The flowsheet of Φ11. 8 mm cold drawn spring steel (/% : 0. 58C
1. 77Si
0. 79Mn
0. 15Cr
0. 015P
0. 005S) is 80 t LD-LF-VD-hot rolled Φ12 mm coil-cold drawing process. The metallographic
mechanical and structural analyses on fracture of spring during coiling spring show that the surface quality of hot rolled products and mechanical properties of cold drawn spring steel are better; the large nonmetallic inclusions with size more than 20 μm in steel and the surface scratch during cold drawing process are causes of fracture of spring during coiling manufacture; the control of large inclusions produced in steel and the improvement of cold drawing lubrication process to avoid deep scratch are available to prevent occurrence of fracture.