Investigating the Effect of the Number of Passes and Tool Design in the Friction-Stirring Process on the Grain Size, Hardness and Wear Resistance of Ck45 Steel.

Friction stir processing is widely used for improvement of properties and microstructure of Aluminum, Copper and Magnesium alloys but investigation on steels are limited. Due to the fact that steel alloys, in addition to aluminum, copper and magnesium alloys, have good engineering properties and vast applications in the industry, they need to be processed by friction-stirring process. In this regard, the present research examines the effect of frictional stirring process on grain size, hardness and wear resistance of Ck45 steel due to the number of passes and tool design. In this research, it was shown that the friction-stirring method can be an effective method to increase the hardness and wear resistance of this steel in such a way that increasing the number of passes causes more heat generation per unit length and also affects the grain size, hardness and probably atomic penetration. In general, with the increase in the number of passes, the size of the grains in the stirring area becomes larger, while the final hardness and wear resistance are determined under the joint effects of grain size and hardness. The results indicate that the hardness has increased by 42% and the amount of wear has decreased by 85% compared to the original sample by the frictional stirring process.Keywords