Tips on How to Ensure the Welding Quality of Titanium Pipes

With the development of the petrochemical industry, more and more new technologies have been applied in petroleum processing. Meanwhile, some strong acids or highly corrosive materials are used in petrochemical reactions due to their strong oxidizing and good catalytic properties. However, once leakage occurs, it will lead to extremely serious consequences. Therefore, how to manufacture containers for these highly acidic and corrosive materials and pipes for transporting these materials has become a major issue.

Titanium and titanium alloys have drawn attention because of their excellent acid corrosion resistance and are increasingly used in manufacturing equipment and process pipes, especially for reactors and transport pipes dealing with strong acid materials. However, titanium and titanium alloys are prone to react and become embrittled with various elements and compounds at high temperatures. Especially during the welding process, once elements such as oxygen and nitrogen in the air are absorbed, they will dissolve in the titanium metal, significantly hardening the alloy, reducing the ductility of the titanium-containing metal and making it brittle, which may result in pipe fractures and equipment damage. Thus, the study of the welding of titanium and titanium alloys is of great significance for the construction and maintenance of the installations where they are applied. Based on the installation of titanium alloy pipes in an acetic acid plant in a certain project, the following briefly discusses the welding quality control of titanium alloy pipes. The following points should be controlled during the welding process:

Effectively control the interlayer temperature during welding to avoid the absorption and dissolution of titanium alloys with nitrogen, hydrogen, oxygen gases as well as iron and carbon elements.

Use high-purity argon as the shielding gas for welding as much as possible. The shielding effect should be good, and its flow rate should be within the specified range.

The surfaces of the welding area and welding wire should be cleaned of contaminants such as oxide scale and grease. The welding work of the welded joints should be completed in one go as far as possible (within 8 hours).

For the welding of on-site welds, try to meet the environmental requirements for titanium material welding as much as possible.

Practice has proved that only when good control is exerted in every aspect during joint welding can the welding quality be ensured to meet the usage requirements. With the guarantee of welding quality, titanium materials can be used in more special environmental conditions.