内件材料的选用原则是根据主体材料的情况、介质特性、结构特点以及零件所起的作用、受力情况综合考虑的。对于常规的通用阀门在标准已规定了内件材料或规定了几种材料由设计者根据具体情况选用。对于一些有特殊要求的阀门，如高温、高压、介质有腐蚀等工况条件，则需按工况条件选择内件材料。

The selection principle of the internal material is based on the situation of the main material, the characteristics of the medium, the structure and the effect and the force of the parts. In the standard general valve, the internal material has been stipulated in the standard or several materials are specified by the designer according to the specific conditions. For some valves with special requirements, such as high temperature, high pressure, corrosion and other conditions of medium, the internal material should be selected according to the working conditions.

1、关闭件密封面材料

1, sealing surface materials for closed parts

关闭件即闸板（阀瓣）、阀座。关闭件的密封面是阀门的主要工作面之一，材料选择是否合理以及它的质量状况直接影响阀门的功能和使用寿命。

The shutter is the gate (valve disc) and the seat. The sealing surface of the closure is one of the main working faces of the valve. Whether the material selection is reasonable or not directly affects the function and service life of the valve.