High-level substitution levels for materials and relevant substitution principles for foreign materials
Thread Content
There are regulations regarding design approval for material substitutions, but the principles behind such substitutions are not very clear. I would like some advice
1. Material substitution should be avoided as much as possible, unless it is unavoidable. 2. Generally, it is not allowed to substitute a lower grade for a higher one. 3. For materials in the same category, it is generally permissible to use a higher grade in place of a lower one; for example, an increased thickness or size can lead to greater strength. 4. Materials of different categories should not be substituted for one another using higher-grade ones in place of lower-grade ones; for example, stainless steel should not be used in place of carbon steel, nor should high-alloy steel be used in place of low-alloy steel, and so on. 5. Any material substitution must be reviewed and approved by authorized personnel.