Titanium has the characteristics of high specific strength, resistance to seawater and marine atmospheric corrosion, non-magnetic, sound-permeable, shock-resistant vibration and good processability. It is a high-quality marine material. For marine materials, welding is an important means of processing for its structural construction. The suitability of various marine titanium and titanium alloys for welding processing and the welding performance are directly related to their application in ship structure.
There are many varieties and grades of titanium materials, and their related performance requirements are different for different fields of application. The main application functions for marine titanium alloys are excellent corrosion resistance to seawater and marine atmosphere, high specific strength, high toughness and excellent processing performance. Due to the wide range of applications of titanium in the marine sector, such as ship structures, propulsion systems, power systems, electronic information systems, auxiliary systems to special equipment, titanium alloy materials of various performances and specifications are required.
When welding titanium and titanium alloys for ships, they usually follow the principle of equal strength and obtain the best strength, plasticity and toughness. Therefore, when using welding materials:
（1）generally use homogenous welding materials;
（2）In order to improve the plasticity of the joint, a welding material having a slightly lower degree of alloying than the base material may be used;
（3）In order to improve the weld metal plasticity, the content of interstitial elements in the welding wire should be lower than that in the base metal.
According to the regression analysis of the research results and test data of marine titanium alloy welding for many years, it is known that in order to obtain the equal strength of the weld metal and the base metal, it is generally required that the wire alloy composition is one Al equivalent lower than the base material. In order to keep the content of impurity elements in the weld metal after welding to a low level, the content of the original impurity elements in the welding wire should be strictly controlled. The reliability of marine titanium welded joints is largely related to the structural shape of the joint. For the stress-relieving heat treatment of marine titanium alloy welded structures, the heat treatment process system should be determined according to the characteristics of different alloys to obtain the best heat treatment effect.
Most marine titanium alloys have excellent weldability. In the application process of the alloy, aiming at the characteristics of various alloys, the working conditions of the structure, correctly designing the joint form, reasonably selecting the welding material, formulating a reasonable welding process, providing good and reliable gas protection in the welding high temperature zone and correctly The use of stress-relieving measures is the key to ensuring a welded titanium alloy welded joint with excellent overall performance.