JPS61553A - High-speed tool steel having superior wear and depositing resistance - Google Patents

Abstract

PURPOSE:To obtain a high-speed tool steel having superior wear and depositing resistances by mixing a specified percentage of gas atomized powder having a specified particle size and a specified composition with specified percentages of Ti nitride, Cr powder and B each having a specified particle size and by molding and sintering the mixture. CONSTITUTION:65-96% Water or gas atomized powder having <=44mum particle size and consisting of, by weight, 0.5-2.2% C, <=1.5% Si, <=1.0% Mn, 3.0-6.0% Cr, <=15% Mo and one or two kinds of <=30% W (W+2Mo=4-30), 0.5-10% V, <=0.1% B and the balance Fe with impurities is uniformly mixed with 2-15% one or more kinds of compounds selected among the nitrides, carbides and carbonitrides of Ti and Zr each having 0.1-10mum particle size, 0.5-20% powder of one or more among Cr, Ni, Mo, W, Cu, Co and Fe each having <=10mum particle size and 0.01-4% B and/or one or more kinds of component B or B compounds each having <=44mum particle size. In the case of B compound each of the B compounds has <=1,200 deg.C m.p. or forms a eutectic with Fe at <=1,200 deg.C. The mix ture is molded and sintered to obtain a high-speed tool steel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-speed tool steel with excellent wear resistance and welding resistance.

When high-speed tool steel is used for cutting tools, cold working tools, sliding parts, etc., it is important to have excellent wear resistance and welding resistance in order to improve tool life. It has been known for a long time that carbides, nitrides, and carbonitrides of Ti and Zr have high hardness and have low affinity with steel, making them excellent in K, wear resistance, and welding resistance. . Applying this, we applied surface treatments such as CVD (chemical vapor deposition) and PVD (physical vapor deposition) to the surface of high-speed steel tools.
~10μ of the above carbonized*, nitride, carbonitride is coated,
A method for improving the life span of a steel sheet by several times to several tens of times has been implemented industrially. However, the above-mentioned surface treatment method is extremely expensive in processing cost, and has many problems such as shape limitations, and cannot be applied to tools at a flat temperature.

Another major problem with surface treatment method 1 is that once the surface layer is lost, the effect is completely lost.

Therefore, if a high-strength tool steel in which the carbides, nitrides, and carbides of Ti and Zr are uniformly dispersed throughout the steel can be produced at a low cost, it will have a great industrial effect.

Ti and Zr are elements that are extremely active and easily form oxides, so a large amount of Ti is
, it is industrially impossible to produce high-speed tool steel containing Zr. In recent years, high-speed tool steel has been manufactured industrially by powder metallurgy. But T
i, Zr carbide, nitride.

It is difficult to directly obtain a powder of high-strength tool steel in which a large amount of carbonitrides are dispersed, for the same reason as mentioned above.

The present invention is based on the current situation, and involves mixing water or gas atomized high-speed copper powder that does not substantially contain Ti and Zr with powders of carbides, nitrides, and carbonitrides of Tj and Zr, and then molding and sintering the powder. From KotoK, carbides of Ti and Zr,
The object of the present invention is to provide a high-speed tool steel that is inexpensive and highly mass-producible, in which nitrides and carbonitrides are uniformly dispersed. That is, the particle size is 44. a or less, and the chemical composition (hereinafter all weight %) is 0.005 to 2.2%.

8ft5% or less, Mn10% or less, Crs, a
~ao % Sara KM0 15% or less, W 30% or less If 1 trap is 2 yearning and 2 types (W+2Mo is 4
~30%),■0.5~10%B0.1% or less/AFe
and water or gas atomized powder consisting of impurities of 65 to 97% in terms of it% and one or more types of Ti, Zr carbide, nitride or carbonitride with a particle size of 0 to 1 to 10 in total. Cr, Ni, and M having a particle size of 2 to 15% and a particle size of 10 s or less.

W, Cu, C0. A total of 0.5 to 20% of one or more types of Fe powder, and B or a compound of B with a particle size of 44 tones or less (however, in the case of a compound of B, the melting point or eutectic with Fe) A total of 0.01 to 4% of one or more of the following: 0.01 to 4%, and if necessary, 0.012% or less, and a uniform carbon powder of 0◆01 to 1.0% of 44 tones or less. After mixing, mold.

The object of the present invention can be achieved by sintering.

The particle size of the water atomized powder or gas atomized powder of the steel used in the present invention must be a fine powder with a particle size of 44 tones or less, so that when mixed with carbides of Ti, Zr, etc., a uniform dispersion structure will not be underestimated.

More desirably, when the material is mechanically pulverized, a more uniformly dispersed structure can be obtained, and the wear resistance, welding resistance, and mechanical strength after sintering are improved by 1%.

High speed tool steel powder is used for tool applications.

Select the most suitable chemical composition depending on usage conditions, etc.

For example, in tools that require toughness, such as punches.

A powder with a chemical composition having a low C content (0.5 to 0.8%) and a low W and Mo content (W+2Mo 5 to 12%) is delivered. Conversely) tools that require high hardness of IRC68 or higher have a high C content (1.5 to 2.2%) W, M
The o-containing lid is also high ((W + 2Mo 20-50%) Sarani 8
The powder has a chemical composition of ~12% CO2. V crystallizes as a Cc carbide and provides an anti-wear effect, but in the present invention, carbides, nitrides, and carbonitrides of Ti and Zr are dispersed in multiple ff1K, so the V content is 0.
It is fine if it is as low as 5 to 2%. However, if powder containing 6 to 10% is used, the amount of Ti will increase.

It has a synergistic effect with Zr carbide, etc., and has extremely wear resistance.
High-speed steel tools with excellent M adhesion resistance are preferred.

B is the week that increases wear resistance, hardenability, and sinterability.
0 because it is effective. It is preferable to contain i% or less.

The particle size of carbides, nitrides, or carbonitrides of Ti and Zr must be 0.1 to 10 μm. If it is less than 0.1 tone, the wear resistance effect is extremely reduced, and if it exceeds 10 seconds, the fracture machinability of the sintered body is significantly reduced. Also.

If the total amount of the mixture is less than 2%, the effect of improving wear resistance and bath adhesion resistance, which is the objective of the present invention, will be small (on the contrary, if it exceeds 15%, the fracture machinability will decrease and the sintered density will decrease. Therefore, one or two tanks of carbides, nitrides, and carbonitrides of Ti and Zr were used in a total amount of 2 to 15%.

Cr, Ni, M0. W, Cu, C0. The mixing of Fe powder is an important element of the present invention. That is, simply mixing the above-mentioned high-speed tool steel powder with Ti, Zr carbide, nitride, and carbonitride powders does not increase the density of the sintered body and cannot be used as a substantial busy tool. Cr, Ni, Mo.

W, Cu, C0. It has been discovered that by further mixing Fe powder, molding and sintering, a sintered body with close to true density can be obtained.

Cr, Nr, M0. W, Cu, C0. If the particle size of the Fe powder exceeds 10 seconds, the above-mentioned effect of increasing the sintered density will be reduced, so it must be 10 tones or less. Cr, Ni
, Mo, W, Cu.

C0. The amount of Fe powder mixed depends on the amount of the Ti, Zr carbides, etc. mixed, and if the latter amount is small, the former may also be small, but in order to sufficiently increase the sintered density, K is added to the liquid bottom. 0.5% is required. On the other hand, Or.

Ni, M0. W, Cu, C0. 1m or 2 at the end of P prayer
When the total amount of the above-mentioned elements exceeds 20%, the quenching-tempering hardness of the sintered body becomes low. There are disadvantages such as high manufacturing costs (Lef) TeCr, Ni, M0. W, Cu
, c0. The amount of Fe powder mixed was 1 ffl or two or more types in a total of 0.5 to 20%.

The mixing of powders of B or B compounds is also an important element of the present invention. That is, high-speed tool steel powder and nitride carbides and carbonitrides of Ti and Zr have very poor sinterability, but the sinterability of Cr, Ni, M0. W, Cu, C0. When 4c, B or B compound powder is added and mixed at the same time as Fe powder,
Furthermore, the sinterability is improved, and a sintered body with close to true density can be obtained. Further, B reacts with MO, W, and Cr to form a high hardness boride, which has the effect of improving wear resistance. In the present invention, the above-mentioned effect of increasing sinterability is achieved!
As for r products, Hachiheya NN R0rHaBO,, NiB
, Nt, H, etc., with a melting point of 1200°C or less.

Alternatively, the eutectic temperature with Fe such as 'B' is 120
The temperature must be below 0°C. That is, it is presumed that by mixing these B or B compounds, a thin molten zone is formed on the surface of the high speed tool steel powder at a relatively low temperature during sintering, thereby improving sinterability. The above effects can be greatly achieved by using fine powder of B or B compound with a particle size of 447I or less.

If the mixing amount is less than 0.01%, the above effect will be small (on the contrary, if the mixing amount is less than 4%
If the sintered body exceeds this value, the sintered body becomes brittle, so the total amount of one or more B or B compounds is 0. oi to 4%.

When mixing the powders, the purpose of the present invention can be achieved even if carbon powder is not particularly added. However, if the powder used has a high oxygen content, the amount of carbon powder may be 0.01 to 1.0% depending on the oxygen content.
When carbon powder is added and mixed in a range of 0%, the sinterability is further improved.

If it is less than 0.001%, the effect is small (on the contrary, if it is added in excess of 10%, the effect is saturated.Also, if the size of the carbon powder is not 44μ or less, the effect of reducing and removing surface oxides of the powder may be localized). Become.

Next, the present invention will be further explained in detail with reference to Examples.

Example 1 Weight % TeC082%, 5i048%, Mn01%
, Cr5.98%.

MO5, 12%lW6.06%, Vt98%, B0
．． 0.006% water atomized powder of 44μ or less, B of 10μ or less, 0.006%. .

HaBO, or NiB, Fe, B and 1 below 44μ
．． T iN of 3 μ, 4.8 tsf) Z rN
Powder and t2a-B, 9j Cr, Ni.

Mo, W, Co, and Fe powders were wet mixed in the proportions shown in the table using a ball mill. The mixing time was 48 hours, and after drying, compression molding was performed using a cold press at a pressure of 5 tons/crn. This green compact was heated in a vacuum at 1250°C
When sintering was carried out for several hours and the density after sintering was measured, as shown in the table, a high density car was obtained which was 98 to 99% of the theoretical density. The density after sintering of symbol E used for comparison is 86
%, and the effect of improving sinterability of the present invention is clear (force) at 1
be.

Next, sintered high-speed tool steel with symbols A-H was quenched at a temperature of 1220.
℃, and a tempering temperature of 560° C. was repeated three times. After finishing the surface by grinding, the abrasion resistance was compared using a large mirror abrasion test. The measurement conditions are the partner machine SCM21.
Friction speed 3.5m/s, friction distance 400°, final load 6
．． It weighs 6 kg. As a result, the wear amount was that of sample No. In both cases, the wear resistance was less than half that of E, and the wear resistance was significantly superior.

Below is the margin Example 2 Chemical composition is C1, 50%, Si 1%, Mn0 in weight%
．． 5%.

Cr 4.1%, MO0.6%, W12.5%
, V4.7%, CO5.2%, HD, 009% N, gas atomized powder was mechanically sanded to obtain a powder with an average particle size Z8μ. This powder is 82!5% and the average particle size is 0.
5% TiC powder of 8μ, 2% TiN powder of average particle size 1.3μ, 3% NjB powder of 44μ or less, and average particle size 3.2a
2% MO powder, 3% W powder with an average particle size of 4.7μ, 2% Cr powder with an average particle size of 89μ, and further 15% carbon powder with an average particle size of 35μ were mechanically mixed in an attritor. Mixing conditions: rotation speed 30 rpm, time 4 hours + A
It is under gas seal.

Next, 2% zinc stearate was added and press molded, and the
Vacuum sintering was performed at 45° C. for 1 hour. The density after sintering was almost close to the theoretical density. In addition, when a large mirror abrasion test was conducted on a sample that had been heat treated 1230°C for quenching and 13 times for tempering at 560°C, compared to μSSKH1o,
The amount of wear was reduced to about 1/3, showing extremely excellent wear resistance.

As described in the above examples, the steel of the present invention is a high-speed tool steel that has significantly superior wear resistance and welding resistance compared to conventional high-speed tool steels.

Claims (1)

[Claims] 1. Particle size is 44μ or less and chemical composition (hereinafter referred to as weight %) is C0.5 to 2.2%, Si1.5% or less, Mn1
．． 0% or less, Cr3. ＾0～6. ^0%More Mo15
% or less, W30% or less (in the case of two types, W+2Mo is 4 to 30%), V0.5 to 10%, B0.
Water or gas atomized powder consisting of 1% or less residual Fe and impurities with a particle size of 65-96% and 0.1-1
Cr, Nv, Mo, W, Cu, with a particle size of 10μ or less and a total of 12 to 15% of one or more of Ti, Zr nitride, carbide, or carbonitride with a particle size of 0μ
One or more types of Co, Fe powder in total of 0.5~
20% and further B or B with a particle size of 44μ or less
(However, in the case of the compound B, the melting point or eutectic point with Fe is 1200 ° C or less). After uniformly mixing a total of 0.01 to 4% of one or more compounds, molding and sintering. High-speed tool steel 2 with excellent wear resistance and welding resistance, with a particle size of 44μ or less and a chemical composition (hereinafter referred to as weight %) of 0.5 to 2.2% C and 1.5% or less Si. , Mn1
．． 0% or less, Cr3. ＾0～6. ^0%More Mo15
% or less, any one or two of W30% or less (in the case of two types, W+2Mo is 4 to 30%), Co12% or less, V
Nitride, carbide or carbonitride of Ti, Zr with particle size of 0.1-10μ and 65-96% water or gas atomized powder consisting of 0.5-10%, B 0.1% or less and remaining Fe and impurities. Cr, N with a total of 2 to 15% of one or more of the following and a particle size of 10μ or less
A total of 0.5 to 20% of one or more of i, Mo, W, Cu, Co, and Fe powders and a particle size of 44
After uniformly mixing a total of 0.01 to 4% of one or more types of B or B compounds (in the case of B compounds, the melting point or eutectic point with Fe is 1200°C or less) below μ , high-speed tool steel 3 with excellent wear resistance and welding resistance, characterized by being molded and sintered, with a particle size of 44μ or less and a chemical composition (hereinafter referred to as weight %) of C0.5 to 2.2%. , Si1.5% or less, Mn
1.0% or less, Cr3. ＾0～6. ^0% more Mo1
5% or less, W30% or less, one or two types (2
In the case of seeds, W+2Mo is 4 to 50%), Co is 12% or less,
V0.5-10%, B0.1% or less Water or gas atomized powder consisting of residual Fe and impurities 65-96%
and a total of 2 to 15% of one or more of Ti, Zr nitrides, carbides, or carbonitrides having a particle size of 0.1 to 10μ, and Cr having a particle size of 10μ or less,
One or two of Ni, Mo, W, Cu, Co, Fe powder
A total of 0.5 to 20% of seeds or more, and a particle size of 4
1 of B or a compound of B (however, in the case of a compound of B, the melting point or eutectic point with Fe is 1200°C or less) with a particle size of 4μ or less
A total of 0.01 to 4% of a species or two or more species and 44μ
A high-speed tool steel with excellent wear resistance and welding resistance, characterized by adding 0% of the following carbon powders and mixing them uniformly, then forming and sintering them.