Welding Technique of Titanium Alloy

Titanium and its alloy are widely used in aerospace, chemical industry, shipbuilding etc, because of its low density, high strength, and corrosion resistance. At present, high quality plane and tank are being made of titanium alloy parts which are being used more widely in oil chemical industry. In the application of titanium in plane and its engine and chemical industry, welding technique is necessary. Welding technique is very important to the developing of titanium alloy application. This article is to point out some of the problems in the process of welding.

1. Welding capability of titanium alloy

Most titanium alloy can be processed in arcogen welding, and all of them can be processed in solid-state welding, such as TIG, MIG, low-current plasma arc welding, laser and electron beam welding. In actual fact, the occurrence tendency of flaw in titanium alloy welding is much smaller than ferrous materials (such as iron alloy and nickel alloy). Although titanium has such superior capability in welding, some engineers still consider it difficult in welding titanium alloy. Because of its especially demand of gas protection in welding, only those very professional can satisfy this requirement. In actual fact, many techniques could be applied in welding titanium alloy. As N2 O2 and carbon material are involved, the welding point become more fragile. So the welding area must be cleaned and protected by inert gas. Welding material are chosen as per the capabilities of welding alloy.

2.Gas cavity in titanium alloy

The occurrence of gas cavity in welding point is mainly due to the clean of the alloy and the length of welding time. Also O2 N2 CO2 and inert gas could result in the occurrence of gas cavity.

The same as aluminum oxide, titanium oxide is moisture absorbing.

Measures of reducing gas cavity in titanium alloy welding:

1. welding material should be dry.
2. prepared welding material should be used within 48 hours.
3. Titanium and welding material should be cleaned.
4. Welding should be protected by high purity nontoxic gas and helium gas.