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:
Nov. 02, 2021
Filed:
May. 31, 2019
Nippon Steel Corporation, Tokyo, JP;
Isuzu Motors Limited, Tokyo, JP;
Yutaka Neishi, Tokyo, JP;
Yorimasa Tsubota, Fujisawa, JP;
Kouji Oosato, Chitose, JP;
Hirohito Eto, Fujisawa, JP;
Wataru Nagai, Fujisawa, JP;
Yoshitomi Yamada, Fujisawa, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
ISUZU MOTORS LIMITED, Tokyo, JP;
Abstract
An upper member of a steel piston has a chemical composition which consists of, in mass %, C: 0.15 to 0.30%, Si: 0.02 to 1.00%, Mn: 0.20 to 0.80%, P: 0.020% or less, S: 0.028% or less, Cr: 0.80 to 1.50%, Mo: 0.08 to 0.40%, V: 0.10 to 0.40%, Al: 0.005 to 0.060%, N: 0.0150% or less, O: 0.0030% or less, and the balance: Fe and impurities, and satisfies Formula (1) and Formula (2), in which, at a cross section parallel to the axial direction of the upper member, the number of Mn sulfides is 100.0 per mmor less, the number of coarse Mn sulfides having an equivalent circular diameter of 3.0 μm or more is within a range of 1.0 to 10.0 per mm, and the number of oxides is 15.0 per mmor less.0.42≤Mo+3V≤1.50  (1)V/Mo≥0.50  (2)