Research On The Roller Shape Curve And The Straightening Process Of Two-roller Straightener For The Large-diameter And Thick-walled Tubes

With the development of the national economy and the improvement of science and technology, the demand for large diameter tubes is increasing year by year in C hina. The finishing after rolling is an important process to improve the product quality, and straightening, which is the final stage of the finishing process, plays a crucial role in the control of the dimension precision and the rolling yield of the product. Two-roller straightening not only has the characteristics of high precision, but also has its own unique advantages in straightening the head and tail of spar. Therefore, it is of important theoretical value and practical significance to design the roller and research the effects of two-roller straightening process of large diameter tube and the new straightening scheme of the two roller straightening.Based on elasto-plastic theory and straightening theory, the relationship between the bending deformation law and its various curvatures during the two-roller straightening process is analyzed. Considering the work hardening and flattening effect, the bending moment equations are derived, which lays the foundation for the following theoretical research.Different traditional methods for roller design are compared and the feature of each method is analyzed, suitable design method of the roller type is selected for large diameter tube, in order to make the roller design more reasonable and the straightening more accurate. The size of the roller is carried out by the programming software Matlab. Furthermore, the theoretical straightening accuracy using this roller type is calculated.A model is established by the finite element software MARC to achieve large diameter tubes straightening, the straightening process is simulated to analyze the straightening effects. The scheme of warm straightening for large diameter tubes is tentatively put forward. The results in different temperatures are compared, which makes the analysis more complete. The optimum temperature is selected for the scheme of warm straightening, which provides reference frame for the development of the theoretical research and determination of the process parameters in production. The analysis on the regulation of the angular adjustment also provides theoretical reference for field operation in practice.