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The low-speed marine high-power bulky diesel engine cylinder block casting process for production, prone to casting defects and repair difficulties, scrap rate. Therefore, the development of a new cylinder block production process in order to adapt to the current high-power diesel engine manufacturing high-quality, high-efficiency, low-cost technology requirements have great significance. Based on this, the study of the process of welding cylinder body. Developed as the first R \u0026 D and manufacturing of welded cylinder block, after a lot of welding procedure test weld cylinder block roof layout and welding parameters; developed a box-type structure of the cylinder block welding sequence, turn over their joints form; the scavenging device C plate and S plate assembly and welding; thereby completing the welding of the entire low-speed marine power cylinder body. Roof welding technology requirements for the cylinder block, the design the groove forms of the workpiece and welding analog parts, CMT mode by orthogonal test, compared weld formation under different process, determine the appropriate for narrow gap welding track pitch, to solve the inter-layer fusion; by fillet weld tests to determine the inclination angle of the welding torch, solved the narrow gap side wall penetration. TANDEM double wire bonding process test study, a mathematical model of the swing welding, weld thickness control method; Process Experimental Study of the swing, torch both sides of the residence time, welding current and weld forming relationship. Tests show that CMT carbon dioxide gas shielded arc welding the roof of the cylinder block lower welding cost, flexible operation, low heat input, suitable for cylinder block. The complete cylinder body temperature and stress field in the test, the test results reflect the distribution of temperature and stress field to provide a reliable basis for the numerical simulation. The cylinder body welding temperature field tests show that the lower steel plate temperature, component, heat is dissipated rapidly, the test point from the weld distant, the curves of the temperature is not high; stress test results indicate that the top plate and the side plate of the welding residual stress distribution law similar, slightly larger than parallel to the weld direction, and the direction perpendicular to the weld the welding residual stress σy σx; perpendicular to the weld direction, with the distance of the weld edge is increased, residual stress σy and σx has significantly decreased; same time, before and after annealing stress test results show that the annealing process can dramatically reduce the welding residual stress, change the distribution of the stress field. Welding process of cylinder block finite element simulation, respectively, from the aspects of the physical model, material characterization, unit type, mesh welding heat source model and a detailed analysis of the appropriate finite element model that should be adopted in the ANSYS environment measures; and calculate the temperature field of welding simulation, and the temperature field of Welding Simulation results and actual test were analyzed, it was found that the test point measurement curve and the calculated curve overall trend is the same, in order to verify the calculation method is reasonable. Welding stress and strain fields calculated on this basis, the welding line energy constraints, the optimization of the welding sequence to reduce welding deformation reference.
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