Patent ID: 8419870
Filing Date: 2013-04-16
Classification: C22C

Abstract:
1. A method for making a strain aging resistant high carbon spring steel with carbon content between 0.54 and 0.77% for wire drawing comprising: setting a free nitrogen content specification, wherein the free nitrogen content specification requires a free nitrogen content that is no more than a set ppm number but no less than 20 ppm below the set ppm number, and the set ppm number is between about 50 ppm and about 80 ppm; adding nitride-forming element to a pre-processed steel to form a resultant steel with a free nitrogen content in conformance with the free nitrogen content specification; forming the resultant steel into a billet, rolling the billet into a rod, and cold drawing the rod into wire; wherein: substantially all of the nitride-forming element in the resultant steel exists as a nitride compound; the rod is cold drawn into wire without heat treatment; and the resultant high carbon spring steel is strain aging resistant.