Low alloy sintered steel and method of preparing the same
US5427600A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1993 |
| Grant date | Jun 27, 1995 |
| Priority date | — |
| Expiry date | Nov 30, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A low alloy sintered steel contains at least 0.15 percent by weight and less than 0.8 percent by weight of carbon. Its matrix is formed by a tempered martensite containing prior austenite crystal grains of not more than 15 .mu.m in mean grain size. Pores and nonmetallic inclusions contained in the matrix are not more than 50 .mu.m in maximum diameter, and the density of the low alloy sintered steel is at least 96 percent of theoretical density. A raw material powder for forming the low alloy sintered steel includes iron alloy powder which is prepared by an atomizing process, and is treated with a dry mill in an inert gas atmosphere or in the atmospheric air. Thus, dislocations are introduced into the raw material powder, and nonmetallic inclusions contained in the raw material powder are pulverized to be not more than 50 .mu.m in maximum diameter. Not only static characteristics but also dynamic characteristics, such as fatigue strength, of the low alloy sintered steel are improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.