Sinter alloys based on high-speed steel

Details Sinter alloys based on high-speed steel Sinter alloys based on high-speed steel

1987-02-17

1988-07-05

Lechert, Jr., Stephen J.

Specialized metallurgical processes, compositions for use therei

Compositions

Consolidated metal powder compositions

75243, 75255, 419 38, 419 39, 419 58, C22C 2300

Patent

active

047552220

DESCRIPTION:

BRIEF SUMMARY
STATE OF THE ART

The invention is directed to sinter alloys based on high-speed steel. Sintered high-speed steels are distinguished by great hardness, very good wear and satisfactory toughness. Powder metallurgical methods for producing articles from such steels assure a very high degree of material utilization and a low energy expenditure. Nevertheless, such steels have thus far been used substantially only in the field of heavy-duty cutting tools; as wearing parts in machinery and vehicle construction, they have not yet been able to gain acceptance because powder prices are high, sintering of the material is time-consuming, and special vacuum furnaces are required; also, the dimensional accuracy of the sintered parts is unsatisfactory, so that expensive finishing is usually necessary. In the aforementioned wearing parts in machinery and vehicle construction, exhaustion of the wear properties of the pure high-speed steels up to the limit is often less critical, while in this case the dimensional accuracy of the parts produced from the material is a weightier argument, as long as such sinter steels offer greater reliability than the normal case-hardened sintered steels.


ADVANTAGES OF THE INVENTION

The sinter alloys according to the invention have the advantage over the prior art that they can be sintered in standard furnaces in protective gases, without the shrinkage that occurs with pure high-speed steels. Deviations in temperature upon sintering in protective gas furnaces, from a command value, which with pure high-speed steel powders are well known to lead to major dispersion of dimensions, is practically insignificant with sintering in the protective gas furnace. These mixed materials, in contrast to pure high-speed steels, are intentionally optimized not for full density but rather for processability with the greatest possible dimensional accuracy. By means of a heat treatment corresponding to the high-speed steels, the properties of these combination steels can be improved analogously to what is done with the pure high-speed steels, without impairing their dimensional accuracy. A further advantage is that by replacing part of the high-speed steel powder with less-expensive iron powder, a savings up to 40% of the cost for powder can be realized. It has already been noted above that although these combination materials--if for no other reason because of the pores they exhibit--do not attain the hardness, wearing and bending strength values of pure high-speed steels, they do exceed the values for standard case-hardened steels. In fact the presence of the pores makes it advantageous to use the sinter steels according to the invention precisely where hard, wear-resistant surfaces having pores for receiving lubricants are needed.
By means of the provisions recited in the dependent claims, advantageous further features of and improvements to the sinter alloys disclosed in the main claim are possible. Sinter alloys comprising 65% by weight of a high-speed steel powder of the type S 6.5.2 having approximately 0.9% C, 6.3% W, 5.2% Mo, 4.2% Cr, 1.9% V and the remainder Fe and 35% by weight of a phosphorus alloy iron powder having 0.45% P, 1.5-2% Si and the remainder Fe are particularly advantageous, because they have particularly good hardness and wearing properties and furthermore can be sintered with high shape stability.


DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Among numerous possible mixture systems, mixtures of the high-speed steel powder type M2, corresponding to S 6.5.2 having 0.9% C, 6.3% W, 5.2% Mo, 4.2% Cr, 1.9% V and the remainder Fe (all the percentages given are by weight) with approximately 50% by weight of pure iron powder and 0.15% carbon powder or 50% of a diffusion alloy iron powder having 1.5% Cu, 4% Ni and 0.5% Mo and 0.2% carbon powder are distinguished by their low powder costs, favorable behavior during sintering and high hardness and wearing values. The low amounts of carbon added improve both behavior during sintering and the values of the properties. These materials can be produ

REFERENCES:
patent: 2352316 (1944-06-01), Goetzel
patent: 4263046 (1981-04-01), Fichte et al.
patent: 4519839 (1985-05-01), Toyoaki et al.
patent: 4618540 (1986-10-01), Holst et al.
"Production of High-Speed Powders at SCM Metal Products", MPR, Apr. 1983, pp. 197-199.
Bruen et al., "Sintered High Speed Steels: Their Application and Uses", MPR, Sep. 1983, pp. 497-500.
Beiss, "PM Methods for the Production of High Speed Steels", MPR, Apr. 1983, pp. 185-194.
Dax, "PM High-Speed Steels by the CAP Process", MPR, Apr. 1983, pp. 200-202.

Affiliated with

Also associated with

Rating

Sinter alloys based on high-speed steel does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Sinter alloys based on high-speed steel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sinter alloys based on high-speed steel will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2330500