Welding of marine titanium and titanium alloy

Titanium material has the characteristics of high specific strength, seawater and Marine atmospheric corrosion resistance, no magnetic, sound transmission, shock resistance and good processability, which is a kind of high quality ship material. For ship materials, welding is an important processing means for its structure manufacturing. The adaptability of various Marine titanium and titanium alloy to welding processing and the quality of welding performance are directly related to their application in ship structure.

There are many varieties and brands of titanium materials, and according to the different application fields, the related performance requirements are also different. The main application function of Marine titanium alloy is the resistance to seawater and Marine atmosphere corrosion, high ratio strength, high toughness and excellent processing process performance. Due to the wide application range of titanium material in the field of ships, such as ship structure, propulsion system, power system, electronic information system, auxiliary system and special devices, etc., so various properties, varieties and specifications of titanium alloy materials are needed.

Marine titanium and titanium alloy welding, usually follow the principle of equal strength, and obtain the strength, plasticity and toughness. Therefore, when selecting the welding material:

①Generally choose homogenous welding materials;

②In order to improve the plasticity of the joint, the welding materials with slightly less alloy degree than the base material can be used;

③In order to improve the metal plasticity of the weld seam, the gap element content in the welding wire should be lower than that of the base metal.

According to the regression analysis of the application research results and test data of Marine titanium alloy welding over many years, it is generally required that in order to obtain the equal strength of weld metal and base material, the welding wire alloy composition is 1 Al equivalent lower than that of the base material. In order to control the content of the impurity elements in the post-weld metal at a low level, the content of the original impurity elements in the welding wire should be strictly controlled. For the Marine titanium alloy welding structure, the heat treatment process system should be determined according to the characteristics of different alloy, so as to obtain the heat treatment effect.

Most marine titanium alloys have excellent welding properties. Alloy application process, according to the characteristics of all kinds of alloy, the working condition of the structure, correct design joint form, reasonable selection of welding materials, make reasonable welding process, provide welding high temperature area good, reliable gas protection and correctly eliminate stress measures, is to ensure that the comprehensive performance of Marine titanium alloy welding joint.