Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap wi...Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap width and groove in steel side on the microstructure and tensile strength of the resultant joints were investigated. For the joint made with 0 mm-wide gap and without groove in steel side, severe incomplete brazing zone occurred along the steel side and bottom surfaces, and consequently seriously deteriorated the joint strength. However, presetting 1.5 mm-wide gap or with groove in steel side could promote the wetting of molten filler metal on the laying surfaces, and then significantly enhance the resultant joint strength. Moreover, post-weld heat treatment could further improve the tensile strength of the joints. During tensile testing, the specimens from the joints made with AI-12%Si flux-cored filler wire fractured through the weld or interracial layer, but those from the heat-treated joints made with Zn-15%AI flux-cored filler wire fractured in the aluminum base metal.展开更多
The galvanized steels were joined using a TIG arc brazing process with CuSi3 as the filler metal.The arcing time ranged from 1 s to 5 s with arcing current of 70 A in flowing argon.The possible reaction products at th...The galvanized steels were joined using a TIG arc brazing process with CuSi3 as the filler metal.The arcing time ranged from 1 s to 5 s with arcing current of 70 A in flowing argon.The possible reaction products at the interface were confirmed using thermodynamics,SEM,and EDS methods.The results show that a fragmention behavior in some whisker-like intermetallic compounds happens,and that there are two layers of Fe2Si and Fe5Si3 formed at the interface of the galvanized steel and copper filler.From this,the schematic cycle of the interface growth behavior of Fe/Si compounds and the fragmentation behavior of whisker-like intermetallic compounds are developed.展开更多
In this study, 5052 steel were joined by a new way aluminum alloy and Q235 of arc milling brazing, with the Zn15%A1 filler metal and no use of flux. Effect of rotation speed on mechanical properties and microstructure...In this study, 5052 steel were joined by a new way aluminum alloy and Q235 of arc milling brazing, with the Zn15%A1 filler metal and no use of flux. Effect of rotation speed on mechanical properties and microstructure of joint interface was investigated. The results show that increasing rotation speed is in favor of formation of weld and spread of filler metal on substrate. The fine grain with homogeneous composition in brazed seam can be realized by the stronger stirring in pool induced by milling at more higher rotation speed. And, a composite joint reinforced with needle-like or block-like Fe-A1-Zn intermetallic compounds （IMCs） particle can be obtained by arc milling brazing, which comes from the reaction between steel scrape and Zn-A1 filler alloy. The test on strength of joint interface shows that with the increase in rotation speed, there is a peak value in variation ranges of strength of joint interface. This is to say, when rotation speed is 2720 r.min-~, the strength of joint has maximum value （182.01 MPa）. Moreover, a thin and discontinuous IMCs layer at joint interface can be obtained by increasing rotation speed. But at a low or high rotation speed, there also is a crack at joint interface, which weakens the strength of joint interface. Only at 2720 r.min-1, a good joint interface without an obvious crack can be realized.展开更多
Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material...Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.展开更多
According to the specification of superalloy-stainless steel arc brazing and characteristic of the base metal,a best filler metal which has relative lower melting point,nice wettability,good weld forming,and adequate ...According to the specification of superalloy-stainless steel arc brazing and characteristic of the base metal,a best filler metal which has relative lower melting point,nice wettability,good weld forming,and adequate shear strength was researched.The experiment results show that wettability of CuFeMn on the stainless steel is very poor,concomitant with a mass of purple soot during the welding which deteriorates the working condition.CuSiMn has the best wettability on both the superalloy and stainless steel,but there remains a lot of pit and slag on the surface of the weld bead.Copper-based solder has the highest melting point and its wettability and clearance fillability are weaker than CuSi3.Wettability and clearance fillability of the CuSi3 are the best in all the candidate filler metals,and its weld is smoothness and has higher shear strength.For its comprehensive ability,CuSi3 is selected as the final filler metal.展开更多
基金supported by the National Natural Science Foundation of China(No.50904012/ E041607)Natural Science Foundation of Liaoning Province(No.20092152)
文摘Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si （wt.%, the same below） and Zn-15%Al flux-cored filler wires. The effects of gap width and groove in steel side on the microstructure and tensile strength of the resultant joints were investigated. For the joint made with 0 mm-wide gap and without groove in steel side, severe incomplete brazing zone occurred along the steel side and bottom surfaces, and consequently seriously deteriorated the joint strength. However, presetting 1.5 mm-wide gap or with groove in steel side could promote the wetting of molten filler metal on the laying surfaces, and then significantly enhance the resultant joint strength. Moreover, post-weld heat treatment could further improve the tensile strength of the joints. During tensile testing, the specimens from the joints made with AI-12%Si flux-cored filler wire fractured through the weld or interracial layer, but those from the heat-treated joints made with Zn-15%AI flux-cored filler wire fractured in the aluminum base metal.
基金Project(50475051) supported by the National Natural Science Foundation of China
文摘The galvanized steels were joined using a TIG arc brazing process with CuSi3 as the filler metal.The arcing time ranged from 1 s to 5 s with arcing current of 70 A in flowing argon.The possible reaction products at the interface were confirmed using thermodynamics,SEM,and EDS methods.The results show that a fragmention behavior in some whisker-like intermetallic compounds happens,and that there are two layers of Fe2Si and Fe5Si3 formed at the interface of the galvanized steel and copper filler.From this,the schematic cycle of the interface growth behavior of Fe/Si compounds and the fragmentation behavior of whisker-like intermetallic compounds are developed.
基金financially supported by the State Key Laboratory of Advanced Welding and Joining of China (No.AWJ-Z16-02)
文摘In this study, 5052 steel were joined by a new way aluminum alloy and Q235 of arc milling brazing, with the Zn15%A1 filler metal and no use of flux. Effect of rotation speed on mechanical properties and microstructure of joint interface was investigated. The results show that increasing rotation speed is in favor of formation of weld and spread of filler metal on substrate. The fine grain with homogeneous composition in brazed seam can be realized by the stronger stirring in pool induced by milling at more higher rotation speed. And, a composite joint reinforced with needle-like or block-like Fe-A1-Zn intermetallic compounds （IMCs） particle can be obtained by arc milling brazing, which comes from the reaction between steel scrape and Zn-A1 filler alloy. The test on strength of joint interface shows that with the increase in rotation speed, there is a peak value in variation ranges of strength of joint interface. This is to say, when rotation speed is 2720 r.min-~, the strength of joint has maximum value （182.01 MPa）. Moreover, a thin and discontinuous IMCs layer at joint interface can be obtained by increasing rotation speed. But at a low or high rotation speed, there also is a crack at joint interface, which weakens the strength of joint interface. Only at 2720 r.min-1, a good joint interface without an obvious crack can be realized.
基金Project (50475051) supported by the National Natural Science Foundation of China
文摘Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.
文摘According to the specification of superalloy-stainless steel arc brazing and characteristic of the base metal,a best filler metal which has relative lower melting point,nice wettability,good weld forming,and adequate shear strength was researched.The experiment results show that wettability of CuFeMn on the stainless steel is very poor,concomitant with a mass of purple soot during the welding which deteriorates the working condition.CuSiMn has the best wettability on both the superalloy and stainless steel,but there remains a lot of pit and slag on the surface of the weld bead.Copper-based solder has the highest melting point and its wettability and clearance fillability are weaker than CuSi3.Wettability and clearance fillability of the CuSi3 are the best in all the candidate filler metals,and its weld is smoothness and has higher shear strength.For its comprehensive ability,CuSi3 is selected as the final filler metal.
