JPS61213348A - Alloy tool steel - Google Patents

Abstract

PURPOSE:To obtain an alloy tool steel having superior strength, toughness, heat check resistance and a long cutting life by specifying a composition consisting of C, Si, Mn, Cr, Mo, W, V and Fe. CONSTITUTION:This alloy tool steel consists of, by weight, 0.20-2.50% C, <=0.10% Si, 0.10-1.50% Mn, 2.0-20.0% Cr, 0.30-30.0% 2Mo+W and/or 0.01-5.0% V and the balance Fe with impurities. The steel is suitable for use as a high-speed alloy tool steel, a cold dies alloy tool steel or a hot dies alloy tool steel. The balance Fe in the steel composition may contain a restricted amount of one or more among REM, Nb, Ta, Zr, Hf, Ti, Sc, Y, Co, Ni, Cu, B, Mg, Ca, Pb, Bi, Te and Se. The amounts of N, S, O, Al and P among the impurities are preferably restricted to <=200ppm N, <=0.0050% S, <=0.0030% O, <=0.020% Al and <=0.020% P.

Description

[Detailed Description of the Invention] Object of the Invention (Industrial Field of Application) The present invention relates to an alloy tool steel used as a tool for hot, warm or cold plastic working or as a cutting tool.

(Prior Art) Conventionally, this type of alloy tool steel includes high-speed tool steel, cold die steel, hot die steel, etc., and these alloy tool steels are used to produce, for example, various punches for plastic working, Dies as well as taps and cutters.

Cutting tools such as reamers, end mills, hobs, rolls, bearings, etc. are made.

(Problems to be solved by the invention) Such alloy tool steels are required to be easy to form into desired shapes and to have excellent high-temperature strength, fatigue properties, etc. to ensure long life. However, there is a problem in that if a huge primary carbide is generated, such requirements cannot be fully met.

This invention was made in order to solve the above-mentioned conventional problems. Huge primary carbides do not remain in the steel, and it improves strength, toughness, and heat checkability.

The purpose is to provide an alloy tool steel with excellent properties such as cutting life.

[Structure of the invention] (Means for solving problems) 0.20-2.50%, Si: 0.10% or less.

Mn: 0, l0~1, 5
0%, Cr:2.0-20.0%, and 2Mo+
It is characterized by comprising one or more of W: 0.30 to 30.0%, V: 0.01 to 5.0%, and the remainder Fe and impurities, and is more preferably an alloy tool steel. When is a high-speed tool steel, in ffi amount %, C:
0.35-1.50%, Si: 0.10% or less, Mn:
0.10-1.50%, Cr: 2.0-10.0%, and 2Mo+W: 1.50-30.0%, V
: One or more of 0.50 to 5.0%, the balance being Fe and impurities, and in the case of cold die steel, C: 0.35 to 2.50% by weight. , Si:0
．． 10% or less, Mn:O, 10-1.50%, Cr23
．． 0-20.0%, and MO=0.10-5.0%,
W: 0.10-5.0%.

V: one or more of 0.01 to 5.0%,
The balance consists of Fe and impurities, hot die 0.50%,
Si: 0.10% or less, Mn: 0.10 to 1.50%,
Cr: 2.0-8.0%, and Mo: 0.10-5
．． 0%, W2 0.10-5.0%, V: 0.01-5,
It is characterized in that it consists of one or more of 0% and the remainder Fe and impurities. In addition, if necessary, a part of the remaining Fe may be REM: 0.001 to 0.6
Contains 0%, Nb: 0.01-5.0%, Ta: 0.0
1 to 5.0%, Zr: 2.0% or less, Hf: 2.0% or less, Ti: 2.0% or less, Sc: 0.001 to 2.0%
.

Y: Contains one or more of 2.0% or less,
Co: 1.0-20.0%, Ni: 0.01-2.0%
, Cu: 0.25-1.0%, B: 0.001-0.0
50% of Mg: 0.
001-0.5%, Ca: 0.002-0.01%.

Pb: 0.4% or less, Bi: 0.5% or less.

Contains one or more of Te: 0.3% or less, Se: 0.3% or less, and if necessary, N+200 ppm or less in impurities.

S: 0.0050% or less, O: 0.0030% or less, A
It is characterized in that L: 0.020% or less and P: 0.020% or less.

Next, the composition range (weight%) of the alloy tool steel according to this invention
The reason for this limitation will be explained.

C: 0.20-2.50% C is an effective element for ensuring the strength, hardness, wear resistance, etc. required for tool steel, and 0.20% is necessary to obtain such effects. It is preferable to contain 0.35% or more, and when the tool steel is high-speed tool steel or cold die steel, it is more preferable to contain 0.35% or more. However, if it is too large, toughness and workability will decrease. Therefore, the content should be 2.50% or less, and if the tool steel is high-speed tool steel, it should be 1.50% or less, and if it is hot die steel, it should be 0.50% or less. is more preferable.

Si: 0.10% or less The giant compound produced in alloy tool steel is
The main cause is that the rib-shaped eutectic carbide crystallized remains as unbroken grains, and by lowering the Si content, it is possible to reduce or prevent the formation of the rib-shaped eutectic carbide, and the Si content increases. By lowering the temperature range, the temperature range of complete solid solution of primary carbide by soaking can be expanded to a lower temperature side, and the carbide can be made into fine grains.

As a result of various studies based on this knowledge, the present inventors found that in this type of alloy tool steel, it is best to keep the Si content at 0.10% or less, more preferably at 0.05% or less. The above range was set because it was confirmed that it was good.

Mn: 0.10-1.50% Mn is an element that acts as a deoxidizing and desulfurizing agent, increasing the cleanliness of steel and also improving hardenability. It is preferable to add 0.10% or more. However, if the amount is too high, hot workability will be impaired, so 1.5
It is preferable to set it to 0% or less.

Cr: 2.0-20.0% Cr increases the strength of tool steel, especially high-temperature strength, and
#It is an effective element for increasing thermal shock resistance, and to obtain such an effect, it is recommended to add 1.0% or more.
Further, when the tool steel is cold die steel, the content is more preferably 3.0% or more. However, if the amount is too high, the toughness and workability will deteriorate, so it is better to keep it below 20.0%. Also, if the tool steel is high speed steel, it should be below 10.0%, and if the tool steel is high speed steel, it should be below 10.0%. In some cases, it is more preferable to set it to 8.0% or less.

2 Mo + W: 0, 30-30, 0%,
v: one or more of 0.01 to 5.0% Mo, W, and V are elements effective in forming carbides, increasing heat treatment hardness, and improving wear resistance. Therefore, it is good to add one or more of these. In this case, Mo is an element that has a greater effect than W, and in order to obtain such an effect, 2Mo + W (one of which is 0 0.30% or more, including cases where
, it is better to add oi% or more, and when the tool steel is high speed steel, 2 M o + W should be added at 1.50% or more, and when the tool steel is cold die steel and hot die steel, it should be added. It is more preferable that Mo is 0°10% or more and W is 0.10% or more, and when the tool steel is high speed steel, it is more preferable that V is 0.50% or more, but ,
If it is too large, the toughness will decrease and the number of coarse carbides will increase, which will have a negative effect on fatigue properties (7) Te2 Mo
+ W is preferably 30.0% or less and More preferably, it is 5.0% or less.

REM (one or more rare earth elements): 0.0
01 to 0.60% REM is an element that is effective in improving the toughness of tool steel, especially in increasing its impact resistance, so in order to obtain such effects, one or more of these can be reduced to zero. It is also desirable to add .001% or more if necessary, but if added in a large amount, toughness and workability deteriorate, so if added, it is preferably 0.60% or less. in this case,
Addition of REM during manufacturing is at 1530-1550°C
In particular, it is desirable to carry out the heating at 1540 to 1545°C, which can considerably suppress the occurrence of base paper defects.

Nb: 0.01-5.0%, Ta: 0.01-5.0%
, Zr: 2.0% or less, Hf: 2.0% or less, Ti: 2
．． 0% or less, Sc: 0.001-2.0%, Y: 2.0
% or more of Nb, Ta, Zr, Hf, Ti, Sc, and Y are all effective elements for forming carbides, increasing heat treatment hardness, and improving wear resistance. Therefore, these elements may be appropriately selected and added within the above range.

Co: 1.0-20.0%, Ni: 0.01-2.0%
, Cu: 0.25-1.0%, B: 0.001-0.0
One or more of 50% (O, Ni, Cu, B all strengthen the base and increase the strength, impact resistance, and heat check resistance of the tool steel,
It is also a good idea to select these elements appropriately and add them within the above range. B is also effective in improving the hardenability of steel and fixing N in steel in the form of BN to eliminate the negative effects of N. Since it is a natural element, it may be added as appropriate within the above range.

Mg: 0.001-0.5%, Ca: 0.002-0.
01%, Pb: 0.4% or less, Bi: 0.5% or less,
One or more of Te: 0.3% or less, Se: 0.3% or less, Mg, Ca, Pb, Bi, Te, Se
are effective elements for improving the machinability of steel, so it is also good to add one or more of these within the above range.

N: 200 ppm or less If a large amount of N is contained in steel, it will form nitrides with other additive elements, and large carbonitrides will be present in the steel, degrading the performance of the tool. It is more desirable to set it to 200 ppm.

S: 0゜0050% or less, 0: 0.0030% or less By reducing the amount of 5.0 in steel, it is possible to suppress the generation of base paper, improve the base paper grade, and improve the Since it depends on improving machinability, it is also desirable to regulate the content of S and/or 0 within the above range as necessary.

AL: L: 0.020% or less, P: 0.020% or less By reducing An and Pi in steel, it is possible to suppress the generation of base paper and improve the base paper grade. It is also desirable to regulate the content of An and/or P within the above range as necessary.

(Example) Materials having the chemical components shown in Table 1 were melted in a vacuum induction melting furnace, and then ingots were obtained by forming ingots.

Next, the ingot was heated to 700 to 750°C for 3 hours, then forged, and then subjected to solution treatment in which it was heated at 800°C for 3 hours and then cooled at 20°C/hr to prepare a test material. The carbide content and average particle size of the material were measured.

The results are shown in Table 2.

Next, the high temperature strength and toughness of each sample material were measured, and the results were also shown in Table 2.

As shown in Tables 1 and 2, among various alloy tool steels, those that satisfy the scope of the present invention have less 1-legal chemical noise and an average primary carbide grain size than those that do not satisfy this range. It is also small. It was confirmed that the material exhibited excellent high-temperature strength and toughness.

"Effects of the Invention" As explained above, the alloy tool steel according to the present invention has C: 0.20 to 2.50% and Si: 0.1% by weight.
0% or less, Mn: 0.10-1.50%, Cr: 2.0
~20.0%, and 2Mo+W: 0.30-30.
0%, ■=0, O1 to 5.0%, one or more of them, remaining iFe and impurities,
It is possible to significantly reduce the formation of giant carbides mainly caused by rib-shaped eutectic carbides, and it is a reamer and engine with excellent properties such as strength, toughness, heat check resistance, and cutting life. This brings about a very good effect of being able to obtain tools, rolls, bearings, etc.

Patent applicant: Daido Steel Co., Ltd. Representative Patent Attorney Yutaka Shio Procedural amendment (formality) July 23, 1985

Claims (13)

[Claims] (1) In weight%, C: 0.20-2.50%, Si: 0
．． 10% or less, Mn: 0.10-1.50%, Cr: 2
．． 0-20.0%, and 2Mo+W: 0.30-30
．． 0%, V: 1 or 2 of 0.01 to 5.0%
1. An alloy tool steel characterized in that the remainder is Fe and impurities. (2) In weight%, C: 0.35-1.50%, Si: 0
．． 10% or less, Mn: 0.10-1.50%, Cr: 2
．． 0-10.0%, and 2Mo+W: 1.50-30
．． 0%, V: one or two of 0.50 to 5.0%
The high-speed alloy tool steel according to claim 1, comprising at least one species, the balance being Fe, and impurities. (3) In weight%, C: 0.35-2.50%, Si: 0
．． 10% or less, Mn: 0.10-1.50%, Cr: 3
．． 0 to 20.0%, and Mo: 0.10 to 5.0%,
The cold treatment according to claim (1), comprising one or more of W: 0.10 to 5.0%, V: 0.01 to 5.0%, and the remainder Fe and impurities. Die alloy tool steel. (4) In weight%, C: 0.20-0.50%, Si: 0
．． 10% or less, Mn: 0.10-1.50%, Cr: 2
．． 0-8.0%, and Mo: 0.10-5.0%, W
0.10 to 5.0%, V: 0.01 to 5.0%, and the remainder is Fe and impurities. Alloy tool steel. (5) Part of the remaining Fe is REM: 0.001 to 0.6
The alloy tool steel according to any one of claims (1) to (4), containing 0%. (6) The alloy tool steel according to any one of claims (1) to (5), wherein the content of N in impurities is 200 ppm or less. (7) Part of the remaining Fe is Nb: 0.01 to 5.0%,
Ta: 0.01 to 5.0%, Zr: 2.0% or less, Hf
: 2.0% or less, Ti: 2.0% or less, Sc: 0.00
1 to 2.0%, Y: 1 or 2 of 2.0% or less
Claims (1) to (6) containing more than one species
Alloy tool steel according to any of paragraphs. (8) Part of the remaining Fe is Co: 1.0 to 20.0%,
Ni: 0.01-2.0%, Cu: 0.25-1.0%
, B: 1 or 2 of 0.001 to 0.050%
Claims (1) to (7) containing more than one species
Alloy tool steel according to any of paragraphs. (9) Part of the remaining Fe is Mg: 0.001 to 0.5%
, Ca: 0.002-0.01%, Pb: 0.4% or less, Bi: 0.5% or less, Te: 0.3% or less, Se: 0
．． The alloy tool steel according to any one of claims (1) to (8), containing one or more of 3% or less. (10) The alloy tool steel according to any one of claims (1) to (9), wherein S: 0.0050% or less in impurities. (11) The alloy tool steel according to any one of claims (1) to (10), wherein the content of impurities is 0:0.0030% or less. (12) The alloy tool steel according to any one of claims (1) to (11), wherein Al is 0.020% or less in impurities. (13) The alloy tool steel according to any one of claims (1) to (12), wherein P: 0.020% or less in impurities.