Effect of Deformation Temperature on the Microstructure and Mechanical Properties of High-Strength Low-Alloy Steel During Hot Compression

The microstructure and mechanical properties of high-strength low-alloy steel were investigated at deformation temperatures of 800-1100 degrees C and strain rates of 0.1-10 s(-1) using an MMS-200 thermal mechanical simulator. The results indicated that the increased deformation processes observed between the starting and finishing temperatures during hot compression testing caused a polygonal ferrite transformation in the material. The polygonal ferrite grain sizes increased with increasing transformation temperatures and gradually grew larger at higher deformation temperatures. Widmanstatten ferrite and acicular ferrite were also formed at high temperatures from 1000-1100 degrees C, which accordingly led to an increase in Vickers microhardness. In addition, the flow stress in the material increased with an increase in the strain and a decrease in the deformation temperature.