Domestic restoration and manufacturing of valve bushings of RMG530 pressure control valves

In this paper, a series of analysis and research are carried out for purpose of domestic restoration and manufacturing of valve bushing, the key fitting of RMG530 pressure control valve which is imported overseas. Firstly, wear mechanisms of valve bushings are identified by analyzing their failure forms. Secondly, the material types are confirmed after analysis is performed on substrates, wear resistant layers and sealing layers in terms of their chemical compositions and compound components by means of metallurgical structure observation, XRD diffraction and infrared transmission. It is shown that coating dropping of pressure control valves is the crucial reason for the failure of valve bushings. The substrate material of valve bushings is 20Mn2V and the sealing layer material for restoring valve bushings is epoxy resin. Finally, domestically manufacutured fitting drawings are prepared, the fitting manufacturing precision is confirmed and restoration and process technologies are optimized. In this way, valve bushings of RMG530 pressure control valves can be restored and manufactured domestically.