Analysis On Springback Of Thick Steel Plate Of Hull In Hot Press Bending

The shape of hull plate is complex and has a large size,and its forming process has always been a technical difficulty in shipbuilding.At present in the domestic and foreign shipyard,the main forming method is the line heating and cold forming technology.The former is the traditional method of plate forming in shipbuilding,the control of forming accuracy depends mainly on the experience of workers,cold forming is usually applied to the forming of plate with large curvature,but due to the spingback problem is serious in the forming process,repetitive work· is usually needed in order to reach the requirements.Based on cold forming technology,the thermal load is introduced into Hot-press bending,hot and cold load together to make deformation of the plate,this forming technology has certain advantages in the control of springback,reduce the loading force compared to cold forming,has received more and more attention in recent years.And the relationship between the parameters and the springback is analyzed and summarized,which can be used for engineering practice.In this paper,the springback characteristics of the thick steel plate in the hot-press bending are studied.The relationship between the parameters and the springback is analyzed and summarized,which could provide theoretical guidance for the optimization of processing parameters,improving the precision and efficiency of plate forming.Compared with theoretical analysis and experimental method,finite element method has the characteristics of strong function,high precision and wide problem solving ability,which is one of the main methods to study the springback problem.In this paper,a Thermo-mechanical coupled finite element model is proposed to simulate the forming process.By comparing with the experimental results,validity of numerical simulation method has been proved.Based on the finite element numerical simulation method,the influential facters of springback in hot press bending are analyzed.The effects of forming temperature,temperature distribution,sheet geometry,magnitude of local load,plate cooling process are discussed respectively.And the relationship between the main influential facters and springback are summeriazed.The results show that as the temperature of the plate exceeds the temperature which yield stress of material begins to decrease remarkably,and the springback decreases significantly.The larger the high-temperature region in the direction which wider local deformation happens,the smaller springback is.The temperature gradient in the thickness direction of the plate center has little effect on the springback in local hot-press bending.The greater the plate surface size in the direction which wider local deformation happens,the smaller springback is.The springback become smaller when the thickness of plate increases.The springback becomes smaller when the magnitude of local load increases.The springback tends to be smaller when using the water cooling instead of air cooling.