Tempering treatment of machine tool body casting

The reason for the tempering treatment of machine tool castings is that the most widely used materials in the machinery industry are iron and steel, and the microstructure of iron and steel is complex and can be controlled by heat treatment. So the heat treatment of steel is the main content of metal heat treatment. In order to make the mechanical properties, physical properties and chemical properties needed for machine tool castings, the heat treatment process is essential except for the reasonable selection of materials and various forming processes.
As a large casting, the casting products of the bed body must undergo heat treatment to improve their performance and improve the internal quality of the cast iron castings. Metal heat treatment is one of the most important processes in mechanical manufacturing. Compared with other processing techniques, heat treatment generally does not change the shape of the workpiece and the chemical composition of the whole, but by changing the microstructure of the workpiece or changing the chemical composition of the workpiece surface, giving or improving the working performance of the workpiece. Its characteristic is to improve the internal quality of the workpiece.
In addition, temper treatment can also reduce the brittleness, eliminate or reduce internal stress, steel parts after quenching there is a large internal stress and brittleness, if not timely tempering will often cause deformation and even cracking of steel parts. Secondly, the mechanical properties required by the workpiece are obtained. The hardness of the workpiece is high and the brittleness is large after quenching. In order to meet the requirements of the different properties of the workpiece, the hardness can be adjusted by proper tempering and the brittleness is reduced, and the required toughness and plasticity can be obtained. In the end, the workpiece size is stabilized. For some alloy steels which are difficult to soften by annealing, high temperature tempering is often used after quenching (or normalizing), so that the carbide in the steel is properly aggregated and the hardness is reduced to be cut.