Research And Practice Of Tandem Cold Rolling Process Of SUS304 Stainless Strip

At present,there is no successful experience on producing 300 series stainless steel using large diameter tandem mill in China.It is crucial to break the technical monopoly on cold tandem mill technology.In addition,it is also urgent to develop the intellectual property rights of cold tandem mill technology on 300 series stainless steel.There are still many theoretical and technical difficulties for the cold rolling mill production of 300 series stainless steel.The austenitic stainless steel has high deformation resistance and strain hardening index.The tandem cold mill has large diameter mill,high rolling speed and emulsion lubrication rolling.In a word,this is a very challenging puzzle for producing 300 series stainless steel using 1750mm cold tandem mill.To produce the high effective and stable 304 stainless steel by the tandem mill,on the basis of cold rolling production process of ferritic stainless steel,this paper focus on the laboratory study and industrial process optimization:(1)The changes of yield strength,tensile strength and elongation of SUS304 stainless steel under different deformation were studied by cold rolling and tensile tests.The pre deformation amount on the mechanical properties of SUS304 austenitic stainless steel was analyzed.The temperature changes of roll and strip in the cold rolling process was small.Consequently,the deformation resistance model of SUS304 stainless steel neglected the rolling temperature.(2)The key technology of production was designed by deformation resistance model and production equipment.For instance,the load distribution system,tension setting system,roll system,lubrication technology,automatic control of thickness and shape parameters and so on.(3)According to the key process design,the rolling plan including raw material acceptance,succession planing,welding experiment,production organization,quality control and emergency response was worked out.In the process of trial rolling,the process parameters were adjusted and optimized timely to ensure that the trial rolling process was stable and controlled.Meanwhile,the problems were recorded during the trial rolling process.(4)The problems that occurred during the trial rolling process were analyzed and researched.The reasons for the corresponding problems were found out.The solutions were given and verified.(5)After studying and solving the problems in the trial rolling process,mass production was carried out by using this process.The production specifications were extended according to the market requirement.The stable SUS304 stainless steel with various specifications produced by Baosteel stainless steel 1750mm cold tandem mill.Based on this subject,the tandem cold rolling technology of SUS304 austenitic stainless steel is developed.The cold rolling sheets of SUS304 steel are also produced successfully at 1750mm Cold rolling mill of Baosteel Stainless Steel Co.,Ltd.It enriches the metallurgical theory of cold tandem mill technology about producing SUS304 stainless steel.Moreover,Baosteel Stainless Steel Co.has a independent intellectual property rights about cold rolling production technology,which plays an important role in enterprises development including productivity increase,costs reducing and competitiveness enhancement.