JPH0568522B2 - - Google Patents
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- Publication number
- JPH0568522B2 JPH0568522B2 JP59261983A JP26198384A JPH0568522B2 JP H0568522 B2 JPH0568522 B2 JP H0568522B2 JP 59261983 A JP59261983 A JP 59261983A JP 26198384 A JP26198384 A JP 26198384A JP H0568522 B2 JPH0568522 B2 JP H0568522B2
- Authority
- JP
- Japan
- Prior art keywords
- low
- powder
- iron powder
- alloy iron
- sintered
- 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.)
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 70
- 229910045601 alloy Inorganic materials 0.000 claims description 58
- 239000000956 alloy Substances 0.000 claims description 58
- 238000000034 method Methods 0.000 claims description 34
- 229910052759 nickel Inorganic materials 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000011812 mixed powder Substances 0.000 claims description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims description 8
- 230000009467 reduction Effects 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 5
- 229910017116 Fe—Mo Inorganic materials 0.000 claims description 4
- 230000001590 oxidative effect Effects 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 2
- 230000008569 process Effects 0.000 claims description 2
- 238000010298 pulverizing process Methods 0.000 claims description 2
- 239000000843 powder Substances 0.000 description 39
- 239000000463 material Substances 0.000 description 32
- 238000005275 alloying Methods 0.000 description 21
- 239000002994 raw material Substances 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- 238000005245 sintering Methods 0.000 description 8
- 238000005728 strengthening Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 238000005056 compaction Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910001182 Mo alloy Inorganic materials 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 238000011946 reduction process Methods 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010835 comparative analysis Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 description 1
Landscapes
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Description
〔産業上の利用分野〕
本発明は、低合金鉄粉の製造方法に関し、詳し
くは、従来から存在する市販の低合金鉄粉に近似
した組成でありながら、焼結材料としての強度を
著しく向上させるとともに、圧粉成形性をも優れ
たものとすることのできる低合金鉄粉の製造方法
にかかる。
〔従来の技術〕
焼結材料の高強度化に対する要望が近年ますま
す強まつてきている。
このような焼結材料の高強度化要求に対して、
合金化、高密度化、均質化等の手段による強度の
優れた焼結材料の開発がなされている。
そして、焼結材料の合金化することによる強化
方向としては、Cu、Ni、Mo、Mn、Cr等の合金
元素を混合法もしくは予備合金法等によつて、鉄
中び固溶させて強化する方法が主として採用され
ている。
また、高密度化による焼結材料の強化方法とし
ては、２回プレス−２回焼結法や焼結鍛造法等が
採用されている。
この他、高温焼結による焼結材料の均質化、空
孔の球状化等による焼結材料の強化方法も採用さ
れている。
しかしながら、上述のような焼結材料と強化方
法は、いずれも、焼結材料の強度向上に有効であ
るとともに、短所も有しており解決すべき問題点
も少なくない。
即ち、合金化による焼結材料の強化方法におい
ては、混合法と予備合金法が通常採用されてい
る。
そして、混合法による焼結材料の強化方法にお
いては、添加した合金元素を充分に鉄中に拡散さ
せるためには長時間の焼結を必要とし、また、活
性元素であるCr、Mo等を使用する場合において
は、焼結雰囲気を厳密にコントロールしないと酸
化反応を引き起こして拡散反応を阻害するという
問題点があつた。
一方、予備合金化による焼結材料の強化方法に
おいては、原料粉末の合金化に伴い粉末冶金用金
属粉末原料の硬さが上昇して圧粉成形性を低下
し、従つて、圧粉成形対の高密度化を阻害するこ
ととなつて、原料粉末の圧粉成形性を改善するこ
とが必要となる。
また、高密度化にる焼結材料の強化方法である
２回プレス−２回焼結法よ焼結鍛造法等において
は、製造プロセスを変更・追加して強加工（圧
縮）を実施することにより、焼結材料の高密度化
を達成するものであり、この方法においては焼結
材料の製造工程が複雑となつて、強加工時におけ
る雰囲気、温度設定等の条件を充分に管理すべき
工程が増加するばかりでなく、製造コストの大幅
な上昇が避けられない。
ところで、上述した従来の問題点に対する解決
方法の１つとして、原料粉末の予備合金化による
圧粉成形性の低下に対して、その改善を図るため
には種々の提案がなされている。
例えば、合金元素を特殊還元法により低合金鉄
粉の表面に付着させる「低合金粉末鉄の製法」
（特公昭45−9649号）や、従来の焼結鍛造用低合
金講粉の焼入性を改善するとともに、芯部の焼入
硬度を高めるために寄与するCuと焼入性向上効
果の高いMoを主添加元素とした「高密度焼結鋼
用鋼粉」（特開昭50−26705号）等である。
しかしながら、前者は圧粉成形性は改善される
ものの、原料粉末自体の価格が市販の低合金鋼粉
に比較して相当に高価となつており、後者におい
ては比較的多量のCuを添加しているため、その
製造工程における条件を厳しく管理する必要があ
ることから、市販の低合金鉄粉に比較すると原料
粉末の価格の高騰が避けられない。
上述のように、圧粉成形性に優れた予備合金化
された原料粉末は、現在いくつかのものが市販さ
れているものの、いずれも、原料粉末自体の価格
が非常に高くなり、製造コストに占める原料粉末
コストの比率の高い焼結材料部品においては、適
用範囲の拡大を図る上で大きな障害となつてい
る。
ところで、本発明法は各種合金化元素のを圧粉
成形性への寄与率の関係、合金化元素と焼入性、
合金化元素とその原料粉末を使用して製造された
焼結体における機械的性質との関係、合金化元素
の添加量と強度との関係等について詳細に検討し
た結果、得られた知見に基づいて発明されたもの
である。
即ち、低合金鉄粉に主として使用されるMo、
Mn、Cr、Ni等の合金元素とその添加方法（予備
合金化もしくはブレンド）について種々検討した
結果、最終組成は近似していながら添加方法を改
善することにより、得られる焼結材料の強度に著
しく大きな差を生じることを発見し、この点に注
目して研究を重ねた結果、本発明を完成するに至
つたものである。
〔発明が解決しようとする問題点〕
上述のような従来の技術の現状に鑑み、本発明
が解決しようとする問題点は、従来において市販
されている従来の低合金鉄粉は、その低合金鉄粉
を用いて製造した焼結材料の強度を優れたものと
すれば圧粉成形性を低下させることとなり、低合
金鉄粉を用いて製造した焼結材料の強度と同時に
予備合金法等により圧粉成形性を改善した従来の
低合金鉄粉は、焼結材料用粉末として著しく高価
となつていたということである。
従つて、本発明の技術的課題とするところは、
低合金鉄粉における合金元素の添加方法の改善に
よつて、従来から存在する市販の低合金鉄粉に近
似化した組成であり、比較的低価格な低合金鉄粉
でありながら、その低合金鉄粉を用いて製造した
焼結材料の強度を著しく向上させるとともに、圧
粉成形性に優れた低合金鉄粉とすることにある。
〔問題点を解決するための手段〕
このような従来の技術における問題点に鑑み、
本発明における従来の技術の問題点を解決するた
めの手段は、重量比率にて、Ｃ；0.05％以下、
Mo；0.2〜2.0％、O2；0.5〜2.0％、残部Feと不可
避の不純物からなり、MoがFe−Mo合金状態を
なして含有されている低合金鉄粉を使用し、
この低合金鉄粉に対して0.5〜4.0％のNiもしく
はNi酸化物を添加・混合する工程と、
上述により混合された混合粉末を非酸化性雰囲
気にて、800〜1000℃×20〜120分間の加熱後除冷
する還元工程と、
上述の還元工程により形成された、低合金鉄粉
のケーキ状に擬似焼結された集合体を粉砕する工
程とからなり、
重量比率にて、Ｃ；0.05％以下、Mo；0.2〜2.0
％、O2；0.20％以下、Ni；0.5〜4.0％、残部Feと
２％以下の不可避の不純物からなる、低合金鉄粉
とすることを特徴とする低合金鉄粉の製造方法か
らなつている。
〔作用〕
以下、本発明の作用について説明する。
本発明において、原料粉末を、重量比率にて
Ｃ；0.05％以下、Mo；0.2〜2.0％、O2；0.20％以
下、Ni；0.5〜4.0％、残部Feと２％以下の不可避
の不純物からなる組成の低合金鉄粉としているの
は、従来市販されている低合金鉄粉と近似した組
成とすることによつて、比較的低価格な低合金鉄
粉とするとともに優れた圧粉成形性を確保するた
めである。
次に、本発明法により製造された低合金鉄粉に
おける組成を、上述の範囲に限定した理由につい
て説明する。
なお、以下の説明において、各合金元素の添加
量はいずれも重量％により表示する。
Ｃは添加量が多くなると圧粉成形性を著しく低
下させることから0.05以下とするのが望ましい。
また、Moは熱処理性（焼入性）を改善する合
金元素として有効であるが、0.2％未満ではその
改善効果が充分でなく、2.0％を越えるとその添
加量に見合つた改善効果の向上が見られないばか
りでなく、代えつて低合金鉄粉の圧粉成形性を悪
化するとともに、低合金鉄粉のコストを高騰させ
ることから0.2〜2.0％とした。
また、Niは熱処理性（焼入性）及び靭性を改
善することから有効であるが、0.5未満ではその
改善効果が充分でなく、4.0％を越えるとその添
加量に見合つた改善効果の向上が見られないこと
から0.5〜4.0％とした。
また、含有O2は圧粉成形性及び熱処理性に対
して著しく悪影響を及ぼすことから、0.2％以下
を抑える必要がある。
即ち、本発明法により製造された低合金鉄粉は
合金元素としてMoとNiを含有したものであつて
これらの合金元素の存在形態により、特に、熱処
理状態における焼結材料の強度に大きな相違を生
ずることを発見し、その知見に基づいて、まず、
Moを予備合金代法により合金化し、ついで、Ni
を前記Fe−Mo予備合金粉末と混合した後、還元
処理することにより、焼結材料の熱処理状態の強
度を最大とすることができることに基づいて発明
されたものである。
また、本発明において、低合金鉄粉にNiもし
くはNi酸化物の混合された混合粉末を非酸化性
雰囲気中にて、800〜1000℃×20〜120分間の加熱
後除冷するととしているのは、混合粉末の焼鈍、
混合粉末中におけるO2含有量の低減及びNiの添
加をNi酸化物にて行つた場合においては、酸化
物を還元して合金Niとするためである。
また、本発明法において、還元工程における温
度はFe−Mo水噴霧粉の酸化物の除去と焼鈍及び
NiOによりNiを添加した場合におけるNiOを還
元するとともに、含有O2量を0.2％以下に抑える
ために800〜1000℃とするのが望ましい。
これは、還元工程における温度が1000℃を越え
ると、低合金鉄粉同士の焼結反応が進行して、還
元工程において形成された低合金鉄粉のケーキ状
に擬似焼結された集合体の粉砕が困難となるから
である。
また、還元工程における加熱保持時間について
も、上述の加熱温度と同様な理由から20〜120分
とするのが望ましい。
〔実施例〕
以下、表に基づいて、本発明の１実施例を説明
する。
まず、本発明材は、重量比率にて0.02％Ｃ−
0.5％Mo−0.92％O2−BalFeからなり、MoがFe
−Mo合金状態をなして含有されている低合金鉄
粉を水噴霧法により製造した。
ついで、この低合金鉄粉に対して重量比率にて
２％のカーボニルNi粉末を添加した後、Ｖ型混
粉機により混粉した。
この混合粉末をアンモニア分解ガス雰囲気中に
て、900℃×30分間加熱後除冷して、低合金鉄粉
のケーキ状に擬似焼結された集合体とした後ハン
マーミルにて粉砕した。
上述により製造された低合金鉄粉の化学成分を
第１表に示す。
次に、本発明材は、重量比率にて0.02％Ｃ−
1.1％Mo−0.8O2−BalFeからなり、MoがFe−
Mo合金状態をなして含有させている低合金鉄粉
を水噴霧法により製造した。
ついで、この低合金鉄粉に対して重量比率にて
2.5％のNiO粉末を添加した後、Ｖ型混粉機によ
り混粉した。
この混合粉末をアンモニア分解ガス雰囲気中に
て、950℃×90分間加熱還元した後除冷して、低
合金鉄粉のケーキ状に擬似焼結された集合体とし
た後ハンマーミルにて粉砕した。
上述により製造された低合金鉄粉の化学成分を
第１表に示す。
次に、比較材として、本発明材と化学成分
の近似した市販の低合金鉄粉を使用した。
その化学成分を第１表に示す。
また、比較材として、重量比率にて0.02％Ｃ
−1.9％Ni−0.8％O2−BalFeからなる低合金鉄粉
を水噴霧法により製造した。
ついで、この低合金鉄粉に対して重量比率にて
0.5％のMo粉末を添加した後、Ｖ型混粉機により
混粉した。
この混粉粉末をアンモニア分解ガス雰囲気中に
て、900℃×30分間加熱還元した後除冷して、低
合金鉄粉のケーキ状に擬似焼結された集合体とし
た後のハンマーミルにて粉砕した。
上述により製造された低合金鉄粉の化学成分を
第１表に示す。
また、比較材として、市販の純鉄粉末とNi
粉末とMo粉末とを添加した後、Ｖ型混粉機によ
り混粉した。
上述により製造された低合金鉄粉の化学成分を
第１表に示す。
[Industrial Application Field] The present invention relates to a method for producing low-alloy iron powder, and more specifically, the present invention relates to a method for producing low-alloy iron powder, which has a composition similar to conventional commercially available low-alloy iron powder, but has significantly improved strength as a sintered material. The present invention relates to a method for producing low-alloy iron powder that can improve the powder compaction properties as well as provide excellent compaction properties. [Prior Art] In recent years, there has been an increasing demand for higher strength sintered materials. In response to the demand for higher strength of sintered materials,
Sintered materials with excellent strength are being developed by means of alloying, densification, homogenization, etc. In order to strengthen the sintered material by alloying it, alloying elements such as Cu, Ni, Mo, Mn, and Cr are solid-dissolved in the iron by a mixing method or a pre-alloying method. method is mainly used. Further, as a method for strengthening the sintered material by increasing the density, a two-time press-double sintering method, a sinter-forging method, etc. are adopted. In addition, methods for strengthening the sintered material, such as homogenizing the sintered material by high-temperature sintering and making pores spheroidal, have also been adopted. However, while the above-mentioned sintered materials and strengthening methods are all effective in improving the strength of the sintered materials, they also have drawbacks, and there are many problems that need to be solved. That is, in the method of strengthening sintered materials by alloying, a mixing method and a pre-alloying method are usually employed. However, in the method of strengthening sintered materials using the mixing method, long sintering times are required to sufficiently diffuse the added alloying elements into the iron, and active elements such as Cr and Mo are used. In this case, there was a problem that unless the sintering atmosphere was strictly controlled, an oxidation reaction would occur and the diffusion reaction would be inhibited. On the other hand, in the method of strengthening sintered materials by pre-alloying, the hardness of the metal powder raw material for powder metallurgy increases as the raw material powder is alloyed, reducing the compactability. As a result, it is necessary to improve the compactability of the raw material powder. In addition, in the double press-double sintering method, sinter forging method, etc., which are methods of strengthening sintered materials for high density, it is necessary to change or add to the manufacturing process and perform strong processing (compression). In this method, the manufacturing process of the sintered material is complicated, and the conditions such as atmosphere and temperature settings during heavy processing must be carefully controlled. Not only does this increase, but also a significant increase in manufacturing costs is unavoidable. By the way, as one of the solutions to the above-mentioned conventional problems, various proposals have been made to improve the deterioration in compactability due to prealloying of raw material powder. For example, a ``low-alloy iron powder manufacturing method'' involves attaching alloying elements to the surface of low-alloy iron powder using a special reduction method.
(Special Publication No. 45-9649), which improves the hardenability of conventional low-alloy powder for sintered forging, and also improves the hardenability of Cu, which contributes to increasing the hardness of the core. Examples include ``steel powder for high-density sintered steel'' (Japanese Patent Application Laid-Open No. 1983-26705), which contains Mo as the main additive element. However, although the former improves compactability, the raw material powder itself is considerably more expensive than commercially available low-alloy steel powder, and the latter requires the addition of a relatively large amount of Cu. Therefore, it is necessary to strictly control the conditions in the manufacturing process, so it is inevitable that the price of the raw material powder will rise compared to commercially available low-alloy iron powder. As mentioned above, although there are several prealloyed raw material powders with excellent compactability currently on the market, the price of the raw material powder itself is extremely high, and the production cost is high. In sintered material parts, where raw material powder costs account for a high proportion, this is a major obstacle in expanding the range of application. By the way, the method of the present invention is based on the relationship between the contribution rate of various alloying elements to powder formability, the relationship between alloying elements and hardenability,
Based on the knowledge obtained from a detailed study of the relationship between alloying elements and the mechanical properties of sintered bodies manufactured using their raw material powder, and the relationship between the amount of alloying elements added and strength, etc. It was invented by That is, Mo, which is mainly used in low alloy iron powder,
As a result of various studies on alloying elements such as Mn, Cr, and Ni and their addition methods (prealloying or blending), we found that although the final composition was similar, improving the addition method significantly improved the strength of the resulting sintered material. As a result of discovering that there is a large difference and conducting repeated research focusing on this point, we have completed the present invention. [Problems to be Solved by the Invention] In view of the current state of the conventional technology as described above, the problem to be solved by the present invention is that the conventional low-alloy iron powder commercially available is If the strength of the sintered material manufactured using iron powder is to be improved, the compactability will be reduced. Conventional low-alloy iron powders with improved compactability have been extremely expensive as powders for sintering materials. Therefore, the technical problem of the present invention is to
By improving the method of adding alloying elements to low-alloy iron powder, it has a composition that approximates that of commercially available low-alloy iron powder, and although it is a relatively low-priced low-alloy iron powder, The object of the present invention is to significantly improve the strength of sintered materials manufactured using iron powder, and to provide low-alloy iron powder with excellent powder formability. [Means for solving the problems] In view of the problems in the conventional technology,
The means for solving the problems of the conventional technology in the present invention is that C; 0.05% or less in weight ratio;
We use low-alloy iron powder that consists of Mo: 0.2-2.0%, O 2 : 0.5-2.0%, the balance being Fe and unavoidable impurities, and Mo is contained in a Fe-Mo alloy state. A process of adding and mixing 0.5 to 4.0% Ni or Ni oxide to the powder, and heating the mixed powder as described above in a non-oxidizing atmosphere for 20 to 120 minutes at 800 to 1000℃, followed by removal. It consists of a reduction step of cooling, and a step of pulverizing the cake-like pseudo-sintered aggregate of low-alloy iron powder formed by the above-mentioned reduction step, with a weight ratio of C: 0.05% or less, Mo. ;0.2~2.0
%, O2 : 0.20% or less, Ni: 0.5-4.0%, balance Fe and 2% or less of unavoidable impurities. There is. [Operation] The operation of the present invention will be explained below. In the present invention, the raw material powder is made of C: 0.05% or less, Mo: 0.2 to 2.0%, O 2 : 0.20% or less, Ni: 0.5 to 4.0%, the balance being Fe and unavoidable impurities of 2% or less. The low-alloy iron powder has a composition similar to that of conventionally commercially available low-alloy iron powder, making it a relatively low-priced low-alloy iron powder with excellent compactability. This is to ensure that Next, the reason why the composition of the low alloy iron powder produced by the method of the present invention is limited to the above range will be explained. In the following description, the amount of each alloying element added is expressed in weight %. C is desirably 0.05 or less since a large amount of C significantly reduces compaction properties. Additionally, Mo is effective as an alloying element for improving heat treatability (hardenability), but if it is less than 0.2%, the improvement effect is not sufficient, and if it exceeds 2.0%, the improvement effect will not increase commensurate with the amount added. Not only is it not observed, but it also worsens the compactability of low-alloy iron powder and increases the cost of low-alloy iron powder, so it is set at 0.2 to 2.0%. In addition, Ni is effective because it improves heat treatability (hardenability) and toughness, but if it is less than 0.5%, the improvement effect is not sufficient, and if it exceeds 4.0%, the improvement effect will not increase commensurate with the amount added. It was set at 0.5 to 4.0% because it was not observed. Furthermore, since the content of O 2 has a significant negative effect on compaction properties and heat treatability, it is necessary to suppress the content to 0.2% or less. That is, the low-alloy iron powder produced by the method of the present invention contains Mo and Ni as alloying elements, and depending on the form of existence of these alloying elements, there is a large difference in the strength of the sintered material, especially in the heat-treated state. First, based on that knowledge,
Mo is alloyed by the pre-alloying method, and then Ni
The invention was based on the fact that the strength of the sintered material in the heat-treated state can be maximized by mixing it with the Fe-Mo preliminary alloy powder and then subjecting it to reduction treatment. Furthermore, in the present invention, the mixed powder of low alloy iron powder mixed with Ni or Ni oxide is heated in a non-oxidizing atmosphere at 800 to 1000°C for 20 to 120 minutes and then slowly cooled. , annealing of mixed powder,
This is because when the O 2 content in the mixed powder is reduced and Ni is added using Ni oxide, the oxide is reduced to form Ni alloy. In addition, in the method of the present invention, the temperature in the reduction step is the same as that for removing oxides from the Fe-Mo water spray powder, annealing, and
The temperature is preferably 800 to 1000° C. in order to reduce NiO when Ni is added and to suppress the amount of O 2 contained to 0.2% or less. This is because when the temperature in the reduction process exceeds 1000℃, the sintering reaction between the low-alloy iron powders progresses, resulting in a cake-like pseudo-sintered aggregate of low-alloy iron powder formed in the reduction process. This is because crushing becomes difficult. Also, the heating holding time in the reduction step is preferably 20 to 120 minutes for the same reason as the heating temperature described above. [Example] Hereinafter, one example of the present invention will be described based on the table. First, the material of the present invention has a weight ratio of 0.02%C-
Consisting of 0.5%Mo−0.92% O2 −BalFe, Mo is Fe
Low-alloy iron powder contained in a -Mo alloy state was produced by a water spray method. Next, carbonyl Ni powder was added at a weight ratio of 2% to the low alloy iron powder, and the powder was mixed using a V-type powder mixer. This mixed powder was heated in an ammonia decomposition gas atmosphere at 900° C. for 30 minutes and then slowly cooled to form a cake-like pseudo-sintered aggregate of low-alloy iron powder, which was then ground in a hammer mill. Table 1 shows the chemical components of the low alloy iron powder produced as described above. Next, the material of the present invention has a weight ratio of 0.02% C-
Consisting of 1.1% Mo−0.8O 2 −BalFe, Mo is Fe−
Low-alloy iron powder containing Mo alloy was produced by a water spray method. Next, in terms of weight ratio to this low alloy iron powder,
After adding 2.5% NiO powder, the powder was mixed using a V-type powder mixer. This mixed powder was heated and reduced in an ammonia decomposition gas atmosphere at 950°C for 90 minutes, then slowly cooled to form a cake-like pseudo-sintered aggregate of low-alloy iron powder, which was then ground in a hammer mill. . Table 1 shows the chemical components of the low alloy iron powder produced as described above. Next, as a comparative material, a commercially available low-alloy iron powder having a chemical composition similar to that of the present invention material was used. Its chemical composition is shown in Table 1. In addition, as a comparative material, 0.02% C by weight
Low alloy iron powder consisting of -1.9%Ni-0.8% O2 -BalFe was produced by a water spray method. Next, in terms of weight ratio to this low alloy iron powder,
After adding 0.5% Mo powder, the powder was mixed using a V-type powder mixer. This mixed powder was reduced by heating at 900℃ for 30 minutes in an ammonia decomposition gas atmosphere, then slowly cooled to form a cake-like pseudo-sintered aggregate of low-alloy iron powder, and then processed in a hammer mill. Shattered. Table 1 shows the chemical components of the low alloy iron powder produced as described above. In addition, commercially available pure iron powder and Ni
After adding the powder and Mo powder, the powder was mixed using a V-type powder mixer. Table 1 shows the chemical components of the low alloy iron powder produced as described above.
【表】【table】
【表】
上述の本発明材、及び比較材〜の各低
合金鉄粉原料を用いて、圧粉成形及び焼結処理し
て焼結体とした状態、及び、その後焼入・焼もど
しの熱処理を施した状態における引張強度を測定
することにより、本発明の低合金鉄粉の製造方法
により製造された低合金鉄粉と従来法により製造
された低合金鉄粉との強度を比較評価した。
その比較評価のための焼結体は、本発明材及び
比較材ともに以下の要領にて製造した。
まず、原料低合金鉄粉に対して0.6％の黒鉛粉
末と0.8％の潤滑剤（ステアリン酸亜鉛）とを添
加し、Ｖ型混粉機により混粉した後、JSPM標準
２−64の引張試験片を圧粉成形体密度7.0ｇ／cm3
となるように圧粉成形し、ついで、アンモニア分
解ガス雰囲気中にて1180℃×60分間の焼結処理を
実施した。
次に、熱処理は真空熱処理炉を用いて870℃×
40分間の加熱保持した後油焼入し、ついで、170
℃×90分間の焼もどし処理を施した。
上述の方法により製造された各試験片を、２
mm／minの引張速度で引張試験を実施し、各試験
片の引張強度を測定した。
第２表のこのようにして測定した各試験片にお
ける焼結体状態及び熱処理状態の引張強度を示し
ている。[Table] Using the above-mentioned low alloy iron powder raw materials of the present invention material and comparative materials ~, powder compacting and sintering treatment to form a sintered body, and subsequent heat treatment of quenching and tempering. By measuring the tensile strength in a state where the iron powder was subjected to the following steps, the strength of the low alloy iron powder produced by the method for producing the low alloy iron powder of the present invention and the low alloy iron powder produced by the conventional method was compared and evaluated. The sintered bodies for the comparative evaluation were manufactured in the following manner for both the present invention material and the comparative material. First, 0.6% graphite powder and 0.8% lubricant (zinc stearate) were added to the raw material low-alloy iron powder, and the powder was mixed using a V-type powder mixer, followed by a tensile test according to JSPM standard 2-64. The piece is compacted into a compact with a density of 7.0 g/cm 3
It was compacted to give the following properties, and then sintered at 1180°C for 60 minutes in an ammonia decomposition gas atmosphere. Next, heat treatment is performed at 870℃ using a vacuum heat treatment furnace.
After heating and holding for 40 minutes, oil quenching, then 170
Tempering treatment was performed at ℃ for 90 minutes. Each test piece produced by the method described above was
A tensile test was conducted at a tensile rate of mm/min, and the tensile strength of each test piece was measured. Table 2 shows the tensile strength of each test piece measured in this manner in the sintered body state and in the heat treated state.
以上により明らかなように、本発明にかかる低
合金鉄粉の製造方法によれば、低合金鉄粉におけ
る合金元素の添加方法の改善によつて、従来から
存在する市販の低合金鉄粉に近似化した組成であ
り、比較的低価格な低合金鉄粉でありながら、そ
の低合金鉄粉を用いて製造した焼結材料の強度を
著しく向上させるとともに、圧粉成形性にも優れ
た低合金鉄粉とすることができる利点がある。
As is clear from the above, according to the method for producing low-alloy iron powder according to the present invention, by improving the method of adding alloying elements to low-alloy iron powder, the low-alloy iron powder can be made to be similar to conventionally available commercially available low-alloy iron powder. Although it is a low-alloy iron powder with a low-alloy composition and a relatively low price, it not only significantly improves the strength of sintered materials manufactured using the low-alloy iron powder, but also has excellent compactability. It has the advantage that it can be made into iron powder.
Claims (1)
2.0％、O2；0.5〜2.0％、残部Feと不可避の不純
物からなり、MoがFe−Mo合金状態をなして含
有されている低合金鉄粉を使用し、 この低合金鉄粉に対して0.5〜4.0％のNiもしく
はNi酸化物を添加・混合する工程と、 上述により混合された混合粉末を非酸化性雰囲
気中にて、800〜1000℃×20〜120分間の加熱後徐
冷する還元工程と、 上述の還元工程により形成された、低合金鉄粉
のケーキ状に擬似焼結された集合体を粉砕する工
程とからなり、 重量比率にて、Ｃ；0.05％以下、Mo；0.2〜2.0
％、O2；0.20％以下、Ni；0.5〜4.0％、残部Feと
２％以下の不可避の不純物からなる、低合金鉄粉
とすることを特徴とする低合金鉄粉の製造方法。[Claims] 1. In terms of weight ratio, C: 0.05% or less, Mo: 0.2~
2.0%, O 2 ; 0.5 to 2.0%, the balance consists of Fe and unavoidable impurities, and a low alloy iron powder containing Mo in the Fe-Mo alloy state is used. The process of adding and mixing 0.5-4.0% Ni or Ni oxide, and the reduction of the mixed powder mixed above in a non-oxidizing atmosphere by heating it at 800-1000℃ for 20-120 minutes and then slowly cooling it. and a step of pulverizing the cake-like pseudo-sintered aggregate of low-alloy iron powder formed by the above-mentioned reduction step, and the weight ratio is C: 0.05% or less, Mo: 0.2~ 2.0
%, O2 : 0.20% or less, Ni: 0.5 to 4.0%, the balance being Fe and 2% or less of unavoidable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26198384A JPS61139602A (en) | 1984-12-12 | 1984-12-12 | Manufacture of low-alloy iron powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26198384A JPS61139602A (en) | 1984-12-12 | 1984-12-12 | Manufacture of low-alloy iron powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61139602A JPS61139602A (en) | 1986-06-26 |
| JPH0568522B2 true JPH0568522B2 (en) | 1993-09-29 |
Family
ID=17369367
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26198384A Granted JPS61139602A (en) | 1984-12-12 | 1984-12-12 | Manufacture of low-alloy iron powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61139602A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0686603B2 (en) * | 1986-09-29 | 1994-11-02 | 川崎製鉄株式会社 | Evaluation method of the degree of compounding of Fe-Ni compound steel powder |
| TWI482865B (en) * | 2009-05-22 | 2015-05-01 | 胡格納斯股份有限公司 | High strength low alloyed sintered steel |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59215401A (en) * | 1983-05-19 | 1984-12-05 | Kawasaki Steel Corp | Alloy steel powder for powder metallurgy and its production |
-
1984
- 1984-12-12 JP JP26198384A patent/JPS61139602A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59215401A (en) * | 1983-05-19 | 1984-12-05 | Kawasaki Steel Corp | Alloy steel powder for powder metallurgy and its production |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61139602A (en) | 1986-06-26 |
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