In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,...In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,which results in a mismatch between the deformation resistance setting and the actual state of the incoming material and thus affects the accuracy of the rolling force during the low-speed rolling process of the strip head.The inverse calculation of deformation resistance was derived to obtain the actual deformation resistance of the strip head in the tandem cold rolling process,and the actual process parameters of the strip in the hot and cold rolling processes were integrated to create the cross-process dataset as the basis to establish the support vector regression(SVR)model.The grey wolf optimization(GWO)algorithm was used to optimize the hyperparameters in the SVR model,and a deformation resistance prediction model based on GWO–SVR was established.Compared with the traditional model,the GWO–SVR model shows different degrees of improvement in each stand,with significant improvement in stands S3–S5.The prediction results of the GWO–SVR model were applied to calculate the head rolling setting of a 1420 mm tandem rolling mill.The head rolling force had a similar degree of improvement in accuracy to the deformation resistance,and the phenomenon of low head rolling force setting from stands S3 to S5 was obviously improved.Meanwhile,the thickness quality and shape quality of the strip head were improved accordingly,and the application results were consistent with expectations.展开更多
More than 99%of the mass in the visible universe—the material that makes up ourselves,our planet,stars—is in the atomic nucleus.Although the matter has existed for billions of years,only over the past few decades ha...More than 99%of the mass in the visible universe—the material that makes up ourselves,our planet,stars—is in the atomic nucleus.Although the matter has existed for billions of years,only over the past few decades have we had the tools and the knowledge necessary to get a basic understanding of the structure and dynamic of nuclei.Nuclear physicists around the world have made tremendous strides by initiating a broad range of key展开更多
To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the...To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the temper rolling.The change of the cross section of the strip and the distribution of the longitudinal stress are analysed under different bending forces to obtain the boundary conditions of the quarter buckle.The generation of the quarter buckle is further analysed from the bending and contact flattening of the roll system and the elastic recovery of the strip after rolling.We found that the quarter buckle is closely related to the high-order distribution of the contact flattening between the work roll and the strip and is less affected by the bending deformation of the roll and the contact flattening between the rolls.Finally,a new work roll contour of the locally variable crown is proposed to change the distribution of contact flattening between the work roll and the strip.It is verified through theoretical calculations and industrial applications that the new contour can effectively improve the quarter buckle.展开更多
基金This work was supported by the National Key Research and Development Plan of China(Grant No.2020YFB1713600)the National Natural Science Foundation of China(Grant No.51975043)+1 种基金China Postdoctoral Science Foundation(Grant No.2021M69035)Fundamental Research Funds for the Central Universities(Grant Nos.FRF-TP-19-002A3 and FRF-TP-20-105A1).
文摘In the traditional rolling force model of tandem cold rolling mills,the calculation of the deformation resistance of the strip head does not consider the actual size and mechanical properties of the incoming material,which results in a mismatch between the deformation resistance setting and the actual state of the incoming material and thus affects the accuracy of the rolling force during the low-speed rolling process of the strip head.The inverse calculation of deformation resistance was derived to obtain the actual deformation resistance of the strip head in the tandem cold rolling process,and the actual process parameters of the strip in the hot and cold rolling processes were integrated to create the cross-process dataset as the basis to establish the support vector regression(SVR)model.The grey wolf optimization(GWO)algorithm was used to optimize the hyperparameters in the SVR model,and a deformation resistance prediction model based on GWO–SVR was established.Compared with the traditional model,the GWO–SVR model shows different degrees of improvement in each stand,with significant improvement in stands S3–S5.The prediction results of the GWO–SVR model were applied to calculate the head rolling setting of a 1420 mm tandem rolling mill.The head rolling force had a similar degree of improvement in accuracy to the deformation resistance,and the phenomenon of low head rolling force setting from stands S3 to S5 was obviously improved.Meanwhile,the thickness quality and shape quality of the strip head were improved accordingly,and the application results were consistent with expectations.
基金supported by the National Key R&D program of China (2016YFA0400504)the National Natural Science Foundation of China (11475014 and 11235002)
文摘More than 99%of the mass in the visible universe—the material that makes up ourselves,our planet,stars—is in the atomic nucleus.Although the matter has existed for billions of years,only over the past few decades have we had the tools and the knowledge necessary to get a basic understanding of the structure and dynamic of nuclei.Nuclear physicists around the world have made tremendous strides by initiating a broad range of key
基金This work was financially supported by the National Natural Science Foundation of China(52004029)the Open Foundation of Engineering Research Centre for Metallurgical Automation and Measurement Technology of Ministry of Education(MADTOF-2019A01)the Postdoctoral Science Foundation of China(2021M690352).
文摘To reveal the generation mechanism of the quarter buckle in the process of hot-rolled temper rolling,the elastic–plastic finite element method is used to calculate the deformation of the roll and the strip during the temper rolling.The change of the cross section of the strip and the distribution of the longitudinal stress are analysed under different bending forces to obtain the boundary conditions of the quarter buckle.The generation of the quarter buckle is further analysed from the bending and contact flattening of the roll system and the elastic recovery of the strip after rolling.We found that the quarter buckle is closely related to the high-order distribution of the contact flattening between the work roll and the strip and is less affected by the bending deformation of the roll and the contact flattening between the rolls.Finally,a new work roll contour of the locally variable crown is proposed to change the distribution of contact flattening between the work roll and the strip.It is verified through theoretical calculations and industrial applications that the new contour can effectively improve the quarter buckle.
