JPS6115145B2 - - Google Patents
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- Publication number
- JPS6115145B2 JPS6115145B2 JP7821277A JP7821277A JPS6115145B2 JP S6115145 B2 JPS6115145 B2 JP S6115145B2 JP 7821277 A JP7821277 A JP 7821277A JP 7821277 A JP7821277 A JP 7821277A JP S6115145 B2 JPS6115145 B2 JP S6115145B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- nitrogen
- speed
- cutting
- speed steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 229910000997 High-speed steel Inorganic materials 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 13
- 238000004663 powder metallurgy Methods 0.000 claims description 12
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 11
- 238000005520 cutting process Methods 0.000 description 21
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- 229910000831 Steel Inorganic materials 0.000 description 16
- 229910052757 nitrogen Inorganic materials 0.000 description 16
- 239000010959 steel Substances 0.000 description 16
- 238000010438 heat treatment Methods 0.000 description 13
- 239000000843 powder Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 7
- 238000005275 alloying Methods 0.000 description 5
- 238000005121 nitriding Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000002436 steel type Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 229910052720 vanadium Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 239000002775 capsule Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000010730 cutting oil Substances 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009689 gas atomisation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
Description
本発明は粉末治金法により製造される含窒素高
速度鋼に関し、鋼中のＣおよびＮの含有量を特定
することにより、高速度鋼としての特性、就中熱
処理に伴う熱歪み、靭性等機械的性質の悪化を伴
うことなく、切削性能を著しく改善したものであ
る。
一般に、Cr、Ｗ、Ｖなどの合金元素を含む高
速度鋼に窒素を含有させることにより、高速度鋼
としての諸性能を向上させることは知られてい
る。このことは、窒化処理によつて、MX或いは
M6X型窒化物（Ｍは合金元素、Ｘは炭素或いは窒
素を表わす。）が形成され、これがMC、M6C型
炭化物より安定であり、適正焼入温度幅が広く、
熱処理管理が容易なこと、二次硬化能が大きいこ
と、また、微細なオーステナイト結晶組織が得ら
れ、機械的性質が向上すること、さらに切削性能
が改善されること等の効果によるものである。
このような含窒素高速度鋼は従来は主として溶
解法によつて製造されている。しかし、この溶解
法による場合、窒化処理のために溶鋼を高圧窒素
雰囲気下で溶製するか、或いは溶鋼に窒化物を投
入するなどの煩雑な工程を必要とし、また、鋼中
に富化する窒素量は少なく、しかも炭窒化物を鋼
中に微細、均一に形成分布させることが困難のた
め、所望の性能をそれ程大きく改善することがで
きない。このような溶解法に伴なう制約を回避す
る手段として、最近に至り粉末治金或いは粉末鍛
造法を用いた含窒素高速度鋼の開発が試みられて
きている。これは粉末の比表面積が大きいこと、
粉末焼結体が多孔質であることを利用し、例えば
原料粉末に予め窒素を添加しておくか、或いは焼
結時に加熱温度、加熱時間、雰囲気中窒素分圧の
調節など比較的操作の容易な手段で任意の窒素量
を鋼中に富化させようとするもので、この方法に
よれば微細、均一に分散する窒化物の形成が期待
できるものである。
しかしながら、従来、粉末治金法により製造さ
れる含窒素高速度鋼については、その切削性能は
必らずしも期待される程改善されず、むしろ劣つ
ている、或いはかかる高速度鋼の価値について疑
問があるという考え方も少なくなく、また、二、
三実用化された粉末治金法により製造される含窒
素高速度鋼についても被削性と耐摩耗性とを兼ね
備えることの理由が不明であること、就中、優れ
た切削性能を付与するための合金元素と窒素富化
量との関係が明らかにされていないこと等が一因
となつて、これまで開発されている粉末治金法に
より製造される含窒素高速度鋼は特定の成分組成
を有する鋼種に限られている。例えば、神戸製鋼
所技報Vol.24、No.3、P10には粉末治金法により
製造されるMo系高速度鋼（JIS SKH9、および
JIS SKH55改良型）に0.4〜0.5％の窒素を添加す
ることにより切削性能が著しく向上したと報告さ
れている。しかしながら、このように既に合金成
分が規格化された高速度鋼に多量の窒素を添加す
ることは耐摩耗性、耐熱性の改善には効果的であ
るが、その反面、高速度鋼の化学量論的な合金成
分のバランスをくずすことになり、焼入時の残留
オーステナイト量を増加させ、焼戻し回数を増加
させる必要があること、熱処理歪みが大きくなる
こと、さらに靭性が低下し切削工具としての適用
範囲が限定されることなどの問題を生じる。
本発明の目的は、上述の如き熱処理上の問題、
靭性等の機械的性質への悪影響を伴うことなく、
切削性能のすぐれた高速度鋼を提供せんとするも
のである。
ところで、高速度鋼の主要合金元素のうち、Ｃ
はＷ、Ｖ、Mo、Cr等の炭化物形成元素と密接な
関係を有し、高速度鋼の諸性質に大きな影響を与
えることから、その添加量については、これら元
素の配合量との関連下に規定され、たとえば、
「鉄と鋼」（第45巻、第５号、P511〜516）にはＣ
％＝0.19＋0.017（Ｗ％＋2Mo％）＋0.22V％の関
係式が示されるなど、他の合金元素と比べて厳し
く規制されている。
一方、Ｎに関しては、一般的にＣと類似した性
質を有しており、両者の原子量はそれぞれ12およ
び14と小さく、鋼に対しては侵入型の原子であつ
て、安定な合金化合物を生成し易い性質を有して
いる。そのため、多量のＮを含有する高速度鋼に
ついて切削性能や機械的性質等の改善を企図する
場合、単にＮ含有量を単独で調達するよりも、Ｃ
量との関連下になされるべきであると考えられ
る。
本発明者等は、粉末治金法が前述の如く、任意
の窒素量を富化し、微細均一な炭窒化物を形成す
るに有利な手段であることを利用し、従来の
AISI M15の溶製材の成分組成に相当する高速度
鋼の諸性能、特に切削性能の改善を図るべく、Ｃ
およびＮについての上記見解に基づき研究を重ね
た結果、これら高速度鋼組成につき、Ｃ量および
Ｃ＋Ｎ量を一定の範囲に特定することにより、上
記目的を達成し得ることを見出し、本発明を完成
するに到つた。
すなわち、本発明の要旨は、Cr3.8〜4.5％、
Mo3.0〜4.0％、W5.5〜6.7％、V4.2〜5.2％、
Co4.2〜5.2％を含有し、かつC1.3％以下、Ｃ＋
N1.4〜2.0％としたことにより、熱処理歪みを少
なくし、靭性等の機械的性質を高度に維持しつ
つ、高速度鋼の切削性能を大幅に改善したもので
ある。
以下、本発明の含窒素粉末治金高速度鋼につい
て説明する。
本発明の含窒素粉末治金高速度鋼の基本成分は
ＣおよびＮを除き、AISI M15で規格化された組
成に相当するもの、すなわち、Cr3.8〜4.5％、
Mo3.0〜4.0％、W5.5〜6.7％、V4.2〜5.2％、
Co4.2〜5.2％、Si0.4％以下、Mn0.4％以下、
P0.03％以下、S0.03％以下に規定される鋼種に適
用される。
上記各鋼種相当の成分組成に対し、更にＣを
1.3％以下とし、かつＣ＋Ｎの量を1.4〜2.0％とす
ることにより後記実施例にも示すように切削性能
の大幅な改善効果がもたらされる。
本発明に係る含窒素粉末治金高速度鋼を製造す
るには、Cr、Mo、Ｗ、Ｖ、Co等の合金元素を、
所望の相等鋼種に応じて含有し、Ｃ量の異なる鋼
粉末（たとえば、ガスアトマイズ鋼粉末）を、Ｃ
量が1.3％以下となるように配合して軟鋼製のカ
プセルに充填し、脱気した後、Ｃ＋Ｎの量が1.4
〜2.0％となるように窒化処理し、ついで熱間ア
イソスタテイツクプレスにより圧縮形成すること
により鋼塊となし、これを成分組成に応じた適当
な熱処理に付すればよい。
次に実施例を挙げて本発明に係る含窒素粉末治
金高速度鋼の切削性能について具体的に説明す
る。
実施例
AISI M15相当の高速度鋼について、Ｃ量の異
なる鋼粉末（80メツシユ以下）をガスアトマイズ
法で製造し、各粉末を適宜の割合で配合して軟鋼
製のカプセルに充填し、脱気した後、窒化処理
し、ついで熱間アイソスタイツクプレスで圧縮成
形して鋼塊とし、これを熱処理に付して製品を得
た。
その製造条件および製品の切削性能を以下に示
す。なお、比較材として、規格どおりの溶製材を
製し、これを熱処理して得られた製品の切削性能
を測定して比較した。
(1) 製造条件
(a) 原料粉末の化学成分：AISI M15種相当の
原料鋼粉末の化学成分を第１表に示す。
The present invention relates to nitrogen-containing high-speed steel manufactured by powder metallurgy, and by specifying the content of C and N in the steel, the characteristics as a high-speed steel, especially thermal distortion due to heat treatment, toughness, etc. Cutting performance has been significantly improved without deterioration of mechanical properties. It is generally known that by adding nitrogen to high-speed steel containing alloying elements such as Cr, W, and V, various performances of the high-speed steel can be improved. This can be confirmed by nitriding treatment.
M6 _
This is due to the effects of easy heat treatment management, high secondary hardening ability, fine austenite crystal structure, improved mechanical properties, and improved cutting performance. Conventionally, such nitrogen-containing high-speed steels have been mainly produced by a melting method. However, this melting method requires complicated processes such as melting the molten steel in a high-pressure nitrogen atmosphere for nitriding treatment, or adding nitrides to the molten steel. Since the amount of nitrogen is small and it is difficult to finely and uniformly form and distribute carbonitrides in the steel, the desired performance cannot be significantly improved. As a means to avoid the limitations associated with such melting methods, attempts have recently been made to develop nitrogen-containing high-speed steels using powder metallurgy or powder forging methods. This is due to the large specific surface area of the powder,
Taking advantage of the porous nature of the powder sintered body, it is relatively easy to operate, for example by adding nitrogen to the raw material powder in advance, or by adjusting the heating temperature, heating time, and nitrogen partial pressure in the atmosphere during sintering. This method attempts to enrich the steel with a desired amount of nitrogen using suitable means, and this method can be expected to form fine and uniformly dispersed nitrides. However, the cutting performance of nitrogen-containing high-speed steels conventionally produced using powder metallurgy methods has not necessarily been improved as much as expected, and is in fact inferior, or the value of such high-speed steels has not been improved. There are many ideas that are questionable, and
3) The reason why nitrogen-containing high-speed steel manufactured by the practically applied powder metallurgy method has both machinability and wear resistance is unknown, and in particular, it is necessary to provide excellent cutting performance. This is partly due to the fact that the relationship between alloying elements and nitrogen enrichment has not been clarified.Nitrogen-containing high-speed steels produced by powder metallurgy methods that have been developed so far have a specific composition. Limited to steel types with For example, Kobe Steel Technical Report Vol. 24, No. 3, P10 describes Mo-based high-speed steel (JIS SKH9 and
It has been reported that cutting performance was significantly improved by adding 0.4 to 0.5% nitrogen to JIS SKH55 (improved type). However, while adding a large amount of nitrogen to high-speed steel whose alloy components have already been standardized is effective in improving wear resistance and heat resistance, on the other hand, the chemical content of high-speed steel This will disrupt the theoretical balance of alloy components, increase the amount of retained austenite during quenching, require an increase in the number of tempering cycles, increase heat treatment distortion, and reduce toughness, making it difficult to use as a cutting tool. This causes problems such as a limited scope of application. The purpose of the present invention is to solve the above-mentioned heat treatment problems,
without adversely affecting mechanical properties such as toughness.
The objective is to provide high-speed steel with excellent cutting performance. By the way, among the main alloying elements of high-speed steel, C
has a close relationship with carbide-forming elements such as W, V, Mo, and Cr, and has a great influence on the properties of high-speed steel. For example,
"Iron and Steel" (Volume 45, No. 5, P511-516) has C.
% = 0.19 + 0.017 (W% + 2Mo%) + 0.22V%, and it is more strictly regulated than other alloying elements. On the other hand, N generally has properties similar to C, and both have small atomic weights of 12 and 14, respectively, and are interstitial atoms in steel, forming stable alloy compounds. It has the property of being easy to use. Therefore, when planning to improve the cutting performance and mechanical properties of high-speed steel that contains a large amount of N, it is necessary to
It is considered that this should be done in relation to the quantity. The present inventors took advantage of the fact that the powder metallurgy method is an advantageous means for enriching any amount of nitrogen and forming fine and uniform carbonitrides, as described above.
C
As a result of repeated research based on the above-mentioned views regarding N and N, it was discovered that the above objectives could be achieved by specifying the C content and C+N content within a certain range for these high-speed steel compositions, and the present invention was completed. I came to the point. That is, the gist of the present invention is that Cr3.8 to 4.5%,
Mo3.0~4.0%, W5.5~6.7%, V4.2~5.2%,
Contains Co4.2-5.2% and C1.3% or less, C+
By setting N1.4 to 2.0%, heat treatment distortion is reduced, mechanical properties such as toughness are maintained at a high level, and the cutting performance of high-speed steel is significantly improved. The nitrogen-containing powder metallurgy high-speed steel of the present invention will be explained below. The basic components of the nitrogen-containing powder metallurgy high-speed steel of the present invention, excluding C and N, correspond to the composition standardized by AISI M15, that is, Cr3.8 to 4.5%,
Mo3.0~4.0%, W5.5~6.7%, V4.2~5.2%,
Co4.2~5.2%, Si0.4% or less, Mn0.4% or less,
Applies to steel types specified as P0.03% or less and S0.03% or less. In addition, C is added to the chemical composition equivalent to each of the above steel types.
By setting the amount of C+N to 1.3% or less and setting the amount of C+N to 1.4 to 2.0%, a significant improvement in cutting performance is brought about, as shown in the examples below. In order to produce the nitrogen-containing powder metallurgy high speed steel according to the present invention, alloying elements such as Cr, Mo, W, V, Co, etc.
Steel powders containing different C amounts (for example, gas atomized steel powders) depending on the desired equivalent steel type are
After blending so that the amount of C+N is 1.3% or less and filling it into a mild steel capsule and degassing, the amount of C + N is 1.4
The steel is nitrided to a concentration of ~2.0%, then compressed using a hot isostatic press to form a steel ingot, which is then subjected to an appropriate heat treatment depending on the component composition. Next, the cutting performance of the nitrogen-containing powder metallurgy high-speed steel according to the present invention will be specifically explained with reference to Examples. Example For high-speed steel equivalent to AISI M15, steel powders with different amounts of C (80 mesh or less) were produced using the gas atomization method, each powder was mixed in an appropriate ratio, filled in a mild steel capsule, and degassed. Thereafter, the steel was subjected to nitriding treatment, and then compressed into a steel ingot using a hot isostatic press, which was then subjected to heat treatment to obtain a product. The manufacturing conditions and cutting performance of the product are shown below. In addition, as a comparative material, a melt-sawn material according to the specifications was produced, and the cutting performance of the product obtained by heat treatment was measured and compared. (1) Manufacturing conditions (a) Chemical composition of raw material powder: The chemical composition of raw steel powder equivalent to AISI M15 class is shown in Table 1.
【表】
(b) 窒化処理
窒素雰囲気中、1000〜1150℃で２時間加熱
して窒化した。但し、製品の窒素含有量の調
節は、雰囲気圧力および温度を適宜制御する
ことにより行つた。
(c) 熱処理
焼入れ：1200〜1300℃×３分間・油冷。
焼もどし：560℃×1.5Hr（２〜４回くり
返し）。
(2) 切削性能
上記の条件下に得られたＣおよびＮ量の異な
る粉末治金高速度鋼並びに溶製材について次の
条件で断続切削試験を行つた。
切削速度：25ｍ／分、切込み：1.5mm、送
り：0.2mm/rev、切削油：使用せず、工具形
状：０゜、15゜、６゜、６゜、15゜、15゜、
0.4R、被削材：SNCM8（ＨB300〜320）、４ロ
ツト。
上記断続切削試験による切削寿命時間（逃げ面
摩耗幅ＶB＝0.6mmに達するまでの切削時間）を第
１図に示す。図中、Ａ，Ｂ，Ｃ，Ｄは、それぞれ
第１表に示す鋼粉末により得られたもの、Ｍは溶
製材を示す。
同図から明らかなように、C1.3％以下、Ｃ＋
Ｎ約1.4〜2.0％の範囲で、従来の溶製材に比し、
約４倍に達する切削寿命が保証されることが認め
られる。
また、別途行つた測定結果により、熱処理歪み
および抗折力についても問題のないことが確認さ
れた。[Table] (b) Nitriding treatment Nitriding was performed by heating at 1000 to 1150°C for 2 hours in a nitrogen atmosphere. However, the nitrogen content of the product was adjusted by appropriately controlling the atmospheric pressure and temperature. (c) Heat treatment Quenching: 1200-1300℃ x 3 minutes, oil cooling. Tempering: 560℃ x 1.5Hr (repeat 2-4 times). (2) Cutting performance Interrupted cutting tests were conducted on powder metallurgy high-speed steels and ingots with different amounts of C and N obtained under the above conditions under the following conditions. Cutting speed: 25m/min, Depth of cut: 1.5mm, Feed: 0.2mm/rev, Cutting oil: Not used, Tool shape: 0°, 15°, 6°, 6°, 15°, 15°,
0.4 R , work material: SNCM8 ( HB 300-320), 4 lots. The cutting life time (cutting time until the flank wear width V B =0.6 mm is reached) in the above-mentioned interrupted cutting test is shown in FIG. In the figure, A, B, C, and D are obtained using the steel powder shown in Table 1, respectively, and M is a melted material. As is clear from the figure, C1.3% or less, C+
In the range of about 1.4 to 2.0% N, compared to conventional melted lumber,
It is recognized that a cutting life of approximately 4 times longer is guaranteed. Furthermore, the results of measurements conducted separately confirmed that there were no problems with respect to heat treatment distortion and transverse rupture strength.
第１図は、Ｃ量をパラメータとし、切削性能と
Ｃ＋Ｎ量との関係を示すグラフである。
FIG. 1 is a graph showing the relationship between cutting performance and C+N amount using C amount as a parameter.
Claims (1)
％、V4.2〜5.2％、Co4.2〜5.2％を含有し、かつ
C1.3％以下、Ｃ＋N1.4〜2.0％であることを特徴
とする粉末治金法により製造される含窒素高速度
鋼。1 Cr3.8~4.5%, Mo3.0~4.0%, W5.5~6.7
%, V4.2~5.2%, Co4.2~5.2%, and
A nitrogen-containing high-speed steel manufactured by a powder metallurgy method characterized by a C+N content of 1.3% or less and a C+N content of 1.4 to 2.0%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7821277A JPS5411816A (en) | 1977-06-29 | 1977-06-29 | High speed steel made of nitrogen-containing powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7821277A JPS5411816A (en) | 1977-06-29 | 1977-06-29 | High speed steel made of nitrogen-containing powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5411816A JPS5411816A (en) | 1979-01-29 |
| JPS6115145B2 true JPS6115145B2 (en) | 1986-04-22 |
Family
ID=13655731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7821277A Granted JPS5411816A (en) | 1977-06-29 | 1977-06-29 | High speed steel made of nitrogen-containing powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5411816A (en) |
-
1977
- 1977-06-29 JP JP7821277A patent/JPS5411816A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5411816A (en) | 1979-01-29 |
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