JPH07103442B2 - Manufacturing method of high strength sintered alloy steel - Google Patents
Manufacturing method of high strength sintered alloy steelInfo
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- JPH07103442B2 JPH07103442B2 JP61175755A JP17575586A JPH07103442B2 JP H07103442 B2 JPH07103442 B2 JP H07103442B2 JP 61175755 A JP61175755 A JP 61175755A JP 17575586 A JP17575586 A JP 17575586A JP H07103442 B2 JPH07103442 B2 JP H07103442B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、引張強さ110kgf/mm2以上の機械部品用の高強
度焼結合金鋼の製造方法に関する。The present invention relates to a method for producing a high-strength sintered alloy steel for machine parts having a tensile strength of 110 kgf / mm 2 or more.
高強度の焼結合金鋼を得るには特公昭58−10962などに
記載されているMn−Cr−Mo系あるいはNi−Cu−Mo系など
の低合金鋼粉を用い、黒鉛粉および潤滑剤を混合した
後、金型成形し、還元雰囲気中で1100℃〜1200℃程度で
焼結後、焼入焼戻し処理を行い、必要な特性を得てい
る。To obtain high-strength sintered alloy steel, use low alloy steel powder such as Mn-Cr-Mo system or Ni-Cu-Mo system described in JP-B-58-10962, and use graphite powder and lubricant. After mixing, they are molded into a mold, sintered at 1100 ° C to 1200 ° C in a reducing atmosphere, and then quenched and tempered to obtain the required properties.
また、特開昭60−114555に記載の如く、低合金鋼粉にC
u、Ｂ、Ｐなどを含む低融点金属粉を添加混合し、液相
焼結を行い、強化する方法がある。Further, as described in JP-A-60-114555, C is added to low alloy steel powder.
There is a method of strengthening by adding and mixing a low melting point metal powder containing u, B, P, etc. and performing liquid phase sintering.
これらの方法によって得られる焼結合金鋼は、引張強さ
80kgf/mm2以上を持ち、高強度を必要とする機械部品に
好適である。しかし特公昭58−10962などに記載の方法
による場合、焼結のままでは100kgf/mm2以上の高強度は
得られない。従ってこの程度の強度を得るには、焼入れ
焼戻し処理が必要である。このため焼入れ焼戻し処理に
よる焼結体製造コストの上昇、寸法精度の低下は避けら
れない。Sintered alloy steel obtained by these methods has a tensile strength
It has a capacity of 80kgf / mm 2 or more and is suitable for machine parts that require high strength. However, in the case of the method described in JP-B-58-10962, etc., high strength of 100 kgf / mm 2 or more cannot be obtained with as-sintered. Therefore, in order to obtain such strength, quenching and tempering treatment is necessary. For this reason, the quenching and tempering treatment inevitably increases the manufacturing cost of the sintered body and reduces the dimensional accuracy.
また特開昭60−114555に記載の方法はＢなどの液相発生
元素が均一に分散しにくく、組織が不均一になりやすく
寸法精度が低下しやすく、さらに0.1％程度のＢを添加
しないと100kgf/mm2以上の引張強さは得られず、焼結体
の製造コストの上昇が避けられない。Further, in the method described in JP-A-60-114555, it is difficult to uniformly disperse a liquid phase generating element such as B, the structure tends to become non-uniform, and the dimensional accuracy tends to decrease, and B of about 0.1% must be added. A tensile strength of 100 kgf / mm 2 or more cannot be obtained, and an increase in the manufacturing cost of the sintered body cannot be avoided.
本発明は、従来焼結のままでは得られなかった高強度の
機械部品用焼結合金鋼を、寸法精度良く比較的安価に焼
結のままで得られる、焼結合金鋼の製造方法を提供する
ことを本発明の目的とする。The present invention provides a method for producing a sintered alloy steel, which can obtain a high-strength sintered alloy steel for mechanical parts, which has not been obtained by conventional sintering as it is, at a relatively low cost with high dimensional accuracy. It is an object of the present invention to do so.
上記目的を達成するための技術手段は次の通りである。 The technical means for achieving the above object are as follows.
まず成分として、 C:0.05重量％以下 Si:0.10重量％以下 P:0.020重量％以下 S:0.020重量％以下 N:0.0015重量％以下 O:0.20重量％以下 Ni:0.5〜４重量％ Cr:2.03〜4.5重量％ Mo:0.15〜1.0重量％ を含む合金鋼粉を用いる。First, as a component, C: 0.05 wt% or less Si: 0.10 wt% or less P: 0.020 wt% or less S: 0.020 wt% or less N: 0.0015 wt% or less O: 0.20 wt% or less Ni: 0.5 to 4 wt% Cr: 2.03 Alloy steel powder containing ~ 4.5 wt% Mo: 0.15-1.0 wt% is used.
この圧粉成形体の密度が6.9g/cm3以上になるように成形
する。The green compact is molded to have a density of 6.9 g / cm 3 or more.
次に、1100〜1350℃、15分間以上の加熱により焼結す
る。Next, it is sintered by heating at 1100-1350 ° C. for 15 minutes or more.
焼結後の冷却を冷却速度0.15℃/sec以上で焼結炉内で炉
冷することとする。Cooling after sintering is performed in a sintering furnace at a cooling rate of 0.15 ° C./sec or more.
本発明は、合金鋼粉の圧縮性と焼入れ性の両特性の優れ
た鋼粉を用い、焼結条件を限定することにより、従来得
られなかった焼結体強度と寸法精度を得られるという知
見に基づき、完成されたものである。INDUSTRIAL APPLICABILITY The present invention uses a steel powder having excellent compressibility and hardenability of alloy steel powder, and by limiting the sintering conditions, it is possible to obtain a sintered body strength and dimensional accuracy that have not been obtained conventionally. It was completed based on.
高強度の焼結合金鋼を得るには、圧縮性、焼入性、焼結
性の優れた粉末が必要である。To obtain a high-strength sintered alloy steel, powder having excellent compressibility, hardenability, and sinterability is required.
高い圧縮性を得るには、不純物の低減が最も効果的であ
る。また焼入性の向上には合金元素の添加の増量が必要
である。さらに焼結性の向上には粒径、合金元素の調整
が必要である。これらの要求特性の全てを得ることは、
各々の特性向上の手段が他の特性の低下をもたらしやす
く、従来困難であった。To obtain high compressibility, the reduction of impurities is the most effective. Further, in order to improve hardenability, it is necessary to increase the amount of alloying element added. Furthermore, in order to improve the sinterability, it is necessary to adjust the particle size and alloy elements. Obtaining all of these required characteristics is
It has been difficult in the past that each of the means for improving the characteristics tends to cause deterioration of other characteristics.
発明者らは不純物元素の低減と合金元素の選択およびそ
の量について検討を行い、さらに焼結条件についても検
討した結果、従来不可能であった高い焼結体強度を有す
る焼結合金鋼を得た。The inventors have studied the reduction of impurity elements, the selection of alloying elements and their amounts, and also the sintering conditions. As a result, a sintered alloy steel having a high sintered body strength, which was impossible in the past, was obtained. It was
すなわち、従来のCr系の低合金鋼粉は焼入性が優れる
が、Ｏその他の不純物が多いために圧縮性が劣り、高強
度が得られなかった。しかし発明者らの検討により、十
分Ｏ量の低い圧縮性の高い鋼粉を得ることが可能とな
り、さらにNi、Moを加えることにより、従来得られなか
った圧縮性、焼入性の両特性の優れる粉末を得ることが
できた。さらに同粉末を成形後の焼結条件を限定するこ
とにより、従来得られなかった焼結体強度が得られた。That is, the conventional Cr-based low alloy steel powder is excellent in hardenability, but it is inferior in compressibility due to a large amount of O and other impurities, and high strength cannot be obtained. However, according to the study by the inventors, it becomes possible to obtain a steel powder having a sufficiently low O content and high compressibility, and by adding Ni and Mo, it is possible to obtain both the compressive and hardenability properties which have not been obtained conventionally. An excellent powder could be obtained. Further, by limiting the sintering conditions after molding the same powder, a sintered body strength that has not been obtained in the past was obtained.
本発明で用いる鋼粉はＣ、Si、Ｐ、Ｓ、Ｎ、Ｏの含有量
を低減し、圧縮性を高くしたものである。次に各成分の
限定理由を述べる。The steel powder used in the present invention is one in which the contents of C, Si, P, S, N, and O are reduced and the compressibility is increased. Next, the reasons for limiting each component will be described.
C: Ｃは浸入型の合金元素であり、Ｃの残留は著しく圧縮性
を低下させるため、極力低くすることが望ましい。特に
本発明の焼結鋼を得るために用いる鋼粉の圧縮性（潤滑
剤１％を加え、成形圧力7t/cm2で金型成形し得た圧粉成
形体の密度が6.9g/cm3以上）は、鋼粉に0.05重量％を越
えるＣが残留した場合、困難である。そこで本発明の鋼
粉のＣ量は0.05重量％以下とする。C: C is an infiltration type alloying element, and residual C significantly reduces the compressibility, so it is desirable to make it as low as possible. In particular, the compressibility of the steel powder used to obtain the sintered steel of the present invention (adding 1% of a lubricant and molding with a molding pressure of 7 t / cm 2 has a density of 6.9 g / cm 3). The above) is difficult when more than 0.05% by weight of C remains in the steel powder. Therefore, the C content of the steel powder of the present invention is set to 0.05% by weight or less.
Si: 溶融鋼の脱Ｏ元素として添加する必要があるが、Siの増
加はSi酸化物となりやすく鋼粉中に残留した圧縮性の低
下、焼結体特性の低下を招き易く、Si添加による焼入性
向上を考慮しても、Siの添加は最低限にすべきである。
従って本発明で用いる鋼粉のSi量は圧縮性の低下の少な
い0.10重量％以下とする。Si: It is necessary to add Si as a deoxidizing element of molten steel, but an increase in Si tends to form Si oxides, which tends to reduce the compressibility remaining in the steel powder and the characteristics of the sintered body. Even considering the improvement of the insertability, the addition of Si should be minimized.
Therefore, the Si content of the steel powder used in the present invention is set to 0.10% by weight or less, which does not significantly reduce the compressibility.
Mn: アトマイズ鉄粉の場合、通常0.18％程度のMnは不可避的
不純物として混入する。例えば「日本鉄鋼協会編：第３
版鉄鋼便覧V:鋳造・鍛造・粉末治金」463頁の表16・３
には0.17％が記載されている。Mn: In the case of atomized iron powder, usually about 0.18% Mn is mixed as an unavoidable impurity. For example, "The Iron and Steel Institute of Japan: Part 3
Iron and Steel Handbook V: Casting, Forging, Powder Metallurgy ", Table 16.3 on page 463
Indicates 0.17%.
本発明のような圧縮性を重視する用途ではMnを添加する
必要はないので0.18％以下とした。0.18％を越えると圧
縮性を害するおそれがある。In applications such as the present invention where importance is placed on compressibility, it is not necessary to add Mn, so the content was made 0.18% or less. If it exceeds 0.18%, the compressibility may be impaired.
しかし、Mnは焼入性を高めるので、場合によっては高強
度焼結合金鋼を得る目的で意図的に添加されることがあ
る。本発明では、焼結後の焼結炉内での炉冷程度の冷却
速度において焼が入るようにNi、Cr、Moを適量添加する
ことによって焼結合金の高強度化を達成しており、Mnを
特に添加する必要はない。However, since Mn enhances hardenability, it is sometimes intentionally added for the purpose of obtaining a high-strength sintered alloy steel. In the present invention, Ni, Cr, to increase the strength of the sintered alloy by adding an appropriate amount of Ni, so that quenching occurs at a cooling rate of about the furnace cooling in the sintering furnace after sintering, It is not necessary to add Mn.
P,S: 鉄中に一般的に含まれる不純物元素であるが、これらの
元素はＣ同様圧縮性を著しく劣化させる元素であり、可
能な限り低いことが望ましい。本発明に用いる合金鋼粉
中のP,Sの量は、それぞれ工業的に低減可能であり、か
つ圧縮性低下の少ない0.020重量％以下とする。これは
P,Sが0.020重量％を超えた場合他の合金元素の影響も加
わり、本発明の目的を達成するに必要な条件である高圧
縮性を得ることができないことによる。P, S: Impurity elements that are generally contained in iron, but these elements are elements that significantly deteriorate the compressibility, like C, and it is desirable that they are as low as possible. The amount of P and S in the alloy steel powder used in the present invention is 0.020% by weight or less, which can be industrially reduced and has a small reduction in compressibility. this is
This is because when P and S exceed 0.020% by weight, the influence of other alloying elements is added, and it is not possible to obtain high compressibility, which is a condition necessary for achieving the object of the present invention.
O: またＯ量の増加は、圧縮性の低下ばかりでなく介在物の
増加、焼入性の低下、合金元素の添加効果の減少が起こ
り、最も好ましくない。O: Further, an increase in the amount of O is not preferable because not only the compressibility is decreased but also inclusions are increased, the hardenability is decreased, and the effect of adding the alloying element is decreased.
従って本発明で用いる鋼粉中のＯ量は量産可能な合金鋼
粉製造設備で得られ、かつ上記Ｏによる悪影響の少ない
0.20重量％以下とする。なおＯ量は鋼粉の合金組成の影
響を強く受けるため合金元素の選択及びその量はＯ量の
増加を考慮した上で決定する必要がある。Therefore, the amount of O in the steel powder used in the present invention can be obtained in a mass-produced alloy steel powder production facility, and the adverse effect of O above is small.
0.20% by weight or less. Since the amount of O is strongly influenced by the alloy composition of the steel powder, it is necessary to select the alloying element and its amount in consideration of the increase in the amount of O.
N: さらにＮはＣなどと同様鋼粉を著しく硬化させ、鋼粉の
圧縮性を損う。そこで本発明で用いる鋼粉のＮ量は、圧
縮性の低下が極く少なく、かつ工業的に製造可能な0.00
15重量％以下とする。N: Further, N remarkably hardens the steel powder as in C, and impairs the compressibility of the steel powder. Therefore, the N content of the steel powder used in the present invention is such that the deterioration of the compressibility is extremely small and the N content is 0.00
15% by weight or less.
次に本発明の重要な点の一つである焼入性向上に必須の
合金元素Ni、Cr、Mo量の限定理由を説明する。Next, the reason for limiting the amounts of alloying elements Ni, Cr, and Mo essential for improving hardenability, which is one of the important points of the present invention, will be described.
Cr: Crは、本発明の焼結鋼の最も重要な合金元素である。Cr
焼入性向上の効果は大きく、また他の合金元素に比べ、
安価である。Crは本発明の焼結鋼の密度、焼入性を決定
づけるため重要である。Cr量の下限はNi、Moを添加した
状態において、一般的な焼結炉の冷却速度においてマル
テンサイト変態しうる量としなければ本発明の目的とす
る強度は得られない。本発明のCr量の下限を2.03重量％
とするが、これは2.03重量％未満のCr量では（Niあるい
はMoを比較的多量に添加した場合においても）本発明の
目的とする焼結体強度が得られないからである。Cr量の
上限はCrの添加による圧縮性の低下すなわち焼結密度の
低下により本発明の目的とする焼結体強度が得られなく
なる量すなわち4.5重量％を上限とする。Cr: Cr is the most important alloying element of the sintered steel of the present invention. Cr
The effect of improving hardenability is great, and compared with other alloy elements,
It is cheap. Cr is important because it determines the density and hardenability of the sintered steel of the present invention. The lower limit of the Cr content is that the strength targeted by the present invention cannot be obtained unless the content of Ni and Mo is added so that the martensitic transformation can be performed at the cooling rate of a general sintering furnace. The lower limit of the Cr amount of the present invention is 2.03% by weight
However, this is because the amount of Cr less than 2.03% by weight (even when Ni or Mo is added in a relatively large amount) makes it impossible to obtain the desired sintered body strength of the present invention. The upper limit of the Cr amount is 4.5% by weight, which is the amount at which the strength of the sintered body, which is the object of the present invention, cannot be obtained due to the decrease in compressibility due to the addition of Cr, that is, the decrease in the sintered density.
Ni: Niは焼入性の向上および焼結体内の空孔の球状化など焼
結を促進する元素である。しかし過剰な添加は合金コス
トの上昇圧縮性の低下をもたらし好ましくなく、他の合
金元素とのバランスも考慮し、Ni量を決定する必要があ
る。本発明の焼結合金鋼のNi量は0.5〜４重量％とす
る。これは0.5重量％未満のNi量においては焼入性およ
び焼結性向上の効果が小さく、目標とする焼結体強度を
得ることができない。Ni: Ni is an element that promotes sintering such as improvement of hardenability and spheroidization of pores in the sintered body. However, excessive addition causes an increase in alloy cost and a decrease in compressibility, which is not preferable, and it is necessary to determine the Ni content in consideration of the balance with other alloying elements. The Ni content of the sintered alloy steel of the present invention is 0.5 to 4% by weight. This is because when the Ni content is less than 0.5% by weight, the effect of improving hardenability and sinterability is small, and the target sintered body strength cannot be obtained.
またNiが４重量％を超えた場合、その焼入性向上の効果
に比べ、圧縮性の低下、合金コストの上昇の負効果が大
きく、本発明の目的とする焼結合金鋼が得られない。そ
こで、Ni量の上限は４重量％とする。On the other hand, when Ni exceeds 4% by weight, the negative effects of a decrease in compressibility and an increase in alloy cost are large compared to the effect of improving the hardenability, and the sintered alloy steel aimed at by the present invention cannot be obtained. . Therefore, the upper limit of the amount of Ni is 4% by weight.
Mo: MoはNiおよびCrと並ぶ本発明の重要な添加元素の一つで
ある。Moの添加により焼入性が向上し、焼結後の機械的
特性の向上が著しい。しかしMoもNi、Crと同様鋼粉を硬
化し圧縮性を低下させやすい。Mo: Mo is one of the important additive elements of the present invention along with Ni and Cr. The addition of Mo improves the hardenability and the mechanical properties after sintering are significantly improved. However, Mo, like Ni and Cr, hardens the steel powder and tends to reduce the compressibility.
従って本発明のMo量は添加効果が明らかでかつ圧縮性低
下の少ない0.15〜1.0重量％とする。Therefore, the amount of Mo in the present invention is set to 0.15 to 1.0% by weight in which the effect of addition is clear and the decrease in compressibility is small.
本発明の焼結合金鋼は上記Ni、Cr、Moを含有することに
より基本的な焼入性が得られる。The sintered alloy steel of the present invention can obtain basic hardenability by containing the above Ni, Cr and Mo.
さらに他の合金元素としてＶ、Co、Cuを加えることによ
り機械部品個々に要求される特性に合致させることが可
能である。By adding V, Co and Cu as other alloying elements, it is possible to meet the characteristics required for individual machine parts.
本発明の焼結合金鋼の製造方法は、焼結条件を1100℃〜
1350℃15分間の焼結と焼結後の冷却速度を0.15℃/sec以
上とする。The manufacturing method of the sintered alloy steel of the present invention, sintering conditions 1100 ℃ ~
Sintering at 1350 ° C for 15 minutes and cooling rate after sintering is 0.15 ° C / sec or more.
焼結温度を1100〜1350℃とする限定理由は1100℃未満で
は焼結が十分に進行しないので、本発明の目的とする焼
結体の強度が得られず、また1350℃を越える高温では焼
結コストが上昇し好ましくない。The reason for limiting the sintering temperature to 1100 to 1350 ° C is that if the temperature is less than 1100 ° C, the sintering does not proceed sufficiently, so that the strength of the sintered body, which is the object of the present invention, cannot be obtained. This is not preferable because the cost of binding increases.
焼結時間は15分以上とするがこれは、15分未満の場合温
度分布が均一となりにくく、焼結体の特性がばらつきや
すいことによる。The sintering time is set to 15 minutes or more. This is because if it is less than 15 minutes, the temperature distribution is difficult to be uniform and the characteristics of the sintered body are likely to vary.
焼結後の冷却速度は0.15℃/sec以上とする。これは0.15
℃/sec未満の冷却速度では、本発明で用いる焼入性の優
れる鋼粉であっても冷却時にマルテンサイト変態せず、
本発明の目的とする強度が得られないことによる。The cooling rate after sintering is 0.15 ° C / sec or more. This is 0.15
At a cooling rate of less than ° C / sec, even steel powder having excellent hardenability used in the present invention does not undergo martensitic transformation during cooling,
This is because the desired strength of the present invention cannot be obtained.
次に実施例を用いて本発明を詳細に説明する。電気炉を
用いて鉄スクラップを溶解後Si脱酸し、合金元素添加後
水圧160kgf/cm2にて水アトマイズを行い、得られた粉末
を脱水、乾燥し、更に真空熱処理炉を用い、脱酸、脱
炭、脱窒および焼鈍を行い、第１表の鋼粉を得た。Next, the present invention will be described in detail with reference to examples. After melting iron scrap using an electric furnace, deoxidizing Si, adding alloying elements, water atomizing at a water pressure of 160 kgf / cm 2 , dehydrating and drying the obtained powder, and further deoxidizing using a vacuum heat treatment furnace. Then, decarburization, denitrification and annealing were performed to obtain the steel powder shown in Table 1.
第１表に本発明で用いた合金鋼粉実施例１〜６および比
較例１〜６を示す。但し、実施例６のCuは製品鋼粉に電
解Cu粉を混熟し供試した。Table 1 shows alloy steel powder Examples 1 to 6 and Comparative Examples 1 to 6 used in the present invention. However, Cu of Example 6 was tested by mixing the product steel powder with electrolytic Cu powder.
同粉末に１重量％の潤滑剤（ステアリン酸亜鉛）を加え
成形圧力7t/cm2でJSPM標準１−64の圧縮性試験片を成形
し、さらに0.7重量％の黒鉛粉を加え混合成形し、JSPM
標準２−64引張試験片を得た。圧縮性試験片により得た
圧粉密度を第１表に示す。また引張試験片は水素雰囲気
中にて1250℃60分間の焼結を行い、0.1および0.2℃/sec
で冷却した。同試験片を用いて引張強さを測定し、その
結果を第１表に示す。1% by weight of lubricant (zinc stearate) was added to the powder to form a compressible test piece of JSPM standard 1-64 at a forming pressure of 7 t / cm 2 , and 0.7% by weight of graphite powder was further added and mixed and formed. JSPM
Standard 2-64 tensile test pieces were obtained. The green density obtained from the compressible test pieces is shown in Table 1. Tensile test pieces were sintered in a hydrogen atmosphere at 1250 ° C for 60 minutes to obtain 0.1 and 0.2 ° C / sec.
Cooled in. Tensile strength was measured using the same test piece, and the results are shown in Table 1.
実施例１〜６はＣ、Si、Ｐ、Ｓ、Ｏ、Ｎの不純物が少な
く、さらにNi,Cr、Moの添加により圧縮性、焼入性の両
特性を備え、焼結冷却時にマルテンサイト変態を伴う結
果、高強度を得ることができた。しかし比較例１〜６に
示すように不純物が多い、あるいは合金元素あるいは合
金量が適当でない場合、圧縮性あるいは焼入性が低下
し、目標とする強度が得られなかった。 Examples 1 to 6 have less impurities of C, Si, P, S, O and N, and have both compressibility and hardenability due to addition of Ni, Cr and Mo, and martensitic transformation during sintering and cooling. As a result, high strength could be obtained. However, as shown in Comparative Examples 1 to 6, when the amount of impurities is large or the alloying element or the amount of alloying is not appropriate, the compressibility or hardenability is deteriorated and the target strength cannot be obtained.
また従来から用いられている例えば比較例６の鋼粉では
焼入性が低いため、高強度が得られない。また冷却速度
0.1℃/secでは本発明で用いる成分の鋼粉であっても、
冷却時にマルテンサイト変態せず、本発明の目的とする
焼結体強度が得られない。Further, for example, the steel powder of Comparative Example 6 which has been conventionally used has low hardenability, so that high strength cannot be obtained. Also cooling rate
At 0.1 ° C / sec, even with the steel powder of the component used in the present invention,
Martensite transformation does not occur during cooling, and the strength of the sintered body aimed at by the present invention cannot be obtained.
実施例中１〜３は本発明の基本となる合金鋼粉であり、
Ni、Cr、Moの必須の合金元素のみ添加した鋼粉である。
実施例に示した鋼粉のＣ、Si、Ｐ、Ｓ、Ｏ、Ｎ量は、比
較例１に代表される従来鋼粉のこれらの元素の含有量に
比べ低く6.90g/cm3以上の高圧圧縮性を得ている。比較
例１は実施例１とほぼ同一のNi、Cr、Moの合金量である
が、圧粉密度が低いため極めて低い強度しか得られなか
った。In Examples, 1-3 are alloy steel powders that are the basis of the present invention,
Steel powder containing only the essential alloying elements of Ni, Cr, and Mo.
The amounts of C, Si, P, S, O, and N in the steel powders shown in the examples are lower than the contents of these elements in the conventional steel powder represented by Comparative Example 1, and the high pressure of 6.90 g / cm 3 or more. It is compressible. In Comparative Example 1, the alloy contents of Ni, Cr, and Mo were almost the same as those in Example 1, but only extremely low strength was obtained due to the low green density.
比較例の２、３、６は合金量が低く、高圧縮性を得てい
るが、比較例２はCr量が低く、比較例３はMo量が低く、
更に比較例６はMn量が高いが、Cr量およびNi量が低い。
このため焼入性が不足し焼結の冷却時程度の冷却速度で
はマルテンサイト変態せず高強度が得られない。Comparative Examples 2, 3 and 6 have a low alloy content and high compressibility, but Comparative Example 2 has a low Cr content and Comparative Example 3 has a low Mo content.
Further, in Comparative Example 6, the amount of Mn is high, but the amounts of Cr and Ni are low.
Therefore, the hardenability is insufficient, and martensite transformation does not occur and high strength cannot be obtained at a cooling rate around the time of cooling during sintering.
比較例４はCr量がやや高いため脱炭が抑えられその結果
圧縮性が劣り、高強度が得られなかった。In Comparative Example 4, since the amount of Cr was slightly high, decarburization was suppressed, and as a result, compressibility was poor and high strength could not be obtained.
比較例５はNi、Moが低く焼入性が劣り、高強度が得られ
なかった。Comparative Example 5 was low in Ni and Mo and inferior in hardenability, so that high strength could not be obtained.
実施例４〜６は実施例１〜３の基本組成に他の合金元素
を加えた場合であり、実施例１〜３に比べ圧縮性は低下
するが110kgf/mm2以上の高強度が得られた。Examples 4 to 6 are cases where other alloying elements were added to the basic compositions of Examples 1 to 3, and the compressibility was lower than those of Examples 1 to 3, but high strength of 110 kgf / mm 2 or more was obtained. It was
第１図（写真）に鋼粉断面組織を示す。第１表中の実施
例５の鋼粉を焼結後、0.2℃/secで冷却した焼結体断面
組織を第１図（写真）（ａ）に示す。針状の組織が観察
でき焼結冷却時にマルテンサイト変態としていることが
確認できた。Figure 1 (photograph) shows the cross-sectional structure of steel powder. The cross-sectional structure of the sintered body obtained by sintering the steel powder of Example 5 in Table 1 and cooling it at 0.2 ° C./sec is shown in FIG. 1 (photograph) (a). A needle-like structure was observed, and it was confirmed that the martensitic transformation occurred during sintering and cooling.
しかし第１図（写真）（ｂ）に示す第１表の比較例６の
鋼粉断面は第１図（ａ）のような針状組織はなく、焼入
性が低いためマルテンサイト変態しなかったと言える。However, the steel powder cross section of Comparative Example 6 in Table 1 shown in FIG. 1 (photograph) (b) does not have the needle-like structure as shown in FIG. 1 (a), and does not undergo martensitic transformation because of its low hardenability. It can be said that
本発明の方法を用いることにより従来、焼入焼戻しある
いは硼素など特殊な添加粉を加えなければ得られなかっ
た高強度を焼結のままで安価に得ることが可能となっ
た。By using the method of the present invention, it has become possible to obtain a high strength which has not been obtained until now by quenching and tempering or adding a special additive powder such as boron, in an as-sintered state at low cost.
第１図は焼結体の断面の金属組織を示す倍率400倍の写
真である。FIG. 1 is a photograph showing the metallographic structure of the cross section of the sintered body at a magnification of 400 times.
Claims (1)
形し、1100〜1350℃、15分間以上の加熱により焼結し、
焼結後、冷却速度0.15℃/sec以上で焼結炉内で炉冷する
ことを特徴とする高強度焼結合金鋼の製造方法。1. C: 0.05% by weight or less Si: 0.10% by weight or less Mn: 0.18% by weight or less P: 0.020% by weight or less S: 0.020% by weight or less N: 0.0015% by weight or less O: 0.20% by weight or less Ni: 0.5 〜4wt% Cr: 2.03〜4.5wt% Mo: 0.15〜1.0wt% Alloy steel powder is compacted into a compact with a density of 6.9g / cm 3 or more and 1100〜1350 ℃ for 15 minutes or more. Sintered by heating,
A method for producing a high-strength sintered alloy steel, characterized by cooling the furnace in a sintering furnace at a cooling rate of 0.15 ° C / sec or more after sintering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61175755A JPH07103442B2 (en) | 1986-07-28 | 1986-07-28 | Manufacturing method of high strength sintered alloy steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61175755A JPH07103442B2 (en) | 1986-07-28 | 1986-07-28 | Manufacturing method of high strength sintered alloy steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6333541A JPS6333541A (en) | 1988-02-13 |
| JPH07103442B2 true JPH07103442B2 (en) | 1995-11-08 |
Family
ID=16001684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61175755A Expired - Fee Related JPH07103442B2 (en) | 1986-07-28 | 1986-07-28 | Manufacturing method of high strength sintered alloy steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07103442B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0772282B2 (en) * | 1990-10-25 | 1995-08-02 | 川崎製鉄株式会社 | High compressibility Cr alloy steel powder and method for producing high strength sintered material using the same |
| JP3258765B2 (en) * | 1993-06-02 | 2002-02-18 | 川崎製鉄株式会社 | Manufacturing method of high-strength iron-based sintered body |
| JP6417573B2 (en) * | 2014-12-24 | 2018-11-07 | 住友電工焼結合金株式会社 | Sintered material |
| KR102571865B1 (en) * | 2023-02-02 | 2023-08-29 | (주)알루텍 | stepped portion forming devices and methods for battery can |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57164901A (en) * | 1981-02-24 | 1982-10-09 | Sumitomo Metal Ind Ltd | Low alloy steel powder of superior compressibility, moldability and hardenability |
-
1986
- 1986-07-28 JP JP61175755A patent/JPH07103442B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6333541A (en) | 1988-02-13 |
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