2、 Factors affecting the safety of valve body welds
1. Stress concentration at weld root Due to the assembly alignment and positioning requirements of all welded pneumatic ball valve body, there is a circular assembly gap at the weld root, which will lead to a large stress concentration at the valve body weld root. Through finite element analysis and calculation, under the working pressure of 10MPa, it can be clearly observed that a large stress concentration occurs at the root of the weld for the valve body of 20in, 600Lb pneumatic ball valve, and the Von misese stress at the root reaches 275MPa, which has exceeded the yield strength of A105 material and reached about 3 times the normal working stress.

2. Valve body inspection Every six months, check whether the valve body appearance is good, whether the installation flange has leakage, if it is convenient to check whether the valve body seal is good, whether there is wear, whether the valve plate operates flexibly, and whether the valve has foreign matters stuck.