Study On Squeeze Casting Processing And Heat Treatment Of 6061 Aluminum Alloy Bracket

6061 belongs to wrought aluminum alloy.It has wide wide range of solidification temperature and poor fluidity.When processed by traditional metal mold casting method,it is easy to form casting defects such as hot cracking,shrinkage and shrinkage cavity,skinning and under pouring.The use of the forging-type process can well eliminate the above-mentioned casting defects,but it will reduce production efficiency,increase production costs,and make it difficult to process complex-shaped parts.Indirect squeeze casting technology combines the characteristics of casting and forging: strong production flexibility,easy to shape complex parts,and suitable for mass production;parts are molded under high mechanical pressure,effectively reducing or even eliminating casting defects.This paper combines 6061 aluminum alloy and indirect squeeze casting to provide a certain reference value for actual production.In this paper,6061 aluminum alloy is used as raw material,and an automobile bracket is taken as research object,which is formed by indirect squeeze casting process.The effects of pressure,pouring temperature,injection speed and holding time on the microstructure and properties of the castings were investigated.The X-ray real-time imaging flaw detector,optical microscope,transmission electron microscope,Vickers hardness tester,electronic universal tensile tester analysis and testing methods are used to analyze the casting defects,microstructure and mechanical properties of the casting.Further heat treatment studies were also carried out on the castings formed by the optimal squeeze casting process.The test results show that when the pressure is 130 MPa,the pouring temperature is 690 °C,the injection speed is 0.20 m/s,and the holding time is 16 s,the filling is complete and the surface quality is good.The tensile strength and elongation of the castings with compact internal structure,fine grain and excellent mechanical properties can reach 174 MPa and 16.5% respectively;after heat treatment at 540 °C × 5 h + 170 °C × 8 h,the tensile strength of the aluminum alloy stent Strength,elongation and Vickers hardness can reach 310 MPa,10.4% and 109.6 HV,respectively.