双丝窄间隙GMAW三元保护气成分对焊缝成形的影响

窄间隙焊接在厚板焊接中有着较大的优势，保护气成分在一定程度上影响电弧行为及熔滴过渡，进而影响焊缝成形。针对30 mm厚Q235低碳钢，研究了窄间隙坡口下Ar，He和CO2构成的三元保护气中，不同的保护气成分比例对焊缝成形的影响。结果表明：固定的He含量为5%，当CO2含量为10%时得到的焊缝表面成形良好，指状熔深相对较小，侧壁熔深相对较大的焊缝。固定CO2含量为10%，当He含量为10%时得到的焊缝表面成形良好，指状熔深相对较小，侧壁熔深相对较大的焊缝。

Influence of ternary shielding gas composition on weld forming of narrow gap tandem wires GMAW

Narrow gap welding has a greater advantage in the thick plate welding, the protective gas composition has the influence on the arc behavior, droplet transfer and the weld formation. Aiming at narrow gap GMAW of 30 mm thick Q235 steel, the effect of different shielding gas compositions on the weld formation was studied in the ternary shield gas composed of Ar, He and CO2. The weld is well formed when the content of He is set at 5% and the content of CO2 is up to 10%, and the weld with smaller finger penetration and larger sidewall penetration can be obtained. The weld appearance is good at the CO2 content of 10% and the He content of 10%, and the finger penetration is smaller and the sidewall penetration is larger.