Wear Characteristic of Surface Hardened Ausferritic Si-Steel

High strength steels can be produced by austempering of Si-containing steels. It is possible to achieve high toughness and good wear resistance in these steels. Surface hardening of this group of steels can further increase the surface hardness and wear resistance and in combination with high strength in the bulk, also the fatigue strength. Surface hardening by laser-hardening has been performed on steel 55Si7 after austempering of the steel in order to create a ferritic-austenitic carbide free microstructure. Tempering effects and hardness values have been studied. Optical as well as scanning electron microscopy has been used together with x-ray diffractometry in the characterization of the micro-structural changes. Wear resistance testing of austempered and laser hardened samples respectively of the Si-alloyed steel have been reported and also compared with that of the conventional Cr-alloyed steel. The results of the specific phase transformation from austenite to martensite during wear process will be reported.