1) The effects of oxygen and nitrogen
The oxygen and nitrogen gaps are solid-melted in titanium, which makes the titanium lattice distorted, the deformation resistance increases, the strength and hardness increase, the plasticity and toughness decrease, and the weld oxygen and nitrogen in the weld are unfavorable, and should be avoided.
2) The effects of hydrogen
The increase in hydrogen causes a sharp drop in the impact toughness of the weld metal of titanium, while the plasticity drops a little, and the hydride causes brittleness of the joint.
3) The effects of carbon
At room temperature, carbon is dissolved in titanium in the form of a gap, which increases the strength and decreases the plasticity, but it is not as good as oxygen and nitrogen. When the carbon content exceeds the solubility, it forms a hard and brittle TiC, which is distributed in a network and is prone to cracks. The carbon content of titanium in its titanium alloy shall not exceed 0.1%. When welding, the oil stain of the workpiece and the welding wire can increase the carbon content, so it needs to be cleaned when welding.