HIGH STRENGTH BEARING JOINT PART HAVING EXCELLENT DELAYED FRACTURE RESISTANCE CHARACTERISTIC AND METHOD FOR MANUFACTURING THE SAME, AND STEEL FOR HIGH STRENGTH BEARING JOINTING PART

摘要

PROBLEM TO BE SOLVED: To provide high strength bearing jointing parts having excellent delayed fracture resistance characteristic against a shearing stress and a method for manufacturing the same, and steel for the bearing jointing parts.;SOLUTION: The high strength bearing jointing parts having the excellent delayed fracture resistance characteristics contain, by mass%, 0.05 to 3% Si, 0.01 to 1% Al, and 0.08 to 3.5% (Si+1.3×Al), and are characterized in that the grain size number of the old austenite crystal is ≥6. The method for manufacturing the high strength bearing jointing parts is characterized by performing tempering treatment by setting a tempering parameter P defined by formula (1) at 6,000 to 12,000: (1) P=(T+273){log(t/3600)+21.3-5.8C-(Si+1.3Al)}. In the formula, C, Si, Al are the contents [mass%] of the components.;COPYRIGHT: (C)2008,JPO&INPIT