Effect of Microstructure Evolution on Mechanical Properties of 87Mnsi Steel Wire Rod for Bridge Cable
According to the abnormal fracture phenomenon of 87MnSi steel wire rod for bridge cable,the evolution of mi-crostructure and mechanical properties during production processing were systematically analyzed.The results show that the microstructure of the rod is composed of pearlite and a small amount of proeutectoid ferrite,and the cementite lamellae are randomly distributed.After cold drawing,the cementite lamellae are rotated or fibrotic,and some cementite are bro-ken and dissolved,the dissolution amount is 1.40wt.%(9.69%).After ho-dip galvanizing,the dissolved cementite is spheroidized.In the process of cold drawing,hot-dip galvanizing and stabilization treatment,the microhardness of wire rod(329.8HV)increases(450.2HV)firstly,then decreases(447.9HV)and increases(474.8HV)finally.The cement-ite dissolved in the cold drawing process increases the hardness of the steel wire to 468.3HV,while the spheroidized ce-mentite in the hot galvanizing process decreases the hardness to 439.8HV,and deteriorates tensile property.When the de-gree of spheroidization of cementite on the edge is obvious,the microstructure and mechanical properties of the steel wire inside and outside are greatly different,and the fracture is eventually caused by uneven force during stabilizing treatment.
万方数据
维普
