Measurement And Analysis Of Residual Stress In Roller Straightening Process

In recent years, with the rapid development of our country’s iron and steel industry, the application of the medium and heavy plate as an important iron and steel products is expanding, and the quality of the medium and heavy plate is also increasing. The quality requirement of the board includes the flatness and the residual stress distribution of the sheet. The straightening machine is an important equipment in the production line of medium and heavy plate, it can guarantee the quality of the medium plate, and directly determines the flatness, the residual stress level and the productivity of the product. Plate straightening process is one of alternating loading and unloading elastic-plastic bending process, accurate analysis of straightening process is very difficult, at present in the straightening process still exist many problems need to be analyzed. Straightener roll bending function, can effectively improve the flatness defect, this paper for the roller straightening roll bending and straightening plate residual force relationship launches the research, for bending and straightening roller straightening process sheet residual stress distribution, the variation rule of the in-depth analysis. Through the experimental study, using blind hole method and longitudinal cutting method of straightening plate residual stress testing, and with the residual stress generation and distribution of the theoretical analysis. Using the Abaqus software to establish the finite element model of the bending roll straightening, the influence of the residual stress and the flatness of the plate in the course of the straightening process is studied. In the process of bending roll straightening, the supporting roller is prone to damage and failure, and the bearing force of the supporting roller is tested. The conclusions of the study are as follows:1) Using blind hole method to measure the residual stress, especially considering the longitudinal residual stress distribution, to select materials for the appropriate amount of bending roll and roll bending, can improve the plate straightening the overall level of residual stress, inappropriate bending will produce new flatness defect. The transverse residual stress is similar to that of the longitudinal stress, but the change range is greater than the longitudinal stress.2) It is the result of the stress release caused by the longitudinal fiber length distribution along the width direction. The relationship between the buckling deformation and the residual stress of the sheet was discussed by using the longitudinal shear method to test the residual stress. Along the length of the same stress level in the same direction, when applying the bending roll, the whole upper part of the stress is lower, the middle of the stress is higher.3) Using ABAQUS software to carry out simulation, the distribution of residual stress of the plate was analyzed, and the experimental results were compared with the experimental results.4) The stress of the supporting roller in the course of the straightening process is monitored by the force test of the supporting roller. Roller bearing load impact and unstable phenomenon and groups supporting and due to the different installation and incoming plate, their load signal differences.