HIGH-STRENGTH PEARLITE RAIL WITH EXCELLENT DELAYED-FRACTURE RESISTANCE

摘要

A high-strength pearlite rail which is inexpensive and, despite this, has a tensile strength of 1,200 MPa or higher and excellent delayed-fracture resisntance. The rail contains, in terms of mass%, 0.6-1.0% C, 0.1-1.5% Si, 0.4-2.0% Mn, up to 0.035% P, and 0.0005-0.010% S, the remainder being iron and unavoidable impurities. It has a tensile strength of 1,200 MPa or higher. In a lengthwise-direction section of at least the head part of the rail, A-type inclusions have a major-axis dimension of 250 µm or smaller and the number of A-type inclusions having a major-axis dimension of 1-250 µm is less than 25 per mm² of the area examined.