JP3009792B2 - Continuous gas carburizing and quenching furnace - Google Patents
Continuous gas carburizing and quenching furnaceInfo
- Publication number
- JP3009792B2 JP3009792B2 JP4307045A JP30704592A JP3009792B2 JP 3009792 B2 JP3009792 B2 JP 3009792B2 JP 4307045 A JP4307045 A JP 4307045A JP 30704592 A JP30704592 A JP 30704592A JP 3009792 B2 JP3009792 B2 JP 3009792B2
- Authority
- JP
- Japan
- Prior art keywords
- chamber
- quenching
- carburizing
- temperature
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Tunnel Furnaces (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、鋼材部品を浸炭焼入す
るための連続ガス浸炭焼入炉に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous gas carburizing and quenching furnace for carburizing and quenching steel parts.
【０００２】[0002]
【従来の技術】鋼材部品のうち０．１〜０．２５％Ｃの
キルド鋼や低合金鋼は、９００〜１０００℃に加熱し、
ＣＯを含む雰囲気にさらして部品表面からＣを拡散浸透
させる浸炭処理が施される。この浸炭処理が施された鋼
材部品は、浸炭温度から直接焼入れられたり、あるいは
改めて焼きならしをして組織を微細化した後焼入れら
れ、その後２００℃付近で焼もどされてから使用され
る。2. Description of the Prior Art Killed steel and low alloy steel of 0.1 to 0.25% C among steel parts are heated to 900 to 1000 ° C.
Carburizing treatment is performed to expose C to an atmosphere containing CO to diffuse and infiltrate C from the component surface. The carburized steel part is directly quenched from the carburizing temperature, or is hardened after normalizing again to refine the structure, and then tempered at around 200 ° C. before use.
【０００３】鋼材部品の浸炭焼入処理方法としては、Ｃ
Ｏ、Ｈ2 などからなる吸熱型雰囲気ガスを含む浸炭雰囲
気ガスを使用して大気圧付近で処理するガス浸炭焼入れ
と、Ｎ2 ガスと炭化水素ガスとの混合ガス等を使用して
減圧下で処理する真空浸炭焼入れとがある。このうちガ
ス浸炭焼入れにおいては、簡単な構成で連続炉を構成で
きる反面、処理材に、いわゆる浸炭色と呼ばれる灰褐色
または灰黒色の着色が生じる。一方、真空浸炭焼入れに
おいては、前記浸炭色は生じず、光輝肌を得ることがで
きるが、連続炉とするには各ゾーン毎に真空仕切扉を設
けて多室型としなければならず、複雑な炉構成としなけ
ればならないという欠点を有する。[0003] As a method of carburizing and quenching steel parts, C
Gas carburizing and quenching at about atmospheric pressure using a carburizing atmosphere gas including an endothermic atmosphere gas composed of O, H 2 and the like, and under reduced pressure using a mixed gas of N 2 gas and hydrocarbon gas, etc. There is vacuum carburizing and quenching to process. Of these, in gas carburizing and quenching, a continuous furnace can be configured with a simple configuration, but the treatment material is colored in a so-called carburizing color of gray brown or gray black. On the other hand, in vacuum carburizing and quenching, the carburizing color does not occur, and bright skin can be obtained.However, in order to form a continuous furnace, a vacuum partition door must be provided for each zone to provide a multi-chamber type, which is complicated. There is a drawback that the furnace configuration must be simple.
【０００４】ところで、前記浸炭色はガス浸炭中に処理
材表面に形成されたＣｒ酸化物や煤の付着によって生じ
るものであるが、浸炭色を有する処理材を約８５０〜９
００℃で１０-1〜１０-2Ｔｏｒｒの減圧下で加熱する
と、Ｏ2 分圧の低下によってＯ 2 が解離し、処理材表面
が光輝肌となること、及び処理材を減圧状態に保持する
ことで煤の付着を除去できることが知られている。Incidentally, the carburizing color is treated during gas carburizing.
Caused by the adhesion of Cr oxide and soot formed on the material surface
However, the treatment material having a carburized color is about 850-9
10 at 00 ° C-1-10-2Heat under reduced pressure of Torr
And OTwoO by the partial pressure drop TwoIs dissociated and treated material surface
Is a brilliant skin, and the processing material is kept under reduced pressure
It is known that the adhesion of soot can be removed by doing so.
【０００５】そこで、特公昭６２−４４６５号公報に
は、上記ガス浸炭焼入法に真空加熱処理を付加した方法
及びこの方法に用いる連続式ガス浸炭焼入炉が開示され
ている。この連続式ガス浸炭焼入炉は、浸炭、拡散ゾー
ンをもつ浸炭処理室と、減圧降温室と、焼入室とを有し
ている。処理材は、まず浸炭雰囲気ガスが供給された浸
炭処理室で、大気圧下、約９５０℃の温度で浸炭・拡散
処理される。そして、浸炭処理した処理材は、減圧降温
室で１０-2Ｔｏｒｒ程度の減圧下、約８５０℃の温度ま
で降温され、その後、大気圧下の焼入室に送られ油焼入
れが行なわれる。このように浸炭処理した後、焼入れす
る前に、減圧加熱することによって、Ｏ2の解離作用や
煤の除去により処理材表面を光輝肌とすることができ
る。したがって、簡単な構成で連続炉を構成できるガス
浸炭焼入法によって、浸炭色のない光輝肌の処理材を得
ることができる。Therefore, Japanese Patent Publication No. 62-4465 discloses a method in which a vacuum heating treatment is added to the gas carburizing and quenching method, and a continuous gas carburizing and quenching furnace used in this method. This continuous gas carburizing and quenching furnace has a carburizing and processing chamber having a carburizing and diffusion zone, a reduced-pressure cooling chamber, and a quenching chamber. The treatment material is first carburized and diffused at a temperature of about 950 ° C. under atmospheric pressure in a carburizing chamber supplied with a carburizing atmosphere gas. The carburized material is cooled to a temperature of about 850 ° C. under reduced pressure of about 10 −2 Torr in a reduced-pressure cooling chamber, and then sent to a quenching chamber under atmospheric pressure to perform oil quenching. By heating under reduced pressure before quenching after carburizing as described above, the surface of the treated material can be made to have a bright skin by dissociating O 2 and removing soot. Therefore, by the gas carburizing and quenching method that can constitute a continuous furnace with a simple configuration, it is possible to obtain a treatment material for shiny skin without carburizing color.
【０００６】[0006]
【発明が解決しようとする課題】しかし、上記特公昭６
２−４４６５号公報に開示された焼入炉においては、減
圧降温室で、約９２０〜９５０℃の温度の浸炭処理材を
８５０℃程度に降温されるわけだが、大気圧下に比べて
減圧下では安定に降温し難く、例えば８５０℃まで十分
に降温しなかったりするなど降温後の温度にばらつきが
生じやすい。[Problems to be solved by the invention]
In the quenching furnace disclosed in Japanese Patent Application Laid-Open No. 2-4465, the temperature of a carburized material at a temperature of about 920 to 950 ° C. is reduced to about 850 ° C. in a reduced pressure cooling chamber. In this case, it is difficult to lower the temperature stably, and the temperature after the temperature lowers easily, for example, the temperature is not sufficiently lowered to 850 ° C.
【０００７】このため、処理材を安定に降温させるため
には長時間を要し、サイクルタイムが長くなるという欠
点がある。また、降温された処理材を減圧降温室から排
出する際には、減圧降温室を一旦Ｎ2 ガスなどの不活性
ガスや浸炭雰囲気ガスでほぼ大気圧に復圧させる必要が
ある。ここで、Ｎ2 ガスは温度が高くなるほど処理材を
脱炭させるという特性があり、また浸炭雰囲気ガスも浸
炭性能を示すＣ．Ｐ．値が高温になるほど低下するとい
う特性がある。このため、これらのガスを用いて復圧さ
せる際の温度にばらつきがあると、処理材の浸炭性に影
響し、焼入れ後の焼入品質がばらつくという不都合があ
る。For this reason, there is a disadvantage that it takes a long time to stably lower the temperature of the processing material, and the cycle time becomes long. Also, when discharging the cooled material from the decompression and cooling chamber, it is necessary to temporarily return the decompression and cooling chamber to almost atmospheric pressure with an inert gas such as N 2 gas or a carburizing atmosphere gas. Here, the N 2 gas has the property of decarburizing the treatment material as the temperature increases, and the carburizing atmosphere gas also exhibits C.I. P. There is a characteristic that the value decreases as the temperature increases. For this reason, if there is a variation in the temperature at the time of restoring the pressure using these gases, there is an inconvenience that the carburizing property of the treated material is affected and the quenching quality after quenching varies.
【０００８】本発明は上記実情に鑑みてなされたもので
あり、浸炭処理材の降温時間を短くしてサイクルタイム
の短縮化を図ることができ、しかも焼入品質も安定させ
ることができる連続ガス浸炭焼入炉を提供することを目
的とする。The present invention has been made in view of the above-mentioned circumstances, and is a continuous gas capable of shortening the cycle time by shortening the cooling time of the carburized material and stabilizing the quenching quality. An object is to provide a carburizing and quenching furnace.
【０００９】[0009]
【課題を解決するための手段】上記課題を解決する本第
１発明の連続式ガス浸炭焼入炉は、浸炭ゾーン及び拡散
ゾーンをもつ浸炭処理室と焼入室とを有する連続式ガス
浸炭焼入炉において、前記浸炭処理室と前記焼入室との
間に、降温室と、減圧保持室とを順に設けたことを特徴
とするものである。The continuous gas carburizing and quenching furnace according to the first aspect of the present invention which solves the above-mentioned problems has a continuous gas carburizing and quenching having a carburizing chamber having a carburizing zone and a diffusion zone and a quenching chamber. In the furnace, a temperature decreasing chamber and a reduced pressure holding chamber are sequentially provided between the carburizing chamber and the quenching chamber.
【００１０】また上記課題を解決する本第２発明の連続
式ガス浸炭焼入炉は、前記第１発明の浸炭焼入炉におい
て、前記焼入室が減圧油焼入室であることを特徴とする
ものである。A continuous gas carburizing and quenching furnace according to a second aspect of the present invention for solving the above-mentioned problems is characterized in that, in the carburizing and quenching furnace of the first aspect, the quenching chamber is a reduced-pressure oil quenching chamber. It is.
【００１１】[0011]
【作用】本第１発明の連続式ガス浸炭焼入炉では、処理
材が、浸炭処理室、降温室、減圧保持室及び焼入室へ搬
送ローラ等により順に送られ、各室での処理が連続的か
つ同期的に行われる。以下、各室での処理を順に説明す
る。処理材は、まず所定の浸炭雰囲気とされた大気圧下
の浸炭処理室で、９５０℃程度に加熱、保持されて浸炭
処理が行われる。浸炭処理室で浸炭処理された処理材
は、大気圧下の降温室に送られ、８５０℃程度まで降温
される。８５０℃程度に降温された処理材は減圧保持室
に送られる。なお、処理材が送り込まれる時の減圧保持
室内の圧力は大気圧程度にされており、処理材が送り込
まれた後、減圧保持室が所定の圧力まで減圧される。そ
して、処理材は減圧保持室で、８５０℃程度の温度で所
定時間、減圧保持される。その後、減圧保持室をＮ2 な
どの不活性ガスや浸炭雰囲気ガスにより大気圧程度に復
圧した状態で、処理材が減圧保持室から排出され、焼入
室に送られる。焼入室では、所定の焼入条件で、油焼入
やガス焼入が行われる。In the continuous gas carburizing and quenching furnace according to the first aspect of the present invention, the processing material is sequentially sent to the carburizing chamber, the cooling chamber, the depressurization holding chamber, and the quenching chamber by transport rollers or the like, and the processing in each chamber is continuously performed. And synchronously. Hereinafter, the processing in each room will be described in order. The treatment material is first heated and held at about 950 ° C. in a carburization chamber under a predetermined carburizing atmosphere under atmospheric pressure to perform carburization. The treated material that has been carburized in the carburizing chamber is sent to a temperature lowering chamber under atmospheric pressure, where it is cooled to about 850 ° C. The processing material cooled to about 850 ° C. is sent to a reduced pressure holding chamber. The pressure in the reduced pressure holding chamber when the processing material is fed is set to about the atmospheric pressure, and after the processing material is fed, the pressure in the reduced pressure holding chamber is reduced to a predetermined pressure. Then, the processing material is held in a reduced pressure holding chamber at a temperature of about 850 ° C. for a predetermined time. Thereafter, the processing material is discharged from the reduced pressure holding chamber and sent to the quenching chamber in a state where the pressure in the reduced pressure holding chamber is restored to about the atmospheric pressure by an inert gas such as N 2 or a carburizing atmosphere gas. In the quenching chamber, oil quenching or gas quenching is performed under predetermined quenching conditions.
【００１２】このように本第１発明の浸炭焼入炉では、
浸炭処理された処理材の降温処理が降温室及び減圧保持
室の独立した２室にまたがって同期的に行われ、しかも
降温室では大気圧下で降温処理される。つまり最初の降
温室では、大気圧下で、処理材がほぼ所定の温度まで極
めて迅速に降温される。そして、このほぼ所定の温度ま
で降温された処理材は、減圧保持室で所定の温度まで確
実に降温される。このため、１室だけでの降温処理や減
圧下での降温処理と比べて、迅速かつ安定に処理材を降
温させることができる。Thus, in the carburizing and quenching furnace of the first invention,
The temperature reduction of the carburized material is performed synchronously over two independent chambers, a temperature reduction chamber and a reduced pressure holding chamber, and the temperature is reduced in the temperature reduction chamber under atmospheric pressure. That is, in the first temperature-lowering chamber, the temperature of the processing material is extremely rapidly lowered to almost the predetermined temperature under the atmospheric pressure. Then, the temperature of the processing material which has been lowered to almost the predetermined temperature is reliably lowered to the predetermined temperature in the reduced pressure holding chamber. Therefore, the temperature of the processing material can be rapidly and stably lowered as compared with the temperature lowering process in only one chamber or the temperature lowering process under reduced pressure.
【００１３】また、減圧保持室での処理終了後、減圧保
持室をＮ2 ガスや浸炭性ガスで大気圧程度に復圧する際
においては、処理材が所定温度まで確実に降温されてい
るので、上記ガスが雰囲気温度の影響を受けることによ
る処理材の浸炭性の低下やばらつきを抑えることができ
る。さらに、減圧保持室において、８５０℃程度の所定
温度で所定時間、減圧保持されることにより、Ｏ2 分圧
の低下によってＯ2 が解離し、また煤の付着が除去され
るので、処理材表面を光輝肌とすることができる。When the pressure in the depressurized holding chamber is restored to about atmospheric pressure with N 2 gas or carburizing gas after the processing in the depressurized holding chamber, the temperature of the processing material is surely lowered to a predetermined temperature. It is possible to suppress a decrease or variation in the carburizing property of the processing material due to the influence of the ambient temperature on the gas. Further, the vacuum holding chamber for a predetermined time at a predetermined temperature of about 850 ° C., by being vacuum held, O 2 is dissociated by reduction of O 2 partial pressure, and because the adhesion of soot are removed, treated material surface Can be used as brilliant skin.
【００１４】本第２発明の連続ガス浸炭焼入炉は、焼入
室が減圧油焼入室とされているので、上記第１発明の浸
炭焼入炉の作用の他に以下に示すような作用も有してい
る。つまり、減圧下で油焼入処理することにより、処理
材の歪み、割れを抑制しつつ、完全に硬化させることが
できる。これは以下のように説明できる。まず、一般的
な油焼入処理における焼入油の焼入冷却過程から説明す
ると、この過程は蒸気膜段階、沸騰段階、及び対流段階
の３つの段階に順に分けられる。蒸気膜段階は、焼入れ
の初期段階で、処理材から油への熱伝達が処理材の表面
を包む油の蒸気膜により阻害されており、冷却速度が遅
い段階である。次の沸騰段階は、処理材の表面の温度が
次第に下がり、処理材の表面を包んでいた蒸気膜が破れ
た後の段階で、沸騰による激しい攪拌効果により冷却速
度が非常に速くなる段階である。最後の対流段階は、処
理材の温度が油の沸点まで下がって沸騰が収まり、それ
以降の主として対流と伝達のみにより冷却される段階
で、冷却速度が非常に遅い段階である。なお、蒸気膜段
階から沸騰段階に移行する温度は特性温度と呼ばれ、沸
騰段階が収まる温度が対流開始温度と呼ばれる。In the continuous gas carburizing and quenching furnace of the second invention, the quenching chamber is a reduced-pressure oil quenching chamber. Therefore, in addition to the function of the carburizing and quenching furnace of the first invention, the following functions are also provided. Have. That is, by performing oil quenching treatment under reduced pressure, it is possible to completely cure the treated material while suppressing distortion and cracking. This can be explained as follows. First, the quenching and cooling process of quenching oil in a general oil quenching process will be described. This process is divided into three stages of a steam film stage, a boiling stage, and a convection stage. In the vapor film stage, in the initial stage of quenching, heat transfer from the treatment material to the oil is hindered by the vapor film of the oil wrapping the surface of the treatment material, and the cooling speed is low. The next boiling stage is a stage after the temperature of the surface of the processing material gradually decreases and the vapor film wrapping the surface of the processing material is broken, and the cooling rate becomes extremely high due to the vigorous stirring effect of the boiling. . The final convection stage is a stage in which the temperature of the treatment material drops to the boiling point of the oil, the boiling stops, and the subsequent cooling is mainly performed only by convection and transmission, and the cooling speed is very slow. The temperature at which the vapor phase shifts to the boiling phase is called the characteristic temperature, and the temperature at which the boiling phase falls is called the convection start temperature.
【００１５】このような焼入冷却過程は、油面圧が大気
圧より下がると、以下のように変化する。油面圧が低下
すると、焼入油の蒸気圧が上昇し、また焼入油の沸点が
低下する。そして、焼入油の蒸気圧が上昇すると、油が
蒸発しやすくなるので、蒸気膜の発生量が多くなり、ま
た発生時間（蒸気膜段階）が長くなる。したがって、上
記特性温度が油面圧の減少に伴って下がることになる。
一方、焼入油の沸点が低下すると、沸騰段階が低温側に
持ち越されるので、対流開始温度が油面圧の減少に伴っ
て下がることとなる。The quenching cooling process changes as follows when the oil surface pressure falls below the atmospheric pressure. When the oil surface pressure decreases, the vapor pressure of the quenched oil increases, and the boiling point of the quenched oil decreases. When the vapor pressure of the quenched oil increases, the oil is likely to evaporate, so that the amount of generated vapor film increases and the generation time (vapor film stage) increases. Therefore, the characteristic temperature decreases as the oil pressure decreases.
On the other hand, when the boiling point of the quenched oil decreases, the boiling stage is carried over to the lower temperature side, so that the convection start temperature decreases as the oil surface pressure decreases.
【００１６】ここで、焼入硬さと歪みとの関係をみる
と、大気圧下で行われる油焼入れでは、焼入硬さと歪み
の度合は相関性がある。この焼入歪みは熱応力による影
響を大きく受け、急冷を避けるほど焼入歪みは減少す
る。減圧下で油焼入すると、上記したように特性温度が
下がり、冷却速度の遅い蒸気膜段階が長くなる。このた
め、減圧油焼入では、熱応力の発生が抑えられ、熱応力
に起因する歪みの発生を抑えることができる。一方、焼
入硬さは処理材を急冷するほど硬くなる。このため、減
圧下で油焼入すると、上記したように冷却速度の非常に
速い沸騰段階が低温側に持ち越されるので、より完全に
硬化させることができる。したがって、減圧下で油焼入
することにより、焼入歪みの発生を抑えるとともに、焼
入硬化を増進させることが可能となる。なお、油面圧を
低くするにしたがって完全焼入硬さを維持したまま、焼
入歪みを小さくすることができる。Looking at the relationship between quenching hardness and distortion, oil quenching performed under atmospheric pressure has a correlation between the degree of quenching hardness and distortion. This quenching distortion is greatly affected by the thermal stress, and the quenching distortion decreases as the quenching is avoided. Oil quenching under reduced pressure reduces the characteristic temperature and lengthens the slower cooling film phase as described above. For this reason, in reduced pressure oil quenching, generation of thermal stress is suppressed, and generation of distortion due to thermal stress can be suppressed. On the other hand, the quenching hardness increases as the processing material is rapidly cooled. For this reason, when oil quenching is performed under reduced pressure, the boiling stage with a very high cooling rate is carried over to the lower temperature side as described above, so that the oil can be more completely cured. Therefore, by performing oil quenching under reduced pressure, it is possible to suppress the occurrence of quenching distortion and to enhance quench hardening. The quenching distortion can be reduced while maintaining the complete quench hardness as the oil surface pressure is lowered.
【００１７】[0017]
【実施例】以下、本発明の連続式ガス浸炭焼入炉を実施
例により具体的に説明する。 （実施例１）図１の概略断面図に示すように、本実施例
の連続式ガス浸炭焼入炉は、予熱室１０と、浸炭処理室
２０と、降温室３０と、減圧保持室４０と、焼入室５０
とが順に配設されて構成されている。DESCRIPTION OF THE PREFERRED EMBODIMENTS The continuous gas carburizing and quenching furnace of the present invention will be specifically described below with reference to embodiments. (Embodiment 1) As shown in a schematic sectional view of FIG. 1, a continuous gas carburizing and quenching furnace of the present embodiment includes a preheating chamber 10, a carburizing chamber 20, a cooling chamber 30, a decompression holding chamber 40, , Quenching room 50
Are sequentially arranged.
【００１８】予熱室１０は、前方扉１０ａ及び後方扉１
０ｂを有しており、浸炭処理室２０より吸熱型雰囲気ガ
スが供給されている。浸炭処理室２０は、前方扉２０ａ
及び後方扉２０ｂを有しており、前方から順に昇温ゾー
ン２１と、浸炭ゾーン２２と、拡散ゾーン２３とに分け
られている。そして、この浸炭処理室２０の各ゾーン２
１、２２、２３には、ＣＯ：２０〜２３％、Ｈ2 ：３１
〜４０％からなる吸熱型雰囲気ガスとＣm Ｈn ガス（例
えばプロパンガス）からなる浸炭雰囲気ガスが供給され
るようになっている。The preheating chamber 10 includes a front door 10a and a rear door 1
0b, and an endothermic atmosphere gas is supplied from the carburizing chamber 20. The carburizing chamber 20 includes a front door 20a.
And a rear door 20b, which is divided into a heating zone 21, a carburizing zone 22, and a diffusion zone 23 in order from the front. And each zone 2 of this carburizing chamber 20
The 1,22,23, CO: 20~23%, H 2: 31
Carburizing atmospheric gas consisting of endothermic atmospheric gases and C m H n gas (such as propane gas) are supplied consisting of 40%.
【００１９】浸炭処理室２０の後方に浸炭処理室２０の
後方扉２０ｂを介して設けられた降温室３０は、後方扉
３０ａを有しており、浸炭処理室２０と同様にＣＯ：２
０〜２３％、Ｈ2 ：３１〜４０％からなる吸熱型雰囲気
ガス（あるいはＮ2 ガス）とＣm Ｈn ガス（例えばプロ
パンガス）からなる浸炭雰囲気ガスが供給されるように
なっている。The temperature lowering chamber 30 provided behind the carburizing chamber 20 via the rear door 20b of the carburizing chamber 20 has a rear door 30a, and has the same CO: 2 as that of the carburizing chamber 20.
0~23%, H 2: endothermic atmosphere gas consisting of 31 to 40% (or N 2 gas) and C m H n gas (such as propane gas) carburizing atmospheric gas consisting of is to be supplied.
【００２０】降温室３０の後方に第１隔室６０を介して
連設された減圧保持室４０は、前方扉４０ａ及び後方扉
４０ｂを有しており、Ｎ2 ガスが供給されるようになっ
ている。そして減圧保持室４０は、第１真空排気装置４
１に接続されている。減圧保持室４０の後方に第２隔室
７０を介して連設された焼入室５０は、前方扉５０ａ及
び後方扉５０ｂを有しており、減圧保持室４０と同様に
Ｎ2 ガスが供給されるようになっている。そして、焼入
室５０は下部の油槽５１と上部の油切り室５２とからな
り、図示しないエレベータ機構を備えている。The decompression holding chamber 40 connected to the rear of the cooling chamber 30 via the first compartment 60 has a front door 40a and a rear door 40b, and is supplied with N 2 gas. ing. The reduced pressure holding chamber 40 is provided with the first evacuation device 4
1 connected. The quenching chamber 50 connected to the rear of the reduced pressure holding chamber 40 via the second compartment 70 has a front door 50a and a rear door 50b, and is supplied with N 2 gas similarly to the reduced pressure holding chamber 40. It has become so. The quenching chamber 50 includes a lower oil tank 51 and an upper oil drain chamber 52, and includes an elevator mechanism (not shown).
【００２１】なお、予熱室１０、浸炭処理室２０、降温
室３０、第１隔室６０、減圧保持室４０、第２隔室７０
及び焼入室５０には、搬送ローラ８０が配設され、減圧
焼入室５０を除く各室には図示しない加熱手段が配設さ
れている。以下、上記構成を有する連続式ガス浸炭焼入
炉の処理について説明する。なお、図２は、この処理に
おける温度と圧力を示すものである。The preheating chamber 10, the carburizing chamber 20, the cooling chamber 30, the first compartment 60, the reduced pressure holding chamber 40, and the second compartment 70
The quenching chamber 50 is provided with a conveying roller 80, and each chamber except the reduced-pressure quenching chamber 50 is provided with a heating means (not shown). Hereinafter, the processing of the continuous gas carburizing and quenching furnace having the above configuration will be described. FIG. 2 shows the temperature and the pressure in this processing.
【００２２】まず、ＳＣＭ４２０等の処理材が予熱室１
０の前方扉１０ａから装入され、そして、吸熱型雰囲気
ガス中で図示しない加熱手段により処理材が６００〜８
００℃程度に加熱される。これにより、処理材に付着す
る不純物が除去される。次に、予熱室１０の後方扉１０
ｂ及び浸炭処理室２０の前方扉２０ａを介して、予熱室
１０から浸炭処理室２０の昇温ゾーン２１に処理材が送
られる。なお、浸炭処理室２０の昇温ゾーン２１、浸炭
ゾーン２２及び拡散ゾーン２２には上記した吸熱型雰囲
気ガスを含む浸炭雰囲気ガスが供給されている。そし
て、処理材は昇温ゾーン２１で図示しない加熱手段によ
り浸炭温度である約９５０℃まで加熱される。First, the processing material such as SCM420 is placed in the preheating chamber 1
0 through the front door 10a, and the processing material is heated to 600 to 8 by a heating means (not shown) in an endothermic atmosphere gas.
It is heated to about 00 ° C. Thereby, impurities adhering to the processing material are removed. Next, the rear door 10 of the preheating chamber 10
Through the b and the front door 20a of the carburizing chamber 20, the processing material is sent from the preheating chamber 10 to the temperature raising zone 21 of the carburizing chamber 20. The carburizing atmosphere gas including the above-mentioned endothermic atmosphere gas is supplied to the temperature raising zone 21, the carburizing zone 22, and the diffusion zone 22 of the carburizing chamber 20. Then, the processing material is heated in the temperature raising zone 21 to about 950 ° C., which is the carburizing temperature, by a heating means (not shown).
【００２３】その後、処理材は、順次浸炭ゾーン２２、
拡散ゾーン２３で浸炭、拡散処理される。なお、浸炭ゾ
ーン２２での処理時間は７０〜９０分であり、拡散ゾー
ン２３での処理時間は５５〜７０分である。また、浸炭
・拡散時の炭素ポテンシャル値はＣｐ０．８〜１．０で
ある。浸炭処理された処理材は、浸炭処理室２０の後方
扉２０ｂを介して降温室３０に送られる。降温室３０に
は、浸炭処理室２０と同様に吸熱型雰囲気ガスを含む浸
炭雰囲気ガスが供給されている。浸炭処理された処理材
は、降温室３０で１０〜１５分保持されて、８５０℃程
度に降温される。Thereafter, the treatment material is sequentially supplied to the carburizing zone 22,
Carburization and diffusion treatment are performed in the diffusion zone 23. The processing time in the carburizing zone 22 is 70 to 90 minutes, and the processing time in the diffusion zone 23 is 55 to 70 minutes. The carbon potential value during carburization and diffusion is Cp 0.8 to 1.0. The carburized treatment material is sent to the cooling chamber 30 via the rear door 20 b of the carburizing chamber 20. The carburizing atmosphere gas including the endothermic atmosphere gas is supplied to the cooling chamber 30 similarly to the carburizing chamber 20. The treated material after the carburizing treatment is held in the cooling chamber 30 for 10 to 15 minutes and cooled to about 850 ° C.
【００２４】降温室３０で８５０℃程度に降温された処
理材は、後方扉３０ｂ、第１隔室６０及び前方扉４０ａ
を介して減圧保持室４０に送られる。なお、処理材が装
入される際の減圧保持室４０はＮ2 ガスで大気圧程度に
復圧されている。処理材が装入された減圧保持室４０は
第１真空排気装置４１で約１．３×１０4 〜６．７×１
０4 Ｐａに真空引きされ、処理材は８５０℃の温度で〜
５分減圧保持される。The processing material which has been cooled to about 850 ° C. in the cooling chamber 30 is supplied to the rear door 30b, the first compartment 60 and the front door 40a.
Is sent to the decompression holding chamber 40 via. The pressure-reducing chamber 40 when the processing material is loaded is returned to the atmospheric pressure with N 2 gas. The reduced pressure holding chamber 40 in which the processing material is charged is about 1.3 × 10 4 to 6.7 × 1 by the first evacuation device 41.
0 4 Pa is evacuated, the treated material is ~ at a temperature of 850 ° C.
The vacuum is maintained for 5 minutes.
【００２５】上記減圧保持室４０での処理終了後、減圧
保持室４０をＮ2 ガスで大気圧程度に復圧した後、処理
材は後方扉４０ｂ、第２隔室７０及び前方扉５０ａを介
して焼入室５０に送られる。なおこの焼入室５０は、Ｎ
2 ガスが供給されて大気圧程度にされている。焼入室５
０に装入された処理材は図示しないエレベータ機構で油
槽５１に浸漬され、油焼入される。浸漬してから３〜５
分経過後、処理材は図示しないエレベータ機構で油切り
室５２に引き上げられ、油切り後、後方扉５０ｂから炉
外に抽出されて浸炭焼入処理が終了する。After the completion of the processing in the reduced pressure holding chamber 40, the pressure in the reduced pressure holding chamber 40 is restored to about atmospheric pressure with N 2 gas, and then the processing material is passed through the rear door 40b, the second compartment 70 and the front door 50a. And sent to the quenching chamber 50. The quenching chamber 50 is made of N
Two gases are supplied to make it about atmospheric pressure. Quenching room 5
The treatment material charged in the tank 0 is immersed in the oil tank 51 by an elevator mechanism (not shown) and is oil-quenched. 3-5 after soaking
After a lapse of minutes, the treated material is pulled up to the oil drain chamber 52 by an elevator mechanism (not shown), and after the oil drain, it is extracted out of the furnace from the rear door 50b, and the carburizing and quenching process ends.
【００２６】このように本実施例の浸炭焼入炉では、浸
炭処理室２０と焼入室５０との間に、降温室３０及び減
圧保持室４０が順に配設されており、浸炭処理された処
理材の降温処理が降温室３０及び減圧保持室４０の２室
にまたがって同期的に行われ、しかも降温室３０では大
気圧下で降温処理される。このため、１室だけでの降温
処理や減圧下での降温処理と比べて、処理材を迅速かつ
確実に所定の温度まで降温させることができる。したが
って、降温処理に要する時間の短縮化により、サイクル
時間の短縮化を図ることができる。As described above, in the carburizing and quenching furnace of this embodiment, the cooling chamber 30 and the depressurization holding chamber 40 are sequentially disposed between the carburizing chamber 20 and the quenching chamber 50, and the carburizing treatment is performed. The temperature lowering process of the material is performed synchronously over the two chambers of the temperature lowering chamber 30 and the reduced pressure holding chamber 40, and the temperature lowering chamber 30 performs the temperature lowering process under the atmospheric pressure. For this reason, the temperature of the treated material can be rapidly and reliably lowered to a predetermined temperature, as compared with the temperature lowering process in only one chamber or the temperature lowering process under reduced pressure. Therefore, the cycle time can be shortened by shortening the time required for the temperature lowering process.
【００２７】また、本実施例では、減圧保持室４０での
処理終了後、減圧保持室４０がＮ2ガスで大気圧程度に
復圧されるが、このとき処理材が所定温度まで確実に降
温されている。このため、本実施例では、Ｎ2 ガスが高
温雰囲気の影響を受けて処理材を脱炭させることがな
く、浸炭性の低下やばらつきを抑えることができ、焼入
品質の向上に寄与する。In this embodiment, after the processing in the reduced pressure holding chamber 40 is completed, the pressure in the reduced pressure holding chamber 40 is restored to about the atmospheric pressure with N 2 gas. Have been. For this reason, in the present embodiment, the N 2 gas does not decarburize the treated material under the influence of the high-temperature atmosphere, and it is possible to suppress a reduction and variation in the carburizing property, thereby contributing to an improvement in quenching quality.
【００２８】さらに、減圧保持室４０において、８５０
℃の温度で所定時間、減圧保持されることにより、Ｏ2
分圧の低下によってＯ2 が解離し、また煤の付着が除去
されるので、処理材表面を光輝肌とすることができ、こ
れによっても焼入品質の向上に寄与する。なお、上記実
施例では、減圧保持室４０での処理終了後、減圧保持室
４０をＮ 2 ガスで大気圧程度に復圧させたが、Ｎ2 ガス
の代わりに浸炭雰囲気ガスを採用することもできる。そ
して、この場合においても、雰囲気温度の影響を受けて
浸炭雰囲気ガスが処理材の浸炭性をばらつかせたりする
ことがなく、焼入品質の向上に寄与する。Further, in the reduced pressure holding chamber 40, 850
By maintaining a reduced pressure at a temperature ofTwo
O by the partial pressure dropTwoDissociates and removes soot
The surface of the treated material can be made to have brilliant skin,
This also contributes to improved quenching quality. Note that the actual
In the embodiment, after the processing in the decompression holding chamber 40 is completed,
40 to N TwoThe pressure was restored to about atmospheric pressure with gas.Twogas
Alternatively, a carburizing atmosphere gas may be employed. So
And, in this case, too,
Carburizing atmosphere gas fluctuates carburizing property of treated material
And contributes to the improvement of quenching quality.
【００２９】また、上記実施例では、焼入室５０を油焼
入室としたが、これの代わりにガス焼入室とすることも
できる。 （実施例２）図３の概略断面図に示す本実施例２の連続
式ガス浸炭焼入炉は、上記実施例１の浸炭焼入炉におい
て、焼入室５０及び第２隔室７０が第２真空排気装置５
３に接続されており、焼入室５０が減圧油焼入室とされ
ている。これ以外の構成は上記実施例１と同様である。In the above embodiment, the quenching chamber 50 is an oil quenching chamber, but may be a gas quenching chamber instead. (Embodiment 2) The continuous gas carburizing and quenching furnace of Embodiment 2 shown in the schematic sectional view of FIG. 3 is the same as the carburizing and quenching furnace of Embodiment 1 except that the quenching chamber 50 and the second compartment 70 are the second chamber. Vacuum exhaust device 5
3 and the quenching chamber 50 is a reduced pressure oil quenching chamber. Other configurations are the same as those in the first embodiment.
【００３０】この浸炭焼入炉においても、図４に示すよ
うに、予熱室１０、浸炭処理室２０、降温室３０及び減
圧保持室４０で上記実施例１と同様にそれぞれ処理され
る。なお、減圧保持室４０での処理途中に、焼入室５０
及び第２隔室７０が第２真空排気装置５３で０．６×１
０4 〜６．７×１０4 Ｐａに真空引きされている。そし
て、減圧保持室４０での処理終了後、処理材は後方扉４
０ｂ、第２隔室７０及び前方扉５０ａを介して、焼入室
５０に送り込まれる。焼入室５０に装入された処理材は
図示しないエレベータ機構で油槽５１に浸漬され、油焼
入される。浸漬してから３〜５分経過後、処理材は図示
しないエレベータ機構で油切り室５２に引き上げられ、
油切りされる。そして、油焼入室５０をＮ2 ガスで大気
圧程度に復圧してから、処理材が後方扉５０ｂから炉外
に抽出されて浸炭焼入処理が終了する。In this carburizing and quenching furnace as well, as shown in FIG. 4, the preheating chamber 10, the carburizing chamber 20, the cooling chamber 30, and the decompression holding chamber 40 are each processed in the same manner as in the first embodiment. During the processing in the decompression holding chamber 40, the quenching chamber 50
And the second compartment 70 is 0.6 × 1 by the second evacuation device 53.
It is evacuated to 0 4 to 6.7 × 10 4 Pa. After the processing in the decompression holding chamber 40 is completed, the processing material is transferred to the rear door 4.
0b, into the quenching chamber 50 via the second compartment 70 and the front door 50a. The processing material charged in the quenching chamber 50 is immersed in an oil tank 51 by an elevator mechanism (not shown) and is oil-quenched. After a lapse of 3 to 5 minutes from the immersion, the processing material is lifted into the oil drain chamber 52 by an elevator mechanism (not shown),
Oil is drained. After the pressure of the oil quenching chamber 50 is restored to about the atmospheric pressure with N 2 gas, the treated material is extracted from the rear door 50b to the outside of the furnace, and the carburizing and quenching process ends.
【００３１】このように本実施例２の浸炭焼入炉では、
減圧下で油焼入処理することにより、前述したように処
理材の歪み、割れを抑制しつつ、完全に硬化させること
ができる。したがって、焼入品質を極めて高めることが
可能である。また、本実施例２においても、降温室３０
及び減圧保持室４０の２室で降温処理されるので、前記
実施例１と同様にサイクルタイムの短縮化を図ることが
できる。そして本実施例２の浸炭焼入炉では、減圧保持
室４０での減圧保持処理中に、焼入室５０及び第２隔室
７０を予め減圧しておき、減圧保持室４０での処理終了
後、すぐに処理材を焼入室５０に送り込み油槽５１に浸
漬させることが可能である。したがって、減圧保持室４
０での処理終了後、同減圧保持室４０を大気圧程度に復
圧させる必要がなく、これに要する時間を節約すること
ができ、上記実施例１の浸炭焼入炉よりさらにサイクル
タイムを短縮することが可能である。As described above, in the carburizing and quenching furnace of the second embodiment,
By performing the oil quenching treatment under reduced pressure, it is possible to completely cure the treated material while suppressing distortion and cracking of the treated material as described above. Therefore, quenching quality can be extremely enhanced. Further, also in the second embodiment, the cooling room 30
Further, since the temperature is reduced in the two chambers of the reduced pressure holding chamber 40, the cycle time can be reduced as in the first embodiment. Then, in the carburizing and quenching furnace of the second embodiment, during the depressurization holding process in the depressurization holding chamber 40, the quenching chamber 50 and the second compartment 70 are previously depressurized, and after the processing in the depressurization holding chamber 40, The processing material can be immediately sent to the quenching chamber 50 and immersed in the oil tank 51. Therefore, the decompression holding chamber 4
After completion of the process at 0, there is no need to restore the pressure in the reduced-pressure holding chamber 40 to about atmospheric pressure, so that the time required for this can be saved, and the cycle time is further reduced as compared with the carburizing and quenching furnace of the first embodiment. It is possible to
【００３２】さらに、減圧保持室４０での処理終了後の
処理材の温度低下を抑えることもでき、これによっても
焼入品質の向上に寄与する。さらにまた、減圧保持室４
０での処理中に、焼入室５０をゆっくり減圧させること
ができるので、真空排気装置５３を小型化させることが
可能である。また、減圧保持室４０と焼入室５０との間
には、減圧保持室４０の後方扉４０ｂ及び焼入室５０の
前方扉５０ａが設けられているので、それぞれの室で単
独で減圧、又は復圧させることが可能となり、設備動作
上の制限も少なく、条件変更を容易に行うことができ
る。Further, it is possible to suppress a decrease in the temperature of the treated material after the completion of the treatment in the reduced pressure holding chamber 40, which also contributes to the improvement of the quenching quality. Furthermore, the vacuum holding chamber 4
During the processing at 0, the quenching chamber 50 can be slowly depressurized, so that the evacuation device 53 can be downsized. Further, between the depressurized holding chamber 40 and the quenching chamber 50, a rear door 40b of the depressurized holding chamber 40 and a front door 50a of the quenching chamber 50 are provided. This makes it possible to change conditions easily with less restrictions on equipment operation.
【００３３】[0033]
【発明の効果】以上詳述したように本第１発明の連続ガ
ス浸炭焼入炉は、降温室及び減圧保持室の２室で浸炭処
理された処理材を迅速かつ安定に処理材を降温させるこ
とができ、降温処理に要する時間の短縮によりサイクル
タイムの短縮化を図ることが可能である。As described in detail above, the continuous gas carburizing and quenching furnace according to the first aspect of the present invention rapidly and stably cools the treated material which has been carburized in two chambers, a cooling chamber and a reduced pressure holding chamber. The cycle time can be shortened by shortening the time required for the temperature lowering process.
【００３４】また、減圧保持室の雰囲気温度の安定化を
図れるので、雰囲気ガスが温度による影響を受けて、処
理材の浸炭性を低下させたりすることがなく、焼入品質
を向上させることが可能である。さらに減圧焼入室とさ
れた本第２発明の連続ガス浸炭焼入炉は、上記効果の他
に、減圧油焼入処理による効果も奏する。つまり、本第
２発明の浸炭焼入炉によれば、焼入歪み、割れを抑制し
つつ、処理材を完全に焼入硬化させることができ、焼入
品質を極めて向上させることが可能である。Further, since the atmospheric temperature of the reduced pressure holding chamber can be stabilized, the quenching quality can be improved without reducing the carburizing property of the processing material due to the influence of the atmospheric gas on the temperature. It is possible. Further, the continuous gas carburizing and quenching furnace of the second invention, which is a reduced pressure quenching chamber, exhibits an effect by a reduced pressure oil quenching process in addition to the above effects. That is, according to the carburizing and quenching furnace of the second aspect of the present invention, the treated material can be completely quenched and hardened while suppressing quenching distortion and cracking, and quenching quality can be significantly improved. .
【図１】実施例１に係る連続ガス浸炭焼入炉を示す概略
断面図である。FIG. 1 is a schematic sectional view showing a continuous gas carburizing and quenching furnace according to a first embodiment.
【図２】実施例１に係る連続ガス浸炭焼入炉の処理中に
おける温度と圧力を示す線図である。FIG. 2 is a diagram showing temperature and pressure during processing of a continuous gas carburizing and quenching furnace according to Example 1.
【図３】実施例２に係る連続ガス浸炭焼入炉を示す概略
断面図である。FIG. 3 is a schematic sectional view showing a continuous gas carburizing and quenching furnace according to a second embodiment.
【図４】実施例２に係る連続ガス浸炭焼入炉の処理中に
おける温度と圧力を示す線図である。FIG. 4 is a diagram showing temperature and pressure during processing in a continuous gas carburizing and quenching furnace according to Example 2.
２０…浸炭処理室 ２１…昇温ゾーン ２２…
浸炭ゾーン ２３…拡散ゾーン ３０…降温室 ４０…
減圧保持室 ５０…焼入室20: carburizing chamber 21: heating zone 22 ...
Carburizing zone 23 ... Diffusion zone 30 ... Cooling room 40 ...
Decompression holding chamber 50: Quenching chamber
フロントページの続き (72)発明者 藤原 康之 愛知県豊田市トヨタ町１番地 トヨタ自 動車株式会社内 (72)発明者 小川 三郎 大阪市西区京町堀２丁目４番７号 中外 炉工業株式会社内 (72)発明者 船本 裕治 大阪市西区京町堀２丁目４番７号 中外 炉工業株式会社内 (56)参考文献 実開 昭62−6364（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) C21C 8/20 - 8/32 Continued on the front page (72) Inventor Yasuyuki Fujiwara 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Saburo Ogawa 2-4-7 Kyomachibori, Nishi-ku, Osaka City Inside Chugai Reactor Industry Co. 72) Inventor Yuji Funamoto 2-4-7, Kyomachibori, Nishi-ku, Osaka-shi Chugai Furnace Industry Co., Ltd. (56) References Japanese Utility Model 1987-6364 (JP, U) (58) Field surveyed (Int.Cl) . 7, DB name) C21C 8/20 - 8/32
Claims (2)
理室と焼入室とを有する連続式ガス浸炭焼入炉におい
て、 前記浸炭処理室と前記焼入室との間に、降温室と、減圧
保持室とを順に設けたことを特徴とする連続式ガス浸炭
焼入炉。1. A continuous gas carburizing and quenching furnace having a carburizing chamber having a carburizing zone and a diffusion zone and a quenching chamber, wherein a cooling chamber and a depressurization holding chamber are provided between the carburizing chamber and the quenching chamber. A continuous gas carburizing and quenching furnace characterized by sequentially providing
特徴とする請求項１記載の連続式ガス浸炭焼入炉。2. The continuous gas carburizing and quenching furnace according to claim 1, wherein the quenching chamber is a vacuum oil quenching chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4307045A JP3009792B2 (en) | 1992-11-17 | 1992-11-17 | Continuous gas carburizing and quenching furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4307045A JP3009792B2 (en) | 1992-11-17 | 1992-11-17 | Continuous gas carburizing and quenching furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06158267A JPH06158267A (en) | 1994-06-07 |
| JP3009792B2 true JP3009792B2 (en) | 2000-02-14 |
Family
ID=17964388
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4307045A Expired - Lifetime JP3009792B2 (en) | 1992-11-17 | 1992-11-17 | Continuous gas carburizing and quenching furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3009792B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3460075B2 (en) * | 1995-12-28 | 2003-10-27 | 同和鉱業株式会社 | Metal carburizing method |
| JP3624096B2 (en) * | 1998-06-16 | 2005-02-23 | 岩谷産業株式会社 | Carburizing method in continuous carburizing furnace |
| JP2009091638A (en) * | 2007-10-11 | 2009-04-30 | Dowa Thermotech Kk | Heat-treatment method and heat-treatment apparatus |
| JP5167301B2 (en) * | 2010-03-29 | 2013-03-21 | トヨタ自動車株式会社 | Continuous gas carburizing furnace |
| JP6209343B2 (en) * | 2013-03-15 | 2017-10-04 | Ｄｏｗａサーモテック株式会社 | Quenching treatment equipment, heat treatment equipment and quenching treatment method |
-
1992
- 1992-11-17 JP JP4307045A patent/JP3009792B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06158267A (en) | 1994-06-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPS624465B2 (en) | ||
| JP4041602B2 (en) | Vacuum carburizing method for steel parts | |
| US20180363123A1 (en) | Method And Facility For Carbonitriding One or More Steel Parts Under Low Pressure And At A High Temperature | |
| US4913749A (en) | Process for case-hardening rolling bearing elements of low-alloy nickeliferous steel | |
| JP4876668B2 (en) | Heat treatment method for steel members | |
| JP3009792B2 (en) | Continuous gas carburizing and quenching furnace | |
| JP3460075B2 (en) | Metal carburizing method | |
| JP2002180235A (en) | VACUUM CARBURIZING METHOD FOR Cr AND/OR Mn-CONTAINING STEEL PARTS | |
| KR100333199B1 (en) | Carburizing Treatment Method | |
| JP3990917B2 (en) | Oil quenching method for steel parts | |
| KR102494316B1 (en) | Gas carburizing method for reductions of raw materials of carburizing and grain boundary oxidation | |
| JP6935326B2 (en) | Gas carburizing method | |
| US5194096A (en) | Carburizing treatment of a steel with reduction of the hydrogen content in the carburized layer | |
| JPH01212748A (en) | Rapid carburizing treatment for steel | |
| CN114790536A (en) | Gear product carburizing process | |
| JPH10204608A (en) | Carburizing and quenching furnace | |
| JPS6214614B2 (en) | ||
| JP2000319723A (en) | Heat treatment of steel products | |
| JPH01290713A (en) | Heat treatment of metallic material | |
| KR20020056059A (en) | Surface hardening method of automotive transmission gear | |
| JP2002294429A (en) | Method and apparatus for carburizing and quenching | |
| JPH0345946Y2 (en) | ||
| JP2833051B2 (en) | Vacuum heat treatment method | |
| JP2004091900A (en) | Gas carburization method and gas carburization system | |
| JPH04293714A (en) | Hardening method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081203 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091203 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101203 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101203 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111203 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111203 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121203 Year of fee payment: 13 |
|
| EXPY | Cancellation because of completion of term |