| TA10 alloys have excellent corrosion resistance,good mechanical properties and easy welding characteristics.Generally,they are used as anti-corrosion resistant materials in practical applications,and are often used in chemical industry,marine power generation facilities,seawater purification facilities,submarines and so on.But when the TA10 titanium alloy is in service in its acidic environment,the damage occurs at the joint without reaching the expected service time.In view of the problem that the welding quality of the TA10 alloy is not passed,the parameters of TIG welding(TIG)welding(TIG)and solidification structure and property evolution of 10 mm thick TA10 titanium alloy plate are analyzed and studied.It is hoped to find the best welding method for 10 mm thick TA10 plate,and to heat treatment and thermal hydrogen treatment of the joint,and to explore the effect of two kinds of post welding on the microstructure and properties of the welding joint.The main results show that:The study on the solidification structure of TA10 weld shows that the microstructure of the weld zone and the heat affected zone consists of acicular alpha + beta,equiaxed primary alpha and lamellar alpha + beta,and the coarse grain boundary of the original beta grain is clear and complete.In the central area of the weld,there are some fine needle like 'alpha' phases with different orientations in the original beta grains.The study of mechanical properties of welded joint found that with the increase of welding current and the decrease of welding speed,the average hardness of the weld zone and the heat affected zone increased.With the increase of the welding current,the strength of the joint increased and the elongation decreased,and the tensile fracture of the welding joint showed typical fracture characteristics of the Vivtorinox.The welding process parameters of TA10 titanium alloy plate with better 10 mm thickness are 130 A welding current,welding voltage 20 V,and welding speed of 10cm/min.The study on the joint microstructure after heat treatment and hydrogen treatment showed that,1)After annealing,the bright white area in the joint was increased,the black area was reduced,the grain size of the weld zone and the heat affected zone was still rough and the grain boundary became blurred.2)The boundary between the various regions of the welding joint was not clear,and the heat shadow was not clear by hot hydrogen treatment.The grain boundary between the grains in the ringing area becomes blurred.During the process of the center of the weld to the parent material,the transition characteristics of the large grain to the small grain are not obvious;3)There is a black strip and a dot like hydride in the hydrogen filled welding head.4)Compared with the original welded joint,the hardness peak value and the hardness of the hydrogen treated joints are slightly higher than those of the original welded joint.After hydrogen permeation at 750 /3h,the strength of the welded joint increases by 6.1% and the plasticity decreases by 66.7% compared with the original welding joint.The prevention and control measures of porosity in weld are mainly in the following two aspects: 1)restricting the molten pool to dissolve or generate gas;2)remove the gas existing in the molten pool.Clean welding materials,pay attention to welding environment,give full play to the effect of gas protection,find the most reasonable protective gas components,rule operation,develop more reasonable welding materials and other measures to limit gas integration or reduce gas production in welding process.At the same time,extend the existence of weld pool by controlling heat output and improving welding parameters,some operations and new technologies are added to increase the fluidity of molten metal in the molten pool,forcing bubbles to overflow and other measures to discharge the gas in the molten pool. |
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