Reasons for the need for tempering in the precision casting process of the machine bed

Steel is a widely used material in the machinery industry. The microstructure of steel is complex and can be controlled by heat treatment. Therefore, the heat treatment of steel is the main content of metal heat treatment. In order to have the required mechanical properties, physical properties and chemical properties of machine tool castings, in addition to the reasonable selection of materials and various forming processes, heat treatment processes are indispensable.

　　 In addition, aluminum, copper, magnesium, titanium, etc. and their alloys can also be heat treated to change their mechanical, physical and chemical properties to obtain different performance properties. Integral heat treatment is a metal heat treatment process that heats the cast iron slab, cast iron bent plate or machine bed castings as a whole, and then cools them at an appropriate speed to change the overall mechanical properties of the cast iron platform, slab, cast iron bent plate or machine tool bed castings.

The heat treatment of machine tool castings is an important process link in mechanical manufacturing. Compared with other machining processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but by changing the internal microstructure of the workpiece, or changing the cast iron platform and the machine tool The chemical composition of the surface of the casting gives or improves the performance of the workpiece. Its characteristic is to improve the inherent quality of cast iron platform and machine bed castings.

　　As a large-scale casting, the machine tool bed casting product must undergo aging treatment to improve its performance and improve the inherent quality of the bed casting. The overall heat treatment of machine tool bed castings, machine bed columns, machine tool tables and other castings generally includes four basic processes: annealing, normalizing, quenching and tempering. When the machine bed castings are tempered, the tempering process should be strictly followed, and supporting ribs should be added to the dense or easily deformable parts of the ribs to prevent deformation and fracture caused by the tempering temperature. There should be a dedicated person to take care of the tempering furnace thermometer and control the temperature in time to prevent the temperature from being too high or too low, which will have a great impact on the tempering workpiece.