JPH05171373A - Powder high speed tool steel - Google Patents
Powder high speed tool steelInfo
- Publication number
- JPH05171373A JPH05171373A JP34068891A JP34068891A JPH05171373A JP H05171373 A JPH05171373 A JP H05171373A JP 34068891 A JP34068891 A JP 34068891A JP 34068891 A JP34068891 A JP 34068891A JP H05171373 A JPH05171373 A JP H05171373A
- Authority
- JP
- Japan
- Prior art keywords
- amount
- speed tool
- high speed
- tool steel
- ceq
- 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
- 229910001315 Tool steel Inorganic materials 0.000 title claims abstract description 16
- 239000000843 powder Substances 0.000 title claims abstract description 15
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 10
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 10
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 8
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 238000005260 corrosion Methods 0.000 abstract description 8
- 230000007797 corrosion Effects 0.000 abstract description 8
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 229910000831 Steel Inorganic materials 0.000 description 19
- 239000010959 steel Substances 0.000 description 19
- 239000013078 crystal Substances 0.000 description 17
- 238000010791 quenching Methods 0.000 description 15
- 230000000171 quenching effect Effects 0.000 description 15
- 150000001247 metal acetylides Chemical class 0.000 description 11
- 239000011159 matrix material Substances 0.000 description 10
- 238000005496 tempering Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 8
- 230000001965 increasing effect Effects 0.000 description 7
- 238000005275 alloying Methods 0.000 description 6
- 239000006104 solid solution Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052750 molybdenum Inorganic materials 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 238000001513 hot isostatic pressing Methods 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000005242 forging Methods 0.000 description 2
- 239000010705 motor oil Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 1
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 1
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000997 High-speed steel Inorganic materials 0.000 description 1
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 1
- 239000005642 Oleic acid Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、切削工具や圧造工具に
用いられ、特に高温における硬さと耐摩耗性が要求され
る高速使用条件下において、顕著に優れた耐摩耗性と同
時に高い靭性を有し、さらに耐食性の優れた粉末高速度
工具鋼に関するものである。BACKGROUND OF THE INVENTION The present invention is used for cutting tools and forging tools, and particularly under high-speed use conditions where hardness and wear resistance at high temperatures are required, it is possible to obtain not only excellent wear resistance but also high toughness. The present invention relates to a powder high speed tool steel having excellent corrosion resistance.
【０００２】[0002]
【従来の技術】切削工具、圧造工具に用いられる高速度
工具鋼は、高硬度で耐摩耗性が優れること、および靭性
に優れること、の２つの要求を満足することが望まれて
いる。また、近年、プラスチック金型、ドットワイヤー
などの用途によっては耐食性も必要とされる。溶製高速
度工具鋼の靭性を向上させる方法としては、Ｎb等の元
素を微量添加し、結晶粒を微細化させて靭性を向上する
方法(例えば特開昭58-73753号、同58-117863号等)、Ｎb
と希土類元素を複合添加することにより、Ｎbを主体と
したＭＣ型炭化物を均一微細化する方法(特公昭61-896
号)等種々提案されている。2. Description of the Related Art High-speed tool steels used for cutting tools and forging tools are required to satisfy the two requirements of high hardness and excellent wear resistance and toughness. Further, in recent years, corrosion resistance is also required depending on applications such as plastic molds and dot wires. As a method for improving the toughness of the molten high speed tool steel, a method of adding a trace amount of an element such as Nb and refining the crystal grains to improve the toughness (for example, JP-A-58-73753 and 58-117863). No.), Nb
A method of uniformly refining MC type carbide mainly composed of Nb by adding a rare earth element together with a rare earth element (Japanese Patent Publication Sho 61-896).
No.) etc. have been proposed.
【０００３】一方、耐摩耗性を向上させる方法として
は、炭化物を均一微細に分布させ、かつ結晶粒の微細化
が可能な粉末高速度工具鋼において、炭化物量を増大さ
せる方法が最も一般的である。例えば、特公昭57-2142
号、特開昭55-148747号は、主にＷ当量を高めることに
より、Ｗ，Ｍoを主体とするＭ6Ｃ型炭化物量を増加さ
せ、高硬度化により耐摩耗性の向上を図ったものであ
る。また、粉末高速度工具鋼において、結晶粒の微細化
と、さらには、焼入温度を高めても結晶粒を粗大化させ
ないことを目的として、Ｎbを含有せしめることが検討
されている｛Metall.Trans.19A(1988) P1395〜1401,特
開平1-212736号｝。On the other hand, the most general method for improving wear resistance is to increase the amount of carbide in powder high speed tool steel in which carbide is uniformly and finely distributed and crystal grains can be refined. is there. For example, Japanese Examined Sho 57-2142
And JP-A-55-148747, the amount of M 6 C type carbides mainly containing W and Mo is increased by mainly increasing the W equivalent, and the wear resistance is improved by increasing the hardness. Is. Further, in the powder high speed tool steel, it is considered to contain Nb for the purpose of refining the crystal grains and further preventing the crystal grains from being coarsened even if the quenching temperature is raised {Metall. Trans. 19A (1988) P1395 to 1401, Japanese Patent Laid-Open No. 1-212736}.
【０００４】[0004]
【発明が解決しようとする課題】しかし、前記特開昭58
-73753号、同58-117863号の溶製高速度工具鋼では、Ｎb
を過度に添加すると、Ｎbを主体としたＮbＣの粗大な炭
化物を晶出し、Ｗ，Ｍoを主体とするＭ6Ｃ型炭化物も、
凝固時に粗大な炭化物を晶出させるために、結晶粒微細
化による靭性向上効果が減殺され、かえって靭性が低下
するといった問題点があった。また、上記の粉末高速度
工具鋼で、耐摩耗性を向上させる目的で、炭化物量の富
化や工具の高硬度化が行なわれてきたが、靭性が低下し
てしまい、工具の折損や欠けが問題となっていた。However, the above-mentioned Japanese Patent Laid-Open No. 58-58
-73753 and 58-117863 melted high speed tool steels have Nb
When N is excessively added, coarse NbC carbides mainly composed of Nb are crystallized, and M 6 C type carbides mainly composed of W and Mo are also
Since a coarse carbide is crystallized during solidification, there is a problem that the effect of improving the toughness by refining the crystal grains is diminished and the toughness is rather lowered. Further, in the above powder high-speed tool steel, the amount of carbide and the hardness of the tool have been increased for the purpose of improving wear resistance, but the toughness is lowered, and the tool is broken or chipped. Was a problem.
【０００５】また、前記特開昭55-148747号に、Ｎbを添
加した粉末高速度鋼が提案されているが、この例ではＮ
bをＶの代替として添加し、硬質の炭化物を形成するこ
とを主眼においたものである。さらに、Metall.Trans.1
9A(1988) P1395〜P1401、特開平1-212736号に開示され
る高速度工具鋼は、Ｎbを添加することにより、結晶粒
を粗大化せずに焼入温度を高めることを可能としている
が、本発明者の考えによると合金元素量、特にＷ当量が
低いために、苛酷な工具使用条件下では高温焼もどし軟
化抵抗が不十分で、また炭化物量も少ないため、耐摩耗
性も不十分である。Further, Japanese Patent Laid-Open No. 55-148747 proposes a powder high-speed steel containing Nb.
The main purpose is to add b as a substitute for V to form a hard carbide. Furthermore, Metall.Trans.1
The high speed tool steel disclosed in 9A (1988) P1395 to P1401 and Japanese Patent Laid-Open No. 1-212736 makes it possible to increase the quenching temperature without coarsening the crystal grains by adding Nb. According to the inventor's idea, the alloying element amount, particularly the W equivalent, is low, so that the high temperature temper softening resistance is insufficient under severe tool use conditions, and the carbide content is also small, so that the wear resistance is insufficient. Is.
【０００６】したがって、以上説明した従来の高速度工
具鋼は、高速化が要求されている近時の工具使用条件に
対応することが困難であった。そこで、本発明は工具使
用条件の高速化に対応できる高温焼もどし軟化抵抗特性
を顕著に高めるとともに、高靭性でかつ耐食性に優れた
粉末高速度工具鋼の提供を課題とする。Therefore, it has been difficult for the conventional high-speed tool steel described above to meet the recent tool usage conditions in which high speed is required. Therefore, an object of the present invention is to provide a powder high-speed tool steel having high toughness and excellent corrosion resistance, while significantly improving high-temperature tempering softening resistance characteristics capable of accommodating high-speed tool usage conditions.
【０００７】[0007]
【課題を解決するための手段】近年、工具の使用条件が
高速化されるにつれ、工具の高硬度化が重要な要因とな
っている。特に工具使用中に、工具が高温になるため、
焼もどし軟化抵抗特性が最も重要であることを知見し
た。In recent years, as the use conditions of tools have become faster, increasing the hardness of the tools has become an important factor. Especially when using the tool, the temperature of the tool becomes high,
It was found that the temper softening resistance characteristics are the most important.
【０００８】本発明は、この知見を考慮してなされたも
ので、下記の２点を基本的な技術思想とするものであ
る。焼もどし軟化抵抗を最大限に高めるために、化学
成分上、特に、Ｗ＋２Ｍo、およびＣ−Ｃeqを特定範囲
内に規制することが有効であることを見出した。すなわ
ち、Ｗ＋２Ｍo量を増すことにより、硬い炭化物を分散
させ、マトリックス中に固溶する合金元素量を増すこと
が有効である。Ｃ量は他の炭化物形成元素量との兼ね合
いで決める必要があり、Ｃ−Ｃeqで調整される。高い焼
もどし軟化抵抗を得るためには、Ｃ−Ｃeqを規制し、マ
トリックス中に固溶するＣ量を確保することが必要であ
る。The present invention has been made in view of this knowledge, and the following two points are the basic technical ideas. It has been found that in order to maximize the temper softening resistance, it is effective to regulate W + 2Mo and C-Ceq within a specific range in terms of chemical composition. That is, it is effective to increase the amount of W + 2Mo to disperse hard carbides and increase the amount of alloying elements dissolved in the matrix. The amount of C needs to be determined in consideration of the amounts of other carbide forming elements, and is adjusted by C-Ceq. In order to obtain a high tempering softening resistance, it is necessary to regulate C-Ceq and secure the amount of C that forms a solid solution in the matrix.
【０００９】多くの合金元素をマトリックス中へ固溶
せしめんとして焼入温度を高くすると、結晶粒が粗大化
するが、これをＮｂを含有せしめ、かつそのＮｂ／Ｖ比
を規制することにより、結晶粒の粗大化を防止し、微細
結晶粒を確保し、靭性の低下を防止する。ＮｂはＶと同
様ＭＣ炭化物を形成するが、結晶粒の粗大化を防止する
のに有効な1μm以下の微細ＮbＣを形成するためには、
原子比でＶよりも多いＮbを含有しなければならない。
重量比ではＮb/Ｖが0.5以上必要である。[0009] When many quenching temperatures are used as a solid solution of many alloying elements in the matrix, the crystal grains become coarse. However, by containing Nb and controlling the Nb / V ratio, Prevents coarsening of crystal grains, secures fine crystal grains, and prevents deterioration of toughness. Nb forms MC carbides like V, but in order to form fine NbC of 1 μm or less, which is effective for preventing coarsening of crystal grains,
It must contain more Nb than V in atomic ratio.
In weight ratio, Nb / V should be 0.5 or more.
【００１０】そして、これらは以下に示すような成分バ
ランスをさらに満たして、はじめて上記の特性を満足で
きることを見い出した。すなわち本発明は、重量比でＣ
1.5%を越え2.6%以下、Ｓi≦1.0%、Ｍn≦0.6%、Ｃr 6.0
%を越え13.0%以下、ＷまたはさらにＭoをＷ＋2Ｍoで14
〜30%、Ｖ≦10.0%、Ｎb 2.0〜7.0%、但しＮb/Ｖ≧0.5、
残部がＦeおよび不可避的不純物よりなり、Ｃ−Ｃeqが
−0.30〜0.05(Ceq=0.24＋0.033・Ｗ＋0.063・Ｍo＋0.2Ｖ
＋0.1・Ｎb)の関係を満たすことを特徴とする粉末高速度
工具鋼である。It has been found that the above characteristics can be satisfied for the first time by satisfying the following component balance. That is, the present invention uses C by weight.
Over 1.5% and up to 2.6%, Si ≦ 1.0%, Mn ≦ 0.6%, Cr 6.0
% And 13.0% or less, W or even Mo is W + 2 Mo 14
~ 30%, V≤10.0%, Nb 2.0 ~ 7.0%, but Nb / V≥0.5,
The balance consists of Fe and inevitable impurities, and C-Ceq is -0.30 to 0.05 (Ceq = 0.24 + 0.033 ・ W + 0.063 ・ Mo + 0.2V
It is a powder high speed tool steel characterized by satisfying the relationship of + 0.1 · Nb).
【００１１】また、本発明は重量比でＣ 1.5%を越え2.6
%以下、Ｓi≦1.0%、Ｍn≦0.6%、Ｃr6.0%を越え13.0%以
下、ＷまたはさらにＭoをＷ＋2Ｍoで14〜30%、Ｖ≦10.0
%、Ｎb 2.0〜7.0%、但しＮb/Ｖ≧0.5、Ｃo 4.0〜15.0
%、残部がＦeおよび不可避的不純物よりなり、Ｃ−Ｃeq
が−0.30〜0.05(Ceq=0.24＋0.033・Ｗ＋0.063・Ｍo＋0.2
Ｖ＋0.1・Ｎb)の関係を満たすことを特徴とする粉末高速
度工具鋼である。また、耐摩耗性を向上するためには、
Ｎｂ＋Ｖ＞６の関係を満たすことが好ましい。The present invention also has a weight ratio of more than C 1.5% and 2.6.
% Or less, Si ≦ 1.0%, Mn ≦ 0.6%, Cr6.0% over 13.0%, W or further Mo is W + 2Mo, 14 to 30%, V ≦ 10.0
%, Nb 2.0 to 7.0%, but Nb / V ≧ 0.5, Co 4.0 to 15.0
%, The balance consisting of Fe and unavoidable impurities, and C-Ceq
Is -0.30 to 0.05 (Ceq = 0.24 + 0.033 ・ W + 0.063 ・ Mo ＋ 0.2
It is a powder high speed tool steel characterized by satisfying the relationship of V + 0.1 · Nb). Also, in order to improve wear resistance,
It is preferable to satisfy the relationship of Nb + V> 6.
【００１２】[0012]
【作用】以下に成分の限定理由を説明する。Ｃは同時に
添加されるＣr,Ｗ，Ｍo,Ｖ,Ｎbと硬い炭化物を形成して
耐摩耗性向上に寄与する。さらに、焼入時にマトリック
ス中に固溶して焼もどし２次硬化を向上する作用もあ
る。しかし、多すぎるとマトリックス中に固溶する炭素
量が著しく増え靭性を低下させる。したがって、Ｃ量は
Ｃr,Ｗ，Ｍo,Ｖ,Ｎb含有量との兼ね合いで決める必要が
あり、本発明では1.5〜2.6%の範囲とＣ-Ｃeqの値が-0.3
00.05の関係を満足するようＣ量を調整する。この関係
を満足させることにより、高い高温焼もどし軟化抵抗を
得るための１条件が達成される。The reason for limiting the components will be described below. C forms a hard carbide with Cr, W, Mo, V, and Nb added at the same time, and contributes to the improvement of wear resistance. Further, it has a function of improving the secondary hardening by solid solution in the matrix during quenching. However, if the amount is too large, the amount of carbon solid-dissolved in the matrix increases remarkably and the toughness decreases. Therefore, the amount of C must be determined in consideration of the contents of Cr, W, Mo, V and Nb. In the present invention, the range of 1.5 to 2.6% and the value of C-Ceq are -0.3.
The amount of C is adjusted so as to satisfy the relationship of 00.05. By satisfying this relationship, one condition for achieving high high temperature temper softening resistance is achieved.
【００１３】Ｓi,Ｍnは脱酸剤として添加するが、多量
に添加すると靭性を害する等の問題があるので、Ｓi 1.
0%以下、Ｍn 0.6%以下に限定する。Ｃrは、本発明にお
いて、最も重要な元素の一つであり、6%を越えて添加す
ることにより、耐食性が著しく向上する。また、焼入性
を高め、焼もどし２次硬化性を高める効果もある。しか
し、13%を越えると焼もどし時の炭化物の凝集を速め、
本発明の第１の目的である軟化抵抗を減ずるため13%以
下とした。Si and Mn are added as deoxidizing agents, but if added in a large amount, there is a problem such as impairing toughness.
It is limited to 0% or less and Mn 0.6% or less. Cr is one of the most important elements in the present invention, and when it is added in excess of 6%, the corrosion resistance is remarkably improved. It also has the effect of enhancing the hardenability and the secondary hardening of the temper. However, when it exceeds 13%, the agglomeration of carbides during tempering is accelerated,
In order to reduce the softening resistance which is the first object of the present invention, it is set to 13% or less.
【００１４】本発明の目的である顕著な耐摩耗性を付与
するためには、硬い炭化物を多量に分散させ、しかもマ
トリックス硬度を高める必要がある。本発明で、Ｗ，Ｍ
o量は、上記の目的で重要な元素である。Ｗまたはさら
にＭoをＷ+2Ｍoで20〜30%とする。20%より少ないと上記
効果が少ない。しかし、Ｗ＋2Ｍoが30%を越えると、連
結した炭化物が急増し、マトリックス中に固溶する合金
元素も極端に多くなって靭性の低下が著しくなるので、
ＷまたはさらにＭoをＷ＋2Ｍoで20〜30%とする。In order to impart remarkable wear resistance, which is the object of the present invention, it is necessary to disperse hard carbides in a large amount and increase the matrix hardness. In the present invention, W, M
o Quantity is an important element for the above purposes. W or further Mo is 20 + 30% at W + 2 Mo. If it is less than 20%, the above effect is small. However, when W + 2Mo exceeds 30%, the number of connected carbides rapidly increases, the amount of alloying elements dissolved in the matrix becomes extremely large, and the toughness decreases remarkably.
W or further Mo is 20 + 30% at W + 2 Mo.
【００１５】Ｖもまた耐摩耗性を高めるのに有効な元素
である。耐摩耗性の目的からは、できるだけ多く含有さ
せたい。しかし、10%を越えると粗大なＭＣ型炭化物が
晶出し易くなり、靭性や工具の被研削性を害するので、
10%以下とした。Ｎbは、本発明において最も重要な元素
の一つである。Ｎbを特定の成分範囲に限定すると、耐
摩耗性に有効な1〜5μmのＮbを主体とした硬質の炭化物
と、1μm以下の微細な炭化物が晶出する。V is also an element effective in enhancing wear resistance. For the purpose of abrasion resistance, it is desirable to contain as much as possible. However, if it exceeds 10%, coarse MC type carbides are likely to crystallize, which impairs toughness and grindability of the tool.
It was set to 10% or less. Nb is one of the most important elements in the present invention. When Nb is limited to a specific component range, a hard carbide mainly composed of 1 to 5 μm Nb effective for wear resistance and a fine carbide of 1 μm or less are crystallized.
【００１６】本発明者は、この微細なＮbＣが結晶粒成
長を抑制し、焼入温度を高めても結晶粒の粗大化を効果
的に抑制する成分範囲を見出した。この微細なＮbＣは
Ｎb量、Ｎb/Ｖ比と密接に関係しておりＮb量及びＮb/Ｖ
比が低いと、微細なＮbＣがほとんど晶出しないため、
Ｎb≧2%およびＮb/Ｖ≧0.5となるようＮb量を調整し
た。しかし、Ｎbが7%を越えると、極めて粗大なＮbＣを
晶出し、靭性や被研削性を害するので、7%以下とした。
またＮbがＶに対して多くなり過ぎるとＮｂ炭化物が粗
大化する傾向となるためＮｂ/Ｖ≦２を満たすことが望
ましい。The present inventors have found a range of components in which this fine NbC suppresses the growth of crystal grains and effectively suppresses the coarsening of crystal grains even if the quenching temperature is raised. This fine NbC is closely related to the Nb amount and the Nb / V ratio, and the Nb amount and the Nb / V ratio.
If the ratio is low, fine NbC is hardly crystallized,
The amount of Nb was adjusted so that Nb ≧ 2% and Nb / V ≧ 0.5. However, when Nb exceeds 7%, extremely coarse NbC is crystallized and impairs toughness and grindability, so it was set to 7% or less.
Further, if Nb is too much with respect to V, Nb carbide tends to be coarsened, so that it is desirable to satisfy Nb / V ≦ 2.
【００１７】Ｃoは本発明鋼の焼きもどし軟化抵抗の向
上するために極めて有効な元素である。マトリックス中
に固溶し、炭化物の析出および凝集を遅らせ、高温にお
ける硬さと強度を著しく向上させる効果があり、切削工
具、エンドミル等の工具とワークの接触部が特に高温に
なる用途にとって極めて重要な添加元素である。しか
し、Ｃoが15.0%を越えると固溶によるＣo単独相の晶出
が生ずることにより靭性が低下するので15.0%以下とし
た。Co is an extremely effective element for improving the temper softening resistance of the steel of the present invention. It forms a solid solution in the matrix, delays the precipitation and agglomeration of carbides, and has the effect of significantly improving the hardness and strength at high temperatures, which is extremely important for applications where the contact part between the tool and the work such as cutting tools and end mills is particularly hot. It is an additive element. However, if Co exceeds 15.0%, the toughness decreases due to crystallization of the Co single phase due to solid solution, so the content was made 15.0% or less.
【００１８】[0018]
【実施例】表１に窒素ガスアトマイズ粉末をＨＩＰ(熱
間静水圧プレス処理)する方法により作製した６種類の
実験材の化学組成を示す。それぞれの材料は、ＨＩＰを
行ない、鍛伸により約16mm角とした後、該鍛伸材を860
℃で焼なまし、結晶粒が粗にならない温度範囲で可能な
限り高い温度で15分間のオーステナイト化を行なった
後、550℃の熱浴焼入を行なった。また、焼もどし温度
は560℃で行なった。なお、表１に示すΔＣはＣ−Ｃeq
の値である。[Examples] Table 1 shows the chemical compositions of six types of experimental materials produced by the method of HIP (hot isostatic pressing) of nitrogen gas atomized powder. Each material was subjected to HIP and forged to approximately 16 mm square, and then the forged material was 860
After annealing at ℃ for 15 minutes, austenitizing at a temperature as high as possible within a temperature range where crystal grains do not become coarse, and then hot bath quenching at 550 ℃ was carried out. The tempering temperature was 560 ° C. In addition, ΔC shown in Table 1 is C−Ceq.
Is the value of.
【００１９】焼もどし後の硬さ、インターセプト法によ
る結晶粒度(焼入後)、650℃で1時間加熱保持後、空冷し
た際の硬さ(焼もどし軟化抵抗と称する)を測定した。こ
の材料の靭性を評価するため、上記した焼入れ、焼もど
しの熱処理を施した後、スパン50Lで曲げ試験を行なっ
た。また、アブレッシブ粒子として平均粒径 30μmのＳ
iＯ2を用い、ＳiＯ2 1200ccに対して、20%オレイン酸モ
ータオイル(商品名：トヨタキャステルモーターオイル)
混合液 400ccの割合で配合したスラリー中で40時間 810
rpmの回転速度で摩耗試験を行ない、腐食とアブレッシ
ブ摩耗を並行して起こさせ、摩耗減量を測定した。これ
らの結果を表２に示す。The hardness after tempering, the grain size by the intercept method (after quenching), and the hardness after air-cooling after holding at 650 ° C. for 1 hour (referred to as tempering softening resistance) were measured. In order to evaluate the toughness of this material, after carrying out the above-mentioned quenching and tempering heat treatment, a bending test was carried out with a span of 50 L. Also, as abrasive particles, S having an average particle size of 30 μm
20% oleic acid motor oil (commercial name: Toyota Castel motor oil) with respect to SiO 2 1200cc using iO 2.
40 hours in slurry mixed with 400cc of mixture 810
A wear test was carried out at a rotation speed of rpm, corrosion and abrasive wear were caused in parallel, and the wear loss was measured. The results are shown in Table 2.
【００２０】[0020]
【表１】 [Table 1]
【００２１】[0021]
【表２】 [Table 2]
【００２２】表１に示す合金のうち試料Ｎo.1〜Ｎo.5
は、Ｎb含有量を変化させたものである。Ｎo.1およびＮ
o.2は、本発明鋼よりもＮbの少ない比較鋼であり、焼入
温度が1210℃を越えて高くなると結晶粒が急激に粗大化
し、抗折力が低下したため、焼入温度を1210℃に設定し
た。しかし、表２に示すように、1210℃の焼入温度で
は、マトリックス中への合金元素の固溶量が不十分で、
十分な焼もどし軟化抵抗が得られなかった。Samples No. 1 to No. 5 among the alloys shown in Table 1
Indicates that the Nb content is changed. No.1 and N
o.2 is a comparative steel containing less Nb than the steel of the present invention, and when the quenching temperature exceeds 1210 ° C and becomes high, the crystal grains abruptly coarsen and the transverse rupture strength decreases, so the quenching temperature is 1210 ° C. Set to. However, as shown in Table 2, at the quenching temperature of 1210 ° C, the solid solution amount of alloying elements in the matrix was insufficient,
Sufficient temper softening resistance could not be obtained.
【００２３】一方、Ｎb量が2%以上、Ｎb/Ｖが0.5以上の
本発明鋼である試料Ｎo.3およびＮo.4では、Ｎbの結晶
粒微細化の効果により、焼入温度 1250℃でも結晶粒の
粗大化が起こらず、1250℃の焼入温度が適用でき、この
焼入により比較鋼である試料Ｎo.1および試料Ｎo.2に比
べ、高い硬さ、高い焼もどし軟化抵抗および少ない摩耗
減量となった。また、Ｎb量が7%を越える比較鋼である
試料Ｎo.5は、5μm以上のＮbＣの巨大炭化物が多く発生
し、抗折強度が著しく低下した。On the other hand, in the samples No. 3 and No. 4 which are the steels of the present invention having an Nb content of 2% or more and an Nb / V of 0.5 or more, the quenching temperature of 1250 ° C. was obtained due to the effect of Nb crystal grain refinement. No quenching of crystal grains occurs, a quenching temperature of 1250 ° C can be applied, and this quenching has higher hardness, higher temper softening resistance and less resistance than the comparative steels No.1 and No.2. The amount of wear was reduced. Further, in sample No. 5, which is a comparative steel having an Nb content of more than 7%, a large amount of NbC giant carbide having a size of 5 μm or more was generated, and the transverse rupture strength was significantly reduced.
【００２４】また、本発明鋼である試料Ｎo.6は、Ｎb＋
Ｖの値が6%以下であるため、ＭＣ炭化物量が少なく摩耗
減量がやや大きくなった。また、Ｖが7%を越える本発明
鋼である試料Ｎo.7は、最も耐摩耗性が優れたものとな
った。また、Ｃが2.6%を越える比較鋼である試料Ｎo.8
では、ＭＣ型炭化物が増加し過ぎ抗折力が著しく低下し
た。また、Ｍoのない本発明鋼である試料Ｎo.9はほぼ同
一組成である試料Ｎo.6とほぼ同等の特性が得られるこ
とがわかった。Further, the sample No. 6 which is the steel of the present invention is Nb +
Since the value of V was 6% or less, the amount of MC carbide was small and the wear loss was slightly large. Further, Sample No. 7, which is a steel of the present invention in which V exceeds 7%, has the best wear resistance. In addition, sample No. 8 which is a comparative steel in which C exceeds 2.6%
Then, the MC type carbides increased too much, and the transverse rupture strength remarkably decreased. Further, it was found that the sample No. 9 which is the steel of the present invention having no Mo has almost the same characteristics as the sample No. 6 having the almost same composition.
【００２５】表１に示す合金のうち試料Ｎo.10〜12は、
Ｃr量を変えたものである。Ｃr量が6%以下の試料Ｎo.10
は、本発明鋼である試料Ｎo.11に比べ摩耗減量が多く耐
食性が劣っていた。また、Ｃr量が13%を越える試料Ｎo.
12は、Ｃrが過度に多いため、抗折力が低下した。Of the alloys shown in Table 1, Sample Nos. 10 to 12 are
The amount of Cr is changed. Sample No. 10 with Cr content of 6% or less
Had a large amount of wear loss and poorer corrosion resistance than Sample No. 11 which is a steel of the present invention. In addition, the sample No. with Cr content exceeding 13%.
In No. 12, since the Cr content was excessively high, the transverse rupture strength was lowered.
【００２６】（実施例２）実施例１と同様に、表３に示
す試料を得た。ここでΔＣはＣ−Ｃeqの値である。ま
た、表３に示す試料に対して、実施例１と同様に焼もど
し後の硬さ、結晶粒度、焼もどし軟化抵抗、摩耗減量お
よび抗折力を測定した。結果を表４に示す。表３中の試
料Ｎo.13〜Ｎo.16はＷ＋2Ｍo量を変化させたものであ
り、Ｗ＋2Ｍo量の14%以下である比較例である試料Ｎo.1
3はマトリックス中に固溶し得る合金元素量が不十分で
あり、本発明鋼である試料Ｎo.14およびＮo.15に比べ
て、焼もどし軟化抵抗が低い。一方、Ｗ＋2Ｍo量が30%
を越える比較例である試料Ｎo.16は抗折力が著しく低下
し好ましくないものであった。Example 2 Samples shown in Table 3 were obtained in the same manner as in Example 1. Here, ΔC is a value of C−Ceq. Further, with respect to the samples shown in Table 3, the hardness after tempering, the grain size, the tempering softening resistance, the abrasion loss and the transverse rupture strength were measured in the same manner as in Example 1. The results are shown in Table 4. Samples No. 13 to No. 16 in Table 3 are those in which the amount of W + 2 Mo is changed, and the sample No. 1 as a comparative example is 14% or less of the amount of W + 2 Mo.
No. 3 has an insufficient amount of alloying elements that can be solid-solved in the matrix, and has a lower resistance to temper softening than Samples No. 14 and No. 15 which are steels of the present invention. On the other hand, W + 2Mo amount is 30%
Sample No. 16, which is a comparative example exceeding 1.0, was not preferable because the transverse rupture strength was remarkably reduced.
【００２７】また、表３中の試料Ｎo.17〜Ｎo.19は、Δ
Ｃ量の特性への影響を確認するために、Ｃ量を変化させ
たものである。ΔＣ量が-0.30未満の比較例である試料
Ｎo.17は、本発明鋼である試料Ｎo.18に比べ硬さも低
く、焼もどし軟化抵抗も低いものとなり、好ましくない
ものであった。一方、ΔＣ量が0.05を越える試料Ｎo.19
は、本発明鋼である試料Ｎo.18に比べ抗折力が低下し好
ましくないものであった。Samples No. 17 to No. 19 in Table 3 are Δ
In order to confirm the influence of the C content on the characteristics, the C content was changed. Sample No. 17, which is a comparative example in which the amount of ΔC was less than −0.30, was lower in hardness and lower in resistance to temper softening than Sample No. 18, which was the steel of the present invention, and was not preferable. On the other hand, sample No. 19 with ΔC exceeding 0.05
Was unfavorable because the transverse rupture strength was lower than that of Sample No. 18 which is a steel of the present invention.
【００２８】また、本発明鋼のうち試料Ｎo.20〜Ｎo.23
はＣoを含む鋼であり、Ｃo量が増加するにしたがって、
焼もどし軟化抵抗が高くなり、Ｃoの添加によりＣoのな
いものに比べ焼もどし軟化抵抗が改善されたことがわか
る。なお、Ｃoを添加する場合は、残留オーステナイト
が存在するのを防ぐため、焼もどしは３回行なった。一
方、Ｃo量が15%を越える比較鋼である試料Ｎo.23では焼
もどし軟化抵抗は、高い値を示すものの、抗折力が著し
く低下し好ましくないものであった。Further, among the steels of the present invention, samples No. 20 to No. 23
Is a steel containing Co. As the amount of Co increases,
It can be seen that the temper softening resistance was increased, and the addition of Co improved the temper softening resistance as compared with the case without Co. When Co was added, tempering was performed three times in order to prevent the presence of residual austenite. On the other hand, in sample No. 23, which is a comparative steel having a Co content of more than 15%, the temper softening resistance is high, but the transverse rupture strength is remarkably reduced, which is not preferable.
【００２９】[0029]
【表３】 [Table 3]
【００３０】[0030]
【表４】 [Table 4]
【００３１】[0031]
【発明の効果】本発明によれば、従来不十分であった高
温での軟化抵抗特性を大幅に向上できるので高温での耐
摩耗性を顕著に改善することができた。また結晶粒が微
細なままで、靭性も従来と同等以上に高いため、工具の
高速使用条件下で、大幅な寿命向上が達成できる。さら
に、耐食性が従来と比べ改善され、腐食環境下でも使用
可能である。According to the present invention, the softening resistance characteristic at high temperature, which has been insufficient in the past, can be remarkably improved, so that the wear resistance at high temperature can be remarkably improved. Further, since the crystal grains remain fine and the toughness is as high as or higher than that of the conventional one, it is possible to significantly improve the service life under the high-speed use condition of the tool. Further, the corrosion resistance is improved as compared with the conventional one, and it can be used even in a corrosive environment.
Claims (3)
1.0%、Ｍn≦0.6%、Ｃr 6.0%を越え13.0%以下、Ｗまたは
さらにＭoをＷ＋2Ｍoで14〜30%、Ｖ≦10.0%、Ｎb 2.0〜
7.0%、但しＮb/Ｖ≧0.5、残部がＦeおよび不可避的不純
物よりなり、Ｃ−Ｃeqが−0.30〜0.05(ただしCeq=0.24
＋0.033・Ｗ＋0.063・Ｍo＋0.2Ｖ＋0.1・Ｎb)の関係を満た
すことを特徴とする粉末高速度工具鋼。1. A weight ratio of more than C 1.5% to 2.6% or less, Si ≦.
1.0%, Mn ≦ 0.6%, Cr 6.0% to 13.0% or less, W or further Mo is W + 2Mo, 14 to 30%, V ≦ 10.0%, Nb 2.0 to
7.0%, Nb / V ≧ 0.5, the balance Fe and inevitable impurities, C-Ceq is -0.30 to 0.05 (where Ceq = 0.24
+0.033 ・ W + 0.063 ・ Mo ＋ 0.2V + 0.1 ・ Nb) powder high speed tool steel.
1.0%、Ｍn≦0.6%、Ｃr 6.0%を越え13.0%以下、Ｗまたは
さらにＭoをＷ＋2Ｍoで 14〜30%、Ｖ≦10.0%、Ｎb 2.0
〜7.0%、但しＮb/Ｖ≧0.5、Ｃo≦15.0%、残部がＦeおよ
び不可避的不純物よりなり、Ｃ−Ｃeqが−0.30〜0.05
(ただしCeq=0.24＋0.033・Ｗ＋0.063・Ｍo＋0.2Ｖ＋0.1・
Ｎb)の関係を満たすことを特徴とする粉末高速度工具
鋼。2. A weight ratio of more than C 1.5% to 2.6% or less, Si ≦.
1.0%, Mn ≤ 0.6%, Cr 6.0% to 13.0% or less, W or further Mo is W + 2 Mo, 14 to 30%, V ≤ 10.0%, Nb 2.0
~ 7.0%, with Nb / V ≥ 0.5, Co ≤ 15.0%, the balance being Fe and unavoidable impurities, and C-Ceq being -0.30 to 0.05
(However, Ceq = 0.24 + 0.033 / W + 0.063 / Mo + 0.2V + 0.1 /
Powder high speed tool steel characterized by satisfying the relationship of Nb).
とする請求項１ないし２に記載の粉末高速度工具鋼。3. The powder high speed tool steel according to claim 1, wherein Nb + V> 6% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34068891A JPH05171373A (en) | 1991-12-24 | 1991-12-24 | Powder high speed tool steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34068891A JPH05171373A (en) | 1991-12-24 | 1991-12-24 | Powder high speed tool steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05171373A true JPH05171373A (en) | 1993-07-09 |
Family
ID=18339362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34068891A Pending JPH05171373A (en) | 1991-12-24 | 1991-12-24 | Powder high speed tool steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05171373A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3005740U (en) * | 1994-06-28 | 1995-01-10 | オーエスジー株式会社 | Hand tap for high hardness materials |
| FR2722211A1 (en) * | 1994-07-06 | 1996-01-12 | Thyssen Aciers Speciaux Sa | Wear-resistant tool steel |
| JP2006322072A (en) * | 2005-05-09 | 2006-11-30 | Crucible Materials Corp | Corrosion and wear resistant alloy |
| WO2007021243A1 (en) * | 2005-08-18 | 2007-02-22 | Erasteel Kloster Aktiebolag | Powder metallurgically manufactured steel, a tool comprising the steel and a method for manufacturing the tool |
| EP1595967A4 (en) * | 2003-02-13 | 2008-12-03 | Mitsubishi Steel Mfg | ALLIED STEEL POWDER FOR METAL MOLDING BY INJECTION, IMPROVED SINTER FEATURES, AND FRITTE PRODUCT |
| JP2014210941A (en) * | 2013-04-17 | 2014-11-13 | 山陽特殊製鋼株式会社 | Powder high-speed tool steel excellent in high-temperature temper hardness |
-
1991
- 1991-12-24 JP JP34068891A patent/JPH05171373A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3005740U (en) * | 1994-06-28 | 1995-01-10 | オーエスジー株式会社 | Hand tap for high hardness materials |
| FR2722211A1 (en) * | 1994-07-06 | 1996-01-12 | Thyssen Aciers Speciaux Sa | Wear-resistant tool steel |
| EP1595967A4 (en) * | 2003-02-13 | 2008-12-03 | Mitsubishi Steel Mfg | ALLIED STEEL POWDER FOR METAL MOLDING BY INJECTION, IMPROVED SINTER FEATURES, AND FRITTE PRODUCT |
| JP2006322072A (en) * | 2005-05-09 | 2006-11-30 | Crucible Materials Corp | Corrosion and wear resistant alloy |
| WO2007021243A1 (en) * | 2005-08-18 | 2007-02-22 | Erasteel Kloster Aktiebolag | Powder metallurgically manufactured steel, a tool comprising the steel and a method for manufacturing the tool |
| JP2014210941A (en) * | 2013-04-17 | 2014-11-13 | 山陽特殊製鋼株式会社 | Powder high-speed tool steel excellent in high-temperature temper hardness |
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