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. 13, 2001
Filed:
Apr. 25, 2001
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
Cutting tools and wear-resistant materials formed of a silicon-nitride-based sintered body having excellent characteristics, such as high wear resistance. Cutting tool,is in the form of a negative chip having a shape prescribed by ISO standard: SNGN 120408. Specifically, the cutting tool,is a chip of a rectangular parallelepiped shape which has a thickness of 4.76 mm and in which each of four sides (cutting edges),on a rake face,side has a length of 12.7 mm. In the region having a width of 0.2 mm or less and extending from the cutting edges,of the cutting tool,, the cutting tool,has a microhardness H. Plast of 21.2 GPa or greater and a microhardness HU of 11.2 GPa or greater. The Vickers hardness of the cutting tool,as measured at a substantial center of the rake face,is 14.5 GPa or greater. Further, the amount of oxygen within the cutting tool,is 1.0 to 2.0 wt. %. Also disclosed is a method of quality control of an article having a surface, at least a portion of which is curved, which includes measuring one or both of microhardness H. Plast and microhardness HU in the vicinity of the curved portion of the surface, and either accepting or rejecting the article based on the measurement values.