If the valve body material can be welded, but very different thermal expansion coefficient, or changes in operating temperature range of a larger thread junction closure weld must be honey.

• 如果阀体的材料是可以焊接的，但膨胀系数差异很大，或者工作温度的变化幅度范围较大，螺纹连接部必须进行蜜封焊。