Study On Deformation Mechanism Of 2205 Duplex Stainless Steel During Variable Thickness Cross Rolling

Duplex stainless steel material,is a kind of special metal material with both austenite and ferrite combination.Because it combines the advantage of austenitic stainless steel and ferritic stainless steel,therefore,it has excellent elasticity,extensibility and welding stability,and due to the amount of nickel in this kind of steel is few,thus overcome the problem of shortage of the industry with nickel resources,the manufacturing cost decreased significantly.2205 duplex stainless steel is a classic duplex stainless steel,the utilization rate is very high,but because it is controlled by two mutually reinforcing ratio,its heat treatment efficiency is low,the rolling process is easy to lead to edge crack,resulting in a decline in its production level.So how to reduce strip edge damage and improve strip shape is still the key problem in rolling process.In view of the problem thatstainless steel is prone to crack in the rolling process,which affects the quality of duplex stainless steel products,this paper takes 2205 duplex stainless steel as the main research object.The edge damage and microstructure evolution of 2205 stainless steel sheet under different rolling paths were studied by finite element numerical simulation and laboratory experiment.The research is mainly conducted from the following three aspects:(1)Based on the true stress-strain curve of 2205 duplex stainless steel obtained from gleeble-3800 hot compression simulation experiment,the thermal deformation behavior of 2205 duplex stainless steel was analyzed.Based on the plastic deformation theory,the thermal deformation constitutive equation of 2205 duplex stainless steel and the hot rolling mechanical model of different rolling zones were established,which provided theoretical basis for the following paper.(2)Based on the variable thickness rolling theory,the finite element numerical simulation software deform-3D was used to simulate the 2205 duplex stainless steel plate at 1000℃ and different technological conditions.First,variable thickness rolling technology is used to make the hot rolled plate in to a thin middle,thick on both sides of the “dog bone” shape,and then changing the rolling direction to make the thickness difference between the plate edge and the middle area,so as to realize the rolling by zone control.The edge damage and metal flow law of variable thickness cross rolling and conventional rolling are compared and analyzed.The results show that thickness of cross rolling can improve the stress distribution at the edge of the strip,which is converted from tensile stress to compressive stress,and the damage at the edge of the strip is reduced and the shape of the strip is improved effectively.(3)Verified by rolling experiment,in the laboratory experiment,the method of adding lining plate was selected to complete the process of changing the thickness of the plate,so as to realize the effect of rolling with different reduction in the edge area and middle area of the plate,and the damage of the edge area of different variable thickness of the plate was compared,at the same time,the damage of 2205 duplex stainless steel under different edge thickness curves was compared and analyzed.The microstructure distribution of strip under different rolling path was observed by metallographic experiment,and a more effective rolling process route was developed by comparison.