Effects of carbon content on wear property in pearlitic steels

To clarify the effects of carbon content on the rolling contact wear in steels, we conducted a two-cylinder rolling contact wear test using pearlitic steels with carbon content in the range from 0.8 to 1.0 mass%, and studied the relation between the carbon content and the rolling contact wear. We examined the dominating factor in the rolling contact wear in pearlitic steels, and discussed the mechanism whereby the work-hardening rate of the rolling contact surface varies as the carbon content increases. The main findings were as follows: (1) The wear resistance of pearlitic steels improves as the carbon content increases. (2) The dominating factor in rolling contact wear of pearlitic steels is the rolling contact surface hardness (RCSH). (3) The improved wear resistance of pearlitic steels is attributable to an increase in RCSH due to raising of the work-hardening rate of the rolling contact surface as the carbon content increases. (4) The rise in the work-hardening rate of the rolling contact surface of pearlitic steel as the carbon content increases is considered to be due to an increase in the cementite volume fraction (carbon content) of pearlite lamellae increasing the dislocations in the matrix ferrite and thus promoting the grain refinement. Moreover, the solid solution of carbon in the matrix ferrite takes place due to the dissolution of cementite. As a result, the matrix ferrite is strengthened through dislocation hardening, grain refinement and solid solution of carbon.