Grey-Fuzzy Logic Based Approach in Multi-Response Optimization of Semi-Solid Forging of A356 Aluminium Alloy

This paper presents an effective approach for the optimization of the semi-solid forging process of A356 Al-alloy based on the orthogonal array with the grey relational analysis and fuzzy logic analysis. Through the grey-fuzzy logic analysis, the optimization of complicated multiple performance characteristics can be converted into the optimization of a single grey-fuzzy reasoning grade. In this semi-solid forging process of A356 Al-alloy, the forging process parameters, namely the forging temperature, percent deformation, and die temperature are optimized with considerations of multiple performance characteristics including the tensile strength and hardness. The experimental results for the optimal setting have shown that the above performance characteristics in the semi-solid forging process of A356 Al-alloy can be improved effectively together through this approach.

Screw Forming by Semi-Solid Forging of Aluminum Alloy A7075

This paper reports the screw forming of aluminum alloy A7075 by semi-solid forging. The experimental devices are a servo press machine and a die cushion. The program motion was used for forging. The nominal diameter of screw is M10. The molten aluminum alloy A7075 was stirred and then semi-solid forged into a female screw under 40 tons with 10 seconds holding during forging. The solid phase rate was 0.3. The microstructure of the specimen that is isometric crystal had sphericalization, and refinement. In the results of compression test at room temperature, the maximum compression rate was 29.4% and the maximum nominal stress was 540 MPa. The screw tightening torque was estimated over 57.55 N · m by torque test. This value indicates for produced M10 screw that the strength is over strength category 8.8 of JIS. These results are indicated that the produced screw is suitable for general applications. In the results of optical observation, the male screw of die transferred to the aluminum forgings. And the surface of screw portion had crack free surface. In summary, screw forming by semi-solid forging of aluminum alloy A7075 was possible.

Semi-Solid Forging of Mg Alloy AZX1311 and Mechanical Properties

This paper describes basic property in semi-solid forging method of magnesium alloy AZX1311. In the semi-solid forging process, an arbitrary fraction of solid is selected at a temperature between the liquidus and the solidus line and rapidly cooled and coagulated simultaneously with deformation of the material in a die to obtain a product. In addition, the magnesium alloy AZX1311 has excellent castability and mechanical properties. In recent years, the use of magnesium alloys for home electric appliances and automotive parts has been increasing because weight reduction can be achieved. These main manufacturing methods are casting and forging. However, these manufacturing methods have disadvantages such as large forming load and poor dimensional accuracy. Therefore, the semi-solidification forging method can improve these disadvantages. In this study, a forged semi-solid material and air cooled semi-solid material were produced using a servo press machine. Focused on impurities, porosity and microstructure. A forged semi-solid material could be produced. A semi-solid structure could be observed.