Research On Springback And Processing Parameters In Hull Steel Straightening-bending Forming

Steel is the main material used in the construction of modern hulls.Steel materials account for about 35% of the construction cost in shipbuilding.Steel material forming has a direct impact on the accuracy of shipbuilding production.Traditional pyroforming has a great influence on the microstructure and mechanical properties of materials,and some steel materials with special requirements need to be formed by cold bending.Compared with roll forming,the compression molding method is simple to operate,has high production efficiency,and is convenient for mechanized mass production.In the process of press forming of steel materials,it is inevitable that springback problems will be encountered.The use of finite element numerical simulation methods to solve the springback problem is currently a more common method.The hull steel is mainly divided into profiles and plates.In this study,first of all,the three-point bending and four-point bending methods are used to establish the die for the bending forming of the channel steel in the profile,and the groove is obtained by finite element numerical simulation.The amount of rebound of steel.In addition,the forming shape of the channel steel at different pressing distances is also obtained,and the simulation results of the section bending forming are brought into the simulation study of straightening forming to verify.Secondly,the finite element numerical simulation of cold bending pressing is carried out on the single curvature plate with simple shape in the plate,and the empirical formula of the optimal die shape and the processing parameters of the die processing required for forming the single curvature plate with the specified curvature is obtained The results show that the springback of this single-curvature sheet has a positive correlation with the increase in die curvature.Then it was extended to the research of cold bending and forming of unidirectionally variable curvature plates,and the finite element simulation calculation of cold bending and forming of a unidirectionally variable curvature plate was carried out.According to the research method of unidirectional curvature plate,the finite element numerical simulation was carried out on the cold bending and press forming of the double curvature plate,the springback of the double curvature plate under different bending flexures of the die was calculated,and the absolute value of the maximum bending deflection was calculated through analysis.The springbacks of the sail-shaped plate and the saddle-shaped plate are basically the same,and the empirical formula of the processing parameters of the compression mold of the double curvature plate is obtained accordingly.Afterwards,a cold-bending press forming finite element simulation was carried out for the actual hull double curvature plate.In this paper,the preparation process and technical difficulties of the cold bending press forming medium-pressure die are studied,which is beneficial to shorten the process cycle of steel bending and straightening.