The Development And Application Research Of High-performance Aluminium-steel Composite Transition Joint

Explosion welding can be a simple, efficient and effective way to large areas of high quality and various forms of the same or different metals, particularly the general welding method can't be welded metal provide an alternative methods and get populor of industrial sector. In the view of present shipping industry, Al-St transition joints exposed shortcomings, according to big warship design and construction requirements of Al-St transition joints requirements, developed high-performance new four layers of Al-Ti–Ni-St transition joints and five layers of Al-Al-Ti–Ni-St transition joints. Comparative study on four kinds of Al-St transition joints of welding performance and four kinds of Al-St transition joints welding compound interface temperature field around the release of the mechanical properties of its impact, and corrosion resistance, etc.Various performance indicators of Al-Al-St and Al-Ti-St combination can Satisfy basically the Al-St transitional connection problems of the civilian ships and small ships building. This study according to large ship design and application requirements, thinking of Ni as the intermediate between Ni-St layers, determine the possibility of new four layers of Al-Ti-Ni-St transition joints and five layers of Al-Al-Ti-Ni-St transition joints including the explosion welding process parameters and process. Contrasting each layer material thickness and weight provide new choose.for super light and high-performance transition joints .By using the Al- St transition joints connect upper aluminum architecture and steel will effectively improve the combination of the joint performance of the hull and corrosion resistance, improve working conditions, etc. However , when welding upper aluminum architecture and steel, the welding heat cycle will obviously influence the mechanical properties of the composite interfaces. This study adopts TIG welding of aluminium alloy and MIG welding of aluminium alloy welding on four different Al-St composite transition joints and aluminum alloy plate welding, research welding methods and welding process parameters inflence on composite interface temperature peak and the mechanics properties of four different compound transition joints. The results of the study show that, by increment of welding current of TIG welding of aluminium alloy, temperature of aluminum side and steel lateral interface are all increase, temperature of aluminum side interface peak higher than steel lateral interface peak. Under the same experimental conditions, interface temperature of both sides of the four and five lays transition joints was significantly lower than three lays transition joints, the instructions to select the middle layer of nickel has obvious advantagesThe results of shear strength and pulled off performance testing of Al-St transition joints before and after welding show that before welding the mechanics properties of four layers and five-layers transition joints are high advantage, after welding four transition joints are lower, the mechanical properties of traditional extensive use of two kinds of three layer transition joints of new thickness and width size conditions already can't satisfy performance requirements, and four layers and five layer transition joints who have high mechanics performance although have reduced, but still satisfy the requirements of operation. The addition of nickel intermediate layer reduces the peak temperature on the interfacial mechanical properties of transition joints.Corrosion potential testing results show that corrosion potential of Al-Ti-St compound transition joints and Al-Ti-Ni-St composite transition joints between aluminum and steel grassroots, accordingly in the forming corrosion battery conditions, the aluminum used as an anode corrosion, and steel grassroots under protection. Artificial seawater corrosion test results show that the aluminium alloy corrodes badly, pure titanium and pure nickel are non-corrosive and steel substrate slightly corroded. Coating protection is an indispensable anti-corrosion method of the transition joints in ship application.