Spinning-punch new technology for aluminum alloy plate-wheels forming
The aluminium alloy plate-wheels are a new kind of wheels with light-weight, energy-saving and environmental protection. Spinning is a conventional technology to form aluminium alloy plate-wheels, but the outline dimension and run-out of rolled lip in end face are difficult to meet the exacting requirements of wheels blueprint. So the new spinning-punch forming technology for aluminium alloy plate-wheels was researched and simulated. 3-D elastic-plastic finite element models were constructed and appropriate boundary conditions were given out. The results show that aluminium alloy plate-wheels with good quality can be formed by spinning-punch forming technology through controlling roller feed rate, roller'diameter, flanging times, and punching stroke, etc. And the relationships between spinning load and roller'diameter, rolled lip forming quality and flanging times are found.
Influence of nominal reduction of the blank radius per path on the neck spinning of oblique tubes
The process of the neck spinning of oblique tubes is simulated by means of the 3D elastic-plastic finite element software, MSC.MARC. The dynamic boundary and contact problems in simulation are solved. The characteristics of the metal flowing, the distributions of the stress and strain, the possible defects and areas during spinning are obtained. The influence of the nominal reduction of the blank radius per path on the metal flowing and deformation is also researched theoretically and experimentally. It shows that the nominal reduction of the blank radius per path has great influence on the neck spinning process of oblique tubes. A reasonable nominal reduction of the blank radius per path is very important to guarantee the proceeding of the spinning process and to obtain a sound products.
Effect of specimen orientation and welding on the fracture and fatigue properties of 2195 Al–Li alloy
Abstract In view of the use of 2195 Al–Li alloy in the construction of super-light-weight external fuel tank of space shuttles, bulkheads of reusable single-stage-to-orbit launch vehicles and in combat ground vehicles, the dependence of tensile properties, fracture toughness and fatigue resistance of this alloy on the specimen orientation and welding is very important and was studied. The T8 base alloy, with primary strengthening precipitates of T 1 (Al 2 CuLi) phase, contained mainly brass-type texture. After welding with AA 4043 filler alloy, the fusion zone (FZ) consisted of T (AlLiSi) phase and in the heat-affected zone (HAZ) T 1 phase was replaced by T B (Al 7 Cu 4 Li) phase, and micro-cracks were observed. The post-weld heat treatment (PWHT) resulted in the spheroidization of primary T phase and the precipitation of more T particles in the FZ, and the dissolution of T B phase and the re-precipitation of T 1 phase in the HAZ. The yield strength, fracture toughness and fatigue threshold of the 2195-T8 alloy was observed to depend on the specimen orientation, with the lowest values obtained at 45° to the rolling direction. Welding resulted in a reduction in the tensile properties and fatigue strength. The post-weld heat treatment enhanced the yield strength, but no increase in fatigue strength was observed. Fracture mechanisms in various cases were evaluated by SEM examination of fracture surfaces and are discussed.