Developments in Large Size Round Bloom Rolling Bearing Steels
SourceIn order to satisfy the demands of the energy industry, aiming at clean and efficient energy production, a project was started in 2006 at Jiangyin Xingcheng Special Steel Works, focusing on improved bearing steels for power generation and wind turbines. The developments resulted in a capability to supply large size round blooms in the range of 280 mm to 1,000 mm in diameter with high metallurgical cleanliness and suitable homogeneity; these parameters are essential for bearing steels. The process steps from hot metal to finished bloom are described; many have been fine-tuned to meet or exceed application requirements. By optimizing the superheat, casting speed, cooling speed, and temperature in the continuous casting machine straightening zone, the casting defect rejection rate was less than 0.1 % in 2015. The details of the process developments and related metallurgical quality characteristics are described in this paper.