Effect of Heat Treatment Parameters on the Mechanical and Microstructure Properties of Low-Alloy Steel

Mohamed H Frihat

doi:10.4236/jsemat.2015.54023

Abstract

This study examines the effect of heat treatment at three different temperatures of 800°C, 950°C and 1100°C on the microstructure and mechanical properties of low-alloy steel with an addition of manganese, chrome and lead. To determine an impact of the applied heat treatment operations, testing of mechanical properties and microstructural examinations of the steel with 0.23%, 0.24%, 0.29% and 0.31% C were conducted. This work shows that the mechanical strengths of the alloy steel are improved with increasing the heat treatment temperature. In addition, the microstructure trends toward recrystallized ferrite grains as the heat treatment temperature increases.

Highlights

During the last decays, there has been a great demand for steels with higher mechanical strength, sufficient ductility and toughness
Uniaxial tensile testing is the most commonly used for obtaining the mechanical properties
Result and Discussion Sample 1 In the sample 1 we were test mechanical properties before Heat treatment and after heat treatment at (800 ̊C, 950 ̊C, 1100 ̊C), the result after test: It was shown that the steel was ductile material before heat treatment as shows in Figure 10 the carve started as a liner line after that show nicking zone it was guided in upper yield point at (405.97 N/mm2) and lower yield point at (405.35 N/mm2) and after that fracture point at which the value of elongation equal 18.46%

Summary

Introduction

There has been a great demand for steels with higher mechanical strength, sufficient ductility and toughness. The lightness of the steel is attractive, as in the automobile and aircraft applications. These requirements can be achieved by an increase in carbon content in a limited way, but even in the heat-treated condition the maximum strength of alloy steel can reach 700 MPa above this value; the ductility dramatically decreases [1]. The heat treatment of alloy steels provides a high strength and yield point, combined with significant ductility even in large sections. Thin section of plain carbon steels can be hardened via water quenching, and this is accompanied by a distortion and cracking. Alloy steels can resist corrosion and oxidation at high temperatures

Results

Discussion

Conclusion