Modified Morphology of Mn S Inclusions in Tellurium Treated 303Cu Stainless Steel

In order to study the influence of tellurium on the morphology of MnS inclusions in 303Cu freecutting stainless steel,various amount of tellurium was added into 303Cu steel,and then the morphology and distribution of MnS inclusions in steels was analyzed by means of OM,SEM and microelectrolysisdding.It was found out that with tellurium addition into 303Cu stainless steel,the number of small-size inclusions in steel decreased,while the number of large-size inclusions increased,and the average equivalent diameter and average area of the inclusions increased. Inclusions modification was achieved the best effect when 0.036 0% tellurium was added.Telluride mainly attached to the surface of MnS inclusions in low-tellurium steel,while MnS inclusions were completely surrounded by telluride in high-tellurium steel.After treated by tellurium,the inclusions in steel were modified from chains and strips into spindles and spheres,which was beneficial to the improvement of mechanical properties and cutting properties.After tellurium was added,the hardness of the inclusion and the matrix firstly increased and then decreased.When the tellurium content was 0.018 0%,the hardness of the matrix and the inclusion reached the maximum values of 209.6 HV10 and 200.3 HV10,respectively.