Titanium has the characteristics of high specific strength, resistance to seawater and marine atmospheric corrosion, non-magnetic, sound permeability, resistance to shock and vibration and good workability, which is a kind of high-quality ship materials. For ship materials, welding is an important processing means for its structure manufacturing. And a variety of marine titanium and titanium alloy on the adaptability of welding processing, welding performance of the advantages and disadvantages, directly related to their application in the ship structure.
Titanium varieties, grades, for its application in different fields, the relevant performance requirements are not the same. The main application function of titanium alloy for ships is 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 field of ships, such as ship structure, propulsion systems, power systems, electronic information systems, auxiliary systems to special devices, etc., and therefore need a variety of properties, varieties and specifications of titanium alloy materials.
Marine titanium and titanium alloy welding, usually follow the principle of equal strength, and get the strength and plasticity, toughness and coordination. Therefore, in the selection of welding materials:
① general selection of homogeneous welding materials;
② In order to improve the plasticity of the joint, can be used than the base metal alloyed slightly lower degree of welding consumables;
③ In order to improve the plasticity of the weld metal, the gap element content in the wire should be lower than the content of the base metal.
According to the results of research on marine titanium alloy welding applications over the years and regression analysis of test data shows that: to obtain the weld metal and base metal isotropy, generally require the alloy composition of the wire than the base material is lower than 1 Al equivalent. In order to control the content of impurity elements in the weld metal after welding at a low level, the original content of impurity elements in the wire should be strictly controlled. The reliability of marine titanium alloy welded joints is largely related to the structural shape of the joint. For marine titanium alloy welded structure stress relief heat treatment, should be based on the characteristics of different alloys, determine the heat treatment process system, in order to obtain the heat treatment effect.
Most marine titanium alloys have excellent welding processing performance. Alloy application process, for the characteristics of various alloys, the structure of the use of working conditions, the correct design of the joint form, a reasonable choice of welding materials, the development of a reasonable welding process, to provide a good welding high temperature zone, reliable gas protection and the correct use of stress relieving measures is to ensure that the comprehensive performance of the marine titanium alloy welded joints is the key to obtaining excellent.
