The arc characteristics of submerged arc welding （SAW） with stainless steel wire were studied by using Analysator Hannover （AH）. The tests were carded out under the same preset arc voltage combined with different ...The arc characteristics of submerged arc welding （SAW） with stainless steel wire were studied by using Analysator Hannover （AH）. The tests were carded out under the same preset arc voltage combined with different welding currents. By comparing the probability density distribution （PDD） curves of arc voltage and welding current, the changes were analyzed, the metal transfer mode in SAW was deduced, and the characteristics of a stable arc were summarized. The analysis results show that, with an increase of welding parameters, the short-circuiting peak in the PDD curves of arc voltage decreases gradually until it disappears, and the dominant metal transfer mode changes from flux-wall guided transfer to projected transfer and then to streaming transfer. Moreover, when the PDD curves of arc voltage are both unimodal and generally symmetrical, the greater the peak probability and the smaller the peak span, the more stable the arc becomes.展开更多
This work investigates the proposed welding of stainless steels with no backing gas by using solid wire ER316L-Si and mixed gases （ He ＋ Ar ＋ CO2 ）. The protection mechanism was also discussed from the view of arc...This work investigates the proposed welding of stainless steels with no backing gas by using solid wire ER316L-Si and mixed gases （ He ＋ Ar ＋ CO2 ）. The protection mechanism was also discussed from the view of arc physics and the alloy elements in the solid wire. The result shows that when the proportion of helium in the above-noted mixed gases excesses 45 percent, the mechanical properties and the intergranular corrosion tendency meet corresponding Chinese standards. Further, the alloy elements in the solid wire can react with oxygen during the period of high temperature boosted by helium arc ; this result in the formation of a bed of thin slag, which can avoid the oxidation of the backing weld and eliminate the need of backing gas.展开更多
To study the influence laws of welding parameters on weld porosity, underwater wet flux-cored arc welding （ FCAW） duplex stainless steel S32101 was carried out in a hyperbaric chamber, and the second-order multiple ...To study the influence laws of welding parameters on weld porosity, underwater wet flux-cored arc welding （ FCAW） duplex stainless steel S32101 was carried out in a hyperbaric chamber, and the second-order multiple regression equation was established. The interactive effects of welding parameters on the porosity were analyzed by the three dimensional response surfaces and the contour plots. The results present that the interaction effect between water depth and voltage on the porosity is the most significant. Theoretically, a non-pores weld bead can be gained by reasonably matching these parameters with water depth less than 10 m. Always, the weld porosity reaches its peak value with a 7 mm/s welding speed.展开更多
A kind of self-protective flux cored wire has been developed for joining 960 MPa high strength steel. Weld metal containing different aluminium elements contents was obtained by changing the content of aluminum powder...A kind of self-protective flux cored wire has been developed for joining 960 MPa high strength steel. Weld metal containing different aluminium elements contents was obtained by changing the content of aluminum powder in the composition of the flux core. The strength and toughness of weld metal were tested by tensile test and impact test at different temperatures, and the influence mechanism of aluminium element on the microstructure and mechanical properties of weld metal was analyzed by means of metallographic microstructure observation and scanning electron microscope observation. The results show that aluminium element content on impact ductility of weld metal of 960 MPa high strength steel is great, but the influence on tensile strength and elongation of weld metal is little. With increasing aluminium element contents of weld metal, the impact energy of weld metal increases at first and then decreases, the best aluminium element content of weld metal is 0.2 wt.%. Aluminium oxide is easy to be formed in weld metal with low aluminium element contents, and the aluminium oxide can easily become nucleation particle for acicular ferrite. It is conducive to formation more acicular ferrite and will improve impact absorbing energy of weld metal. Aluminium nitride will easily formed in weld metal with high aluminium element content, and the coarse ferrite microstructure appears in weld metal and reduces impact energy of weld metal.展开更多
To obtain the compatible material of high hardness and high toughness,Hadfield steel matrix composites,reinforced by high-Cr cast iron bars made of flux-cored welding wires,which were inserted into the Hadfield steel ...To obtain the compatible material of high hardness and high toughness,Hadfield steel matrix composites,reinforced by high-Cr cast iron bars made of flux-cored welding wires,which were inserted into the Hadfield steel melt,were investigated.The mechanical properties of three materials,i e,composites for as-cast and quenching-water condition,as well as Hadfield steel,were compared.The results show that the alloy powder inside flux-cored welding wires can be melted by the heat capacity of Hadfield steel melt and solidify into high-Cr cast iron bars.The impact toughness of the composite for quenching-water condition is higher than that of the composite for as-cast condition and is lower than that of the Hadfield steel,but it can still meet the requirements of hardness and toughness in industrial application.Regardless of load variation,composite for quenching-water condition shows better wear resistance than those of the composite for as-cast condition and Hadfield steel.The modified fracture toughness and wear resistance of composites are attributed to not only the combining actions of Hadfield steel matrix and high-Cr cast iron bars,but also the effect of heat treatment.展开更多
基金financially supported by the Shanxi Provincial Key Programs for Science and Technology Development (No. 20100321084)Taiyuan Special Foundation for Excellent Talents (No. 20111075)
文摘The arc characteristics of submerged arc welding （SAW） with stainless steel wire were studied by using Analysator Hannover （AH）. The tests were carded out under the same preset arc voltage combined with different welding currents. By comparing the probability density distribution （PDD） curves of arc voltage and welding current, the changes were analyzed, the metal transfer mode in SAW was deduced, and the characteristics of a stable arc were summarized. The analysis results show that, with an increase of welding parameters, the short-circuiting peak in the PDD curves of arc voltage decreases gradually until it disappears, and the dominant metal transfer mode changes from flux-wall guided transfer to projected transfer and then to streaming transfer. Moreover, when the PDD curves of arc voltage are both unimodal and generally symmetrical, the greater the peak probability and the smaller the peak span, the more stable the arc becomes.
基金Acknowledgement The authors would like to appreciate the financial support from the National Natural Science Foundation of China （Grant No. 50874033 ）.
文摘This work investigates the proposed welding of stainless steels with no backing gas by using solid wire ER316L-Si and mixed gases （ He ＋ Ar ＋ CO2 ）. The protection mechanism was also discussed from the view of arc physics and the alloy elements in the solid wire. The result shows that when the proportion of helium in the above-noted mixed gases excesses 45 percent, the mechanical properties and the intergranular corrosion tendency meet corresponding Chinese standards. Further, the alloy elements in the solid wire can react with oxygen during the period of high temperature boosted by helium arc ; this result in the formation of a bed of thin slag, which can avoid the oxidation of the backing weld and eliminate the need of backing gas.
基金the National Natural Science Foundation of China(Grant No.51374111&51175185)Science and Technology Plan Project of Guangdong Province(Grant No.2015B050502005)for financial support
文摘To study the influence laws of welding parameters on weld porosity, underwater wet flux-cored arc welding （ FCAW） duplex stainless steel S32101 was carried out in a hyperbaric chamber, and the second-order multiple regression equation was established. The interactive effects of welding parameters on the porosity were analyzed by the three dimensional response surfaces and the contour plots. The results present that the interaction effect between water depth and voltage on the porosity is the most significant. Theoretically, a non-pores weld bead can be gained by reasonably matching these parameters with water depth less than 10 m. Always, the weld porosity reaches its peak value with a 7 mm/s welding speed.
基金Project(52130509) supported by the National Natural Science Foundation,ChinaProject(BIPTACF-010) supported by the Cultivation Foundation from Beijing Institute of Petrochemical Technology,China。
基金Project was supported by the 2019 Scientific Research Foundation of Liaoning Provincial Education Department (Grant No. LJJF201902)Special Research Foundation of Liaoning Equipment Manufacture College of Vocational and Technology (Grant No.2018YYYJ-5)。
文摘A kind of self-protective flux cored wire has been developed for joining 960 MPa high strength steel. Weld metal containing different aluminium elements contents was obtained by changing the content of aluminum powder in the composition of the flux core. The strength and toughness of weld metal were tested by tensile test and impact test at different temperatures, and the influence mechanism of aluminium element on the microstructure and mechanical properties of weld metal was analyzed by means of metallographic microstructure observation and scanning electron microscope observation. The results show that aluminium element content on impact ductility of weld metal of 960 MPa high strength steel is great, but the influence on tensile strength and elongation of weld metal is little. With increasing aluminium element contents of weld metal, the impact energy of weld metal increases at first and then decreases, the best aluminium element content of weld metal is 0.2 wt.%. Aluminium oxide is easy to be formed in weld metal with low aluminium element contents, and the aluminium oxide can easily become nucleation particle for acicular ferrite. It is conducive to formation more acicular ferrite and will improve impact absorbing energy of weld metal. Aluminium nitride will easily formed in weld metal with high aluminium element content, and the coarse ferrite microstructure appears in weld metal and reduces impact energy of weld metal.
基金Funded by the Research Center for lnnovation Engineering in Science and Technology,Shaan Xi Province,China (No.2007ZDGC-17)
文摘To obtain the compatible material of high hardness and high toughness,Hadfield steel matrix composites,reinforced by high-Cr cast iron bars made of flux-cored welding wires,which were inserted into the Hadfield steel melt,were investigated.The mechanical properties of three materials,i e,composites for as-cast and quenching-water condition,as well as Hadfield steel,were compared.The results show that the alloy powder inside flux-cored welding wires can be melted by the heat capacity of Hadfield steel melt and solidify into high-Cr cast iron bars.The impact toughness of the composite for quenching-water condition is higher than that of the composite for as-cast condition and is lower than that of the Hadfield steel,but it can still meet the requirements of hardness and toughness in industrial application.Regardless of load variation,composite for quenching-water condition shows better wear resistance than those of the composite for as-cast condition and Hadfield steel.The modified fracture toughness and wear resistance of composites are attributed to not only the combining actions of Hadfield steel matrix and high-Cr cast iron bars,but also the effect of heat treatment.
