Process improvement method in manufacturing high temperature and high pressure solenoid valve

In order to solve the reliability and maintainability problems of high temperature and high pressure solenoid valve, in addition to giving full consideration to the design, it is necessary to strictly control its key process in the manufacturing process. The key technologies and implementation ways of manufacturing high-temperature and high-pressure solenoid valve with high reliability and maintainability include welding, processing, verification test and functional test.

（1）焊接。电磁阀的焊接部位包括套筒、活塞、阀头密封面堆焊、活塞外表面堆焊及屏蔽套组件自熔焊等。在焊前、焊中和焊后进行全程检验，确保焊接质量符合规定要求。

(1) welding. The welding parts of the solenoid valve include sleeve, piston, valve head sealing surface overlay welding, piston external surface overlay welding and shield sleeve assembly self fusion welding. Conduct the whole process inspection before, during and after welding to ensure the welding quality meets the specified requirements.

（2）机械加工。电磁阀机械加工的关键技术在于套筒、活塞及阀头密封面精加工，套筒内孔、活塞内外精加工、阀头外圆精加工。这些部位表面硬度高，尺寸精度高，因此加工难度大。首先这些加工过程应被定为关键工艺过程，在加工制造前必须进行过程能力鉴定，合格后方可进行加工。零件加工过程中采取定人员、定设备和定工艺的控制程序，保证零件的加工质量。

(2) machining. The key technology of solenoid valve machining is the finishing of sleeve, piston and valve head sealing surface, the finishing of sleeve inner hole, piston inner and outer, and valve head outer circle. The surface hardness of these parts is high and the dimension precision is high, so it is difficult to process. First of all, these processing processes should be identified as key process. Process capability identification must be carried out before processing and manufacturing, and processing can only be carried out after being qualified. In the process of parts processing, the control procedures of fixed personnel, fixed equipment and fixed process are adopted to ensure the processing quality of parts.

（3）密封面研磨。为了保证其阀座密封性，必须对密封面进行研磨，使密封面的粗糙度值达0.2μm 以上。活塞与套筒、活塞与阀头接触面应采用对研工艺，保证密封性达到规定要求。

(3) grind the sealing surface. In order to ensure the sealing performance of the valve seat, the sealing surface must be grinded so that the roughness value of the sealing surface is more than 0.2 μ M. The contact surface between piston and sleeve, piston and valve head shall adopt the opposite lapping process to ensure that the tightness meets the specified requirements.

（4）验证性试验和功能性试验。功能性试验是用于检验和验证产品是否满足规定要求的最直观手段。功能性试验可以验证产品设计、制造的合理性，也将决定产品是否能真正用于规定的系统中。高温高压产品的功能性试验一般包括阀座密封试验、冷态循环试验、热态循环试验及寿命试验等。应具备完美的试验条件和试验设备，至少应有高温高压试验台架才能完成相应的验证性试验和功能性试验。

(4) verification test and functional test. Functional test is the most intuitive means to check and verify whether the product meets the specified requirements. Functional test can verify the rationality of product design and manufacturing, and also determine whether the product can be truly used in the specified system. The functional test of high temperature and high pressure products generally includes valve seat sealing test, cold cycle test, hot cycle test and life test, etc. Perfect test conditions and equipment shall be available, and at least high temperature and high pressure test bench shall be available to complete corresponding verification test and functional test.