The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the...The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the phenomena. As a result, the droplet transfer mode obtained from this calculation was regarded as a projected transfer mode in which the liquid column grew about 1 mm and a droplet grew up until its diameter became large the same as a wire diameter,?after that it was detached from the tip of the column. In addition, 10 droplets were formed for 0.1 s through these growth and detachment processes at the tip of a wire. To compare with the numerical results, actual GMA welding was carried out and molten metal droplet transfers were taken by high speed camera. The diameter of a wire, the length of a liquid column, the velocity of a droplet right before it reached a weld pool obtained by simulation showed good agreement with experiment.展开更多
Metal transfer behavior of six kinds of self shielded flux cored wire(SSFCW) is studied using the apparatus of SSFCW high speed photography self made. Six kinds of metal transfer modes of SSFCW were obtained throu...Metal transfer behavior of six kinds of self shielded flux cored wire(SSFCW) is studied using the apparatus of SSFCW high speed photography self made. Six kinds of metal transfer modes of SSFCW were obtained through observation for high speed photograph film and analysis. It is believed that the research is of magnificent for improving operative performance and mechanical properties of SSFCW and dynamics characteristic of welding power.展开更多
综述了涉及工程应用的冷丝熔化极气体保护焊(Cold wire gas metal arc welding,CW-GMAW)熔滴过渡形态特征。结果表明,在大电流、强规范、富氩混合气体保护下,CW-GMAW工艺的熔滴过渡形态呈喷射过渡;当电流较小、电弧电压较低时,可能为滴...综述了涉及工程应用的冷丝熔化极气体保护焊(Cold wire gas metal arc welding,CW-GMAW)熔滴过渡形态特征。结果表明,在大电流、强规范、富氩混合气体保护下,CW-GMAW工艺的熔滴过渡形态呈喷射过渡;当电流较小、电弧电压较低时,可能为滴状过渡,甚至在弧压很低时,呈现短路过渡形态。该工艺电弧发生偏向冷丝的位移,弧长变短甚至发生短路,与冷丝送进速率比增高及冷丝在电弧中产生大量金属蒸气时弧柱电阻下降有关。在具有富氩混合保护气体的相同工艺参数下,CWGMAW转变电流比GMAW降低了4%~7%。焊接工艺参数对CW-GMAW和GMAW工艺熔滴过渡形态的影响规律大致相近,但前者因涉及冷丝送进速率比和电极焊丝送进速度,以及它们的匹配等,使焊接电流的影响更为复杂。展开更多
The effect of nonmetallic inclusions in the droplet of the stainless steel covered electrode on the porosity was researched.The result shows that the nonmetallic inclusions in the droplet are spherical,their compositi...The effect of nonmetallic inclusions in the droplet of the stainless steel covered electrode on the porosity was researched.The result shows that the nonmetallic inclusions in the droplet are spherical,their composition is different from the one of slag and the inclusions have the character of “inner formation”.When the ratio of rutile to ilmenite in the coated material is increased, the droplet becomes coarse, the content of nonmetallic inclusion in the droplet decreases,and the porosity sensitivity in the weld metal also decreases.When the ratio of fledspar to ilmenite in the coated material is increased, the droplet becomes fine,the content of nonmetallic inclusion in the droplet increases, and the porosity sensitivity in the weld metal increases. When the ratio of Fe_2O_3 to ilmenite in the coated material is increased, the droplet becomes fine, the content of nonmetallic inclusion decreases, while the porosity sensitivity does not reduce.展开更多
为提升高氮钢焊接质量和优化焊接工艺,研究焊丝氮、锰含量带来的焊接工艺稳定性。采用冷金属过渡加脉冲(Cold Metal Transfer plus Pulse,CMT+P)焊技术对5种高氮钢焊丝进行焊接试验,研究焊丝成分对电信号、熔滴过渡、飞溅率的影响。研...为提升高氮钢焊接质量和优化焊接工艺,研究焊丝氮、锰含量带来的焊接工艺稳定性。采用冷金属过渡加脉冲(Cold Metal Transfer plus Pulse,CMT+P)焊技术对5种高氮钢焊丝进行焊接试验,研究焊丝成分对电信号、熔滴过渡、飞溅率的影响。研究结果表明:氮含量的增加会引起电信号波动变大且分布离散,而锰含量的变化对电信号的影响较小,焊丝中氮含量对高氮钢CMT+P焊接稳定性影响大于锰含量的影响;随着氮含量的增加,熔滴过渡模式由一脉一滴转变为多脉一滴,熔滴形状不规律且尺寸变大,焊丝工艺性变差;当焊丝中氮、锰含量较小,分别为0.42%、7.19%时,焊接工艺稳定性较好;氮逸出、锰蒸发导致高氮钢熔滴剧烈爆炸产生大量飞溅,焊接飞溅率随着氮、锰含量的增加而不断增大。展开更多
文摘The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the phenomena. As a result, the droplet transfer mode obtained from this calculation was regarded as a projected transfer mode in which the liquid column grew about 1 mm and a droplet grew up until its diameter became large the same as a wire diameter,?after that it was detached from the tip of the column. In addition, 10 droplets were formed for 0.1 s through these growth and detachment processes at the tip of a wire. To compare with the numerical results, actual GMA welding was carried out and molten metal droplet transfers were taken by high speed camera. The diameter of a wire, the length of a liquid column, the velocity of a droplet right before it reached a weld pool obtained by simulation showed good agreement with experiment.
文摘Metal transfer behavior of six kinds of self shielded flux cored wire(SSFCW) is studied using the apparatus of SSFCW high speed photography self made. Six kinds of metal transfer modes of SSFCW were obtained through observation for high speed photograph film and analysis. It is believed that the research is of magnificent for improving operative performance and mechanical properties of SSFCW and dynamics characteristic of welding power.
文摘综述了涉及工程应用的冷丝熔化极气体保护焊(Cold wire gas metal arc welding,CW-GMAW)熔滴过渡形态特征。结果表明,在大电流、强规范、富氩混合气体保护下,CW-GMAW工艺的熔滴过渡形态呈喷射过渡;当电流较小、电弧电压较低时,可能为滴状过渡,甚至在弧压很低时,呈现短路过渡形态。该工艺电弧发生偏向冷丝的位移,弧长变短甚至发生短路,与冷丝送进速率比增高及冷丝在电弧中产生大量金属蒸气时弧柱电阻下降有关。在具有富氩混合保护气体的相同工艺参数下,CWGMAW转变电流比GMAW降低了4%~7%。焊接工艺参数对CW-GMAW和GMAW工艺熔滴过渡形态的影响规律大致相近,但前者因涉及冷丝送进速率比和电极焊丝送进速度,以及它们的匹配等,使焊接电流的影响更为复杂。
文摘The effect of nonmetallic inclusions in the droplet of the stainless steel covered electrode on the porosity was researched.The result shows that the nonmetallic inclusions in the droplet are spherical,their composition is different from the one of slag and the inclusions have the character of “inner formation”.When the ratio of rutile to ilmenite in the coated material is increased, the droplet becomes coarse, the content of nonmetallic inclusion in the droplet decreases,and the porosity sensitivity in the weld metal also decreases.When the ratio of fledspar to ilmenite in the coated material is increased, the droplet becomes fine,the content of nonmetallic inclusion in the droplet increases, and the porosity sensitivity in the weld metal increases. When the ratio of Fe_2O_3 to ilmenite in the coated material is increased, the droplet becomes fine, the content of nonmetallic inclusion decreases, while the porosity sensitivity does not reduce.
文摘为提升高氮钢焊接质量和优化焊接工艺,研究焊丝氮、锰含量带来的焊接工艺稳定性。采用冷金属过渡加脉冲(Cold Metal Transfer plus Pulse,CMT+P)焊技术对5种高氮钢焊丝进行焊接试验,研究焊丝成分对电信号、熔滴过渡、飞溅率的影响。研究结果表明:氮含量的增加会引起电信号波动变大且分布离散,而锰含量的变化对电信号的影响较小,焊丝中氮含量对高氮钢CMT+P焊接稳定性影响大于锰含量的影响;随着氮含量的增加,熔滴过渡模式由一脉一滴转变为多脉一滴,熔滴形状不规律且尺寸变大,焊丝工艺性变差;当焊丝中氮、锰含量较小,分别为0.42%、7.19%时,焊接工艺稳定性较好;氮逸出、锰蒸发导致高氮钢熔滴剧烈爆炸产生大量飞溅,焊接飞溅率随着氮、锰含量的增加而不断增大。
