Research On Changing Casting Technology To Forging Technology Of Cylinder Bottom

Bottom is the critical and important part of the automotive hydraulic system and the important key components, the comprehensive performance and quality of the products have an important influence on the mechanical movement of the cylinder system. Currently, Bottom domestic manufacturers began to gradually adopt the new forging process to replace the traditional casting process.Bottom is a hydraulic cylinder and rod system connecting part, connecting rod and the piston rod role is to produce hydraulic pressure to promote the piston rod reciprocates and thus the quality of the operating state directly determines the stability of the hydraulic system. Bottom has the characterize of the large size, heavy weight, medium and large symmetric forgings.The steel bottom products are manufactured with inherent defects, the poor mechanical properties of steel castings and the poor mechanical fatigue resistance, the poor impact properties, there are some products casting porosity, loose, inclusions, cracks, shrinkage, etc., which bear relatively large tensile stress load and is damaged easily, in order to avoid casting defects, the new forging process is proposed for bottom instead of the original casting process, forging process simulation to verify the feasibility of the finite element method, and further forging process optimization. The main research contents are as follows:(1)To analyze the unstable of the fuel tank system of the company due to the presence of a low fracture and fatigue resistance bottom casting defects and Bottom freedom Forging-forging process and to design the corresponding mold structure.(2)On the basis of the design of the mold structure, for different preform program to do numerical analysis, select the best solution, at the same time,to determine the process parameters based on experience in the design of the structure, carried out trial production, mold design and verification selection process reliability.(3)On the basis of the analysis of the forging process, we carried out trial production, Some forging parts have a lot of scale, decarbonization and burns, to optimize the process parameters for this problem, different process parameters is simulated by use the positive post test design optimization analysis to forming maximum load, maximum wear and forging mold cavity maximum damage to the objective function to determine the optimum parameters billet preheating temperature is 1160 ?, the upper and lower mold preheating temperature of 300 ?, forging speed 40 mm / s and friction factor of 0.2, to optimize the process parameters is not only help to good die forging and to avoid the problems of scale, decarbonization and burns.(4)To combinate the above analysis of the optimization of the process parameters, on the basis of the actual use of plant equipment on the structure of the mold and billet sizes response surface method for multi-objective optimization, the maximum forming load, maximum wear and forging mold cavity damage as the objective function, to analyze the draft angle, while flying bridge height, skin thickness and diameter of four forging stock on three main structural parameters of the objective function by the finite element numerical simulation,and ultimately determine the Bottom hammer forging a 4 oof draft angle,the 3mm of burr bridge height, the 18 mm of skin thickness, the 220 mm of forging billet diameter, as all forging optimal structural parameters on above, and be used in the production, access to production verification.By the studying of this subject, to avoid the bottom casting defects, and improve effectively the product quality and mechanical properties, to provide reference data for the enterprise actual production. At the same time,the research methods can also be used as a reference basis for quality improvement of other similar type parts and to promote the development and application of precision forging process...