Articles 

Ideal Spheroid Annealing Technique for Bearing Steel

2011-02-23

Bearing steels are vital parts in the rotary systems of motor vehicles and industrial machines. Its functional usage makes emphases on properties such as wear resistance and fatigue resistance. High-quality bearing steel requires fatigue lifetime to be ≧3.0x107; therefore, the quality of steel material must endure strict assessments. Taiwanese bearing steel industry has experienced extensive growth in the last few years. In order to meet market demand, China Steel has researched and developed the proficient SUJ2 bearing steel. After quenching and tempering, bearing steel exhibits excellent wear resistance, rotary resistance, fatigue resistance, impact resistance and compression resistance. High-carbon chromium bearing steel is considered a representing steel type. The common SUJ2 (equivalence of SAE 52100) belongs to a category of low-alloy hypereutectoid steel, whose primary chemical compositions are (0.95~1.10)%C and (1.3~1.6)%Cr(1). Its specified components are displayed in Chart 1. SUJ2 is popularly adopted throughout the world, taking up 80% of the total bearing steel produced, and mainly used for inner/outer ring, ball bearing, and axis. (Figure 1)