JPH0478716B2 - - Google Patents
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- Publication number
- JPH0478716B2 JPH0478716B2 JP57098111A JP9811182A JPH0478716B2 JP H0478716 B2 JPH0478716 B2 JP H0478716B2 JP 57098111 A JP57098111 A JP 57098111A JP 9811182 A JP9811182 A JP 9811182A JP H0478716 B2 JPH0478716 B2 JP H0478716B2
- Authority
- JP
- Japan
- Prior art keywords
- content
- hardness
- steel
- relationship
- wear resistance
- 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
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- 229910000831 Steel Inorganic materials 0.000 claims description 33
- 239000010959 steel Substances 0.000 claims description 33
- 229910001315 Tool steel Inorganic materials 0.000 claims description 30
- 229910052804 chromium Inorganic materials 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 3
- 238000005245 sintering Methods 0.000 claims description 3
- 239000004615 ingredient Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 description 19
- 238000000137 annealing Methods 0.000 description 15
- 239000000463 material Substances 0.000 description 13
- 238000010791 quenching Methods 0.000 description 11
- 230000000171 quenching effect Effects 0.000 description 11
- 229910052750 molybdenum Inorganic materials 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 229910002467 CrFe Inorganic materials 0.000 description 6
- 150000001247 metal acetylides Chemical class 0.000 description 6
- 238000005496 tempering Methods 0.000 description 6
- 229910052721 tungsten Inorganic materials 0.000 description 6
- 238000003754 machining Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- 238000004663 powder metallurgy Methods 0.000 description 3
- 238000005242 forging Methods 0.000 description 2
- 238000005461 lubrication Methods 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000009689 gas atomisation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
- Powder Metallurgy (AREA)
Description
［産業上の利用分野］
本発明は高靱性高耐摩耗性工具鋼に関し、さら
に詳しくは、鋼粉を熱間静水圧処理（HIP処理）
により緻密化させるという粉末治金法により製造
されした高靱性高耐摩耗性工具鋼に関する。
［従来の技術］
従来から、Cr系工具鋼が冷間圧延用ロール材、
冷間加工用金型等に広く使用されている。
しかしながら、種々の素材の加工に際して、近
年になつて高精度、低コストが強く要求され、か
つ、被加工材の高硬度化、加工速度の高速化等に
よる工具の使用条件が一層苛酷なものとなつてき
ている。そのため、ＣおよびCrの含有量を増加
させて耐摩耗性の改善を図つてきたが、一方、高
合金化により靱性や加工性が著しく低下するとい
う問題が発生した。
さらに、上記の問題と共に加工法も冷間成形−
焼結というプロセスを採用するために、密度およ
び硬度を向上させることができないという問題も
発生した。
［発明が解決しようとする課題］
本発明は、上記に説明した従来から使用されて
きているCr系工具鋼の種々の問題点を解決した
ものであり、例えば、JIS G4404 SKD11より靱
性、耐摩耗性に優れた鋼粉を熱間静水圧処理
（HIP処理）により焼結および緻密化させる粉末
治金法により製造された高靱性高耐摩耗性工具鋼
を提供するものである。
［課題を解決するための手段］
本発明に係る高靱整高耐摩耗性工具鋼は、
鋼粉を熱間静水圧処理により焼結および緻密化
させた工具鋼であつて、含有成分、成分割合は、
Cr15〜21％、
Ｃを７≦Cr％／（Ｃ％−0.2V％）≦11
の比率
で含有し、さらに、
V3.5％以下、W0.3％以上、Mo0.15％以上で、
かつ、
（Ｗ＋2Mo）８％以下
の１種または２種以上
を含み、残部Feおよび不純物からなり抗折力250
Kg／mm2以上の高靱性高耐摩耗性HIP処理工具鋼を
要旨とするものである。
本発明に係る高靱性高耐摩耗性工具鋼について
詳細に説明する。
先ず、本発明に係る高靱性高耐摩耗性工具鋼の
含有成分、成分割合について説明する。
Crは基質および炭窒化物中に存在して焼入れ
性を改善し、焼戻し効果、高温硬さを付与する元
素であり、その含有量が15％未満ではこれらの効
果は少なく、また、含有量が21％を越えるとこれ
らの効果が飽和してしまうと共に、焼なまし硬さ
が増大して機械加工性を劣化させる。よつて、
Cr含有量は15〜21％とする。
Ｃは硬度を付与する元素であり、M7C3のCr系
炭化物中最高の硬さを示す炭化物を形成するが、
このCr系炭化物中最高の硬さを示すためには、
Cr％とＣ％との比が重要であり、Cr％／Ｃ％が
７未満ではマトリツクスへのＣの固溶量の増加に
より靱性の低下が著しく、また、Cr％／Ｃ％が
11を越えると硬さが不充分となる。また、Ｖが含
有されると、ＶはCrより炭化物を生成し易くVC
として結合するものであるから、Ｖ含有量１％に
対してＣを0.2％多く含有させなければならず、
Ｖ含有の場合のＣは７≦Cr％／（Ｃ％−0.2V％）
≦11とするのである。
なお、Cr含有量については後述する第２図な
いし第６図の説明より明らかであるが、17〜21％
の範囲が好ましいものであり、また、Ｃ含有量お
よびＣとCrとの含有量の関係についても後述す
る第８図〜第１２図の説明から明らかである。
Ｖは２次硬化による熱処理硬さが増加し、耐摩
耗性を向上させる元素であるが、多く含有される
と靱性や加工性が低下するようになる。よつて、
Ｖ含有量は3.5％以下とする。
Moもまた２次硬化による熱処理硬さを増加さ
せ、耐摩耗性を向上させる。そのためには0.15％
以上を含有させることが必要であるが、多く含有
させると靱性や加工性が低下する。また、Ｗは工
具鋼ではMoと略同様な働きをし、そのためには
0.3％以上を含有させることが必要であるが、多
く含有させると靱性、加工性が低下する。従つ
て、ＷとMoには含有量の上限が必要で、Ｗの場
合、その効果はMoの約1/2（重量比）に相当す
るので、Mo，Ｗを単独、または、複合して含有
させる場合には、含有量は（1/2Ｗ＋Mo）≦４
％、即ち、（Ｗ＋2Mo）≦８％とする。
なお、不純物として、Si，Mn，Ｐ，Ｓ，Niお
よびＮ等が含有されることがあるが、Niは含有
量は１％以下とすることが望ましい。
また、本発明に係る高靱性高耐摩耗性工具鋼の
製造方法として、従来の冷間成形−焼結による方
法では、密度は向上せず、抗折力も低いものとな
るので、HIP処理されることが必要である。
［実施例］
次いで、本発明に係る高靱性高耐摩耗性工具鋼
の実施例について比較材と共に説明する。
実施例
ガスアトマイズ法により、C2〜３％、Cr8〜25
％およびその他の成分を含む鋼粉としてから、
HIP処理（1100℃、2000atm、２時間処理）によ
り微細化したビレツトを供試材とした。その含有
成分、成分割合は第１表に示す通りである。
なお、第１表中の(イ)はＣ含有量を各々２％、３
％台の一定とし、Cr含有量を変化させた鋼で、
第１図〜第６図に実線Ａと破線Ｂとで各々結ばれ
プロツトされている鋼、(ロ)はCr含有量を18％台
の一定とし、Ｃ含有量を変化させて第７図〜第１
２図に実線Ｄで各々結ばれてプロツトされている
鋼、(ハ)はＣ含有量が２〜３％の範囲に含有され、
かつ、Cr含有量が18％台と一定である鋼のＶ含
有量を変化させたものであり、第１５図、第１６
図に実線Ｄで各々結ばれてプロツトされている
鋼、(ニ)は２％Ｃ−18％Cr鋼で、各々Moの有無が
違うのみの鋼であり、第１７図、第１８図に各々
棒グラフ化された鋼である。
[Industrial Application Field] The present invention relates to high toughness and high wear resistance tool steel, and more specifically, hot isostatic pressure treatment (HIP treatment) of steel powder.
This invention relates to a high-toughness, high-wear-resistant tool steel manufactured by a powder metallurgy method in which the steel is densified. [Conventional technology] Traditionally, Cr-based tool steel has been used as roll material for cold rolling,
Widely used in cold working molds, etc. However, in recent years, there has been a strong demand for high precision and low cost when machining various materials, and the conditions for using tools have become even more severe due to increased hardness of workpieces and faster machining speeds. I'm getting used to it. Therefore, efforts have been made to improve wear resistance by increasing the C and Cr contents, but on the other hand, the problem has arisen that toughness and workability are significantly reduced due to high alloying. Furthermore, in addition to the above problems, the processing method is also cold forming.
Since the process of sintering is used, there is also the problem that density and hardness cannot be improved. [Problems to be Solved by the Invention] The present invention solves the various problems of the conventionally used Cr-based tool steel explained above. The present invention provides a tool steel with high toughness and high wear resistance manufactured by a powder metallurgy method in which steel powder with excellent properties is sintered and densified by hot isostatic pressure treatment (HIP treatment). [Means for Solving the Problems] The high-toughness, high-wear-resistant tool steel according to the present invention is a tool steel in which steel powder is sintered and densified by hot isostatic pressure treatment. Contains Cr15-21%, C at a ratio of 7≦Cr%/(C%-0.2V%)≦11, and further contains V3.5% or less, W0.3% or more, and Mo0.15% or more. in,
Contains one or more of (W + 2Mo) 8% or less, with the balance consisting of Fe and impurities, and has a transverse rupture strength of 250
The gist is a high-toughness, high-wear-resistant HIP-treated tool steel of Kg/mm 2 or more. The high toughness and high wear resistance tool steel according to the present invention will be explained in detail. First, the components and component ratios of the high toughness and high wear resistance tool steel according to the present invention will be explained. Cr is an element that exists in the matrix and carbonitrides and improves hardenability, imparts a tempering effect and high-temperature hardness.If the content is less than 15%, these effects will be small, and if the content is less than 15%, If it exceeds 21%, these effects will be saturated, and the annealing hardness will increase, resulting in poor machinability. Then,
The Cr content shall be 15-21%. C is an element that imparts hardness, and forms a carbide that exhibits the highest hardness among Cr-based carbides of M 7 C 3 .
In order to exhibit the highest hardness among these Cr-based carbides,
The ratio between Cr% and C% is important; when Cr%/C% is less than 7, the toughness decreases significantly due to an increase in the amount of solid solution of C in the matrix;
If it exceeds 11, the hardness is insufficient. In addition, when V is contained, V is more likely to form carbides than Cr, and VC
Therefore, it is necessary to contain 0.2% more C per 1% V content.
When containing V, C is 7≦Cr%/(C%-0.2V%)
≦11. The Cr content is clear from the explanations in Figures 2 to 6 below, but it is 17 to 21%.
The C content and the relationship between the C and Cr contents are also clear from the description of FIGS. 8 to 12, which will be described later. V is an element that increases heat treatment hardness through secondary hardening and improves wear resistance, but when contained in a large amount, toughness and workability decrease. Then,
The V content shall be 3.5% or less. Mo also increases heat treatment hardness through secondary hardening and improves wear resistance. For that, 0.15%
It is necessary to contain the above, but if too much is contained, toughness and workability will decrease. In addition, W acts almost the same as Mo in tool steel, and for that purpose,
It is necessary to contain 0.3% or more, but if the content is too large, toughness and workability will decrease. Therefore, an upper limit is required for the content of W and Mo, and in the case of W, the effect is equivalent to about 1/2 (weight ratio) of Mo, so Mo and W should be contained alone or in combination. If the content is (1/2W+Mo)≦4
%, that is, (W+2Mo)≦8%. Note that impurities such as Si, Mn, P, S, Ni, and N may be contained, but the content of Ni is preferably 1% or less. In addition, as a manufacturing method for the high toughness and high wear resistance tool steel according to the present invention, the density is not improved and the transverse rupture strength is low using the conventional cold forming and sintering method, so HIP treatment is used. It is necessary. [Example] Next, examples of the high toughness and high wear resistance tool steel according to the present invention will be described together with comparative materials. Example C2~3%, Cr8~25 by gas atomization method
As steel powder containing % and other ingredients,
The test material was a billet made fine by HIP treatment (1100°C, 2000atm, 2 hours treatment). The components and proportions thereof are shown in Table 1. Note that (a) in Table 1 indicates C content of 2% and 3%, respectively.
Steel with a constant Cr content in the % range,
The steels connected and plotted by solid lines A and broken lines B in Figures 1 to 6, (b), have a constant Cr content of 18% and vary the C content, and are plotted in Figures 7 to 6. 1st
In Figure 2, the steels (C) are plotted connected by solid lines D, and the C content is in the range of 2 to 3%.
In addition, the V content of steel with a constant Cr content of 18% is changed, and Figs. 15 and 16
The steels connected by solid lines D in the figure (d) are 2%C-18%Cr steels, which differ only in the presence or absence of Mo. It is a bar graph of steel.
【表】
※：本発明。
[Table] *: This invention.
【表】
先ず、Ｃ含有量のCr含有量と種々の特性との
関係に与える影響を調べるため第１表の鋼の中か
らＣ含有量が２％と３％の(イ)を選択して試験を行
つた。
なお、第１図〜第６図において、ＡはC2％材、
ＢはC3％材、ＣはSKD11（溶解材）を示すもので
ある。
第１図は、以下の特性試験を行なう際の試験条
件のうち、焼入れ温度を選定するための試験結果
を示している。
即ち、第１図は単に各鋼のCr含有量において、
最高の焼入れ硬さとなる焼入れ温度との関係を示
す。
以下に説明する各試験は、もともと耐摩耗性向
上を目的とするため、各Cr含有量に対応した最
高焼入れ硬さを示す焼入れ温度に15分間保持後油
冷し、150〜600℃で焼戻しを行なう条件によつて
製造した試験材により行なつた。
第２図はCr含有量と硬さの関係を示すが、特
に、500℃焼戻し硬さを示してあり、実線Ａに示
すように２％ＣでCr含有量が18％までは硬さが
著しく増加するが、Cr含有量が18％を越えても
硬さが増加せず大差がない。しかし、破線Ｂで示
すように３％Ｃは同じCr含有量（10％〜20％）
では硬さは２％Ｃに比して低いことがわかる。
第３図はCr含有量と抗折力との関係を示す。
実線Ａの２％ＣはCr量によらず高靱性を示すが、
破線Ｂの３％Ｃは実線Ａの２％Ｃよりも抗折力が
劣つているものの、18％のCr鋼が最高の靱性を
示している。従つて、３％Ｃの場合を考慮するな
らばCrが18％程度が好ましいことがわかる。
第４図、第５図はHv750における大越式摩耗試
験機による摩耗特性を、摩擦速度0.3m／secの酸
化摩耗領域（第４図）と摩擦速度2.86m／secの
凝着摩耗領域（第５図）とについて、夫々Cr含
有量と比摩耗量との関係を示したものである。
この場合の摩擦条件は次の通りである。
相手材：SCM415
摩擦距離：400m
最終荷重：6.3Kg
潤滑：無し
即ち、第４図の酸化摩耗（アブレツシブ摩耗）
領域では、２％Ｃ（実線Ａ）の方が３％Ｃ（破線
Ｂ）より優れ、何れの場合もCr量が多い程耐摩
耗性に優れている。また、第５図の凝着摩耗領域
では２％Ｃ、３％Ｃ共にCr含有量が18％以上は
耐摩耗性に変わりはない
従つて、第４図および第５図の結果より、耐摩
耗性の点からはCr量は最低17％以上必要である
ことがわかる。
第６図はCr含有量と焼なまし硬さとの関係を
示したもので、焼なまし硬さは、アトマイズ粉→
HIP処理→（熱間加工）→焼なまし→機械加工→
熱処理（焼入れ、焼戻し）される製造行程からす
ると、機械加工の点で低い方が好ましい。また、
第６図から３％ＣはCr量の影響をあまり受けな
いものの、２％ＣはCrが20％を越えると焼なま
し硬さが急に立ち上がつており、工具製造に大き
な影響を与える焼なまし硬さの観点からは、Cr
量は最大21％以下に抑える必要があることがわか
る。
以上の特に第５図、第６図の結果より、Cr含
有量は耐摩耗性の観点からは17％以上で、焼なま
し硬さの観点からは、21％以下とする必要のある
ことが裏付けられる。
次に、Ｃ含有量によつてCr含有量と特性との
関係は大きく影響をうけることは明らかであり、
最適の特性を示すためには、Ｃ含有量とCr含有
量との相関関係を把握する必要があることも明ら
かである。
従つて、このため第７図〜第１２図に示す通り
Cr含有量を18％と一定にし、Ｃ含有量を変化さ
せた第１表の(ロ)を用いて上記第１図〜第６図の場
合と同様にＣ含有量と特性との関係を調査した。
第７図は第１図と同じ単に各鋼のＣ含有量にお
いて最高の硬さとなる焼入れ温度を示す。以下説
明する各種試験は、この各鋼のＣ含有量に応じて
最高の焼入れ硬さとなる焼入れ温度に15分間保持
後油冷し、150〜600℃で焼戻しを行なつて製造し
た試験材により行なつた。以下の図面におけるＤ
は18％Cr材である。
第８図はＣ含有量と硬さとの関係を示すが、特
に、工具鋼としての製品硬さを決定する500℃焼
戻し硬さを示してあり、高いほど好ましい。この
第８図より明らかなように、Ｃ含有量は1.7％ま
では硬さが増大するものの、それよりＣ量が増え
ても硬さは増大しない。
第９図はＣ含有量と抗折力との関係を示すが、
最大の抗折力を示すＣ含有量は２％である。
第１０図、第１１図はHv750における大越式摩
耗試験機による摩耗特性を、第４図、第５図と同
じく摩擦速度0.3m／secの酸化摩耗領域（第１０
図）と摩擦速度2.86m／secの凝着摩耗領域（第
１１図）とについて、Ｃ含有量と比摩耗量との関
係を示したものである。
この場合の摩擦条件は次の通りである。
相手材：SCM415
摩擦距離：400m
最終荷重：6.3Kg
潤滑：無し
即ち、第１０図では、Ｃ含有量が２％で比摩耗
量が極小となり、第１１図では、Ｃ含有量が1.7
％を越えると比摩耗量は充分少なくなつている。
第１２図はＣ含有量と上記した機械加工の点か
ら低い方が好ましい焼なまし硬さとの関係を示す
もので、Ｃ含有量が2.5％を越えると急に硬くな
つている。
従つて、第８図〜第１２図、特に、第１１図、
第１２図の結果より、耐摩耗性の観点（第１１
図）からはＣは少なくとも1.6％以上必要であり、
また、焼なまし硬さ（＝機械加工性（第１２図））
の観点からは、Ｃを2.5％以下に抑える必要があ
る。そして、第８図〜第１２図のCr含有量は18
％であるので、Ｃの最適範囲である1.6〜2.5％に
対してCr％／Ｃ％をとると、７〜11となつて、
上記に説明したCrとＣとの比の値が裏付けられ
る。
上記に説明した第１図〜第１２図の結果をさら
に裏付けるため、第２図〜第１２図より、500℃
における焼戻し硬さHv750における抗折力、焼な
まし硬さのデータを第１３図に、また、比摩耗量
＝耐摩耗性についてのデータを第１４図に各々Ｃ
とCrの量でプロツトし直して再度整理してみた。
また、Cr系炭化物中最高の硬さを示すM7C3の
炭化物生成領域（図中ｙ）もＣ含有量とCr含有
量より予測して特定してみた。
第１３図、第１４図共に縦線で示す範囲が、こ
れまでに特定した抗折力、焼なまし硬さ、耐摩耗
性が共に優れている本発明に係る高靱性高耐摩耗
性工具鋼の範囲である。即ち、縦線で示す範囲の
中横軸の上限、下限はCr含有量の上限値、下限
値によつて規定されており、縦軸の上限、下限は
Cr含有量とＣ含有量との比７〜11（第１３図およ
び第１４図において、Cr／Ｃ＝７の線１が上限
の斜めの線で、Cr／Ｃ＝11の線２が下限の斜め
の線）によつて規定している。
また、第１３図、第１４図で◎は各特性が良で
×は悪いことを示し、
ｘは（CrFe）3Ｃ＋（CrFe）7C3を、
ｙは所望とするM7C3型炭化物（CrFe）7C3、
ｚは（CrFe）7C3＋（CrFe）23C6を、
ｗは（CrFe）23C6を夫々示す。
この第１３図、第１４図の結果より、本発明の
高靱性高耐摩耗性工具鋼において規定した範囲
が、ｙの領域＝所望するM7C3型炭化物生成領域
と一致しており、本発明に係る高靱性高耐摩耗性
工具鋼における規定が炭化物生成の観点からも裏
付けられることがわかる。
第１５図、第１６図は18％Cr材のＶ含有量と
抗折力と焼なまし硬さについての関係を示すもの
で、Ｖ含有量が約３％を越えると抗折力250Kg／
mm2以下に低くなり、逆に焼なまし硬さは高くな
る。よつて、Ｖ含有量は3.5％以下とするのがよ
いのである。
第１７図はHv750における抗折力を、2C−
18Cr鋼と２％Ｃ−18％Cr−２％Mo鋼を比較して
示したもので、抗折力には差がないものである。
第１８図は２％Ｃ−18％Cr鋼と２％Ｃ−18％
Cr−２％Mo鋼の焼なまし硬さを示すが、略同じ
硬さを示している。
さらに、本発明に係る高靱性高耐摩耗性工具鋼
と従来の工具鋼との顕微鏡組織について説明する
と、従来の工具鋼（SKD11で鍛練比20以上）は
第１９図に示し、また、２％Ｃ−18％Cr−２％
Mo鋼（asHIP）を第２０図に示す。この第１９
図および第２０図の顕微鏡写真からも明らかであ
るが、第２０図に示す本発明に係る高靱性高耐摩
耗性工具鋼（２％Ｃ−18％Cr−2Mo鋼）の粉末
治金法による鋼が、従来の工具鋼（SKD11、溶
融法）により炭化物が均一微細に分布しているこ
とがわかる。
また、MoとＷとを単独、或いは、同時に含有
させた場合の工具鋼の性能を与える影響について
調査を行つた。
即ち、第１表（続）に記載した2C−18Cr−1V
を基本とし、これにMoのみを含有させたもの
（2C−18Cr−1V−2Mo）、MoとＷを同時に含有
させたもの（2C−18Cr−1V−1Mo−2W）、Ｗの
みを含有させたもの（2C−18Cr−1V−4W）の
３種類の工具鋼の性能を第２表に示す。
なお、第１表（続）の工具鋼は、第１表に記載
の工具鋼と同一の製造条件であり、熱処理のみ
1030℃の温度において焼入れ、550℃の温度にお
いて焼戻しを行つたものである。
第２表から明らかな通り、MoとＷとを単独、
或いは、MoとＷとを同時に含有させた場合のそ
れぞれの抗折力、硬さ、および、比摩耗量には大
差のないことがわかる。[Table] First, in order to investigate the influence of C content on the relationship between Cr content and various properties, steels (a) with C contents of 2% and 3% were selected from among the steels in Table 1. I conducted a test. In addition, in Figures 1 to 6, A is C2% material,
B indicates C3% material, and C indicates SKD11 (melted material). FIG. 1 shows the test results for selecting the quenching temperature among the test conditions for conducting the following characteristic tests. In other words, Figure 1 simply shows that the Cr content of each steel is
The relationship between the quenching temperature and the maximum quenching hardness is shown. Each test described below was originally intended to improve wear resistance, so it was held for 15 minutes at the quenching temperature that indicates the highest quenched hardness corresponding to each Cr content, cooled in oil, and tempered at 150 to 600℃. The test was carried out using test materials manufactured under the conditions specified for the test. Figure 2 shows the relationship between Cr content and hardness. In particular, it shows the hardness after tempering at 500°C. As shown by solid line A, at 2%C and up to 18% Cr content, the hardness is extremely high. However, even if the Cr content exceeds 18%, the hardness does not increase and there is no significant difference. However, as shown by dashed line B, 3%C has the same Cr content (10%~20%)
It can be seen that the hardness is lower than that of 2%C. Figure 3 shows the relationship between Cr content and transverse rupture strength.
2%C in solid line A shows high toughness regardless of the Cr content, but
Although the 3% C shown by the broken line B has a lower transverse rupture strength than the 2% C shown by the solid line A, the 18% Cr steel exhibits the highest toughness. Therefore, considering the case of 3% C, it can be seen that Cr of about 18% is preferable. Figures 4 and 5 show the wear characteristics measured by the Okoshi type wear tester at Hv750, in the oxidative wear region with a friction speed of 0.3 m/sec (Figure 4) and in the adhesive wear region with a friction speed of 2.86 m/sec (Figure 5). The relationship between the Cr content and the specific wear amount is shown for each of the above figures. The friction conditions in this case are as follows. Mating material: SCM415 Friction distance: 400m Final load: 6.3Kg Lubrication: None In other words, oxidation wear (abrasive wear) shown in Figure 4
In this range, 2% C (solid line A) is superior to 3% C (broken line B), and in either case, the greater the Cr content, the better the wear resistance. In addition, in the adhesive wear region shown in Figure 5, there is no change in wear resistance when the Cr content is 18% or more for both 2%C and 3%C.Therefore, from the results in Figures 4 and 5, the wear resistance From the viewpoint of properties, it is clear that the Cr content must be at least 17%. Figure 6 shows the relationship between Cr content and annealing hardness.
HIP treatment → (hot working) → annealing → machining →
Considering the manufacturing process that involves heat treatment (quenching, tempering), a lower value is preferable in terms of machining. Also,
Figure 6 shows that 3%C is not affected much by the Cr content, but for 2%C, when the Cr content exceeds 20%, the annealing hardness rises suddenly, which has a big impact on tool manufacturing. From the perspective of annealing hardness, Cr
It can be seen that the amount needs to be kept to a maximum of 21% or less. From the above results, especially in Figures 5 and 6, it is clear that the Cr content needs to be 17% or more from the perspective of wear resistance, and 21% or less from the perspective of annealing hardness. It is supported. Next, it is clear that the relationship between Cr content and properties is greatly influenced by C content.
It is also clear that in order to exhibit optimal properties, it is necessary to understand the correlation between C content and Cr content. Therefore, as shown in FIGS. 7 to 12,
Using (b) in Table 1 with the Cr content constant at 18% and the C content varied, investigate the relationship between the C content and properties in the same way as in Figures 1 to 6 above. did. FIG. 7 is the same as FIG. 1 and simply shows the quenching temperature at which the maximum hardness is obtained for each steel with a C content. The various tests described below were carried out using test materials manufactured by holding the quenching temperature for 15 minutes at the quenching temperature that gives the highest quenching hardness according to the C content of each steel, cooling in oil, and tempering at 150 to 600℃. Summer. D in the following drawings
is a 18% Cr material. FIG. 8 shows the relationship between C content and hardness, and particularly shows the 500°C tempering hardness, which determines the product hardness as a tool steel, and the higher the hardness, the better. As is clear from FIG. 8, the hardness increases when the C content reaches 1.7%, but the hardness does not increase even if the C content increases beyond that. Figure 9 shows the relationship between C content and transverse rupture strength.
The C content exhibiting the maximum transverse rupture strength is 2%. Figures 10 and 11 show the wear characteristics measured by the Ohkoshi wear tester at Hv750 in the oxidative wear region (10
Fig. 11 shows the relationship between C content and specific wear amount for the adhesive wear region (Fig. 11) where the friction speed is 2.86 m/sec. The friction conditions in this case are as follows. Mating material: SCM415 Friction distance: 400m Final load: 6.3Kg Lubrication: None In other words, in Figure 10, the specific wear amount is minimal when the C content is 2%, and in Figure 11, the C content is 1.7
%, the specific wear amount is sufficiently small. Figure 12 shows the relationship between the C content and the annealing hardness, which is preferable from the viewpoint of machining as described above, and when the C content exceeds 2.5%, the steel suddenly becomes hard. Therefore, FIGS. 8 to 12, especially FIG. 11,
From the results shown in Figure 12, from the viewpoint of wear resistance (11
From the figure), C is required to be at least 1.6%,
Also, annealing hardness (= machinability (Fig. 12))
From this point of view, it is necessary to suppress C to 2.5% or less. And the Cr content in Figures 8 to 12 is 18
%, so if we take Cr%/C% for the optimal range of C, 1.6-2.5%, it becomes 7-11.
The value of the ratio of Cr and C explained above is supported. In order to further support the results shown in Figs. 1 to 12 explained above, from Figs.
Figure 13 shows data on transverse rupture strength and annealing hardness at tempering hardness Hv750, and Figure 14 shows data on specific wear = wear resistance.
I re-plotted it with the amount of Cr and rearranged it again. In addition, the carbide formation region (y in the figure) of M 7 C 3 , which exhibits the highest hardness among Cr-based carbides, was also predicted and specified from the C content and Cr content. The range shown by vertical lines in both FIGS. 13 and 14 is the high-toughness, high-wear-resistant tool steel of the present invention that has been identified so far as having excellent transverse rupture strength, annealing hardness, and wear resistance. is within the range of In other words, in the range indicated by the vertical line, the upper and lower limits on the horizontal axis are defined by the upper and lower limits of the Cr content, and the upper and lower limits on the vertical axis are defined by the upper and lower limits of the Cr content.
The ratio of Cr content to C content is 7 to 11 (in Figures 13 and 14, line 1 for Cr/C = 7 is the upper diagonal line, and line 2 for Cr/C = 11 is the lower limit. (diagonal line). In addition, in Figures 13 and 14, ◎ indicates that each property is good and × indicates that each property is poor, x indicates (CrFe) 3 C + (CrFe) 7 C 3 , and y indicates the desired M 7 C 3 type carbide. (CrFe) 7 C 3 , z represents (CrFe) 7 C 3 + (CrFe) 23 C 6 , and w represents (CrFe) 23 C 6 , respectively. From the results shown in FIGS. 13 and 14, the range specified for the high toughness and high wear resistance tool steel of the present invention matches the region of y = desired M 7 C 3 type carbide formation region, and the present invention It can be seen that the provisions regarding the high toughness and high wear resistance tool steel according to the invention are also supported from the viewpoint of carbide formation. Figures 15 and 16 show the relationship between the V content, transverse rupture strength, and annealing hardness of 18% Cr material. When the V content exceeds about 3%, the transverse rupture strength is 250 kg/
mm 2 or less, and conversely, the annealing hardness increases. Therefore, the V content is preferably 3.5% or less. Figure 17 shows the transverse rupture force at Hv750, 2C-
This is a comparison of 18Cr steel and 2%C-18%Cr-2%Mo steel, and there is no difference in transverse rupture strength. Figure 18 shows 2%C-18%Cr steel and 2%C-18%
The annealing hardness of Cr-2%Mo steel is shown, and the hardness is approximately the same. Furthermore, to explain the microstructures of the high toughness and high wear resistance tool steel according to the present invention and conventional tool steels, the conventional tool steel (SKD11 with a forging ratio of 20 or more) is shown in FIG. C-18%Cr-2%
Figure 20 shows Mo steel (asHIP). This 19th
As is clear from the micrographs shown in Fig. 20 and Fig. 20, the high toughness and high wear resistance tool steel (2%C-18%Cr-2Mo steel) according to the present invention shown in Fig. 20 was produced by powder metallurgy. It can be seen that the carbides are uniformly and finely distributed in the steel due to the conventional tool steel (SKD11, melting method). We also investigated the effects on the performance of tool steel when Mo and W are contained singly or simultaneously. That is, 2C−18Cr−1V listed in Table 1 (continued)
Based on this, one containing only Mo (2C-18Cr-1V-2Mo), one containing Mo and W at the same time (2C-18Cr-1V-1Mo-2W), and one containing only W. Table 2 shows the performance of three types of tool steel (2C-18Cr-1V-4W). Note that the tool steels in Table 1 (continued) are produced under the same manufacturing conditions as the tool steels listed in Table 1, and only heat treated.
It was quenched at a temperature of 1030°C and tempered at a temperature of 550°C. As is clear from Table 2, when Mo and W are used alone,
Alternatively, it can be seen that when Mo and W are contained at the same time, there is no significant difference in transverse rupture strength, hardness, and specific wear amount.
【表】
この実施例からわかるように、本発明に係る高
靱性高耐摩耗性工具鋼は、従来の溶融法による工
具鋼（SKD11）に比して、硬さ、抗折力、比摩
耗量において同等かそれ以上の優れた性能を示し
ていることは明らかである。
［発明の効果］
以上説明したように、本発明に係る高靱性高耐
摩耗性工具鋼は上記の構成を有しており、かつ、
HIP処理により製造されたものであるから、炭化
物が均一微細に分布しているため、靱性、疲労、
熱疲労等の機械的性質、鍛造、引抜き加工、研削
等の加工性および熱処理性を改善することがで
き、さらに、耐熱性、耐摩耗性が改善されるので
高合金化が可能となる等の優れた効果を奏するも
のである。[Table] As can be seen from this example, the high toughness and high wear resistance tool steel according to the present invention has higher hardness, transverse rupture strength, and specific wear amount than the tool steel produced by the conventional melting method (SKD11). It is clear that the performance is equivalent to or even better than that of the previous one. [Effects of the Invention] As explained above, the high toughness and high wear resistance tool steel according to the present invention has the above configuration, and
Because it is manufactured by HIP processing, the carbides are uniformly and finely distributed, which improves toughness, fatigue, and
Mechanical properties such as thermal fatigue, workability such as forging, drawing, and grinding, and heat treatability can be improved.Furthermore, heat resistance and wear resistance are improved, making it possible to form high alloys. It has excellent effects.
第１図はCr含有量と焼入れ温度との関係を示
すグラフ、第２図はCr含有量と硬さの関係を示
すグラフ、第３図はCr含有量と抗折力との関係
を示すグラフ、第４図、第５図はCr含有量と比
摩耗量との関係を示すグラフ、第６図はCr含有
量と焼なまし硬さとの関係を示すグラフ、第７図
はＣ含有量と焼入れ温度の関係を示すグラフ、第
８図はＣ含有量と硬さの関係を示すグラフ、第９
図はＣ含有量と抗折力との関係を示すグラフ、第
１０図、第１１図はＣ含有量と比摩耗量との関係
を示すグラフ、第１２図はＣ含有量と硬さとの関
係を示すグラフ、第１３図、第１４図は本発明に
係る高靱性高耐摩耗性工具鋼のCr含有量とＣ含
有量との関係を示すグラフ、第１５図、第１６図
はＶ含有量と抗折力と硬さとの関係を示すグラ
フ、第１７図、第１８図は２％−18％Cr鋼と、
２％−18％Cr−2Mo％鋼との抗折力と硬さにつ
いて示したグラフ、第１９図はSKD11の金属組
織を示す顕微鏡写真、第２０図は本発明に係る高
靱性高耐摩耗性工具鋼（２％−18％Cr−2Mo％
鋼）の金属組織を示す顕微鏡写真である。
Figure 1 is a graph showing the relationship between Cr content and quenching temperature, Figure 2 is a graph showing the relationship between Cr content and hardness, and Figure 3 is a graph showing the relationship between Cr content and transverse rupture strength. , Figures 4 and 5 are graphs showing the relationship between Cr content and specific wear amount, Figure 6 is a graph showing the relationship between Cr content and annealing hardness, and Figure 7 is a graph showing the relationship between Cr content and annealing hardness. Figure 8 is a graph showing the relationship between quenching temperature and Figure 9 is a graph showing the relationship between C content and hardness.
The figure is a graph showing the relationship between C content and transverse rupture strength, Figures 10 and 11 are graphs showing the relationship between C content and specific wear amount, and Figure 12 is the relationship between C content and hardness. FIGS. 13 and 14 are graphs showing the relationship between the Cr content and C content of the high toughness and high wear resistance tool steel according to the present invention, and FIGS. 15 and 16 are graphs showing the relationship between the V content. Graphs showing the relationship between transverse rupture strength and hardness, Figures 17 and 18 are for 2%-18% Cr steel,
A graph showing the transverse rupture strength and hardness of 2%-18%Cr-2Mo% steel, Figure 19 is a micrograph showing the metal structure of SKD11, and Figure 20 is the high toughness and high wear resistance according to the present invention. Tool steel (2%-18%Cr-2Mo%
Fig. 2 is a micrograph showing the metallographic structure of steel.
Claims (1)
化させた工具鋼であつて、含有成分、成分割合
が、 Cr15〜21％、 Ｃを７≦Cr％（Ｃ％−0.2V％）≦11 の比率 で含有し、さらに、 V3.5％以下、W0.3％以上、Mo0.15％以上で、
かつ、 （Ｗ＋2Mo）８％以下 の１種または２種以上 を含み、残部Feおよび不純物からなり抗折力250
Kg／mm2以上の高靱性高耐摩耗性HIP処理工具鋼。[Scope of Claims] 1. A tool steel made by sintering and densifying steel powder through hot isostatic pressure treatment, the ingredients and proportions of which are 15 to 21% Cr and 7≦Cr% (C%). −0.2V%)≦11, and furthermore, V3.5% or less, W0.3% or more, Mo0.15% or more,
Contains one or more of (W + 2Mo) 8% or less, with the balance consisting of Fe and impurities, and has a transverse rupture strength of 250
High toughness and high wear resistance HIP treated tool steel with Kg/mm 2 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9811182A JPS58213856A (en) | 1982-06-08 | 1982-06-08 | Tool steel of high toughness and high wear resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9811182A JPS58213856A (en) | 1982-06-08 | 1982-06-08 | Tool steel of high toughness and high wear resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58213856A JPS58213856A (en) | 1983-12-12 |
| JPH0478716B2 true JPH0478716B2 (en) | 1992-12-11 |
Family
ID=14211208
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9811182A Granted JPS58213856A (en) | 1982-06-08 | 1982-06-08 | Tool steel of high toughness and high wear resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58213856A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59200743A (en) * | 1983-04-26 | 1984-11-14 | Daido Steel Co Ltd | Sintered alloy steel |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5538938A (en) * | 1978-09-11 | 1980-03-18 | Mitsubishi Metal Corp | Fe base sintered alloy with wear resistance |
| JPS55148745A (en) * | 1979-05-08 | 1980-11-19 | Mitsubishi Metal Corp | Manufacture of iron type sintered alloy member |
| JPS57198240A (en) * | 1981-05-29 | 1982-12-04 | Sumitomo Electric Ind Ltd | Manufacture of wear resistant sintered alloy |
-
1982
- 1982-06-08 JP JP9811182A patent/JPS58213856A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5538938A (en) * | 1978-09-11 | 1980-03-18 | Mitsubishi Metal Corp | Fe base sintered alloy with wear resistance |
| JPS55148745A (en) * | 1979-05-08 | 1980-11-19 | Mitsubishi Metal Corp | Manufacture of iron type sintered alloy member |
| JPS57198240A (en) * | 1981-05-29 | 1982-12-04 | Sumitomo Electric Ind Ltd | Manufacture of wear resistant sintered alloy |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58213856A (en) | 1983-12-12 |
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