Experiment Research On EDM-Mechanical Combined Grinding Of Alloy Surface Of Large-caliber Metallic Valve Sealing Pair

With the development of oil industry、chemical engineering、nuclear industry, High temperature resistance (≥500℃), high hardness (≥30MPa), high wear resistance are the properties of alloy surface of a large ball valve, the surface of the ball must be conducted hardening treatment. Uaually, we spray coating material with high hardness such as WC or Nickel base alloy on the surface of ball, the HRC>62, at this point when use a way of traditional mechanical grinding usually acquire a low machining efficiency.Due to the alloy spherical and valve seat in a equipment method of rigidity seal,for the requirement of leakproofness,the diameter of 400mm usually require the deviation from circular in 0.008mm,so it’s hard to machining and also achieve low efficiency and requires hand lapping at last to assure the precision.So,Struggle for high efficiency of large area high-hard coated-sphere has become one of the key problems to be solved.In this paper we overally summarized the research status of the Spherical surface processing and wear-resisting material processing, the research status of various special processing methods, advantages and disadvantages of high hardness and grinding materials.In guarantee of the machining accuracy and improve the efficiency of wear-resistant alloy material grinding,it proposes a new processing methods of alloy surface of the ball valve-put forward to use the combined method to machining the alloy spherical surface,study the mechanism of EDM-Mechanical combined grinding.This paper do research and design the combined-tool electrode-Cup wheel、EDM pulse power、Special working fluid. Studied on the law of EDM-Mechanical combined grinding, analysis on the effect law of electric parameters on the composite processing and discuss the parameter group of the optimal processing efficiency and processing quality with orthogonal test.Under the same grinding test conditions conduct contrast experiment between the EDM-Mechanical combined grinding and pure mechanical grinding.The experiment results show that,via the experiment research indicated that compared with traditional mechanical grinding,the combined method enhanced machining efficiency with 2-3 times.The surface smoothness and roundness are in requirement after processing.According to the theoritical and experimental studies can be obtained that this paper put forward the new processing method EDM-Mechanical combined grinding not only can improve the processing efficiency,but also can guarantee a high surface roughness,It is of important of theoretical and practical significance both for spherical precision and efficient processing and Ball valve industry.