20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded.The effects of the compositions of filler wires,the heat input and the compositions of shielding gas on the mechanical properties and micros...20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded.The effects of the compositions of filler wires,the heat input and the compositions of shielding gas on the mechanical properties and microstructure of the welded joint have been investigated.The results indicate that finer microstructure,better mechanical properties and higher value of hardness of HAZ can be obtained by using lower heat input.The use of Ar/He mixed shielding gas has several advantages over pure Ar shielding gas.With the increase of the proportion of He in the mixed shielding gas,the grain size of the weld metal as well as porosity susceptibility decreases.When the volume ratio of He to Ar reaches 7:3,the porosity and the grain size of weld metal reach the minimum,and the porosity can be further reduced by filling some CO_(2).展开更多
By means of metallographic microscope(OM),scanning electron microscope(SEM),back scattering electron diffraction(EBSD)and transmission electron microscope(TEM),the effect of Cu on microstructure transformation and mec...By means of metallographic microscope(OM),scanning electron microscope(SEM),back scattering electron diffraction(EBSD)and transmission electron microscope(TEM),the effect of Cu on microstructure transformation and mechanical properties of deposited metal of 590MPa class steel welding wire was studied.The results show that the microstructure of deposited metal is composed of acicular ferrite,lamellar bainite,granular bainite and residual austenite.With the increase of Cu content,the phase transition temperature of the deposited metal decreases,making the phase transition region of ferrite and pearlite shift to the right,expanding the phase transition region of bainite and shrinking the phase transition region of ferrite and pearlite.The microstructure of deposited metal changed,the content of M-A elements increased but the size decreased,and the ferrite-bainite biphasic microstructure was matched.The reduction of M-A component content in strips and blocks and the reduction of effective grain size will reduce the nucleation probability of microcracks,increase crack growth resistance,and improve the impact toughness of the deposited metal.展开更多
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program,No.2002AA305402).
文摘20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded.The effects of the compositions of filler wires,the heat input and the compositions of shielding gas on the mechanical properties and microstructure of the welded joint have been investigated.The results indicate that finer microstructure,better mechanical properties and higher value of hardness of HAZ can be obtained by using lower heat input.The use of Ar/He mixed shielding gas has several advantages over pure Ar shielding gas.With the increase of the proportion of He in the mixed shielding gas,the grain size of the weld metal as well as porosity susceptibility decreases.When the volume ratio of He to Ar reaches 7:3,the porosity and the grain size of weld metal reach the minimum,and the porosity can be further reduced by filling some CO_(2).
文摘By means of metallographic microscope(OM),scanning electron microscope(SEM),back scattering electron diffraction(EBSD)and transmission electron microscope(TEM),the effect of Cu on microstructure transformation and mechanical properties of deposited metal of 590MPa class steel welding wire was studied.The results show that the microstructure of deposited metal is composed of acicular ferrite,lamellar bainite,granular bainite and residual austenite.With the increase of Cu content,the phase transition temperature of the deposited metal decreases,making the phase transition region of ferrite and pearlite shift to the right,expanding the phase transition region of bainite and shrinking the phase transition region of ferrite and pearlite.The microstructure of deposited metal changed,the content of M-A elements increased but the size decreased,and the ferrite-bainite biphasic microstructure was matched.The reduction of M-A component content in strips and blocks and the reduction of effective grain size will reduce the nucleation probability of microcracks,increase crack growth resistance,and improve the impact toughness of the deposited metal.
