Medical casting quality standard: 

1. The degree to which the shape, size, composition, microstructure and properties of the castings meet the requirements for use. It includes three aspects: appearance quality, internal quality and use quality of castings. 

2. Internal quality of castings: generally speaking, the internal condition of castings that can not be detected by the naked eye and the degree to which they meet the requirements of users. It includes the chemical composition, physical and mechanical properties, metallographic structure and defects such as voids, cracks, inclusions and so on. 

Chemical analysis, material test, metallographic examination, nondestructive testing and other methods can be used to check the internal quality of castings. 

3. Appearance quality of castings: the surface condition of castings and the degree to which they meet the requirements of users. 

Including casting surface roughness, surface defects, dimensional tolerance, shape deviation, weight deviation and so on. 

To check the surface quality of castings, generally use observation or related measuring tools, instruments, etc. 

4. Casting quality classification: the grade specified for each quality item of the casting. 

5. Casting quality analysis: analyze the casting quality to find out the problems and the ways to improve the quality.