Study On Welding Technology Of Electric Water Heater Tank By Enamel Steel BTC330R

Electric water heater has been widely popular in residents life,our country has become the biggest country of household electric water heater production and sales.In the water heater tank processing operations,welding is the key technology to the water tank manufacturing process.Welding joint is the most prone to corrosion perforation,fracture to leaking.It directly affects the stability and reliability of the electric water heater tank quality and affects the production efficiency and cost.Enamel steel BTC330 R is a kind of fine grained micro alloying steel.In addition,because the electric water heater tank wall thickness is very thin,usually in 1.6~1.8mm,welding joint is extremely sensitive to heat input,more defects and easy to appear stress concentration.Under the background of fierce competition,companies seeking product upgrading.In the current home appliances industry,enterprise and industry puts forward higher requirements on welding quality.This paper designed to study characteristics of enamelled steel BTC330 R electric water heater tank welding technical,under the premise of without any increase in plate thickness to improv the quality of welding joint,so as to prolong the service life of the product.This paper using optical microscope(OM),scanning electron microscope(SEM)combined with mechanics test,make analysis of organization,composition and mechanical properties of enamelled steel BTC330 R.The analysis results show that the enamel steel BTC330 R is a kind of low carbon low silicon micro alloyed steel,organization consists of equiaxed ferrite,a small amount of granular,lamellar pearlite and a small amount of tertiary cementite along the grain boundary,the ferrite grain size 7-9,non-metallic inclusion magnitude 2.5 or less.Second,this paper have traced the site quality of current electric water heater production line of enterprise,used the optical microscope and scanning electron microscope analyzed the welding joint microstructure,ports and morphology.Metallographic analysis shows that there are large difference between weld area organization and parent metal,more hard brittle organizations,joint toughness is poor.Port morphology analysis shows that the welding seam under restraint stress,the joint caused by a lack of toughness of brittle fracture.In addition,on the basis of familiar with the welding specification,this paper used UG 3D drawing software and Visual-Environment meshing software established the model of electric water heater tank.Respectively according to straight seam and circular seam welding process characteristics and actual process specification and the clamping constraints,based on the finite element analysis theory,used SYSWELD welding simulation software,simulated the temperature field and stress field.This paper solves two welding temperature field distribution and weld thermal cycle curve and its nearby area,and quantitative solution of the welded joint trends and size of the distribution of residual stress after welding deformation trends and deformation size of each part.Comparing with the actual joint,consistent basicly,proves that the welding temperature field and stress field simulation results is reliable.Finally,according to the parent metal characteristics,trial-manufactured the matching welding wire,and put forward the improvement of electric water heater tank welding specification based on the experimental analysis and the simulation result,got the organization obviously improve welding joint.Laid a theoretical foundation for solve the problem of welding quality in actual production.