Analyze the service conditions of the parts to find out the specific load conditions, stress states, temperatures, corrosion and wear of the parts during use.
Most of the parts are used in the normal temperature atmosphere, and the mechanical properties of the material are mainly required. Parts used under other conditions require materials to have certain special physical and chemical properties. For example, when used under high-temperature conditions, the parts materials are required to have certain high-temperature strength and oxidation resistance; chemical equipment requires materials to have high corrosion resistance; some instrument parts require materials to have electromagnetic properties, etc. Welded structures used in severe cold areas should have additional requirements for low-temperature toughness; when used in humid areas, additional requirements for atmospheric corrosion resistance should be added.
(1) Through analysis or test, combined with the results of failure analysis of similar materials, determine the generalized allowable stress indicators that allow materials to be used, such as allowable strength, allowable strain, allowable deformation and service time, etc.
(2) Find out the main and secondary generalized allowable stress indicators, and use important indicators as the main basis for material selection.
(3) According to the main performance indicators, select several materials that meet the requirements.
(4) Select the material and its molding process according to the molding process of the material, the complexity of the parts, the production batch of the parts, the existing production conditions, and the technical conditions.
(5) Comprehensively consider material cost, molding processability, material performance, reliability of use, etc., and use optimization methods to select the most suitable material.
(6) When necessary, the selection of materials should be tested and put into production, and then verified or adjusted.
