Machine tool casting

The quality of machine tool castings can be considered from the following aspects:
1. Material quality: gray cast iron should have good compressive strength, hardness and wear resistance, while having good shock absorption.
2. Casting accuracy: The dimensional tolerances and geometric tolerances of machine tool castings must meet the standards, especially the flatness, parallelism and verticality of key parts (such as guide rails).
3. Surface quality: There should be no obvious defects on the surface of the casting, such as pores, sand holes, cracks, porosity, sand and so on. If the surface defects are more or too serious, it will affect the structural strength, appearance and subsequent processing quality of the casting.
4. Internal organization: gray iron castings should have a uniform organizational structure, without serious shrinkage, porosity and other defects. Poor internal organization will affect the mechanical properties of the casting, resulting in shortened fatigue life.
5. Stress control: A certain amount of stress is inevitably generated during the casting process, but it is necessary to carry out stress relief annealing and other treatments to reduce the residual stress and prevent deformation or cracking in subsequent use.
6. Hardness distribution: The hardness of machine tool castings should be uniform, especially the hardness of key parts needs to meet the design requirements, otherwise it is easy to produce local wear, affecting the service life and processing accuracy.
7. Weight and wall thickness uniformity: castings with uniform wall thickness are not easy to produce deformation and cracks in use, especially large castings, which should avoid excessive mass deviation to ensure the stability of the casting structure.
8. Machinability: Machine tool castings should have good machinability, and the surface hardness should not be too high to ensure that the tool is not easy to wear during processing.
Machine tool castings should meet the design requirements on the basis of ensuring durability, pr