Torsion Failure Analysis of 0Cr17Ni7Al Precipitation Hardening Stainless Steel Wire

0Cr17Ni7Al is a precipitation hardening stainless steel, which combines the advantages of austenitic stainless steel and martensitic stainless steel. 0Cr17Ni7Al shows good corrosion resistance, excellent processability and high strength. This paper is mainly focused on the fracture morphology of 0Cr17Ni7Al wire during torsional deformation. Cracking mechanism and torsion failure reason is analyzed in detail. The results show that AlN inclusions are observed both in raw steel wire and fracture, the micro-cracks appear along the axial direction of the steel wire. The torsion strength is normally 2958MPa. but, the local stress of steel wire reaches up to5295MPa when a 0.4mm deep micro-crack locates on the surface of steel wire, and the local stress is obtained to 2953MPa around a 10μm AlN inclusion. Stress concentrating is caused by inclusions and micro-cracks, and the crack propagation lead to the torsion failure of steel wire when the local stress is beyond the torsion limit.