JPH049402A - Method for executing reduction-annealing to metal powder - Google Patents
Method for executing reduction-annealing to metal powderInfo
- Publication number
- JPH049402A JPH049402A JP2108882A JP10888290A JPH049402A JP H049402 A JPH049402 A JP H049402A JP 2108882 A JP2108882 A JP 2108882A JP 10888290 A JP10888290 A JP 10888290A JP H049402 A JPH049402 A JP H049402A
- Authority
- JP
- Japan
- Prior art keywords
- reduction
- annealing
- powder
- preheating
- reaction
- 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.)
- Pending
Links
- 238000000137 annealing Methods 0.000 title claims abstract description 67
- 239000000843 powder Substances 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 41
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 18
- 239000002184 metal Substances 0.000 title claims abstract description 18
- 238000006722 reduction reaction Methods 0.000 claims abstract description 94
- 238000001816 cooling Methods 0.000 claims abstract description 18
- 230000002829 reductive effect Effects 0.000 claims abstract description 9
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 12
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 3
- 229910000423 chromium oxide Inorganic materials 0.000 claims description 3
- 230000001737 promoting effect Effects 0.000 claims description 3
- 229910000831 Steel Inorganic materials 0.000 abstract description 28
- 239000010959 steel Substances 0.000 abstract description 28
- 238000006243 chemical reaction Methods 0.000 abstract description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 17
- 239000007789 gas Substances 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 12
- 239000002994 raw material Substances 0.000 description 9
- 239000011651 chromium Substances 0.000 description 8
- 238000007796 conventional method Methods 0.000 description 8
- 229910052742 iron Inorganic materials 0.000 description 8
- 238000012545 processing Methods 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 7
- 235000013980 iron oxide Nutrition 0.000 description 7
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000009692 water atomization Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- UOUJSJZBMCDAEU-UHFFFAOYSA-N chromium(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[Cr+3].[Cr+3] UOUJSJZBMCDAEU-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- 229910002544 Fe-Cr Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、金属粉末の還元焼鈍方法に関し、とくに粉
末冶金等の原料となる低合金粉の如き金属粉末（以下は
「鋼粉」の例で述べる）を、炭素を予合金化させたアト
マイズ鉄粉などを原料にして、これを還元焼鈍すること
によって、効率的に得る新規な還元焼鈍技術について提
案するものである。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a reduction annealing method for metal powder, and in particular metal powder such as low alloy powder (hereinafter referred to as "steel powder") which is a raw material for powder metallurgy etc. This paper proposes a new reduction annealing technology that efficiently obtains the atomized iron powder (described in Section 2) by using atomized iron powder prealloyed with carbon as a raw material and subjecting it to reduction annealing.
（従来の技術）
従来、金属粉末とりわけ鋼粉の還元焼鈍では、原料鉄粉
として例えば水アトマイズ法で粉化させた生粉が使用さ
れ、そのための設備としてはベルト式ガス還元炉が適用
されてきた。(Prior art) Conventionally, in reduction annealing of metal powders, especially steel powders, raw powder powdered by water atomization, for example, has been used as the raw material iron powder, and a belt-type gas reduction furnace has been used as the equipment for this purpose. Ta.
最近に至ってはこうした鋼粉等に対する要求も一段と厳
しくなり、とくに合金成分を含有させた鋼粉の製造が望
まれるようになってきた。しかし、合金成分であるＭｎ
やＣｒ等、易酸化性合金成分を含有する鋼粉は、それを
水アトマイズ法を適用して製造した場合にＭｎやＣｒが
難還元性酸化物を成形するために従来のベルト式ガス還
元炉を用いて還元することは不可能だったのである。す
なわち、上記のような従来のガス還元炉では、炉温を１
０００℃以上に保持しなければならないこと、および低
露点低酸素雰囲気に保つことが工業的に困難であるとい
う理由による。Recently, the requirements for such steel powders have become even more severe, and in particular, it has become desirable to produce steel powders containing alloy components. However, the alloy component Mn
When steel powder containing easily oxidizable alloying components such as Mn and Cr is produced by applying the water atomization method, Mn and Cr form into refractory oxides using a conventional belt-type gas reduction furnace. It was impossible to reduce it using . In other words, in the conventional gas reduction furnace as described above, the furnace temperature is
This is because the temperature must be maintained at 000° C. or higher, and it is industrially difficult to maintain a low dew point, low oxygen atmosphere.
この点に関する先行文献として例えば特開昭５２−１０
０３０８号公報には、鉄系原料粉に、予め炭素を固溶さ
せるか、又は液体状もしくは粉末状の炭素源を添加混合
するかして、これを減圧雰囲気下で高温処理し鋼粉中の
酸素含有量を低下させる鉄系粉末の還元焼鈍方法が提案
されている。As a prior document on this point, for example, JP-A-52-10
Publication No. 0308 discloses that iron-based raw material powder is dissolved in carbon in advance, or a liquid or powdered carbon source is added and mixed, and then treated at high temperature in a reduced pressure atmosphere to improve the concentration of carbon in steel powder. Reductive annealing methods for iron-based powders have been proposed that reduce the oxygen content.
しかしながら、かかる従来技術の場合、原料鉄粉の昇温
、還元、冷却を一つの炉で行うバッチ方式であるため生
産性の点で劣るという不利があった。こうした欠点を克
服する試みとして、特開昭６１−１．９０００４号公報
には炉本体の内部構造に工夫を加えた還元焼鈍炉が開示
されている。However, in the case of such conventional technology, there is a disadvantage in that productivity is poor because it is a batch method in which heating, reduction, and cooling of raw material iron powder is performed in one furnace. In an attempt to overcome these drawbacks, Japanese Patent Application Laid-Open No. 1983-190004 discloses a reduction annealing furnace in which the internal structure of the furnace body is modified.
（発明が解決しようとする課題）
上記公報に開示の還元焼鈍炉は、炉本体を、含炭素原料
粉末を予熱・乾燥するための予熱室と、予熱・乾燥後の
原料粉末を含有炭素の利用によって脱酸、焼鈍するため
の還元焼鈍室および還元焼鈍室を経た粉末を冷却するた
めの冷却室とに区画して、これを横並びに連続配置し、
各室の境界にはそれぞれ可動扉を設けることにより各室
が独立した画成空間となるように構成し、かつそれら各
室にはそれぞれ減圧用排気装置を設けた構造のものであ
って、かかる装置によれば、とくに還元焼鈍室内を大気
圧から減圧する操作を繰り返す必要がなく連続的に原料
粉末を装入、取り出すことができハツチ方式に比較し生
産性を飛躍的に改善することができる。しかしながら、
上記の還元焼鈍炉を適用してたとえば水アトマイズ法で
製造された針粉を減圧高温下で還元焼鈍する場合に以下
に述べるような問題があったのである。(Problems to be Solved by the Invention) The reduction annealing furnace disclosed in the above publication includes a furnace body, a preheating chamber for preheating and drying carbon-containing raw material powder, and a carbon-containing raw material powder that is used after preheating and drying. divided into a reduction annealing chamber for deoxidizing and annealing and a cooling chamber for cooling the powder that has passed through the reduction annealing chamber, and these are arranged side by side in series,
A movable door is provided at the boundary of each room so that each room becomes an independent defined space, and each room is equipped with an exhaust device for depressurization. According to the device, there is no need to repeat the operation of reducing the pressure in the reduction annealing chamber from atmospheric pressure, and raw material powder can be continuously charged and taken out, dramatically improving productivity compared to the hatch method. . however,
When applying the above-mentioned reduction annealing furnace to reduction annealing needle powder produced by, for example, a water atomization method under reduced pressure and high temperature, there were problems as described below.
すなわち、従来要領に従えば鋼粉はまず予熱過程で鋼粉
の乾燥と次工程である還元焼鈍へ移行する前の予備加熱
として約８００″Ｃ未満で加熱され、次いで還元焼鈍過
程では該銅粉を一挙に１３００℃近傍まで加熱して還元
焼鈍を行っている。この還元焼鈍過程では、鉄酸化物等
の易還元性酸化物やクロム酸化物等の難還元性酸化物に
対してほぼ同時に還元反応を起こさせることになるが、
このような処理要領では還元時に生成するｃｏ、 ｃｏ
２ガスにより炉内のｃｏ、 ｃｏ□分圧が上昇すること
、及び炉内の真空度が低下することになって鋼粉の還元
反応速度が遅くなり、したがって処理時間の短縮による
生産性の、より一層の改善は望め得ながったのである。In other words, according to the conventional procedure, the steel powder is first heated to less than about 800"C in the preheating process to dry the steel powder and preheat before moving on to the next process, reduction annealing. Then, in the reduction annealing process, the copper powder is is heated all at once to around 1300°C to perform reduction annealing.In this reduction annealing process, easily reducible oxides such as iron oxides and difficult to reduce oxides such as chromium oxides are reduced almost simultaneously. This will cause a reaction, but
In such a processing procedure, the co generated during reduction, co
The 2 gases increase the partial pressure of co and co□ in the furnace, and the degree of vacuum in the furnace decreases, slowing down the reduction reaction rate of the steel powder, thus reducing productivity by shortening processing time. Further improvement could not be expected.
ここに、上記の構成になる還元焼鈍炉における銅粉の処
理トータル時間（予熱−ト還元焼鈍→冷却）は各工程が
バッチ移動式であるため、主目的である鋼粉の還元焼鈍
での処理時間が一番長くこれに併せて予熱時間および冷
却時間が決定される。Here, the total processing time of copper powder in the reduction annealing furnace with the above configuration (preheating - reduction annealing → cooling) is shorter than the main purpose of reduction annealing of steel powder, since each process is a batch transfer type. The time is the longest, and the preheating time and cooling time are determined accordingly.
この発明の目的は、鋼粉を予熱工程、還元焼鈍工程、さ
らに冷却工程を通して還元焼鈍する際に生じる上述の如
き問題を解消して生産性のより一層の改善を図ることが
できる新規な還元焼鈍方法を提案することにある。The purpose of this invention is to provide a novel reduction annealing method that can solve the above-mentioned problems that occur when steel powder is subjected to reduction annealing through a preheating process, a reduction annealing process, and a cooling process, thereby further improving productivity. The goal is to propose a method.
（課題を解決するための手段）
この発明は、金属粉末を減圧雰囲気下で予熱、還元焼鈍
及び冷却の各工程を通して還元焼鈍するに当たり、上記
金属粉末の予熱過程で、雰囲気温度を調整して該金属粉
末の乾燥を行うとともに主として鉄酸化物等の易還元性
酸化物の還元反応を促進させ、次いで上記金属粉末の還
元焼鈍工程では雰囲気温度の調整にて主としてクロム酸
化物等の難還元性酸化物の還元反応を促進させることを
特徴とする金属粉末の還元焼鈍方法であり、ここにこの
発明では、予熱の際の雰囲気温度は８００〜１０００℃
の範囲に、また還元焼鈍の際の雰囲気温度ニツイてハ１
０００〜１４００’Ｃの範囲に調整するものとする。(Means for Solving the Problems) This invention provides reduction annealing of metal powder through the steps of preheating, reduction annealing, and cooling in a reduced pressure atmosphere, by adjusting the ambient temperature during the preheating process of the metal powder. While drying the metal powder, the reduction reaction of easily reducible oxides such as iron oxide is promoted, and then in the reduction annealing process of the metal powder, the atmospheric temperature is adjusted to reduce the reductive reaction of mainly reducible oxides such as chromium oxide. This is a reduction annealing method for metal powder characterized by promoting the reduction reaction of a substance, and in this invention, the ambient temperature during preheating is 800 to 1000°C.
within the range of 1, and the atmospheric temperature during reduction annealing.
It shall be adjusted to a range of 000 to 1400'C.
なお、この発明において易還元性酸化物とは、Ｃｕ、
Ｆｅ、 ＣｏあるいはＭｏ等の酸化物であり、また難還
元性酸化物とはＭｎ、 Ｃｒ、 Ｓｉ、 Ｎｂあるいは
Ｂ等の酸化物である。In addition, in this invention, easily reducible oxides include Cu,
These are oxides of Fe, Co, Mo, etc., and the refractory oxides are oxides of Mn, Cr, Si, Nb, B, etc.
（作 用）
鋼粉の予熱過程で雰囲気温度を８００〜１０００″Ｃに
保持すると、主として生成エネルギーの低い鉄系酸化物
の還元反応のみを起こさせることができ、その際の反応
によって生成されるｃｏやｃｏ２ガスの発生量はＣｒ酸
化物などの難還元性酸化物の還元反応が起こらない分少
なく、したがって炉内のＣＯやＣＯ□分圧も下がり還元
反応速度が高まり、予熱工程で主として鉄酸化物の還元
反応を終了させることができる。(Function) If the ambient temperature is maintained at 800 to 1000"C during the preheating process of steel powder, only the reduction reaction of iron-based oxides, which have a low production energy, can occur, and the The amount of CO and CO2 gas generated is small because the reduction reaction of refractory oxides such as Cr oxides does not occur, so the partial pressure of CO and CO□ in the furnace decreases and the reduction reaction rate increases, and the preheating process mainly removes iron. The reduction reaction of the oxide can be terminated.
また還元焼鈍過程において、その雰囲気温度を１ｏｏｏ
’ｃ以上に保持すると、釦粉中に残っている主としてＣ
ｒ酸化物等、難還元性酸化物の還元反応が起こることに
なる。この際の反応によって生成されるＣ０１ＣＯ□ガ
スの発生量は鉄系酸化物の還元反応が起こらない分少な
く、したがって炉内のＣ０１ＣＯ２分圧も下がり還元反
応速度も高まる。In addition, in the reduction annealing process, the ambient temperature is set to 100
'C or higher, the remaining C in the button powder is mainly
A reduction reaction of refractory oxides such as r-oxides will occur. The amount of C01CO□ gas generated by this reaction is small because the reduction reaction of the iron-based oxide does not occur, and therefore the partial pressure of C01CO2 in the furnace also decreases and the rate of the reduction reaction increases.
従来法によれば、鋼粉の鉄酸化物等の易還元性酸化物と
クロム酸化物等の難還元性酸化物の還元反応を、予熱工
程に引き続く還元焼鈍の加熱工程で同時に起こさせてい
たために加熱工程に要する処理時間が長く１．これに律
速する予熱工程、冷却！程を含めたトータル時間が増大
し生産性の向上を阻む原因となっていたが、この発明で
は、予熱工程で主として鉄酸化物の易還元性酸化物の還
元焼鈍を終了させるようにし、加熱過程でＣｒ酸化物等
の難還元性酸化物の還元焼鈍を行うようにしたから、銅
粉処理のトータル時間を短縮することができ、したがっ
て生産性の効果的な改善を図るとこができるのである。According to the conventional method, the reduction reaction of easily reducible oxides such as iron oxides and hard-to-reducible oxides such as chromium oxides in steel powder occurs simultaneously in the heating process of reduction annealing that follows the preheating process. 1. The processing time required for the heating process is long. This is the rate-limiting preheating process and cooling! However, in this invention, the preheating process mainly finishes the reduction annealing of the easily reducible oxide of iron oxide, and the heating process increases. Since the reduction annealing of a hard-to-reducible oxide such as Cr oxide is performed in the process, the total time for copper powder treatment can be shortened, and productivity can therefore be effectively improved.
この発明で予熱工程における雰囲気温度を８００〜１０
００℃としたのは、鉄酸化物等の易還元性酸化物の還元
反応を起こさせるためには少なくとも８００゛Ｃ以上に
する必要があるからであり、一方ｌ０００”Ｃを超える
と昇温に時間がかかり却って処理時間が延び、また予熱
室内への鋼粉を装入する際大気開放となるので、その際
の鋒温大きく炉壁や加熱ヒータ等の損傷を招く他、エネ
ルギーロスも大きくなる不利があるからである。In this invention, the ambient temperature in the preheating process is set to 800 to 10
The reason for setting the temperature at 00°C is that the temperature needs to be at least 800°C or higher in order to cause a reduction reaction of easily reducible oxides such as iron oxides. In fact, the processing time is prolonged, and since the steel powder is charged into the preheating chamber, it is exposed to the atmosphere, which increases the temperature of the steel and causes damage to the furnace walls, heaters, etc., and also increases energy loss. This is because there are disadvantages.
また、還元焼鈍工程における雰囲気温度を１０００〜１
４００℃とたのは、ＣｒＭ化物等の難還元性酸化物の還
元反応を促進するためには少なくとも１０００℃に加熱
する必要があるからであり、雰囲気温度が１４００℃を
超えると過焼結となって粉末製造時の還元粉末の解砕負
荷が大きくなるからである。In addition, the atmospheric temperature in the reduction annealing process was set to 1000 to 1
The reason for setting the temperature at 400°C is that heating to at least 1000°C is necessary to promote the reduction reaction of refractory oxides such as CrM compounds, and if the ambient temperature exceeds 1400°C, oversintering may occur. This is because the crushing load of the reduced powder during powder production becomes large.
第１図は、Ｆ６−Ｃｒ合金鋼粉の製造を対象にして、こ
の発明に従って還元焼鈍を行った実験（実験ｌ）のヒー
トパターンを、また第２図はその際の圧カバターンを示
すグラフである。Figure 1 shows the heat pattern of an experiment (experiment 1) in which reduction annealing was performed according to the present invention for the production of F6-Cr alloy steel powder, and Figure 2 is a graph showing the pressure cover turn at that time. be.
この発明とこ従い予熱過程で雰囲気温度を８００〜１０
００’ＣＯ間で保持することムこより、釦粉中の主とと
、て鉄酸化物の還元反応が起こり、この際乙こ発生する
ｃｏ、 ｃｏ□ガスにより復圧現象がみられ、引き続く
還元焼鈍の加熱過程においてその雰囲気温度を１０００
℃以上に保持することにより、残りのＣｒ酸化物の還元
を主体とじた反応が起こり、この際発生ｌ、またＣ０２
ｅｏｚガスによる復圧現象（門ａｘ：ｏ、３−０．７Ｔ
ｏｒｒ）がみられるが、そのピークは従来法に従うより
も約Ｑ、４ Ｔｏｒｒはと低く、加熱開始時の圧力に戻
るまでの加熱時間は３．４時間であった。According to this invention, the ambient temperature in the preheating process is 800 to 10
By maintaining the temperature between 00'CO and 20%, a reduction reaction between iron oxide and the main body in the button powder occurs, and a pressure recovery phenomenon is observed due to the CO and CO gases generated at this time, and the subsequent reduction occurs. During the heating process of annealing, the ambient temperature is set to 1000℃.
By keeping the temperature above ℃, a reaction mainly consisting of the reduction of the remaining Cr oxide occurs, and at this time, the generated l and CO2
Repressurization phenomenon due to eoz gas (gate ax: o, 3-0.7T
orr), but the peak was about Q, 4 Torr lower than that according to the conventional method, and the heating time until the pressure returned to the pressure at the start of heating was 3.4 hours.
上記の結果を従来法と比較するために行った実験（実験
−２）における還元焼鈍のヒートパターンと圧カバター
ンをそれぞれ第３図及び第４図に示す。The heat pattern and pressure cover turn of reduction annealing in an experiment (experiment-2) conducted to compare the above results with the conventional method are shown in FIGS. 3 and 4, respectively.
従来法に従い予熱過程で、鋼粉の予熱、乾燥を目的とし
て８００℃未満で予熱した場合では還元反応によって発
生するＣｏ、 Ｃｏ２ガスによる復圧現象が起こらない
（還元反応が起こっていないことを示ず）が、還元焼鈍
のための加熱過程ムこおいては、その雰囲気温度を１０
００’Ｃとするために、鋼粉の鉄酸化物、Ｃｒ酸化物等
の還元が起こり、その反応によって発生するＣ０１ＣＯ
□ガスにょる復圧現象（Ｍａｘ：０．６〜１．０ Ｔｏ
ｒｒ）が起こった。特にＦｅ−Ｃｒ系合金鋼粉の場合で
は脱酸、脱炭をある一定レベルまで行うには、還元反応
が終了した段階、すなわち発生ガスによる復圧現象がな
くなり、元の加熱開始時の圧力レベルに戻る点まで、保
持する必要があり、これにかかる時間は約４時間程であ
った。In the preheating process according to the conventional method, if the steel powder is preheated to less than 800℃ for the purpose of preheating and drying, the pressure back phenomenon due to Co and Co2 gas generated by the reduction reaction does not occur (indicating that the reduction reaction is not occurring). However, during the heating process for reduction annealing, the ambient temperature is set to 10
In order to achieve 00'C, reduction of iron oxides, Cr oxides, etc. in steel powder occurs, and CO1CO generated by the reaction occurs.
□Repressure phenomenon caused by gas (Max: 0.6~1.0 To
rr) happened. In particular, in the case of Fe-Cr alloy steel powder, in order to perform deoxidation and decarburization to a certain level, it is necessary to complete the reduction reaction at the stage where the pressure back phenomenon caused by the generated gas has disappeared and the pressure has returned to the original pressure level at the start of heating. It was necessary to hold it until the point where it returned to , and this took about 4 hours.
以上の結果からこの発明に従う場合、還元焼鈍炉におけ
る生産性は従来法に比較し、
（（４，ＯＨｒ／９イクル／３．４Ｈｒ／９イクル）−
１１ｘｌｏＯ＝１７．６％向上した。From the above results, when this invention is followed, the productivity in the reduction annealing furnace is ((4,OHr/9 cycles/3.4Hr/9 cycles) -
11xloO=17.6% improvement.
第５図は、この発明に用いて好適な還元焼鈍炉の一例を
示すものであって、図中の１は予熱室、２は還元焼鈍室
、３は冷却室、４は予熱室１へ通じる入口扉、５．６は
各空間へ通じる可動扉、７はトレイそして８は受皿であ
る。FIG. 5 shows an example of a reduction annealing furnace suitable for use in the present invention, in which 1 is a preheating chamber, 2 is a reduction annealing chamber, 3 is a cooling chamber, and 4 is connected to the preheating chamber 1. An entrance door, 5.6 is a movable door leading to each space, 7 is a tray, and 8 is a saucer.
原料となる金属粉末（ｆｉｔ粉）は、受皿８に収容され
この受皿８とともにトレイ７に装てん、炉の入口扉４を
経て予熱室１にて、鋼粉中の易還元性酸化物の還元反応
を促進させ、次いで可動扉５を経て還元焼鈍室２にて、
主に難還元性酸化物の還元反応を促進させるように、そ
して可動扉６を経て冷却室３にて冷却後、得られた焼結
鋼粉の解砕によって製品鋼粉とされる。The metal powder (fit powder) serving as the raw material is stored in a tray 8 and loaded into the tray 7 together with the tray 8, and then passed through the inlet door 4 of the furnace to the preheating chamber 1 where it undergoes a reduction reaction of easily reducible oxides in the steel powder. is promoted, and then passes through the movable door 5 to the reduction annealing chamber 2.
After being cooled in the cooling chamber 3 via the movable door 6 so as to mainly promote the reduction reaction of the refractory oxides, the obtained sintered steel powder is crushed into product steel powder.
（実施例）
炭素で予合金化したＣ：０．５ｗｔ％、Ｏ： ０．９
ｗｔ％、Ｍｎ ： ０．７ ｗｔ％、Ｃｒ ： １．Ｏ
ｗｔ％、Ｆｅ ： Ｂａ１ａｎｃｅの組成になるアトマ
イズ鋼粉（水アトマイズ法）を、上掲第５図に示した構
成になる還元焼鈍炉を用いて処理した。このとき予熱室
の最高温度を９００℃に保持したが、その際発生した還
元反応生成ガスによって０．４ Ｔｏｒｒまで復圧現象
が見られ、主として易還元性酸化物の還元反応が起こっ
ていることが確認できた。また還元焼鈍室においては最
高温度を１２００’Ｃに保持したところ、その際に発生
する還元反応生成ガスによりＱ、４ Ｔｏｒｒまで復圧
現象が見られ、主に難還元性酸化物の還元反応が起こっ
ているが確認された。このときの復圧現象のピークは、
従来法に従うよりも０．３〜０．６ Ｔｏｒｒ程度低く
、また加熱開始時の圧力である０、０１Ｔｏｒｒに再び
戻るまでの時間（還元焼鈍室での還元時間）は３．４時
間であって従来よりも０．６時間程短縮された。この結
果、還元焼鈍室での加熱時間に応じて設定される予熱、
冷却工程での処理時間はそれぞれ３．４時間ノサイクル
に短縮することができ、還元焼鈍炉での生産性は、従来
法に従うよりも１７，６％はど向上することが確かめら
れた。なお、還元焼鈍後の鋼粉の組成について調査した
ところ、Ｃ：０．００５ ｗｔ％、Ｏ：０．Ｏｈｔ％、
ＦＩｎ ： ０．７ ｗｔ％、Ｆｅ：Ｂａ１ａｎｃｅで
あった。(Example) Prealloyed with carbon: C: 0.5 wt%, O: 0.9
wt%, Mn: 0.7 wt%, Cr: 1. O
Atomized steel powder (water atomization method) having a composition of wt%, Fe:Ba1ance was treated using a reduction annealing furnace configured as shown in FIG. 5 above. At this time, the maximum temperature of the preheating chamber was maintained at 900°C, but a pressure return phenomenon was observed to 0.4 Torr due to the reduction reaction product gas generated at that time, indicating that the reduction reaction of mainly easily reducible oxides was occurring. was confirmed. In addition, when the maximum temperature was maintained at 1200'C in the reduction annealing chamber, a pressure recovery phenomenon was observed up to Q,4 Torr due to the gas generated by the reduction reaction, and the reduction reaction of refractory oxides was observed. Confirmed happening. The peak of the pressure recovery phenomenon at this time is
It is about 0.3 to 0.6 Torr lower than that according to the conventional method, and the time it takes to return to 0.01 Torr, which is the pressure at the start of heating (reduction time in the reduction annealing chamber), is 3.4 hours. This is about 0.6 hours shorter than before. As a result, preheating is set according to the heating time in the reduction annealing chamber.
It was confirmed that the processing time in the cooling step could be shortened to 3.4 hours per cycle, and the productivity in the reduction annealing furnace was improved by 17.6% compared to the conventional method. In addition, when the composition of the steel powder after reduction annealing was investigated, it was found that C: 0.005 wt%, O: 0. Oht%,
Fin: 0.7 wt%, Fe:Ba1ance.
（発明の効果）
かくしてこの発明によれば、金属粉末の還元焼鈍におい
て、該粉末中の易還元性酸化物の還元反応過程と難還元
性酸化物の反応過程とを分離したので、とくに炉の還元
焼鈍室における処理時間が短縮され、その結果従来還元
焼鈍に律速しでいた予熱、冷却工程での処理時間につい
ても短縮され、これによって生産性の大幅な改善を図る
ことができた。(Effects of the Invention) Thus, according to the present invention, in the reduction annealing of metal powder, the reduction reaction process of the easily reducible oxide and the reaction process of the hard to reduce oxide in the powder are separated, so that the reduction annealing process is particularly effective in the furnace. The processing time in the reduction annealing chamber was shortened, and as a result, the processing time in the preheating and cooling steps, which were rate-limiting in conventional reduction annealing, was also shortened, making it possible to significantly improve productivity.
第１図はこの発明に従った還元焼鈍炉におけるヒートパ
ターンの一例を示したグラフ
第２図はこの発明に従った還元焼鈍炉における圧カバタ
ーンの一例を示したグラフ
第３図は従来法に従った還元焼鈍炉におけるヒートパタ
ーンの一例を示したグラフ
第４図は従来法に従った還元焼鈍炉における圧カバター
ンの一例を示したグラフ
第５図はこの発明に用いて好適な還元焼鈍炉の構成説明
図である。
１・・・予熱室 ２・・・還元焼鈍室３・・
・冷却室 ４・・・入口扉５．６・・・可動
扉 ７・・・トレイ８・・・受皿
第１図
第２図
第３図
第４図
Ｓ！！ Ｍ （Ｈｒ＞
第５ＮFIG. 1 is a graph showing an example of a heat pattern in a reduction annealing furnace according to the present invention. FIG. 2 is a graph showing an example of a pressure cover turn in a reduction annealing furnace according to the invention. FIG. Figure 4 is a graph showing an example of a heat pattern in a reduction annealing furnace according to the conventional method. Figure 5 is a graph showing an example of a pressure cover turn in a reduction annealing furnace according to the conventional method. It is an explanatory diagram. 1... Preheating chamber 2... Reduction annealing chamber 3...
・Cooling room 4...Entrance door 5.6...Movable door 7...Tray 8...Saucer Figure 1 Figure 2 Figure 3 Figure 4 S! ! M (Hr> 5th N
Claims (1)
の各工程を通して還元焼鈍するに当たり、 上記金属粉末の予熱工程で、該金属粉末の乾燥を行うと
ともに主として鉄酸化物等の易還元性酸化物の還元反応
を促進させ、次いで上記金属粉末の還元焼鈍工程では主
としてクロム酸化物等の難還元性酸化物の還元反応を促
進させることを特徴とする金属粉末の還元焼鈍方法。 ２、予熱の際の雰囲気温度を８００〜１０００℃の範囲
に、また還元焼鈍の際の雰囲気温度を１０００〜１４０
０℃の範囲に調整する請求項１記載の方法。[Claims] 1. In reduction annealing the metal powder through the steps of preheating, reduction annealing, and cooling in a reduced pressure atmosphere, in the preheating step of the metal powder, the metal powder is dried and mainly iron oxide is Reduction annealing of metal powder characterized by promoting the reduction reaction of easily reducible oxides such as chromium oxide, etc., and then promoting the reduction reaction of hardly reducible oxides such as chromium oxide in the reduction annealing step of the metal powder. Method. 2. Set the ambient temperature during preheating to a range of 800 to 1000°C, and set the ambient temperature during reduction annealing to 1000 to 140°C.
The method according to claim 1, wherein the temperature is adjusted to a range of 0°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2108882A JPH049402A (en) | 1990-04-26 | 1990-04-26 | Method for executing reduction-annealing to metal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2108882A JPH049402A (en) | 1990-04-26 | 1990-04-26 | Method for executing reduction-annealing to metal powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH049402A true JPH049402A (en) | 1992-01-14 |
Family
ID=14495985
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2108882A Pending JPH049402A (en) | 1990-04-26 | 1990-04-26 | Method for executing reduction-annealing to metal powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH049402A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04136101A (en) * | 1990-09-27 | 1992-05-11 | Kawasaki Steel Corp | Method for finish-reducing alloy steel powder |
| WO2012127760A1 (en) * | 2011-03-23 | 2012-09-27 | Ｊｆｅスチール株式会社 | Method of finish heat treatment of iron powder and apparatus for finish heat treatment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61190004A (en) * | 1985-02-18 | 1986-08-23 | Kawasaki Steel Corp | Reduction annealing furnace of metallic powder |
| JPS6425901A (en) * | 1987-07-17 | 1989-01-27 | Kobe Steel Ltd | Production of low alloy steel powder for low c and low o powder metallurgy |
-
1990
- 1990-04-26 JP JP2108882A patent/JPH049402A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61190004A (en) * | 1985-02-18 | 1986-08-23 | Kawasaki Steel Corp | Reduction annealing furnace of metallic powder |
| JPS6425901A (en) * | 1987-07-17 | 1989-01-27 | Kobe Steel Ltd | Production of low alloy steel powder for low c and low o powder metallurgy |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04136101A (en) * | 1990-09-27 | 1992-05-11 | Kawasaki Steel Corp | Method for finish-reducing alloy steel powder |
| WO2012127760A1 (en) * | 2011-03-23 | 2012-09-27 | Ｊｆｅスチール株式会社 | Method of finish heat treatment of iron powder and apparatus for finish heat treatment |
| JP2012211383A (en) * | 2011-03-23 | 2012-11-01 | Jfe Steel Corp | Method and apparatus for finish heat treatment of iron powder |
| US9321103B2 (en) | 2011-03-23 | 2016-04-26 | Jfe Steel Corporation | Finish heat treatment method and finish heat treatment apparatus for iron powder |
| US9815115B2 (en) | 2011-03-23 | 2017-11-14 | Jfe Steel Corporation | Finish heat treatment method and finish heat treatment apparatus for iron powder |
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