Influence the quenching and tempering on the microstructure, mechanical properties and surface roughness, of medium carbon steel

Abstract EN

One of ways to improve properties of materials without changing the product shape to obtain the desired engineering applications is heating and cooling under effect of controlled sequence of heat treatment.

The main aim of this study was to investigate the effect of heating and cooling on the surface roughness, microstructure and some selected properties such as the hardness and impact strength of Medium Carbon Steel which treated at different types of heat treatment processes.

Heat treatment achieved in this work was respectively, heating, quenching and tempering.

The specimens were heated to 850°C and left for 45 minutes inside the furnace as a holding time at that temperature, then quenching process was performed in four types of quenching media (still air, cold water (2°C), oil and polymer solution), respectively.

Thereafter, the samples were tempered at 200°C, 400°C, and 600°C with one hour as a soaking time for each temperature, then were all cooled by still air.

When the heat treatment process was completed, the surface roughness, hardness, impact strength and microstructure tests were performed.

The results showed a change and clear improvement of surface roughness, mechanical properties and microstructure after quenching was achieved, as well as the change that took place due to the increasing toughness and ductility by reducing of brittleness of samples.