The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1992
Filed:
Aug. 24, 1990
Applicant:
Inventor:
Yoshiki Hirai, Tokyo, JP;
Assignee:
Hitachi Powdered Metals Co., Ltd., Chiba, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B22F / ; C22F / ;
U.S. Cl.
CPC ...
75246 ; 148902 ; 148514 ; 428547 ;
Abstract
A cylindrical, iron-based sintered slug comprising an iron-based sintered alloy having a surface hardness represented by an HRB of 40-90 is formed such that its interior porosity is 5% or less but greater than 0%, the porosities of both its surface layer regions lying at most 1 mm below its outer and inner surfaces are fixed at at least 3% or less but greater than 0% and the distribution of pores in each of the surface layers is decreased gradually toward the surface.