Effect of shielding gas on the properties of CP titanium Grade 2 laser weld joints

Abstract

The paper deals with the evaluation of the shielding gas influence on the properties of titanium Grade 2 weld joints produced with disk laser. Butt weld joints were produced under different shielding gas types, namely Ar, He, Ar + 5 vol.% He, Ar + 30 vol.% He, and without shielding weld pool. Light and electron microscopy, microhardness measurements, computed tomography, and tensile testing were used for evaluation of weld joint properties. He-shielded weld joints were the narrowest ones. On the other hand, Ar-shielded weld joints exhibited the largest weld width. The choice of shielding gas had a significant influence on the porosity of welds. The lowest porosity was observed in the weld joint produced in Ar with the addition of 30 vol.% He shielding atmosphere (only 0.03 %), while the highest level of porosity was detected in weld joint produced without shielding gas (0.76 %). Except for unshielded titanium Grade 2 weld joint, the lowest tensile strength was recorded in Ar-shielded weld joints. On the contrary, the highest average microhardness, except unshielded weld joint, was measured in He-shielded weld joints.

Microstructural Characterization and Mechanical Properties of Fiber Laser Welded CP-Ti and Ti-6Al-4V Similar and Dissimilar Joints

“…A wide range of mechanical properties portrayed by these five types of titanium alloys has allowed industries to adopt the best one that suits their purpose [2]. The good formability, toughness, and corrosion resistance of commercially pure titanium (CP-Ti), an α alloy, have paved the way for this alloy to be used in aerospace applications, including floor support structure in the galley and lavatory areas, tubes or pipes in the lavatory system, clips and brackets, and ducting for the anti-icing and environmental control systems [2,3]. Ti-6Al-4V (Ti-64), an α-β alloy, has a high strength-to-weight ratio and excellent corrosion resistance, which make it the most versatile titanium alloy in the aerospace industry.…”