This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base ...This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base metal, and with lower carbon content and slightly higher alloy elements content compared to the first one. Test plates then exerted three different pre-heat and post-heat treatments on both groups. The three types of heat treatments were alternatively without pre-heat and post-heat, with pre-heat only, and finally with pre-heat and post-heat. Tensile, side bends and impact tests (for weld zone and HAZ) have been conducted. Results show that using low-carbon filler wire along with pre- and post-heat resulted in outstanding mechanical properties.展开更多
In this study, the effects of main welding parameters （rotation speed （ω） and welding speed （υ）） on the microstructure, micro-hardness distribution and tensile properties of friction stir welded （FSW） 2195-T...In this study, the effects of main welding parameters （rotation speed （ω） and welding speed （υ）） on the microstructure, micro-hardness distribution and tensile properties of friction stir welded （FSW） 2195-T8 Al-Li alloy were investigated. The effects of T6 post-treatments at different solution and aging conditions on the mechanical properties and microstructure characteristics of the FSW joints were also investigated. The results show that with increasing to and v, both strength and elongation of the joints increase first, and then decrease with further increase of ω and υ. All the joints under varied welding parameters show significant strength loss, and the strength reaches only 65% of the base metal, The effect of T6 post-heat treatment on the mechanical properties of the joints depends on the solution and aging conditions. Two heat treatment processes （480 ℃×0.5 h quenching＋ 180 ℃× 12 h, 520 ℃× 0.5 h quenching＋ 180 ℃×12h aging） are found to increase the joint strength. Furthermore, low temperature quenching （480℃） is more beneficial to the joint strength. The joint strength can reach 85% of the base metal. Whereas both low temperature aging （140 ℃× 56h） and stepped aging （ 100 ℃× 12 h ＋ 180 ℃× 3 h） processes decrease the joint strength. After heat treatment all the joints show decreased ductility due to the obvious grain coarsening in the nugget zone （NZ） and thermo-mechanically affected zone （TMAZ）.展开更多
文摘This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base metal, and with lower carbon content and slightly higher alloy elements content compared to the first one. Test plates then exerted three different pre-heat and post-heat treatments on both groups. The three types of heat treatments were alternatively without pre-heat and post-heat, with pre-heat only, and finally with pre-heat and post-heat. Tensile, side bends and impact tests (for weld zone and HAZ) have been conducted. Results show that using low-carbon filler wire along with pre- and post-heat resulted in outstanding mechanical properties.
基金supported by the National Natural Science Foundation of China(No.51305272)
文摘In this study, the effects of main welding parameters （rotation speed （ω） and welding speed （υ）） on the microstructure, micro-hardness distribution and tensile properties of friction stir welded （FSW） 2195-T8 Al-Li alloy were investigated. The effects of T6 post-treatments at different solution and aging conditions on the mechanical properties and microstructure characteristics of the FSW joints were also investigated. The results show that with increasing to and v, both strength and elongation of the joints increase first, and then decrease with further increase of ω and υ. All the joints under varied welding parameters show significant strength loss, and the strength reaches only 65% of the base metal, The effect of T6 post-heat treatment on the mechanical properties of the joints depends on the solution and aging conditions. Two heat treatment processes （480 ℃×0.5 h quenching＋ 180 ℃× 12 h, 520 ℃× 0.5 h quenching＋ 180 ℃×12h aging） are found to increase the joint strength. Furthermore, low temperature quenching （480℃） is more beneficial to the joint strength. The joint strength can reach 85% of the base metal. Whereas both low temperature aging （140 ℃× 56h） and stepped aging （ 100 ℃× 12 h ＋ 180 ℃× 3 h） processes decrease the joint strength. After heat treatment all the joints show decreased ductility due to the obvious grain coarsening in the nugget zone （NZ） and thermo-mechanically affected zone （TMAZ）.
