Fatigue Fracture of Stainless Steel Wires in Metal Rubber Damper

Using laser scanning confocal microscope (LSCM),the surface contour of  0.3 mm cold-drawn stainless steel wires with the composition close to 302 austenitic stainless steel was studied and the microstructure was observed by SEM. Fatigue test was performed on hollow cylinder-shaped metal rubber damper made of such wires,and the fatigue fracture reason of the wires was analyzed. The results show that there were a lot of concavo and convex micro bodies on the surface of the steel and the wires surface roughness Ra was 3.447 μm. There were shuttle-shaped micro holes along the drawing axis with hard particles as core in the microstructure of the steel. The cracks originated from the surface of the wires and each fracture had more than one crack origins. Steady and fast spreading area both took up 50% of the toal fracture. Waviness fatigue striation was piled with tongue-shaped wrinkles which had important relationship with the shuttle-shaped micro holes.