Metallographic diagram of W6Mo5Cr4V2 (after vacuum quenching, tempered three times at 560°C)

With the rise of human resource and technology in the world, Vacuum tempering of steel has become a more popular, efficient, and cost effective way to manufacture and perform modifications to steel parts and components. The Vacuum tempering process involves heating the steel to more than 800°C in a vacuum condition and then cooling it at a slow rate of usually below 20°C per hour. During this process, the steel undergoes metallurgical changes resulting in a higher strength, improved hardness and ductility.

In this study, a specimen obtained from 5Cr4V2 steel was subjected to Vacuum tempering. The specimen was heated to 560 °C in Vacuum condition and then cooled to lower temperatures at a rate of three times. After the specimen cooled, an optical microscope was used to observe the microstructure of the steel and a metallurgical analysis was performed to characterize the microstructure and hardness of the steel specimen.

The optical microscope revealed that the specimen was identified to be a ferrite and pearlite structure, with some presence of carbides. The metallurgical analysis disclosed that the specimen displayed a microhardness of ~450HV. The hardness and microstructure suggests that the specimen was tempered to the desired degree and had the appropriate temperature during the tempering process to result in desired hardness and strength properties.

The Vacuum tempering process is a powerful tool to modify the properties of steel parts. It offers a cost effective, time effective, and foolproof way to modify the properties of steel. The results obtained from the analysis of the 5Cr4V2 steel revealed that a desired strength and hardness modification can be successfully achieved with Vacuum tempering. This makes it a suitable, viable solution for the industrial requirements.

Since the Vacuum tempering process is non-destructive and allows for easier manipulation of the steel in the tempering procedure, it is currently one of the most popular heat treatments available to change the properties of steel. The fact that it can produce desired results with precision and accuracy makes it a preferred method for manipulating the mechanical properties of steel.

Therefore, Vacuum tempering of steel proves to be a powerful and potential alternative to traditional tempering techniques and can help provide reliable and cost-effective solutions to modify and improve the properties of steel parts and components.

The microstructure of metal acuerding to the heat treatment of vacuum carburizing and quenching at 560°C thrice, is presented in the polycrystalline grain fashioned by the use of metallurgical microscope.

The sample reveals grain structure of martensite and some grain dislocation in perimeter. The dislocation of grain across the board help in strengthening the metal block. Most of the grain boundaries bare witness to its carburized surface. Generally, the structure holds ferrite phase and bainite structure along the grain boundary.

In the initial phase of heat treatment such as carburization the grain pulls the material apart and produces strong grain boundary leaving a greater amount of alloy atoms trapped beneath the surface. As we study the sample, it reveals a presence of a plaque-like bainite structure near its surface that is harder and at the same time absorbs more energy than the core of its matrix.

The sample further reveals a negligibly small amount of carbide, mainly as necks post ferrite transformation that benefit the source of better strength and wear resistance. The vacuum carburizing worked with a decrease in the particle size of the end structure.

The sample perfectly reveals a homogenous structure after the heat treatment. The study of the microstructure shows metallurgical processes used to be highly influential in achieving desired applications and characteristics. To finish the processes related to carburization, heat treatment was required to attain the desired microstructure. This sample held up its specified properties on heat treatment.