Effect of Ultrafine-Grained Formation on Tribological Properties of Low Carbon Shipbuilding Steel
AbstractLow carbon steels have been used in a wide range of shipbuilding applications due to their low cost, high workability and good weldability. However, they have relatively low hardness which lead to low wear resistance. As well known, wear of engineering materials is an important phenomena and needs to be improved by any means. It is also well known that harder materials provide relatively high wear resistance and low friction coefficient. There are various ways to enhance the hardness of steels. Grain refinement by sever plastic deformation (SPD) is one of them. Among SPD methods, equal channel angular pressing (ECAP) is one of the most commonly used one due to its capacity for achieving bulk fine-grained (FG) materials. According to the available literature, no study has been performed on tribological properties of FG low carbon shipbuilding steels via ECAP. Therefore, the main purpose of this study is to enhance the wear resistance of a low carbon ship building steel (ASTM 131A) by formation of FG via ECAP. The tribological behavior of the steel before and after ECAP was investigated by a reciprocating-type tribometer (UTS Tribometer T30M-HT). According to the experimental results, FG formation by ECAP resulted in a considerable increase in hardness from 130 Hv0.5 to about 283 Hv0.5. FG formation affected the wear resistance of the steel. After ECAP, the wear rate of the steel samples slightly decreased due to the improved hardness values.