Study On Repairing Technology Of Die For Surfacing Of High Pressure Cylinder Bearing

High pressure oil cylinder is an important part of mechanical equipment. With the development of equipment manufacturing industry, the market demand of high pressure oil cylinder is growing. Cylinder support is an important part of high pressure cylinder. Support mould exist some problems, such as short service life, high production cost, and low production efficiency. The welding technology of repairing cylinder mould is the green remanufacturing technology, which oriented to circular economy, the service life of the mould can be improved and the cost of enterprise can be reduced by that.The service condition of support mould in a forging factory was studied in this paper. Welding repair technology of die was discussed. The best welding materials and heat treatment process was obtained. Finally the result of the study was applied in the engineering. The main research included the following aspects:1, the failure forms and reasons were studied, the main factors affecting of service life of the die was gotten. The crack failure was about 62%,the wear was about 38%, the deformation was about 60% and the fracture phenomenon was about 0%, so crack, wear and deformation were the main failure of support mold. The sulfides and oxides had an important influence on the mould. High temperature and load had great influence on the mould by forging simulation. In summary, alloy elements, the hardness, tensile properties, wear resistance and thermal stability were important parameters about support mould.2, the welding parameters were ensured. The welding equipment was gas protection whose type was Dimension 812, the materials were 9650, D650, D397. The preheating method was chosen for furnace preheating and the preheating parameter was conformed, temperature was 450℃, time was 12 h, the welding current was 650 A, the welding voltage was 36-38 V and the wire feeding speed was 10-15cm/min.3, the welding material 9650 was researched and confirmed. The element similarities of welding materials 9650, D650, D397 were studied and the main alloy elements on the matrix were analyzed. Then the mechanical properties about the three materials were contrasted and studied. Finally the best welding material was 9650 which hardness, tensile strength were better than the other two.4, Heat treatment process parameters were researched and confirmed. The optimum heat treatment process was 550℃×3h, which was determined by the study of the influence. The microstructure and properties of surfacing layer under the different heat treatment time and temperature were analyzed.5, the result of the study was applied in the engineering. Compared with the conventional method of repair, the mould service life increased 50% after repair welding; the economic and social benefits are significant improved.