The Research Of Mechanical And Weld Properties Of 400 Series Hot Rolled Ferritic Stainless Steel Plates

400 ferritic stainless steel is a kind of non-Ni and low-Ni stainless steel,compactibility, corrosion resistance and oxidation resistance are very good.Which is known as an economic stainless steel,it is also set store by each country.Based on that 430,410S and 409L,which are representative type of 400 ferritic stainless steel,combine with their microstructure, mechnical and melted properties are selectively studied,and comparing with 304.That is favorable to raise product quality and reform processing parameter,and offer theory rest.It also offers experimental data for exploiting ferritic stainless steel,and guide production.First,tensile behavior and fracture characteristic of 430,410S and 409L ferrite hot rolled stainless steel plates at room temperature were studied.430 and 410S stainless steel are high strength,but low plastic;plasticity of 409L is better than 430 and 410S.Strength of 410S steel which is lower carbon and Cr is higher than 430,because of a mass of martensite formation in 410S steel when it is air-cooled.The fracture at room temperature is toughness fracture;layer fracture and side crack of 430 and 410S are discovered among partial fracture.Mechanical behavior and fracture characteristic above was resulted by rolling-direction length banded structure.The properties of 400 ferritic stainless steel TIG welded joint was studied through nondestructive examination(NDE),mechanical property and measuring ferrite content and microhardness,and contrast with austenite stainless steel 304.Adopting TIG welding and little welding variables,welded properties which are tested are good;position of tension fracture of weld joint of 400 ferritic stainless steels is base-material(heat affect zone), because ferrite crystal of HAZ of 400 ferritic stainless steels do grows up severely and welded seam is austenite stainless steel,grain-boundary area of HAZ of 430 occurred M→γ→M, Martensite phase near HAZ of 410S created M→γ→M.microstructure of HAZ of 409L is all ferrolites,carbides are not obviously precipitated,but ferrite crystal grows up severely,its grain size is 2-2.5 grade.Microstructure of welded beam of 400 stainless steel are not difference,Microstructure of weld joint is characterized slender austhentic granular crystal+δferrolites along austhentic,the shape of ferrite are mainly worm and skeleton.The anodic polarization curves in sulphuric acid,hydrochloric acid,mixtural acid(10% HCl+10%HNO₃) and 6%FeCl₃.Different electrolyte solutions were measured by the experiments of electrochemical corrosion.The electrochemical corrosion properties was aggravated with H₂SO₄ concentration first,the worst was 60%,passivation zone is more length.Passivation zone of HCl is very short,activation zone is long.Passivation zone of mix-acid is very long,but no remarkable passivation flatform.The anode polarization curves of 6%FeCl₃ represent remarkable pitting corrosion.The electrochemical corrosion property of weld metal is better than the base metal by analyzing electrochemical eigenvalue in different solution.The H₂SO₄-CuSO₄ method and electrochemical potentiokinetic reactivation(EPR) is adopted for evaluating the tendency to intergranular attack(IGA).IGA of welded joint of 304 is well assessed by both methods,and Both are very anastomotic;Because the erosion resistance of the base material of 410S is not good,its tendency to IGA can not be evaluated by the H₂SO₄-CuSO₄ method,and intergranular attack(IGA) is quantitatively and fast tested by EPR,it is finded that the welded beam,heat-affected zone(HAZ) and base material is tendency to IGA,and.welded joints of 430 and 409L have no susceptibility to intergranular attack.