Effects of Heat Treatment on the Microstructure and Mechanical Properties of Low-carbon Microalloyed Steels

Abstract

In this study, the effect of cooling rate and heat treatment on the microstructural and mechanical characteristics such as microhardness of low-carbon microalloyed steel was investigated by means of optical microscopy and Vickers hardness tests. The cooling rates were controlled by introducing air-cooling, furnace-cooling, water-quenching and liquid nitrogen quenching. The obtained results showed that the difference of cooling rates and the heat treatments significantly affect the microstructure and mechanical properties of steels. These tendencies were dominant in liquid nitrogen cooled for 1073 K at 4 h and 1273 K heat treatment processes.

Keywords

• microalloyed steels
• heat treatment
• hardness testing
• microstructure