Research On The Roll Forming Process Of The S-type High-strength

With the trend of lightweight in construction industry, the characteristics of new type outer wall roof contour plates are thinner thickness, higher strength, lower elongation and with S-shaped section shape. These will make it liable to appear crack problem in the process of production. However, due to the research on the crack problem in the production process of S-type contour plate is little, the relevant theoretical research and reference is deficiency.So this paper take the new S-type contour plate as the research object, the mechanical performance of the contour plate’sheet is studied through the static uniaxial tensile experiment, the microscopic structure observation experiment and the cold roll forming experiment. The roller flower and roller drawing of the new S-type contour plate are also designed. Based on the anisotropic yield criterion-Hill48, the cold roll forming finite element model of the S-type contour plate is established with using the finite element software MSC.Marc, and the S-type contour plate cold roll forming theory is analyzed. Besides, the S-type contour plate forming process parameters is studied using the finite element orthogonal experiments.The static uniaxial tensile experiment, the microscopic structure observation experiment and the cold roll forming experiment show that the yield strength of plate is more than550MPa, the strong flexor ratio is close to1, the cracking strain is less than5%, and the anisotropic phenomenon is very obviously. The galvanized layer of the plate mainly composes by three elements:aluminum, zinc and silicon. The galvanized layer effect the substrate mechanics performance significantly, especially the elongation、yield strength and tensile strength. In addition, the minimum bending radius of the plate is R/T=3.The cold roll forming mechanism of the S-type contour plate is researched through the finite element simulation, the reason of contour plate’crack problem is analyzed. The analysis show that the reason of crack is the area of the S-type curved section has large residual strain after the first forming stage, and the first and second forming stage has a quite different shrinkage rate which make the S-type curved section suffered a larger forming force when enter the second forming stage.The forming process parameters of the S-type contour plate are studied through the finite element orthogonal experiments, the influence of different process parameters of the contour plate forming process is analyzed and a reasonable forming process parameters optimization scheme is put forward which is verified by the finite element experiments. The results show that the significant order of forming process parameters which affecting the quality of contour plate is:the inside bending radius> the forming speed> the distance between rollers> the diameter of below roller. To sum up, the optimization scheme of forming process parameters is to increase the inside bend radius, decrease the forming speed, optimize the contraction speed between the forming stage1and2. The verification results show that the equivalent stress and equivalent plastic strain of the contour plate after optimization is decreased, which proved the accuracy of the optimization scheme which has a certain guiding role for actual production. Moreover, the law of edge contraction curve is researched in this paper, the Chapman equation is used to describe the optimal contraction curve equation, which can provided a certain reference value for the design of the number of roller and each pass contraction quantity.