Study On Electron Beam Welding And Tungsten-arc Inert-Gas Welding Techniques Of Shell Made Of Super-Strength Steel

This paper sets a project required by the development of Shell. The body of Shell not only has to endure great impact load in the process of penetrating the tamped earth, concrete and pebble bed, but also should not be deformed severely, so it requires very high intensity and plasticity. The design that super-strength steel of "D6A " and large length-diameter ratio and welding fabrication after being machined in segments are adopted in the overall design of the bomb shape. Therefore, to solve the problem of welding crack and to acquire high quality welding joint with high Strength, plasticity and flexibility are critical technology issue which determine the success of the overall design in developing and producing of Shell and it must be settled.For "D6A" super-strength steel, we calculated its the welding crack susceptibility, analysed its crack mechanism and compared manifold welding method. Aiming at the demands of this item, we establish the target, blue print and content of our research, and we made Electron Beam Welding technology research and Tungsten-arc Inert-Gas Welding technology research as emphases. We optimized the dependable and effective welding technology and after manufacturing Shell, we validated the dependability of welding technology, welding parameters and weld quality by concussion of Shell at last. Results are showed as follow:1. Calculating of welding crack susceptibility, Analysis of weldability and crack mechanism and welding technology experiment indicated that the weld joint of "D6A" super-strength steel is easy to break welding crack if the welding technology and welding parameters are not appropriate.2. In Tungsten-arc Inert-Gas welding technology research, we chose "H18CrMoA" welding rod to fill in and adopted reasonable technical measures. In result, the welding quality is up to "I" welding line, the strength is up to 1030 MPa and the toughness excels that of "D6A" base metal.3. In Tungsten-arc Inert-Gas welding technology, it is efficacious to prevent welding crack that "HlCrl8Ni9Ti" welding rod was adopted to lay the foundations, we adopted "HISCrMoA" welding rod to fill in, we cortrolled the temperature at 270^1, made matching post-weld heat treatment at 360t for one hour.4. In Electron Beam Welding technology research, we solved the problem that "D6A" steel is easy to accrue welding crack and gas porosity by optimizing welding parameters and adopting effective measures. In result, the welding quality is up to "IT welding line, the mechanical properties of the welded joint are equal to those of "D6A" base metal.5. In Electron Beam Welding technology, it is efficacious to prevent welding crack, gas porosity and ameliorate molding of welded joint to adopt "? deflexion function, optimiz welding parameters and lay the Electron Beam Focus 4mm underlying the surface of workpiece.6. By comparing and choosing, we found out the dependable and effective welding technology for developing and mass-produce of Shell.7. According to concussion, the structure made by Electron Beam Welding on the warhead works is feasible in the penetrating test, and the warhead kept in very good condition even the body of the bomb seriously deformed. This research solved the problem of the designer's worry about the vulnerable spot in the structure of the welding line. The satisfactory welding quality get a good opinion from the overall design organization.