EFFECT OF COMPOSITION AND MNS ADDITION ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF POWDER FORGED COPPER STEEL PARTS

In this work, the effects of carbon content and manganese sulfide addition on the microstructure and mechanical properties of copper steel parts have been studied. Steel powder mixture containing 2%Cu and different graphite contents with and without MnS additions were compacted, sintered and forged to almost full density. Forged samples, with near theoretical densities, were tested for tensile, hardness, impact and fatigue properties. The microstructures of samples were also studied using optical microscope and scanning electron microscope. It was found that increasing the carbon content did not have any significant effect on fatigue properties of samples, but endurance strength was reduced due to addition of MnS. Furthermore, tensile and yield strength increased by increasing carbon content. Additions of manganese sulfide decreased both tensile and yield strengths but significantly improved the impact energy and elongation of the products.