Iron-based sintered alloy and method for producing the same

Patent metadata

Field	Value
Publication number	US-10745786-B2
Application number	US-201615190643-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Jun 24, 2015
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

A method for producing an iron-based sintered alloy, which is used in sliding components in pairs and has a composition including, in terms of percent by mass, Ti: 18.4 to 24.6%, Mo: 2.8 to 6.6%, C: 4.7 to 7.0%, Cr: 7.5 to 10.0%, Ni: 4.5 to 6.5%, Co: 1.5 to 4.5%, Al: 0.6 to 1.0%, the balance being Fe and unavoidable impurities, wherein the method is carried out such that the alloy has a structure in which hard particles are dispersed in an island form in a matrix and, while an area ratio thereof is kept constant, a maximum circle equivalent diameter thereof is controlled to a predetermined value of 40 to 10 μm.

First claim

What is claimed is:

1. A method for producing an iron-based sintered alloy that is used in sliding components which are used in pairs, the iron-based sintered alloy having a composition comprising, in terms of percent by mass, Ti: 18.4 to 24.6%, Mo: 2.8 to 6.6%, C: 4.7 to 7.0%, Cr: 7.5 to 10.0%, Ni: 4.5 to 6.5%, Co: 1.5 to 4.5%, Al: 0.6 to 1.0%, the balance being Fe and unavoidable impurities, and the alloy having a structure in which hard particles are dispersed in a matrix,
the method comprising:
forming a compact by mixing material powders and by subjecting the mixture to a cold isostatic pressing method; and
subjecting the formed compact to a vacuum sintering, a solution treatment and an aging treatment,
wherein the method comprises, in the vacuum sintering heating the formed compact under vacuum at a sintering temperature of 1,380° C. to 1,400° C., and controlling a maximum value of a circle equivalent diameter of the hard particles dispersed in the matrix and including Ti, Mo, and C supplied from a TiC powder and a Mo metal powder to a predetermined value of 26.77 to 10 μm while keeping an area ratio of the hard particles constant, based on a characteristic of the maximum value of the circle equivalent diameter of the hard particles decreasing in reverse proportion to the sintering temperature.

2. The method for producing an iron-based sintered alloy according to claim 1 , wherein the area ratio of the hard particles is 38% to 41% and standard deviation of the area ratio of the hard particles is 2.5 to 3.5.

3. The method for producing an iron-based sintered alloy according to claim 1 , wherein the components which are used in pairs are components to be used as a die and a cutter blade.

4. The method for producing an iron-based sintered alloy according to claim 1 , wherein the iron-based sintered alloy has a composition comprising, in terms of percent by mass, Ti: 18.4 to 24.6%, Mo: 2.8 to 6.6%, C: 4.7 to 7.0%, Cr: 7.5 to 8.8%, Ni: 4.5 to 6.5%, Co: 1.5 to 4.5%, Al: 0.6 to 1.0%, the balance being Fe and unavoidable impurities.

Assignees

• Japan Steel Works Ltd

Inventors

• Watanabe Yusuke
• Kusada Kakeru
• Makida Tetsuo
• Sawamura Youhei

Classifications

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F2304/10

  Micron size particles, i.e. above 1 micrometer up to 500 micrometer · CPC title

• B22F2302/10

  Carbide · CPC title

• B22F2301/35

  Iron · CPC title