Abstract：?7.5 mm]0Cr17Ni7Al stainless spring steel wire breaks at the bending hook during winding spring. The causes of spring breakage are analyzed by means of quality control process investigation， chemical composition analysis， metallographic examination， microhardness test and scanning electron microscope fracture observation. The results show that the spring fracture originates from the surface defect. The surface defect is caused by the scraping or knocking of steel wire during hoisting or transporting. When the spring is winding the hook， the stress concentration is formed. Under the action of bending stress， the crack expands rapidly， which causes the spring to break in the process of winding the spring.It is suggested that surface quality inspection should be strengthened during the use of steel wire in order to avoid potential failure crack source on spring surface.
2020, Vol. 38 
