用 加熱器1 〇及變壓器1 1。後部的門裝置9爲使下一段恆溫 保持室3的門同時作動的型式。 恆溫保持室3具備有不僅將所投入的工件w保持在 依轉態點溫度所設定之恆溫保持的溫度例如：3 〇〇 t：，並 將從加熱室4所投入的工件W冷卻到恆溫保持的溫度之 功能。 如第2圖和第3圖所示，恆溫保持室3在外部具有循 • 環路2。本例子是以可交互通風的方式來構成循環路2。1257428 (1) IX. Description of the Invention [Technical Field of the Invention] The present invention relates to the application of a dry constant temperature maintenance heat treatment system using an inert gas whose temperature has been heated to a temperature near the transition point of a metal, and is related to In the front and rear of the system, there are associated processing chambers such as the front chamber, the pre-cooling chamber, and the cooling chamber, and the continuous drawing metal heat treatment system that performs the heat treatment of the metal is comprehensive and efficient. Further, the present invention relates to a product which has been carburized on the surface (hereinafter referred to as a workpiece), and is put into a gas cooling furnace which can be maintained in a constant temperature which has been developed in recent years, and which does not use a salt bath but passes through the aforementioned workpiece (martensite) The temperature of the temperature above the transition point is maintained at a constant temperature, and the gas is quenched by a gas that is at a temperature lower than the normal temperature, and a carburizing gas quenching method capable of performing a high-temperature bonfire at a height that cannot be achieved by a salt bath. [Prior Art] Φ metal quenching method, it is known that the preheating to the quenching start temperature of the workpiece is cooled to the hanging temperature 'after the fj tempering ~ 'like bonfire, there is also known as constant temperature heat treatment , according to the intermediate temperature set by the S curve (T, T, τ curve), after a certain period of time to maintain a constant temperature, then rapidly cooled to room temperature after the tempering method (austemper), martensite tempering method (martempe〇 , and the method of heat treatment of steel or cast iron components, which is described in Japanese Patent Laid-Open Publication No. Hei 2 No. 1 293 6 1 (heat treatment method for steel or cast iron components). Displaced iron (martensite) transition temperature 'connector rapid cooling _ Ma Tianying female fishing ^ ( (2) 1257428 martensite) to start the quenching at the beginning of the transition, until the partial transition to the tough iron (bainite) to maintain a constant temperature with a salt bath After cooling to room temperature, followed by instantaneous quenching, the dimensional stability of the components can be significantly improved. In the past, the heat treatment of the constant temperature was carried out using a salt bath (refer to the editor of the Japan Heat Treatment Technology Association) Handbook of heat treatment technology, issued on August 30, 2000, ρ·144~147 (salt bath heat treatment)). Quenching is used at a low temperature of 150~550 °C, medium temperature of 570~950 °C, φ 1 〇〇 〇~13 ο 〇°c is a salt bath for high temperature. The salt bath is made of KN02 or KN〇3, and NaCL, and LiCl or KC1 depending on the temperature. The heat treatment of the metal with a salt bath cannot be done from a vacuum furnace or In the preheating furnace of a gas phase furnace, the workpiece is taken out and cooled to the desired temperature, and various measures are taken (refer to the editor of the Japan Heat Treatment Technology Association, the heat treatment technology manual, issued on August 30, 2000, ρ· 769~773 (salt bath furnace)) 〇 For example, a high-temperature salt bath is placed in a vacuum furnace, and the workpiece is taken out while the salt is attached to the surface φ, and then the rust-proof coating is applied. Move to a salt bath with a very low temperature, and finally keep it at a constant temperature in a salt bath at an intermediate temperature. The movement between the salt baths is carried out by a chain block, etc. The work on high temperature workpieces and high temperature heat baths must be both skilled and extremely Be careful, besides In the continuous type, a salt bath for the Worm-back and fire treatment is placed under the preheating furnace, and the small workpiece discharged from the preheating furnace is moved to the salt bath, and the workpiece is sequentially moved by the conveyor belt. The disadvantage is that there are many restrictions on the treated products and can only be used in the tempering method of the tempering body. -6- (3) 1257428 Also known as multi-purpose, the batch tray type self-heating furnace and the salt cooling tank are connected. Automatically carry out the example of Worms. However, this method still requires large-scale use of salt bath salts. Because of any method of use, it is still used for cooling or constant temperature maintenance. It is necessary to have immersion and section 'and thus itself In the treatment, it will be subjected to a lot of limited tempering method. After rapid cooling to 200 °C, it will rapidly heat up and maintain the temperature constant. After cooling to the cumbersome process salt bath at normal temperature, it is necessary to transfer the workpiece with a relative salt bath. The reason for the increase in the cost of the product. In addition, in recent years, environmental pollution caused by the use of salt baths, when the workpiece is cooled, especially when quenching, it has been cooled and replaced with N 2 gas or Ar gas for cooling, 曰本专利专利平平 5-6 6 0 In the case of storing the workpiece in the pressure-resistant furnace body, it is heated and then cooled. Therefore, the inert gas of the furnace body can be quickly driven by the operation of the turbo blower. The treatment is cooled. The vacuum furnace is provided with a series of heat treatment processes such as heat removal of the device, one preheating, two preheating, and a barrel temperature maintenance to the quenching temperature, and then a series of preheating treatments can be performed. 5 Blow in, cool, and quench. This furnace is also called! However, in the past gas-quenchable spray furnace, the workpiece can be rapidly cooled to normal temperature, and can be moved at room temperature. The pre-tempered condition is immersed in the salt bath to pull up the workpiece. hand. Just like warming up to 2 5 (there is a need for multiple TCs to become a large device, when you gradually avoid salting with hardening. For example: vacuum furnace, in order to introduce 5 Bar body cycle within 1000~1200 〇C, it is more Preheating of the internal working temperature, heating means. Bar's ν2 gas turbulent furnace. After preheating and quenching, but - 7- (4) 1257428 is cooled by water cooling with a water-cooled pipe directly disposed in the circulation path. Because of the relationship, it is impossible to carry out the middle of the constant temperature. Therefore, it is necessary to perform the heat treatment of the constant temperature holding such as the tempering method such as the tempering method, the tempering method, and the tempering method. In this case, the target temperature of the control device is set here to mean that the I-flow furnace is operated according to the command, and the gas temperature is lower than the target temperature, and the heating is performed when the temperature is higher than the target temperature. Between the time, the gas flow circulated by the blower is cooled at any time. Therefore, the upper spray path is as high as 50 to 100 ° C, and the temperature change is so large that it is unbearable. In addition, the problem of excessive partial cooling due to the inert gas is that the introduction temperature of the inert gas can be raised only. Φ Japanese Patent Laid-Open No. 3-25 5 5 1 2 In the medium-cooled tempering method for the treatment of the tempering method, the method described in the publication of the Japanese Patent Publication No. 2000- 1 293 161, which is incorporated herein by reference. The tempering process is maintained at a temperature of 300 to 50,000 ° C for a certain period of time. Japanese Patent Laid-Open No. Hei 3 - 2 5 3 5 1 2 is equipped with a high-pressure chamber for accommodating a workpiece at 900 °C: a storage tank of the body, and the pipes are connected to each other to carry out the gas itself. The temperature is maintained at a constant temperature by a fire method or a martensite quenching method. An example of constant temperature quenching is to maintain the temperature at a constant temperature. Therefore, the workpiece heating device stops operating during the above spraying. This is carried out by a water-cooling device at a temperature of 5 to 100 ° C. It is a conventional gasifier that is introduced into a normal temperature. However, this is not the case (high temperature and high pressure gas, the heat treatment of the Japanese patent special temperature is maintained. It is as shown in Figure 1 of the application of the heated workpiece and the storage of high pressure N2 gas. In the reserve gas tank -8- ( 5) 1257428 The piping on the input side, the circuit with the control valve and the compressor and the parallel circuit of the circuit with the control valve and the heat-resistant fan are assembled. The suitable device is introduced into the storage tank by the storage tank when the workpiece starts to cool. The N2 gas at °C blows the workpiece, so there is no problem of excessive cooling. Then, with the action of the heat-resistant fan, the circulating flow flows to the piping through the reserve gas tank, and the workpiece is controlled at a constant temperature of 300 to 500 °C. However, it may be possible to use a workpiece with a small number of Kg, but a general quenching device of 50 or more K0 Kg or more, because the heat of heat generation of the workpiece is large, the pipe size must be set to, for example, a diameter of 30 cm, and the like. It is not suitable for high temperature above 500 ° C. The reserve gas tank is only in the beginning of the introduction of inert gas of 3000 ~ 500 ° C. It has no other significance. Especially the general quenching device is not suitable for practical use. The second picture in the Japanese Patent Laid-Open No. Hei No. 3-25 3 5丨2 is only for the supply of N 2 gas from the reserve gas tank at the beginning, and the gas for forming the cooling air is carried out in the pressure vessel. Circulation, and inside the pressure vessel, there are: a circulation circuit, a heat-resistant fan for forming a circulation flow, and a cooler for cooling the circulating gas to 300 to 500 ° C. But although it is only in the circulation road The structure in which the cooler is arranged is not specifically described, but considering that the temperature of the cold coal in cooling is 300 to 500 t which is in equilibrium with the temperature of the circulating gas, this causes the apparatus to be excessively large, at least: it cannot be used as a general purpose. The right is to set the cold coal temperature of the cooler to 3 〇0~5 0 〇 °C, it is necessary to have a heat control device other than the figure, if the heat capacity is large, the large-scale device is required. : There must be an oil sump that stores 300 00 to 500 ° C of cold coal outside the unit, and a cooling pump that regulates the temperature of the oil tank (6) 1257428 and a heating heater, and a circulating pump for heat resistance. Configured to exceed the size of the furnace body The heat treatment plant itself is not easy. In addition, the thermostatically held device shown in Figures 1 and 2 of the Japanese Patent Laid-Open No. Hei 3-25 3 5 1 2 only has a very light workpiece and a workpiece. The heat capacity is small, and the experimental equipment that can be accepted by the hot father to change the equipment can be implemented. However, since it is installed in one furnace with the cooling φ after the constant temperature is maintained, the efficiency is poor. It is not suitable for the problem of mass production. In addition, it takes time to maintain and cool the thermostat separately, so it takes at least 6 to 8 hours for one workpiece to be heat treated. Furthermore, due to the complicated structure of the device used to maintain the constant temperature, The method of preheating or cooling is limited, and defects such as an efficient and highly effective heat treatment method cannot be achieved. In addition, the conventional carburizing and quenching method is described in, for example, Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. The carburizing and quenching method shown in Japanese Laid-Open Patent Publication No. Hei 5-22244-5 is characterized in that the heated workpiece is immersed in a temperature which has been maintained inside the transition point of the arsenic iron (400~4 50 t). After the first hot bath, it is then immersed in a hot bath at a temperature just above the transition point of the granulated iron (20 0 to 2 5 (TC), and then cooled. This method is based on carburizing treatment. The internal and surface of the workpiece are very different from the temperature of the transition point of the granulated iron in the field. The time points of the two transition states are consistent to promote the homogeneity of the internal non-carburizing part. Here, the first and the first 2 The hot bath is a salt bath of nitric acid - 10- (7) 1257428 potassium and nitrite carbon. The carburizing and quenching method shown in the Japanese Patent Laid-Open Publication No. Hei 6 - 1 2 2 9 1 9 The temperature of the surface of the 麻田散铁 transition point is very different, and the rapid cooling (for example, above 200 °C / sec) to the temperature above the surface of the gynoscopic iron transfer point, that is, cooling to the quenching point (23 0 . (:). The method of rapid cooling is not explained, but this Cooling still has to rely on a hot bath such as a salt bath, and must also be considered for stirring, blowing, etc., and is limited to a thin workpiece. In the past, this carburized workpiece was held at a constant temperature with a salt bath, followed by quenching. Therefore, the dimensional accuracy of the gear, the spline shaft, and the keyed carburizing component is improved. However, since the salt bath is used for the constant temperature holding process, not only the equipment is large, the working environment is deteriorated, and the implementation thereof is not It is easy to change the equipment, and it is not easy to change the conditions according to the work key, and as a result, it is not easy to apply to various workpieces. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described past technology, and an object thereof is to provide inertness. The dry constant temperature maintenance heat treatment system in which the gas is kept at a constant temperature for heat treatment is put into practical use, and the front and rear portions are provided with relevant processing chambers of the front chamber, the heating chamber, the cooling chamber, etc., and the metal heat treatment can be performed more efficiently and with high quality. A drawing metal heat treatment system. The other object of the present invention is to develop a 1 in the present invention by the inventors of the present invention. 0 0~5 0 0 °C Any intermediate temperature can maintain the constant temperature of the constant temperature holding chamber gas cooling furnace, in any cooling form after the carburizing treatment of the workers -11 - (8) 1257428 pieces of cooling, so do not The salt bath is still easy to perform high-quality carburizing and quenching. In order to solve the above problems, the continuous metal heat treatment system of the present invention having a constant temperature holding chamber is characterized in that it is provided to adjust the input heated workpiece to a metal transition state. a constant temperature holding chamber maintained at a constant temperature in a constant temperature gas atmosphere at a point temperature, and a heating chamber for heating the workpiece to a quenching φ fire temperature at a front portion of the constant temperature holding chamber, and a workpiece holding the constant temperature at a rear portion The gas cooling chamber which is rapidly cooled to a temperature below normal temperature is continuously connected to each chamber via an openable and closable door device, and the workpiece is continuously flowed to the respective chambers, and an independent heat treatment is applied to each chamber. Since the heating chamber is provided at the front portion of the constant temperature holding g, the heated workpiece is sent to the constant temperature holding chamber, and is cooled to a constant temperature and maintained at a constant temperature in the constant temperature holding chamber. Further, since the gas cooling chamber is provided at the rear of the constant temperature holding chamber, the workpiece which has been kept at a constant temperature can be sent to the gas cooling φ chamber and rapidly cooled to a desired temperature. The configuration of the cooling chamber is not limited, and it is not cooled to, for example, quenching treatment of rapid cooling to a negative temperature at room temperature. The heating and the constant temperature are maintained in the respective chambers for cooling, so that the continuous heating can be carried out in accordance with the production tact time nh of the maximum required time. The constant temperature holding chamber of claim 1, wherein the constant temperature holding chamber is provided with a circulation path for discharging the gas sucked from a part of the chamber to the inside, and the circulation path is divided into two suction ends by One of the diverging tubes remains the same, while the other side of the diverging tube 'configures useful -12- (9) 1257428 normal temperature cold coal moderately cools the gas to a temperature significantly lower than the temperature of the aforementioned thermostat, in two divergences A fan for gas circulation is disposed behind the junction of the tubes, and both of the manifolds are provided with a valve for controlling the flow rate, and the temperature is adjusted to be the temperature of the constant temperature. The controller of the valve opening degree. This thermostatic holding chamber is extremely simple in construction, and even if the heat capacity of the workpiece is large, it can correspond to temporary changes. The cooler can be set to be water-cooled or air-cooled with cold coal of about 20 to 50 °C. It is most practical to use the same water-cooled tube as the one that has been put into practical use. The constant temperature holding chamber has a circulation path, and the suction end is divided by two 'one of the branch tubes to maintain the original, and the other side of the branch tube is equipped with a cooler of normal temperature and cold coal' at the junction of the two branch pipes. 'The fan equipped with a gas circulation' has two valves for controlling the flow rate* such as a butterfly valve. In order to make the temperature behind the junction point the temperature of the front φ constant temperature (200~5 0 0 °C) A controller that adjusts the opening of each valve. Therefore, the temperature of the fan is not higher than the temperature maintained by the constant temperature. The workpiece to be placed may be a workpiece of 8 2 0 to 1 2 500 ° C immediately after heating, or a workpiece which has been pre-cooled to a temperature maintained at a constant temperature. The workpiece that is put into the thermostatic word room is oriented in the direction in which it should be cooled. Therefore, it is not necessary to provide a heater in the stomach. In the case of the cold gas P in the tube, the temperature of the cold water P is not particularly high, and it is necessary to have a small capacity. . -13- (10) 1257428 When the constant temperature is maintained, the opening degree of the regulating valve is maintained at a constant temperature. Any heat is released from the component, and the flow rate can be calculated freely. The workpiece weight is 5 0 0~1 0 0 0 K g and the circle is 3 0~5 0 c m. The comparison of the heating chamber, the constant temperature holding chamber, and the gas cooling chamber can be freely set, and when the workpiece is sent from the heating chamber to φ, the previous workpiece is sent from the constant temperature holding chamber to the gas for continuous processing. A pre-cooling chamber for blowing a cold-warm gas to the heated workpiece between the thermostatic holding chamber and the heating chamber to heat the workpiece. The pre-cooling chamber is fed, for example, to rapidly cool the workpiece to a temperature maintained at a constant temperature. It can be sharpened from the next angle. It is characterized in that it is provided with a constant temperature in a constant temperature gas atmosphere in which the temperature of the φ metal transition point is placed. In the front portion of the constant temperature holding chamber, a heating chamber for preheating temperature is provided, and in the rear portion, a heating chamber is provided. There is a gas cooling chamber door device that rapidly cools the temperature to a temperature below normal temperature to continuously connect the chambers, and a constant temperature heat treatment system is provided for continuously heat-treating the workpiece in each of the chambers, continuously connected to the heating chamber, and kept at a constant temperature, and The workpiece can be transferred sequentially and sequentially. Because it can be freely designed, the gas in the circulation road can be adjusted from the heating work. It can be carried out by the same cooling chamber of the thermostat holding chamber of the diameter of the desired hot-form circulation path, or it can be configured with rapid cooling to constant temperature protection: N2 gas can adjust the cooling profile of the cooling workpiece to the temperature constant temperature After the workpiece is heated to the quenched and held workpiece, it is transferred to each chamber through the openable and closable, and the chamber is in the continuous metal chamber or the gas cooling chamber. Therefore, the configuration of each structure is simple. Composition. Further, since the production tact time determined by the maximum required time of each room is sequentially transferred to the workpiece, heat treatment can be performed efficiently. Because of the constant temperature maintenance during cooling, the dimensional stability of the components is improved. Because it is dry and does not require a salt bath, the environment is improved and safe and hygienic work can be carried out. Moreover, the composition of the constant temperature holding chamber and the front heating chamber and the rear gas cooling chamber is not limited, so that the design has a degree of freedom and the application can be controlled to achieve a more heat-treated product. According to the feature, the constant temperature holding chamber is provided with a circulation path for discharging the gas sucked from a part of the chamber to the inside, and the circulation path is divided into two suction ends, and one of the branch pipes is maintained as it is. In the other branch pipe, a cooler that cools the gas moderately to a temperature lower than the temperature of the constant temperature maintained by the normal temperature cold coal is disposed, and a fan for gas circulation is disposed behind the junction point of the two branch pipes. The two branch pipes are each provided with a valve for controlling the flow rate, and # is provided with a constant temperature maintaining chamber for the controller for adjusting the opening degree of the valve in order to make the temperature behind the joining point become the temperature of the constant temperature holding. Since the metal heat treatment system is extremely simple, it constitutes a constant temperature holding chamber, so that it can be constructed with high practicability and is small and inexpensive. It is necessary to recycle the circuit, but it is not necessary to reserve a gas tank or a large heat exchange equipment. Since the cold coal at room temperature can be used with water or air, the device is extremely simple and practical. In addition, since the cooling chamber is provided at the rear, the constant temperature holding chamber does not need to be cooled to room temperature or lower. As long as the temperature can be maintained at -15-(12) 1257428, the system configuration is simple. According to the feature, in the constant temperature holding chamber and the above-mentioned addition, a continuous system for pre-cooling chambers for blowing cold-temperature gas to the heated workpiece for cooling the heating to a constant temperature is provided. The sequence transfer control is OK, so there is no control error in each room control. According to the feature, the pre-cooling chamber is provided with a pre-cooling chamber in which the cold-temperature holding chamber and the above-mentioned n are disposed, and a pre-cooling chamber for cooling the heating workpiece to a temperature maintained at a constant temperature is disposed. And the constant temperature holding chamber is processed in one production cycle, which can speed up the cooling curve of the constant temperature holding chamber. Pre-cooling and gas cooling (main cooling). Because of different working hours, the inertia used for main cooling is used. The gas is used at 2 degrees, so that the effective use of the inert gas can also be achieved. Further, the carburizing gas φ method of the present invention for solving the above problems is to put a carburized workpiece into a constant temperature holding furnace, and the surface of the workpiece is just kept at a constant temperature of the transition temperature of the granulated iron. A method of quenching a gas-carburizing gas which is a temperature below normal temperature, wherein the temperature of the cooling temperature is maintained by changing the pressure of the cooling gas of the gas cooling furnace and the change of the target temperature of the wind. The cooling rate is changed, and the time at which the aforementioned work and the surface reaches the transition point of the granulated iron is managed, and the target temperature of the constant temperature is adjusted. In the gas cooling furnace described above, it is possible to control the rapid heat of the workpiece between the hot chambers, the metal heat is simple, and the workpiece between the hot chambers is in a rapid metal heat time. The amount of body quenching which can be above the cold point of the gas in the quenching side of the pre-cooling body, and the control target temperature controlled to the inside of the above-mentioned constant member are -16 - (13) 1257428 degrees, and the constant temperature holding chamber of the workpiece is kept constant. And in the constant temperature holding chamber, a circulation path for discharging the gas from the mouth and the gas introduced from a part of the chamber to the inside is attached, and the circulation path is divided into two suction ends, and one of the branch pipes is maintained as it is, and The other branch pipe is provided with a cooler which cools the gas moderately to a temperature which is substantially lower than the temperature maintained by the constant temperature, and a fan for gas circulation is disposed behind the junction point of the two branch pipes. The branch pipe is provided with a valve for controlling the flow rate, and a controller for adjusting the opening degree of the valve is provided in order to make the temperature behind the junction point the temperature maintained by the constant temperature. Examples of the gas cooling furnace which has been developed by the inventors of the present invention include, for example, the international publication W003/080876 A1 (hot gas quenching device and hot gas heat treatment system). This international publication W 0 0 3 / 0 8 0 8 7 6 describes two flow paths in which the circulation furnace is divided into the first (high temperature) and the second (low temperature), and the control windows provided for the two flow paths are adjusted. The opening degree is a basic type hot gas quenching device or the like that controls the outflow temperature of the mixer at the end position of the φ first and second flow paths. According to this hot gas quenching device, by setting an arbitrary control target temperature and putting the heated workpiece into the furnace, it is possible to cool the arbitrarily set control target temperature between 100 and 500 °C and maintain a constant temperature. Thereafter, the gas can be rapidly cooled to a temperature below normal temperature by the same furnace or another gas rapid cooling chamber connected to the furnace. Therefore, in the present invention, the control element is changed by the air pressure, the air volume, the control target temperature, and the like of the constant temperature gas cooling furnace, and the control target temperature of the constant temperature holding is adjusted, and the inside and the surface of the workpiece are managed to reach the Ma Tian-17- (14 1257428 Political moments turn to sorrowful moments. The appropriate quenching method is also an example in which the two-stage target temperatures of the first and second hot baths described in the past examples are set, and the transition between the surface and the internal gyro iron is started. The change of the control target temperature can be changed only by changing the set temperature of the electric controller. It is also possible to change it in the middle of cooling or in the middle of the room temperature control. Can control the soil below 5 C, for example: error 2~3 its control. In particular, since the temperature maintained by the constant temperature is set to a temperature at which the surface just changes above the temperature point, the fact that the temperature is changed up and down means that the transition of the granulated iron in the vicinity of the surface of the workpiece can be finely adjusted. Since the gas pressure can be adjusted between 1 and 7 Bar, the gas density of the blowing gas can also be adjusted and the cooling rate can be changed. Since the air volume is the density of gas molecules directly blown onto the surface of the workpiece, the cooling rate can also be changed. The gas pressure and air volume can be changed in the middle of constant temperature maintenance. The surface position of the workpiece is not the actual surface but its representative position, preferably a position where the reference surface is deeper 0 · 2~0 · 5 m m depth. This position φ can also be the center position of the carburized portion. For example, when the workpiece is a gear, the internal and the reference position set at a reference position of 0.2 to 0.5 mm from the surface is set to 40 ° C, 250 ° C, respectively, relative to the actual surface of the field. The transfer point of the loose iron is 200 °C and the control target temperature is set to 220~23 0 °C. When the control target temperature is changed within this range, the reference position can be adjusted greatly before and after the internal transition point is reached. Arrived at the transition point time, etc. The gas cooling furnace has a constant temperature holding chamber and a gas rapid cooling chamber as a gas cooling chamber, and the constant temperature holding chamber is first low and then high to obtain a target temperature of -18-(15) 1257428, which can be just according to the final surface of the Ma Tian loose iron. The temperature above the transition point temperature is kept constant. If so, use a gas at a temperature lower than the surface transition temperature of the surface of the gyno, and use a gas of, for example, 150 °C to accelerate the cooling rate, and perform a nose that does not involve the TTT curve (S curve). ( η 〇se ) cools and can alleviate the temperature difference between the inside and the surface. Further, the gas cooling furnace has a pre-cooling chamber and a constant temperature holding chamber, and gas cooling is used as a gas cooling chamber, and the surface temperature energy φ of the workpiece is cooled in the pre-cooling chamber to a temperature near the constant temperature, followed by a constant temperature holding chamber. Keep it at a constant temperature. If so, it is possible to form a relatively rapid cooling in the pre-cooling chamber, and it is possible to perform cooling of the nose which does not involve the TTT graph, and to alleviate the temperature difference between the inside and the surface. As described above, according to the present invention, the gas cooling furnace which can be kept at a constant temperature according to an arbitrary intermediate temperature is used to perform cooling until the workpiece after the carburization treatment is kept at a constant temperature, and the control target temperature, gas pressure, air volume, and the like are controlled. The cooling rate is changed by the element, and it is possible to easily set an arbitrary cooling form without using a salt bath, and it is possible to easily perform a heat treatment with little distortion and high quality. In the case of the gas cooling, the operating environment is also greatly improved. The gas cooling furnace that can be kept at a constant temperature can be adjusted by the two flow paths that are divided into the first (high temperature) and the second (low temperature). The gas cooling furnace in which the temperature of the junction of the two flow paths is adjusted to the control target temperature can be controlled in accordance with the control temperature of ± 5 t or less, and the control target temperature can be arbitrarily set. Gas pressure and air volume can also be freely changed. These two control elements can be changed -19- (16) 1257428 in the middle of cooling and constant temperature maintenance, and the control target temperature is determined into a plurality of segments of 2 segments and 3 segments. It is not necessary to replace the salt bath with a change in the longitude of the salt bath. If the surface of the workpiece is deeper by 0.2 to 0.5 mm, the depth of the workpiece is set as the reference position, and the temperature of the internal and surface is controlled to reach the transition point W1 Μ 'there can be the surface of the workpiece and the internal reach of the Ma Tian loose iron turn Performs less distortion and is a high quality carburizing and quenching. [Embodiment] Hereinafter, a side view of a continuous metal heat treatment system 1 formed by arranging a front chamber, a heating chamber, a constant temperature holding chamber, and a cold temperature gas in series will be described with reference to the drawings. Fig. 2 is a cross-sectional view along the line F2 - F2 in the side view of the circulation path 2 of the second drawing. Fig. 3 is a plan view showing an enlarged portion of the second circulation path. Fig. 4 is a diagram showing the control of the φ system 1 in the first to third figures. In the first embodiment, the continuous metal heat system 1 for carrying out the present invention has a constant temperature holding chamber 3 having a circulation path 2 as a core, a heating chamber 4, and a cold temperature cooling chamber 5 at a rear portion. The front chamber 6 is disposed in the heating chamber portion, and the workpiece W is sequentially transferred and processed in the order of the front chamber 6, the heating chamber 6, the constant chamber 3, and the cold temperature cooling chamber 5. A transport roller R is provided in order to transfer the workpiece W. The heating chamber 4 includes a single vacuum for heating the workpiece W, and a carburization heating degree for carburizing the heated workpiece W to a target temperature position temperature. 1st cooling chamber Sectional view The treatment shown in the figure of the furnace section 1 is the front temperature of the front part 4. The heat of the furnace is -20- (17) 1257428. In the case of the carburizing furnace, in addition to the heater, an injection device such as a propylene gas or the like, or an auxiliary device for venting the exhaust gas from the device is provided. It is also possible to reheat the workpiece W after the carburization treatment in the other carburizing furnace to perform carburization and quenching. The front chamber 6 holds the workpiece W with a corresponding negative pressure for the workpiece W' in order to supply the workpiece w to the heating chamber 4 at a normal pressure or a negative pressure. The heating chamber 4 heats the workpiece w to 8 2 0 to 〖2 5 0 • °C in a vacuum state, and has respective door devices 8 and 9 at the front and rear, and has a heating heater 1 and a transformer 1 1 . The rear door device 9 is of a type in which the doors of the lower stage thermostat holding chamber 3 are simultaneously actuated. The constant temperature holding chamber 3 is provided with a temperature at which the input workpiece w is held at a constant temperature set by the temperature of the transition point, for example, 3 〇〇t:, and the workpiece W loaded from the heating chamber 4 is cooled to a constant temperature The function of the temperature. As shown in Figs. 2 and 3, the constant temperature holding chamber 3 has a loop 2 on the outside. This example constitutes the circulation path 2 in an interactively ventilated manner.
在恆溫保持室3的側面開設有一對的窗1 2、1 3，在其 內部配置有整流板1 4。在各隔窗1 2、1 3各別立設有向上 方豎起之豎立管道15R 、1 5 L。該管道1 5 R、1 5 L則連接一對的平行管道1 6 、1 7。在連接口配置有用來變更通風方向的蝶形閥1 8、1 9 。在各平行管道1 6、1 7的各個中央，各別連接吸引管道 2 〇或是排出管道2 1。吸引管道2 0介於各別蝶形閥2 2、2 3 分歧成第1、第2分歧管24、25，在第2分歧管25配置 -21 - (18) 1257428 有冷卻器26。冷卻器26係以與一般的噴流爐同樣的水 管所構成。也能是空冷但水冷較爲實用。兩分歧管2 4、 的合流點2 6 S也可以是僅將管接合的構造，不過功能上 作用是將兩分歧管2 4、2 5所流入之不同溫度的氣體均 混合。因而也有適度配置整流板、攪拌板、攪拌風扇、 屬或碳材質等的接觸材之情形。 在前述合流點2 6 S接著是配置風扇2 7，接著介於 B 助加熱器2 8連接至前述排出管道2 1 ’全體上則成爲循 路2。輔助加熱器2 8或管路的加熱器只是在剛開始調節 環路2內的溫度，恆溫保持的作動中則幾乎不作動，小 量的加熱器即可。輔助加熱器2 8可設在恆溫保持室3 ，也可以設在配管的周圍。在循環路2施加有保溫材29 以上構成的恆溫保持室3，經切換蝶形閥1 8、1 9就 切換循環流3 0的流動方向。即是能夠從工件W的右方 是從左方噴吹溫度已調節成恆溫保持的溫度之惰性氣體 φ 也可以取代整流板1 4而改爲配置有多數細管製成的氣 分配器（distributor)。 述說將惰性氣調節成用來保持恆溫的溫度，即是調 成設定在轉態點溫度附近的溫度例如：3 00 °C之方式， 是對工件W噴吹過後的惰性氣體介於窗1 2或是1 3而 過吸引管道20，流入到第1和第2分歧管24、25。 流入到第1和第2分歧管24、2 5的氣體量是利用 制器3 1的控制，依照蝶形閥22、23的張開度進行調節 制。控制器3 1依照安裝在例如：風扇2 7之後的溫度感 冷 25 其 勻 金 輔 環 循 容 內 〇 能 或 〇 體 節 則 通 控 控 測 -22- (19) 1257428 器32之檢測訊號，當檢測溫度比3 0 0 °C還高時往開啓冷卻 器26側的閥23方向，當比3 0 0 °C還低時往關閉該閥23方 向來調控閥的張開度。溫度感測器的安裝位置定沒有受限 制。 冷卻開始時，風扇2 7旋轉，循環流3 0對工件W噴 吹，氣體溫度上升而流入至豎立管道15R或是15L，接著 流入到吸引管道20。這時候的上升溫度爲1〇〇〜30 (TC程度 P 。爲了緩和隨著這溫度上升之吹入氣體的溫度，可以在豎 立管道15R' 15L或/及窗12、13吸引管道20等的循環 路中，中介設置用來緩和熱量吸收的接觸材。接觸材係由 鐵球、鐵管或是碳質材等所構成，與氣體接觸而進行熱交 換，將通過氣體的溫度變成預先所設定之恆溫保持的溫度 ，也就是變成接觸材的溫度。使循環氣體接觸到接觸材， 就能緩和噴入氣體的溫度，且能消除溫度的不均勻。接觸 材的量係在工件重量的倍率之0 . 1〜0 · 5倍程度的範圍內進 • 行設定。 工件 W在於恆溫保持剛開始時有例如：8 2 0〜1 2 5 0 °C ，所以必須要冷卻，冷卻器2 6吸收該熱量。在這之間加 熱器2 8幾乎不作動。 回到第1圖中，在恆溫保持室3與冷溫氣體冷卻室5 之間，設有同時動作將門開閉之門裝置3 3。在冷溫冷卻室 5的後部，設有工件取出用的門裝置3 4。 能夠在冷溫冷卻室5，設置惰性氣體噴出用的噴出口 3 5，對從恆溫保持室3所送來的工件w噴吹負的溫度例 •23· (20) 1257428 如··- 5 0 °C的惰性氣體並進行急速冷卻淬火。冷溫冷卻室 5只用來進行負溫度的急速冷卻處理較佳，恆溫保持室3 只用來保持恆溫較佳，而能簡單構成恆溫保持室3的功能 。又因在恆溫保持室3中一直進行到變爲負溫度的淬火處 理爲止，則恆溫保持室從+ 3 0 (TC到一 5 (TC則要強化溫度 的急遽變化，造成耐熱構造相當複雜且構成變困難。因此 處理上兩室分擔功用，各別構成就變簡單。 ϋ 用第4圖來說明以上構成之連續式金屬熱處理系統1 的作用。以各室6、4、3、5的生產節拍時間nh設爲一定 ，例如：4小時來作說明。述說有關工件W的移送，先取 出冷溫冷卻室5中的工件W，使門裝置3 4作動來關閉該 門，將恆溫保持室3中的工件W導入到冷溫冷卻室5。恆 溫保持室3中導入加熱室4所加熱過的工件W。加熱室4 中則是從前室6導入工件W。 現在工件W在加熱室4開始加熱。爲了要給前室6 φ 供應下一個工件w而裝入處理用的工件w。加熱室4所 加熱過後的工件W移送至冷溫冷卻室5。在這時間點工件 W進行滲碳處理。依照這些工件W的移送，各室進行所 要壓力的變化、惰性氣體的導入，有關其詳細說明則省略 。說明的方便上，恆溫保持室3的處理壓力和氣體冷卻室 5的處理壓力都設爲3 B ar。如同後述，這個壓力可任意 設定，且載處理的中途還能變更。 如第4圖所示，前室6中工件w是保持在室溫（2 0 °C )，不過此處可以預熱到1 00〜600 °C程度。加熱室4則 -24- (21) 1257428 根據預定的預熱曲線使工件w升溫到82 0〜1 2 5 0 t。 示爐室溫度，T W表示工件溫度。 在恆溫保持室3中將之前的工件W恆溫保持 接收下一個工件 W時的爐室溫度爲恆溫保持的溫 處爲舉例）3 0 0 °C (只要不更改控制目標溫度隨時 一定）。使門裝置9作動來減壓成與加熱室4同壓 工件W。關閉門裝置9並進行恆溫保持處理。 p 恆溫保持係利用第2圖和第3圖所示之循環路 動，對工件W交互噴吹例如：3 0 (TC的惰性氣體流 行工件 W的冷卻和恆溫保持。冷卻曲線的形狀係 重量、形狀、循環路2的冷卻器26能力等而有所 有關該狀況則是在於工件重量3 00〜5 00 Kg、冷卻 2 5〜50萬 kcal / Η的條件下，可以經15〜30分鐘程 化。爲了要達到惰性氣體的有效利用，也可以將冷 室5所用過的惰性氣體導入到冷卻器2 6。工件W φ 特別是形狀很薄的情狀，也可以將要到恆溫化的時 到5分鐘程度。 在恆溫保持室3中將工件 W冷卻並進行恆溫 間，在冷溫冷卻室5結束氣體冷卻。冷溫冷卻室5 在於這時刻te取出工件W並等待下一個的冷卻。 以上，工件W能夠介於前室6、加熱室4、恆 室3、冷溫氣體冷卻室5而從820〜1 2 5 0 °C冷卻來進 t：的恆溫保持，接著進行變爲- 5 t的淬火，以只 氣體的乾式就能高效率進行過去的鹽浴所無法實現 TR表 過後’ 度（此 都維持 並投入 2的作 30，進 依工件 不同。 器能力 度恆溫 溫冷卻 很小， 間縮減 保持之 則能夠 溫保持 行3 00 用惰性 之局品 -25- (22) 1257428 質的淬火處理。然而用鹽浴進行冷卻則鹽浴溫度變化，要 將鹽浴溫度重新調節到所要的溫度是非常困難的技術。另 外，中途在 ± 5它的範圍內變更溫度等畢竟是不可能的。 即使作成連續浴也只有連續使用時才有效，其變更不容易 。處理能將生產節拍時間配合爐的最大所要時間來連續進 行而有高效率。因可以反覆將裝置構成比較複雜且是高成 本裝置的恆溫保持室3設爲專用機來利用，所以能夠降低 裝置全體的成本。又因恆溫保持的溫度可以經變更其控制 目標溫度來自由設定，所以各種金屬、各種淬火方法都能 適用且具高泛用性。 說明本發明實施所能用的另一種連續式金屬熱處理系 統的例子。第5圖所示的連續式金屬熱處理系統3 6係相 對第1圖所示的系統1而在恆溫保持室3的前段設有預冷 卻室3 8。在預冷卻室3 8與恆溫保持室3之間則設有新的 門裝置3 7。 如第6圖所示，預冷卻室3 8係將加熱過後的工件W 冷卻到用來保持恆溫的溫度附近，再從該處移送至恆溫保 持室3。預冷卻係在恆溫保持的生產節拍時間nh當中進行 。冷卻方式爲直接噴吹低溫氣體，這氣體也能用與冷溫冷 卻室5之間所架設的氣體排氣管3 9來有效利用冷卻氣體 。因能在預冷卻室3 8中急速冷卻到恆溫保持的溫度附近 才移送至恆溫保持室3，所以即使是比較大型的工件仍能 加快冷卻速度而達到有效率的冷卻。 另外，因將預冷卻室38配置在恒溫保持室3的前部 -26- (23) 1257428 ，所以不論是否要預冷卻都能依照工件W的需求能不進 行預冷卻就在恆溫保持室3中冷卻並進行恆溫保持。因㉟ 依工件W採取種種的對應，所以具有高度的泛用性。 以上，從第1圖〜第5圖所示的裝置構成中就能明白 ，恆溫保持室3係具有循環路2，將吸引管道2 0連接到用 蝶形閥2 2、2 3調節張開度之第1、第2分歧管2 4、2 5 ’ 接著連接到吹出管道2 1之構造。因此，若是將本恆溫保 φ 持室3的分歧管24、2 5當中其中一方的分歧管2 4關閉’ 將冷卻器2 6側的分歧管2 5全開，則這種爐的構成能達到 與日本專利特開平5- 66090號公報中也有記載之過去的 噴流爐同樣的功能。 因此，本發明的恆溫保持室3 ’依照使用方法也可以 具有與過去噴流爐同樣的功能’也進行成爲水冷溫度（2 0 °C )的急速冷卻淬火。再則’既然是這種構成，所以將第 5圖所示的預冷卻室3 8設成與恆溫保持室3相同的構造’ φ 依照淬火手法也可以在剛好恆溫保持之前就進行成爲水冷 溫度的淬火。接著能將完成淬火的工件W經恆溫保持後 進行回火，再度進行成爲負溫度的淬火等。若是更加擴充 而將預冷卻室3 8、及恆溫保持室3、及冷溫氣體冷卻室5 設成與第1圖〜第3圖所示之恆溫保持室3相同的構成， 則將各室3 8、3、5的功能經種種的變更而能自由設計冷 卻曲線，又能既動態又效率良好進行包括恆溫保持的各種 處理。 如此，若是在本發明之恆溫保持室3的前後，設置與 -27- (24) 1257428 這恆溫保持室相同或類似的恆溫保持室3，則能時而將中 間溫度設定爲複數段，時而變更冷卻方式，或者一面改變 工件W的移送順序，一面進行各種熱處理，且可擴張該 種種的應用。 本發明並不侷限於上述實施形態，只要不脫離本發明 的要旨範圍能適度施加設計上的變更，且能在各種形態下 實施。 • 其次，用上述構成的連續式金屬熱處理系統來說明本 發明的滲碳淬火方法。 如第7圖的擴大所示，滲碳過後之比如齒輪的工件w ，從面Ps到琛部Pc，依第8圖所示的分布進行滲碳。在 第7圖中表示到深度1 mm之碳滲入的例子。第8圖中， 横軸表不深度d m m，縱軸表示碳濃度C %。在由表面p s 點依序ί朱0.2 m m的位置設爲P 1、P 2 · · · P 5。最深位置 則設爲PC。 φ 因各位置Pi ( PS、PI、P2 . · · P5 )的碳濃度不同 ’所以各位置P i的麻田散鐵（m a r t e n s i t e )轉態點溫度， 在例如·· 200 °C、2 5 0 °C、3 00 °C、3 5 0 °C、400 °C 時有很大 的不同。 本發明係提供不用鹽浴而改用已說明過的連續式金屬 熱處理系統1、3 6來減少畸變之滲碳淳火方法。 爲了實施本發明，連續式金屬熱處理系統丨、3 6能以 1〜2 °C單位自由設定恆溫保持室3的控制目標溫度。在恆 溫保持的平衡狀態下的溫度控制誤差，上限爲± 5 °c，窨 -28- (25) 1257428 際上’在於平衡狀態下誤差可以控制在2〜3 °C以下。另外 壓力以3 b a r爲基準但能在1〜7 b a r進行變更。再則， 經控制風扇2 7的旋轉速度就能自由調節風量。這些控制 要素即使恆溫保持的處理中仍能在其中途進行變更。 因此，本發明是將滲碳處理過後的工件投入到可保持 恆溫的恆溫保持室3，介於前述工件w的表面剛好麻田散 鐵轉態點之上的溫度（例如2 3 0。(：）之恆溫保持，在冷溫 φ 氣體冷卻室5中進行成爲常溫以下（例如-5 01：)的氣體 淬火之滲碳氣體淬火方法， 藉由前述恆溫保持室3之冷卻氣體的氣體壓、風量、 控制目標溫度的變更等進行控制要素的變更，來使冷卻速 度變化，可以在時間軸上管理前述工件W的內部PC及表 面PS〜P4及到達麻田散鐵轉態點時刻並進行前後調節。 第9圖爲表示一種控制條件下之工件W的冷卻曲線 。N表示TTT曲線的鼻頭（nose )。冷卻開始溫度爲900 φ °C。恆溫保持的控制目標溫度爲23(TC。横軸時間表示參 考性以2 0 0秒左右平衡的狀態。 如第9圖所示，表面PS接著每深入0.2 mm的位置 P 1、P2 · · •依序延遲冷卻，內部位置PC則會相當延遲 。將位置PC達到轉態點溫度（400°C )的時刻設爲U ’將 更深入表面〇.4 的位置P2達到轉態點溫度（2 5 0 °C ) 的時刻設爲12 ’則能時而使兩時刻幾乎一致’時而使相互 偏離。只不過本發明的要點並不是要使這時刻一致。 此外，第1 0圖爲表示其他的條件設成相同而使控制 -29- (26) 1257428 要素的一部分例如：風量從2 Ο 0秒時刻左右的時刻開始降 下，並使冷卻速度變化的情況之冷卻曲線。如同圖不，相 對內部位置P C達到轉態點溫度的時刻U而更深入表面 0.4 mm的位置Ρ2達到轉態點溫度的時刻t2則大幅延遲。 從這些情形顯示，能將內部的位置P C及更深入表面 一定深度的參考位置P2到達轉態點溫度的時刻t 1、t2相 互前後調節。即使使控制目標溫度上升5 t或是1 〇 °C程度 φ 仍能達到同樣的效果。即使改變氣體壓也同樣。A pair of windows 1 2, 1 3 are opened on the side surface of the constant temperature holding chamber 3, and a rectifying plate 14 is disposed inside the window. Upright pipes 15R and 15L which are erected upward are provided in each of the partitions 1 2, 1 3, respectively. The pipes 1 5 R, 15 5 L connect a pair of parallel pipes 16 6 , 17 . A butterfly valve 18, 19 for changing the direction of ventilation is disposed at the connection port. At each center of each of the parallel pipes 16 and 17 , a suction pipe 2 排出 or a discharge pipe 2 1 is connected. The suction duct 20 is interposed between the respective butterfly valves 2, 2, 3, and the first and second branch pipes 24, 25, and the second branch pipe 25 is provided with a cooler 26 at -21 - (18) 1257428. The cooler 26 is constructed of the same water pipe as a general jet furnace. It can also be air-cooled but water-cooled is more practical. The junction point 2 6 S of the two branch pipes 24 may also be a structure in which only the pipes are joined, but it is functionally to mix the gases of different temperatures into which the two branch pipes 24, 25 are flowing. Therefore, there is also a case where a contact material such as a rectifying plate, a stirring plate, a stirring fan, a genus or a carbon material is appropriately disposed. At the junction point 26S, the fan 2 is placed next, and then the B heater 24 is connected to the exhaust pipe 2 1 'to the entire circumference. The auxiliary heater 28 or the heater of the pipeline is only at the beginning of the adjustment of the temperature in the loop 2, and the operation of the constant temperature is almost no operation, and a small amount of the heater can be used. The auxiliary heater 28 may be provided in the constant temperature holding chamber 3 or may be provided around the piping. The constant temperature holding chamber 3 having the heat insulating material 29 or more is applied to the circulation path 2, and the flow direction of the circulating flow 30 is switched by switching the butterfly valves 18 and 19. That is, it is possible to blow the inert gas φ from the right side of the workpiece W from the left to the temperature at which the temperature has been adjusted to the constant temperature, or to replace the flow regulating plate 14 and to dispose the distributor with a plurality of thin tubes. . The inert gas is adjusted to a temperature for maintaining a constant temperature, that is, a temperature set to be near the temperature of the transition point, for example, 300 ° C, and the inert gas after the workpiece W is blown is located in the window 1 2 Or, the suction pipe 20 passes through the first and second branch pipes 24 and 25. The amount of gas flowing into the first and second branch pipes 24, 25 is controlled by the controller 31, and is adjusted in accordance with the degree of opening of the butterfly valves 22, 23. The controller 3 1 is in accordance with the temperature sensing 25 installed after, for example, the fan 2 7 , and the detection signal of the -22- (19) 1257428 device 32 is detected when the uniform voltage or the corpus callosum is controlled. When the temperature is higher than 300 ° C, the valve 23 is opened in the direction of the valve 26 on the side of the cooler 26, and when it is lower than 300 ° C, the valve 23 is closed to regulate the opening degree of the valve. The temperature sensor installation position is not limited. At the start of cooling, the fan 27 rotates, and the circulation flow 30 blows the workpiece W, and the temperature of the gas rises to flow into the upright pipe 15R or 15L, and then flows into the suction pipe 20. At this time, the rising temperature is 1 〇〇 30 30 (TC degree P. In order to alleviate the temperature of the blown gas as the temperature rises, the circulation of the pipe 20 or the like can be attracted to the erecting pipe 15R' 15L or/and the windows 12, 13. In the road, the contact material is used to moderate the heat absorption. The contact material is composed of iron balls, iron pipes or carbon materials, and is in contact with the gas for heat exchange, and the temperature of the passing gas is changed to a predetermined value. The temperature maintained at a constant temperature, that is, the temperature at which the contact material is turned into. When the circulating gas is brought into contact with the contact material, the temperature of the injected gas can be alleviated, and the temperature unevenness can be eliminated. The amount of the contact material is 0 in the weight of the workpiece. 1~0 · 5 times the range of the line setting. The workpiece W is at the beginning of the constant temperature hold, for example: 8 2 0~1 2 5 0 °C, so it must be cooled, the cooler 26 absorbs the heat. In the meantime, the heater 28 is hardly operated. Returning to Fig. 1, between the constant temperature holding chamber 3 and the cold temperature gas cooling chamber 5, a door device 3 3 for simultaneously opening and closing the door is provided. The rear part of the cooling chamber 5 is provided with a workpiece The door device 34 for take-out is provided. In the cold-temperature cooling chamber 5, the discharge port 35 for the inert gas discharge can be provided, and the negative temperature of the workpiece w sent from the constant temperature holding chamber 3 can be blown. 1257428 Such as ··· 50 ° C inert gas and rapid cooling quenching. Cold temperature cooling chamber 5 is used for rapid cooling of the negative temperature is better, the constant temperature holding chamber 3 is only used to maintain a constant temperature, and can The function of the constant temperature holding chamber 3 is simply constituted. Further, since the constant temperature holding chamber 3 is continuously subjected to the quenching treatment to become a negative temperature, the constant temperature holding chamber is from +30 (TC to a 5 (TC is required to strengthen the temperature). The change causes the heat-resistant structure to be quite complicated and the composition becomes difficult. Therefore, the treatment of the upper two chambers is complicated, and the individual compositions are simplified. 第 The function of the continuous metal heat treatment system 1 constructed above is explained by the fourth diagram. The production tact time nh of 4, 3, and 5 is set to be constant, for example, 4 hours for explanation. Referring to the transfer of the workpiece W, the workpiece W in the cold-temperature cooling chamber 5 is taken out first, and the door device 34 is actuated to close. The door will be kept in the constant temperature chamber 3 The workpiece W is introduced into the cold-warm cooling chamber 5. The workpiece W heated by the heating chamber 4 is introduced into the constant temperature holding chamber 3. In the heating chamber 4, the workpiece W is introduced from the front chamber 6. The workpiece W is now heated in the heating chamber 4. The workpiece w is supplied to the front chamber 6 φ and loaded into the processing workpiece w. The workpiece W heated by the heating chamber 4 is transferred to the cold-temperature cooling chamber 5. At this point in time, the workpiece W is carburized. The transfer of the workpiece W, the change of the required pressure and the introduction of the inert gas in each chamber are omitted, and the detailed description thereof will be omitted. For the convenience of description, the processing pressure of the constant temperature holding chamber 3 and the processing pressure of the gas cooling chamber 5 are both set to 3 B. Ar. As will be described later, this pressure can be arbitrarily set and can be changed in the middle of the load processing. As shown in Fig. 4, the workpiece w in the front chamber 6 is kept at room temperature (20 ° C), but it can be preheated to a temperature of about 100 to 600 °C. The heating chamber 4 is -24- (21) 1257428 The workpiece w is heated to 82 0~1 2 5 0 t according to a predetermined preheating curve. The furnace chamber temperature, T W , represents the workpiece temperature. In the constant temperature holding chamber 3, the previous workpiece W is kept at a constant temperature. When the next workpiece W is received, the temperature of the furnace chamber is a constant temperature. For example, 300 ° C (as long as the control target temperature is not changed). The door device 9 is actuated to decompress the workpiece W in the same manner as the heating chamber 4. The door device 9 is closed and subjected to constant temperature holding processing. p Constant temperature maintenance system uses the cyclical motion shown in Fig. 2 and Fig. 3 to alternately blow the workpiece W, for example: 30 (cooling and constant temperature maintenance of the inert gas prevailing workpiece W of TC. The shape of the cooling curve is weight, The shape, the capacity of the cooler 26 of the circulation path 2, etc. may be related to the situation, and the workpiece weight may be 30 to 30 00 Kg, and the cooling may be 25 to 500,000 kcal / Η. In order to achieve effective use of the inert gas, the inert gas used in the cold chamber 5 can also be introduced into the cooler 26. The workpiece W φ is particularly thin in shape, and can be heated to a temperature of 5 minutes. The workpiece W is cooled and kept at a constant temperature in the constant temperature holding chamber 3, and the gas cooling is completed in the cold temperature cooling chamber 5. The cold temperature cooling chamber 5 at this time te takes out the workpiece W and waits for the next cooling. It can be cooled in the front chamber 6, the heating chamber 4, the constant chamber 3, and the cold-temperature gas cooling chamber 5 from 820 to 1 250 ° C to maintain the constant temperature of t:, and then quenching becomes -5 t. The salt of the past can be efficiently performed with a dry gas-only type It is impossible to achieve the degree after the TR table (this is maintained and put into the work of 30, depending on the workpiece. The capacity of the device is constant, the temperature and temperature are very small, and the reduction between the two can maintain the temperature of the line. 25- (22) 1257428 Qualitative quenching treatment. However, if the salt bath temperature is changed by cooling with a salt bath, it is very difficult to adjust the temperature of the salt bath to the desired temperature. In addition, it is within the range of ± 5 It is impossible to change the temperature, etc. Even if it is made into a continuous bath, it is only effective when it is used continuously, and the change is not easy. The treatment can continuously produce the tact time in accordance with the maximum time required by the furnace and has high efficiency. Since the constant temperature holding chamber 3 having a relatively complicated device configuration and a high-cost device is used as a dedicated machine, the cost of the entire apparatus can be reduced. Further, since the temperature of the constant temperature can be changed by setting the temperature of the control target, various metals, Various quenching methods are applicable and highly versatile. Describe another continuous metal heat station that can be used in the practice of the present invention. An example of the system. The continuous metal heat treatment system 36 shown in Fig. 5 is provided with a pre-cooling chamber 38 in the front stage of the constant temperature holding chamber 3 with respect to the system 1 shown in Fig. 1. In the pre-cooling chamber 38 A new door device 3 is provided between the thermostatic holding chambers 3. As shown in Fig. 6, the pre-cooling chamber 38 cools the heated workpiece W to a temperature near which the temperature is maintained, and then transfers therefrom. To the constant temperature holding chamber 3. The pre-cooling is performed in the tact time nh of the constant temperature maintenance. The cooling method is to directly blow the low-temperature gas, and the gas can also be used with the gas exhaust pipe 3 installed between the cold-temperature cooling chamber 5. 9 to effectively use the cooling gas. Since it can be transferred to the constant temperature holding chamber 3 in the vicinity of the rapid cooling in the pre-cooling chamber 38, the cooling rate can be increased to achieve efficient cooling even in the case of a relatively large workpiece. Further, since the pre-cooling chamber 38 is disposed in the front portion -26-(23) 1257428 of the constant temperature holding chamber 3, it can be pre-cooled in the constant temperature holding chamber 3 in accordance with the demand of the workpiece W regardless of whether or not pre-cooling is required. Cool and maintain at constant temperature. Since 35 takes various correspondences depending on the workpiece W, it has a high degree of versatility. As described above, it can be understood from the configuration of the apparatus shown in Figs. 1 to 5 that the constant temperature holding chamber 3 has the circulation path 2, and the suction duct 20 is connected to the first degree of adjustment of the opening degree by the butterfly valves 2 2, 2 3 1. The second branch pipe 2 4, 2 5 ' is then connected to the structure of the blow-out pipe 2 1 . Therefore, if the branch pipe 24 of one of the branch pipes 24 and 25 of the constant temperature maintaining chamber 3 is closed, and the branch pipe 2 5 on the side of the cooler 26 is fully opened, the structure of the furnace can be achieved. The same function as the conventional jet furnace described in Japanese Laid-Open Patent Publication No. Hei 5-66090 is also known. Therefore, the constant temperature holding chamber 3' of the present invention may have the same function as that of the conventional jet furnace according to the method of use, and also performs rapid cooling quenching at a water cooling temperature (20 °C). Further, since it is such a configuration, the pre-cooling chamber 38 shown in Fig. 5 is set to have the same structure as the constant temperature holding chamber 3'. According to the quenching method, it is also possible to perform the water-cooling temperature just before the constant temperature is maintained. Quenching. Then, the workpiece W which has been quenched can be tempered after being held at a constant temperature, and quenching or the like which becomes a negative temperature is again performed. If the pre-cooling chamber 38, the constant temperature holding chamber 3, and the cold-temperature gas cooling chamber 5 are configured to be the same as the thermostatic holding chamber 3 shown in FIGS. 1 to 3, the chambers 3 are further expanded. The functions of 8, 3, and 5 can be freely designed to be designed with various changes, and dynamic and efficient, including various treatments including constant temperature maintenance. Thus, if the constant temperature holding chamber 3 which is the same as or similar to the constant temperature holding chamber of -27-(24) 1257428 is provided before and after the constant temperature holding chamber 3 of the present invention, the intermediate temperature can be set to a plurality of stages from time to time, and sometimes The cooling method is changed, or various heat treatments are performed while changing the transfer order of the workpiece W, and the various applications can be expanded. The present invention is not limited to the above-described embodiments, and various modifications can be made as appropriate without departing from the scope of the invention, and can be carried out in various forms. • Next, the carburizing and quenching method of the present invention will be described using the continuous metal heat treatment system constructed as described above. As shown in the enlargement of Fig. 7, the workpiece w, such as a gear after carburization, is carburized according to the distribution shown in Fig. 8 from the surface Ps to the crotch portion Pc. An example of carbon infiltration to a depth of 1 mm is shown in Fig. 7. In Fig. 8, the horizontal axis represents the depth d m m and the vertical axis represents the carbon concentration C %. In the position where the surface p s point is 0.2 m m in order, P 1 , P 2 · · · P 5 are set. The deepest position is set to PC. φ Since the carbon concentration of each position Pi (PS, PI, P2 . · · P5 ) is different, the temperature of the Martensite transition point of each position P i is, for example, 200 ° C, 250 ° ° C, 3 00 °C, 3 50 °C, 400 °C are very different. SUMMARY OF THE INVENTION The present invention provides a carburizing and smoldering method for reducing distortion by using a continuous metal heat treatment system 1, 3, which has been described without a salt bath. In order to carry out the invention, the continuous metal heat treatment system 丨, 3 6 can freely set the control target temperature of the constant temperature holding chamber 3 in units of 1 to 2 °C. The temperature control error in the equilibrium state maintained at constant temperature has an upper limit of ± 5 °c, and 窨 -28-(25) 1257428 is that the error can be controlled below 2 to 3 °C under equilibrium conditions. In addition, the pressure is based on 3 b a r but can be changed from 1 to 7 b a r. Further, the air volume can be freely adjusted by controlling the rotational speed of the fan 27. These control elements can be changed in the middle even in the process of constant temperature maintenance. Therefore, in the present invention, the carburized processed workpiece is placed in a thermostatic holding chamber 3 which can be kept at a constant temperature, and the temperature of the surface of the workpiece w is just above the transition point of the granulated iron (for example, 2 3 0. (:) In the cold temperature φ gas cooling chamber 5, a carburizing gas quenching method of gas quenching at a normal temperature or lower (for example, -5 01:) is performed, and the gas pressure and the air volume of the cooling gas in the constant temperature holding chamber 3 are When the control element is changed such as the change of the control target temperature, the cooling rate is changed, and the internal PC and the surfaces PS to P4 of the workpiece W and the time of reaching the transition point of the granulated iron can be managed on the time axis and adjusted forward and backward. Figure 9 shows the cooling curve of the workpiece W under a controlled condition. N represents the nose of the TTT curve. The cooling start temperature is 900 φ ° C. The control target temperature for the constant temperature hold is 23 (TC. The horizontal axis time indicates the reference. The state is balanced by about 200 seconds. As shown in Fig. 9, the surface PS is then cooled by the position P 1 , P2 · · · every 0.2 mm. The internal position PC is quite delayed. When the PC reaches the transition point temperature (400 °C), the time is set to U 'will go deeper into the surface 〇.4. When the position P2 reaches the transition point temperature (250 °C), the time is set to 12'. The two moments are almost identical' and sometimes deviate from each other. However, the gist of the present invention is not to make the timing coincide. In addition, the tenth figure shows that other conditions are set to be the same so that the control -29-(26) 1257428 A part of the element is, for example, a cooling curve in which the air volume is lowered from the time of about 2 Ο 0 second, and the cooling rate is changed. As shown in the figure, the internal position PC reaches the time U of the transition point temperature and goes deeper to the surface 0.4. When the position of mm Ρ2 reaches the temperature of the transition point, the time t2 is greatly delayed. From these cases, it is shown that the internal position PC and the reference position P2 which is deeper into the surface to a certain depth can reach the time t 1 and t2 of the transition point temperature. Adjustment. Even if the control target temperature is increased by 5 t or 1 〇 °C degree φ, the same effect can be achieved. Even if the gas pressure is changed, the same is true.
如此’經管理內部的位置PC及表面參考位置P2達到 各別的轉態點溫度的時刻，就能將參考位置P2設成交界 ’而將各位置在鼻頭（nose ) N的下面保持既均勻又適當 的溫度。一般，兩者的時刻大致一致或是使後者延遲進行 控制即可。即是第丨的條件是內部的點P(：要通過鼻頭N 的下面 '及參考位置P2與內部沒有太大的偏差而保持均 勻的恆溫。 φ 依據本發明的恆溫保持室3，能使參考位置P 2的轉 態點之恆溫保持與內部轉態相關聯來既微細又微妙進行控 制° ί空制目標溫度在於恆溫保持的中途也能在5 t：的範圍 內脈動’又能一定程度控制各點P 1、P2、P3。 第圖爲表示用第1圖〜第4圖所示之連續式金屬熱 處理系統1的恆溫保持室3，在冷卻中途改變控制目標溫 度TA、TB，使冷卻速度變化之例子。能將內部位置pc 達到麻田散鐡轉態點溫度的時刻11比較提早，且使參考 位置P 2達到麻田散鐵轉態點溫度的時刻12接近。最重要 -30- (27) 1257428 的點是使工件W的各位置不牽扯到鼻頭N ’且不會有通過 比控制目標溫度T A、T B還下面的可能性，能穩定且在於 鼻頭（η 〇 s e ) N下面控制全體之點。如同反覆的說明，控 制目標溫度TB無關工件W的量’控制在誤差2〜3 °C以下 ，因而能以參考位置P2爲基準進行微細的控制。 第12圖爲表示用第5圖和第6圖所示之金屬熱處理 系統3 6的預冷卻室3 8和恆溫保持室3 ’急速冷卻接著保 0 持恆溫，使冷卻速度變化之例子。與前述例子同樣，能將 內部位置P C達到麻田散鐵轉態點溫度的時刻11比較提早 ，且使參考位置P2達到麻田散鐵轉態點溫度的時刻t2接 近。能在於鼻頭（η 〇 s e ) N下面且***在恆溫保持室3的 控制目標溫度To之間，以參考位置P2爲基準，微細的控 制工件全體。 第9圖〜第1 2圖中表示具體的溫度、時間數據，不過 這只是參考數據而已，實際的爐則時間上有數分之1至數 • 倍的不同。 有關恆溫保持且冷溫冷卻過後的工件，接著也能進行 珠擊處理（shot peening)。如同日本專利特開平 6 — 172 8 5 3號公報所示，若是用負溫度進行珠擊處理，則能更 加提高壓縮殘留應力的分布。因可以連續處理所以效率良 好。 本發明並不侷限於上述的實施形態，只要不脫離本發 明的要旨的範圍內各種變形皆能實施。 -31 - (28) 1257428 【圖式簡單說明】 第1圖爲本發明的實施形態之連續式金屬熱處理系統 之側面剖面圖。 第2圖爲表示第1圖之循環路的側面圖中有關爐體部 分沿著F2 - F2線之剖面圖。 第3圖爲表示擴大第1圖的循環路部分之俯視圖。 第4圖爲第1圖〜第3圖所示的系統之控制說明圖。 第5圖爲有關本發明的實施形態，也是表示在加熱室 與恆溫保持室之間備有預冷卻室之連續式金屬處理系統之 側面剖面圖。 第6圖爲第5圖所不的系統之控制說明圖。 第7圖爲表示擴大本發明的滲碳處理過後之工件的溫 度狀況之剖面說明圖。 第8圖爲表示第7圖所示之工件的深度和碳濃度的關 係之曲線圖。 第9圖爲表示本發明的滲碳淬火方法中直到恆溫保持 的溫度爲止之冷卻方式的時間和溫度之曲線圖。 第1 〇圖爲表示能改變第9圖的冷卻速度之曲線圖。 第1 1圖爲表示能將恆溫保持的控制目標溫度更改成2 段之實施例的時間和溫度之曲線圖。 第1 2圖爲在預冷卻室中進行冷卻接著在恆溫保持室 中進行冷卻並進行恆溫保持之實施例的時間和溫度之曲線 圖。 -32- (29) 1257428Thus, when the managed internal position PC and the surface reference position P2 reach the respective transition point temperatures, the reference position P2 can be set to the transaction boundary', and the positions are kept even under the nose N. The proper temperature. In general, the timing of the two is approximately the same or the latter is delayed for control. That is, the condition of the third is that the internal point P (the lower side of the nose N) and the reference position P2 do not have much deviation from the inside to maintain a uniform constant temperature. φ According to the constant temperature holding chamber 3 of the present invention, the reference can be made. The constant temperature of the transition point of position P 2 is maintained in relation to the internal transition state to control both finely and subtly. The temperature of the air target is also pulsating in the range of 5 t: in the middle of constant temperature maintenance. Each of the points P1, P2, and P3. The first figure shows the constant temperature holding chamber 3 of the continuous metal heat treatment system 1 shown in Figs. 1 to 4, and the control target temperatures TA and TB are changed during cooling to make the cooling rate. An example of the change. The time 11 at which the internal position pc reaches the temperature at the transition point of the gyro is relatively early, and the time at which the reference position P 2 reaches the temperature of the transition point of the granulated iron is close to 12. The most important -30- (27) The point of 1257428 is that the position of the workpiece W is not involved in the nose N' and there is no possibility of passing below the control target temperature TA, TB, and it is stable and the whole point is controlled under the nose (η 〇se ) N As repeated It is to be noted that the control target temperature TB regardless of the amount of the workpiece W is controlled to be less than or equal to 2 to 3 ° C. Therefore, fine control can be performed based on the reference position P2. Fig. 12 is a view showing the fifth and sixth figures. The preheating chamber 38 of the metal heat treatment system 36 and the constant temperature holding chamber 3' are rapidly cooled and then maintained at a constant temperature to change the cooling rate. As in the previous example, the internal position PC can be reached to the transition point of the granita iron. The time 11 of the temperature is relatively early, and is close to the time t2 at which the reference position P2 reaches the temperature of the transition point of the granulated iron. It can be placed under the nose (η 〇se ) N and inserted between the control target temperatures To of the constant temperature holding chamber 3, Based on the reference position P2, the whole workpiece is finely controlled. The specific temperature and time data are shown in Fig. 9 to Fig. 2, but this is only the reference data, and the actual furnace time is 1 to several. The difference between the temperature and the cold-cooled workpiece can be followed by shot peening. As shown in Japanese Patent Laid-Open No. 6-172 8 5 3, if When the bead blasting treatment is carried out at a negative temperature, the distribution of the compressive residual stress can be further increased. Since it can be continuously processed, the efficiency is good. The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention. -31 - (28) 1257428 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side cross-sectional view showing a continuous metal heat treatment system according to an embodiment of the present invention. Fig. 2 is a side view showing a circulation path of Fig. 1. Fig. 3 is a plan view showing a portion of the circulation path of the first drawing. Fig. 4 is a control explanatory view of the system shown in Figs. 1 to 3 . Fig. 5 is a side cross-sectional view showing a continuous metal processing system in which a pre-cooling chamber is provided between a heating chamber and a thermostatic holding chamber according to an embodiment of the present invention. Fig. 6 is a control explanatory diagram of the system shown in Fig. 5. Fig. 7 is a cross-sectional explanatory view showing a state in which the temperature of the workpiece after the carburization treatment of the present invention is expanded. Fig. 8 is a graph showing the relationship between the depth of the workpiece and the carbon concentration shown in Fig. 7. Fig. 9 is a graph showing the time and temperature of the cooling method up to the temperature maintained at a constant temperature in the carburizing and quenching method of the present invention. The first diagram is a graph showing the change of the cooling rate of Fig. 9. Fig. 1 is a graph showing the time and temperature of an embodiment in which the control target temperature of the constant temperature holding can be changed to two stages. Fig. 12 is a graph showing the time and temperature of an embodiment in which cooling is performed in a pre-cooling chamber followed by cooling in a constant temperature holding chamber and constant temperature holding. -32- (29) 1257428
【主要元件符號說明】 1 連續式金屬熱處理系統 2 循環路 3 恆溫保持室 4 加熱室 5 冷溫氣體冷卻室 6 前室 7 門裝置 8 門裝置 9 門裝置 10 加熱器 11 變壓器 1 2 窗 13 窗 14 整流板 1 5R 管道 1 5L 管道 16 平行管道 17 平行管道 18 蝶形閥 19 蝶形閥 20 吸引管道 2 1 排出管道 22 蝶形閥 -33 (30) 1257428 2 4 分歧管 2 5 分歧管 26 冷卻器 26S 合流點 2 7 風扇 28 2 9[Main component symbol description] 1 Continuous metal heat treatment system 2 Circulating circuit 3 Constant temperature holding chamber 4 Heating chamber 5 Cold temperature gas cooling chamber 6 Front chamber 7 Door device 8 Door device 9 Door device 10 Heater 11 Transformer 1 2 Window 13 Window 14 Rectifier 1 5R Pipe 1 5L Pipe 16 Parallel Pipe 17 Parallel Pipe 18 Butterfly Valve 19 Butterfly Valve 20 Suction Pipe 2 1 Drain Pipe 22 Butterfly Valve -33 (30) 1257428 2 4 Branch Pipe 2 5 Branch Pipe 26 Cooling 26S junction point 2 7 fan 28 2 9
3 1 3 2 33 34 輔助加熱器 保溫材 循環流 控制器 溫度感測器 門裝置 門裝置 35 噴出口 36 連續式金屬熱處理系統 37 門裝置 φ 38 預冷卻室 3 9 氣體排氣管 W 工件 R 輸送滾筒 -343 1 3 2 33 34 Auxiliary heater insulation material circulation flow controller temperature sensor door device door device 35 discharge port 36 continuous metal heat treatment system 37 door device φ 38 pre-cooling chamber 3 9 gas exhaust pipe W workpiece R conveying Roller-34