Abstract:

In order to obtain large and light supporting frames by replacing spheroidal graphite iron with Al alloy , an indirect squeeze casting system of supporting frames was designed. The processing simulation and design were then carried out , and the dies of the frames were fabricated. Moreover , the supporting frame castings of AI-Cu-Mn alloy were trial-produced , and the defects in the trial production were analyzed. Finally , the mechanical properties and microstructures of the specimens from the castings with T5 heat treatment were discussed. The results show that , by shortening the cycle and reducing the moisture of lubricants , high-quality supporting frame castings without pores and inclusion can be fabricated , and that the castings are of good mechanical properties , dense microstructure and fine grains , whose average tensile strength , elongation and crystal size are 388 MPa , 8. 7 % and not more than o. 08 mm. All these above-mentioned results indicate the feasibility of the designed indirect squeeze casting system and the selected processing parameters.

Key words: supporting frame, indirect squeeze casting, AI-Cu -Mn alloy, processing design, microstructure, mechanicalproperty