Research On Brazing Of Tantalum Ta1 And OCr18Ni9 Stainless Steel Plates

Owing to the excellent elevated temperature strength and corrosion resistance,tantalum has been widely used in petroleum chemical of corrosion resistant equipment manufacturing field.Ttantalum-steel composite structure can fully exert the property advantages of tantalum and can reduce the cost of production.The preparation of tantalum-steel composite structure may relates to the connection problems.As a result of tantalum and steel physical and chemistry performance differs greatly,the key point is connected to solve the problems of steel's excessive melting and Fe2Ta intermetallic compounds produce that lead to joint crack.The temperature of brazing is low,this mothed can not only reduce the brittle intermetallic compound content,but also can aviod the melting of the base metal,is an effective method suitable for tantalum-steel connection.In this paper,design and preparationed of two series of filler metals foil,using method of high frequency induction brazing and resistance spot welding achieved the connection of tantalum-steel,studied the alloy composition of filler metals and welding parameters on the influence of joint microstructure and properties.The research results show that:Though orthogonal test and single factor test optimized the(Ti37.5Zr37.5Cu15Co10)95V5 brazing filler,which has a good formability and flow ability.The addition of V element promotes the combination of brazing filler with tantalum,use it to brazing Tal/0Cr18Ni9,the brazing seam are dense and fully filled,the maximum shear strength of the joint is 71.0MPa.Ni-7Cr-5Zr-3Fe-3B-4.5Si brazing filler can achieve the effective connection of tantalum Ta1 and 0Crl8Ni9 stainless steel.When use high frequency induction brazing process,the microstr,ucture of the brazing seem is fine and uniform,brazing seem has a high brazed rate and mainly made up with Ni based solid solution,near Tal side in the brazing seem a small amount of Ni3Ta and Ni2Ta intermetallic compound has produced.When the brazing parameters are:welding current 12.5A,heating time 10s,heat holding time 25s,the joi.nt shear strength can reach 146.0MPa.Using Ni-7Cr-5Zr-3Fe-3B-4.5Si brazing filler as the interlayer achieved the resistance spot welding of Ta1/0Cr18Ni9,the nugget of the joint is obviously offset to steel,the main metal of the nugget are steeel and the interlayer group elements solid dissolve in it,this largely inhibits the formation of intermetallic compounds.When the welding parameters is I=9.5kA,F=3.5kN,t=0.06s,the joint shear stren,gth up to 188.0MPa.Ni-7Cr-5Zr-3Fe-3B-4.5Si amorphous brazing alloy has good fluidity and antioxidant properties.High performance connection of tantalum-steel can be achieved by this brazing filler,the joint strength meet the engineering requirements(??140.OMPa).