Titanium has high specific strength, resistance to seawater and marine atmospheric corrosion, non-magnetic, sound-permeable, anti-shock and good workability, etc. It is a high-quality ship material. For ship materials, welding is an important processing method for its structural manufacturing. The adaptability of various marine titanium and titanium alloys to the welding process and the quality of the welding performance are directly related to their application in the ship structure.
There are many types and brands of titanium materials, and their performance requirements are different for different application fields. The main application functions of 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 application range of titanium materials in the field of ships, such as ship structures, propulsion systems, power systems, electronic information systems, auxiliary systems and special devices, etc., titanium alloy materials with various performances and specifications are required.
Marine titanium and titanium alloy welding generally follow the principle of equal strength and obtain the best combination of strength, plasticity and toughness. Therefore, when selecting welding materials:
① Generally, homogeneous welding materials are used;
②In order to improve the plasticity of the joint, a welding material with a slightly lower alloying degree than the base metal can be used;
③In order to improve the weld metal plasticity, the content of gap elements in the welding wire should be lower than that in the base metal.
According to the regression analysis of the application results and test data of marine titanium alloy welding for many years, it can be known that to obtain the equal strength of the weld metal and the base metal, the welding wire alloy composition is generally required to be 1 Al equivalent lower than the base metal. In order to control 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 alloy welded joints is largely related to the structural shape of the joint. For the stress relief heat treatment of the marine titanium alloy welded structure, 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 welding performance. In the application process of alloys, according to the characteristics of various alloys, the working conditions of the structure, the correct design of the joint form, the reasonable selection of welding materials, the formulation of reasonable welding processes, provide good, reliable gas protection in welding high temperature areas and correct The use of stress relief measures is the key to ensuring a marine titanium alloy welded joint with excellent overall performance.
Welding of Marine Titanium and Titanium Alloy
