Microstructure and Mechanical Properties of Calcium Treated 42CRMO4 Steel with Improved Machinability

The steel 42CrMo4 with improved machinability was studied. The steel containing high amount of sulfur was calcium treated during metallurgical production stage. The size and area distribution of non-metallic inclusions present in the studied steel was analyzed and compared to the conventional Cr-Mn-Mo steels with low sulfur and calcium content. The dilatometric investigation was performed to reveal the features of the austenite transformations in studied Cr-Mn-Mo steels with various content of alloying elements. The mechanical properties of the high and low sulfur steels were analyzed in heat treated condition (oil quenching and tempering). The results proved that calcium treated 42CrMo4 steel with high sulfur content possessed almost the same characteristics of hardenability and mechanical behavior as the conventional low-sulfur steels. This implies that the steel with improved machinability can be successfully applied for the production of the heavy duty and high strength parts using automated lines and machines.