Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully.A Cu alloy interlayer was added between Al alloy and high-strength steel.The effect of the adhe...Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully.A Cu alloy interlayer was added between Al alloy and high-strength steel.The effect of the adhesive on laser-arc-adhesive hybrid welding of Al alloy to high-strength steel was discussed.The optical microscope,scanning electron microscope and electron probe micro-analysis were applied to observe the microstructural evolution and phase transition at Al-Fe interface of laser-arc-adhesive hybrid welded joints.The results showed the maximum tensile shear strength of the joint without adhesive was 256 MPa.After adding adhesive,the maximum tensile shear strength reached 282 MPa.The combination of the mechanical bonding and the metallurgical effect could improve the mechanical performances.The shape of the joint in Al alloy changed into a canine-like morphology.There was no porosity in welds because the molten pool of Al alloy and the special keyhole phenomenon of laser welding provided a channel for the decomposed gas to escape from fusion zone.展开更多
To realize good point connection between high-strength steel and aluminum alloy,a process of drawing-upsetting-extrusion-clinching was proposed.First,the sheets were drawn;then,the bottom of the protrusion part was ex...To realize good point connection between high-strength steel and aluminum alloy,a process of drawing-upsetting-extrusion-clinching was proposed.First,the sheets were drawn;then,the bottom of the protrusion part was extruded,forming the necessary initial interlock;and finally,the protrusion part was reverse press clinched,forming a certain height of the clinched head.Taking DP980 high-strength steel and A15083 aluminum alloy as the connection objects and using the method of numerical simulation combined with experimental test,the mold was made,and the experiment was carried out on the basis of numerical simulation.The experimental results proved the feasibility of the process and the effectiveness of the numerical model.The simulation and experimental results show that the necessary interlock in the drawing-upsetting-extrusion stage is the premise of effective connection.The relative protrusion height should be around 55.6%after reverse-press-clinching.The best comprehensive mechanical properties measured by strength test were shear resistance of 2644 N,fatigue life of 24,535 times and peel resistance of 1522 N.Through failure analysis,the relationship between the interlock Tu and the neck thickness Tn of the joint with the best comprehensive mechanical properties was established as Tu=0.35Tn.The design method of die and process parameters when the sheet thickness changes was researched by numerical simulation.The results show that the clearance between the punch and the die and the bottom thickness are directly proportional to the sheet thickness,and the drawing depth is directly proportional to the punch radius.展开更多
In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and al...In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and aluminum deoxidization sequences. Thermodynamic calculations demonstrated that the complex inclusions with low melting point （harmless inclusions） are more favorable to be formed in condition that the melt was deoxidized using ferrosilicon first and then pure aluminum （Si/A1 deoxidization） than that deoxidized using pure aluminum first and then ferrosilicon （AI/Si deoxidization）. Al-rich inclusion decreases 83% from A1/Si deoxidization to Si/A1 deoxidization. The experimental results showed that the total quantity of inclusions decreases by 24% and the proportion of harmless inclusions is doubled when comparing Si/Al deoxidization with Al/Si deoxidization. The morphology of complex inclusion tends to be spherical, and the mean size is less than 5μm in condition of Si/Al deoxidization. The formation mechanism of harmless inclusions was discussed, and it is believed that the inclusions can be controlled reasonably in high aluminum steel using Si/Al deoxidization.展开更多
基金This work was supported by the National Key R&D Program of China(2018YFB1107900)the National Natural Science Foundation of China(Grant Nos.U1764251 and 51975090).
文摘Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully.A Cu alloy interlayer was added between Al alloy and high-strength steel.The effect of the adhesive on laser-arc-adhesive hybrid welding of Al alloy to high-strength steel was discussed.The optical microscope,scanning electron microscope and electron probe micro-analysis were applied to observe the microstructural evolution and phase transition at Al-Fe interface of laser-arc-adhesive hybrid welded joints.The results showed the maximum tensile shear strength of the joint without adhesive was 256 MPa.After adding adhesive,the maximum tensile shear strength reached 282 MPa.The combination of the mechanical bonding and the metallurgical effect could improve the mechanical performances.The shape of the joint in Al alloy changed into a canine-like morphology.There was no porosity in welds because the molten pool of Al alloy and the special keyhole phenomenon of laser welding provided a channel for the decomposed gas to escape from fusion zone.
文摘To realize good point connection between high-strength steel and aluminum alloy,a process of drawing-upsetting-extrusion-clinching was proposed.First,the sheets were drawn;then,the bottom of the protrusion part was extruded,forming the necessary initial interlock;and finally,the protrusion part was reverse press clinched,forming a certain height of the clinched head.Taking DP980 high-strength steel and A15083 aluminum alloy as the connection objects and using the method of numerical simulation combined with experimental test,the mold was made,and the experiment was carried out on the basis of numerical simulation.The experimental results proved the feasibility of the process and the effectiveness of the numerical model.The simulation and experimental results show that the necessary interlock in the drawing-upsetting-extrusion stage is the premise of effective connection.The relative protrusion height should be around 55.6%after reverse-press-clinching.The best comprehensive mechanical properties measured by strength test were shear resistance of 2644 N,fatigue life of 24,535 times and peel resistance of 1522 N.Through failure analysis,the relationship between the interlock Tu and the neck thickness Tn of the joint with the best comprehensive mechanical properties was established as Tu=0.35Tn.The design method of die and process parameters when the sheet thickness changes was researched by numerical simulation.The results show that the clearance between the punch and the die and the bottom thickness are directly proportional to the sheet thickness,and the drawing depth is directly proportional to the punch radius.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （No. U1460103）. Support was also provided by the Instrumental Analysis ＆ Research Center in Shanghai University.
文摘In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and aluminum deoxidization sequences. Thermodynamic calculations demonstrated that the complex inclusions with low melting point （harmless inclusions） are more favorable to be formed in condition that the melt was deoxidized using ferrosilicon first and then pure aluminum （Si/A1 deoxidization） than that deoxidized using pure aluminum first and then ferrosilicon （AI/Si deoxidization）. Al-rich inclusion decreases 83% from A1/Si deoxidization to Si/A1 deoxidization. The experimental results showed that the total quantity of inclusions decreases by 24% and the proportion of harmless inclusions is doubled when comparing Si/Al deoxidization with Al/Si deoxidization. The morphology of complex inclusion tends to be spherical, and the mean size is less than 5μm in condition of Si/Al deoxidization. The formation mechanism of harmless inclusions was discussed, and it is believed that the inclusions can be controlled reasonably in high aluminum steel using Si/Al deoxidization.
