Effect Of Production Process On Microstructure And Mechanical Properties Of B441 Ferritic Stainless Steel

B441 is a typical representative steel in ultra pure ferritic stainless steel for automobiles,and widely used in industrial production and daily life because of good high temperature strength,corrosion resistance,good weldability,excellent processing performance,etc.Nowadays,B441 can be used in automotive exhaust system for the exhaust manifold,former pipe,heat exchanger,electronic components,heat-resistant apparatus,home appliances,tableware,decorative materials,etc.Based on the industrial production line of smelting B441,the paper selects ultra pure ferritic stainless steel plate as the experimental material.Surface 2D is formed after welding,rolling,annealing,pickling,etc.The paper confirms the feasibility of ultra pure ferritic no electro-chemical production and discusses and analysis whether welding,annealing and pickling process effect the performance of the organization or not under different condition combined with the structure,mechanical properties,corrosion resistance and other related analysis.The study makes effective support for B441 in no electro-chemical process and direct rolling and annealing process in mass production.The results show that B441 ferritic stainless steel has good welding speed,welding seam organization performance,and weld strength,ductility and toughness are close to the base level with laser arc compound welding production.The tensile strength reaches 94%of the base metal and the maximum elongation reaches 80%of base metal.When the rolling reduction is 70%,the composite weld does not crack,but also there is no obvious crack.Intergranular corrosion test prove B441 ferritic weld has good corrosion resistance.There is no obvious rust by salt spray corrosion and the peak value of chromium passivation layer is greater than 17%and the depth of chromium depleted layer is 3.5?m and the pitting potential is about 330mV in no electro-chemical pickling process.The surface in no electro-chemical pickling process is similar to the electro-chemical treatment.Based on B441 ultra-low carbon steel,the effect of different cold rolling on microstructure,texture and formability was studied.The shear zone of micro structure was thinner in tandem cold rolling mill(TCM)condition.The gain size in the final band of tandem cold rolling mill is bigger than that of 20-high cold rolling mill(CRM)after the texture of the central layer was mainly {111}<112>in the final band of TCM,which The texture of the central layer was mainly {554}<225>in the final band of CRM.The deep-drawing property in the final band of TCM was a little better.