Analysis on Linear Defect of 65Si2MnWA Spring Steel

Linear defect was found on the cross section of 65Si2MnWA spring steel during grinding. Through visual inspection, metallographic examination, scanning electron microscope observation and energy spectrum analysis of the defect part, the nature and causes of the defect were determined. The test results show that the defect was not cracks, but non-metallic inclusions, and it was a kind of raw material metallurgical defect. The defect was mainly caused by the shrinkage of the steel formed during the process of electro slag remelting and casting. Because the slag residue in the shrinkage of the steel was not cut, it deformed to linear defect during the subsequent rolling and drawing. Finally, the improvement and preventive measures were put forward.