Nickel Austenitic Stainless Steel Welding Technology Research

Nickel austenitic stainless steel is developed as a substitute for the 300 series stainless steel,the purpose is to reduce the dependence on nickel.Nickel austenite stainless steel is based on reducing the nickel on economic type stainless steel with manganese,nitrogen and other elements to obtain austenite at room temperature.Compared with conventional austenitic stainless steel,it is more economical and practical.It can be applied to other products such as pan,bathroom and so on.It can replace conventional austenitic stainless steel under weak corrosion conditions,such as replacing some SUS304 varieties.In recent years,this kind of stainless steel has been favored by more and more stainless steel manufacturers because of its excellent corrosion resistance and mechanical properties,and low production cost.The annual varieties and output are all developing rapidly.The nickelsaving austenitic stainless steel needs to be welded in the cold rolling process so as to achieve continuous production.However,few documents have been reported on the welding problems in the production process of the cold rolling process of the nickel-type austenitic stainless steel.Therefore,studying the technical problems closely related to the welding technology of nickel saving austenitic stainless steel is of great significance for providing scientific basis for product production and quality control.Taking the cold rolling production line of Baosteel Stainless Steel Co.,Ltd.as the research object,the welding process and key experimental data of the typical stainless steel of the 200 series stainless steel are studied and determined,which lays the foundation for ensuring stable and efficient welding of the welding seam satisfying the release condition.The main research contents are as follows:(1)Research on the welding process and equipment of stainless steel at home and abroad,and understand the status of welding process model and welding equipment at home and abroad,and draw lessons from the research results;(2)The main products test of BN hot rolled plate system including BN4,BNDDQ,BN ID,BN1H,the microstructure composition mainly in austenite,on properties of welding joint were tested,the tail plate of hot rolled strip shape and surface cleanliness is poor,prone to lack of penetration,porosity and other defects in the welding process.By improving the welding current and increasing the clearance of the butt joint,it can be effectively alleviated,and finally the optimization of the standard line is set;(3)The main products test of BN series of cold-rolled plates including BN4,BN1D,BN1P,as a result of mill multi pass rolling,the microstructure of martensite containing body composition,weld precipitates in the low temperature heat affected zone boundary,low temperature heat affected zone still exists in the sensitization phenomenon;grain heat affected zone have the tendency of growing up.The defects can be effectively controlled by reducing welding current,increasing welding speed and reducing heat output;(4)In view of the present situation of Baosteel stainless steel cold rolling mill,the existing products are analyzed and explored,and the improvement of the direction is discussed.Combined with the typical accidents of welding seam broken in the production of the unit,the following corrective measures are drawn up by analyzing the causes of the broken belt.