Some Factors Affecting the Hot Working of Commercial Aluminium Alloys

Abstract

This project was concerned with some of the aspects of the hot working of commercial aluminium alloys. The topic was approached broadly from the three following areas of interest: i) An investigation of the temperature variation of a rolling slab as it passed through its rolling schedule was made. The investigation was tackled by a mathematical approach and the model formulated compared against experimentally determined cooling curves for commercially rolled slabs. ii) Rolling schedules were simulated using the hot compression test, and the structures produced were compared with those produced by industrial hot rolling. The simulation also allowed an investigation of structure changes early in the rolling schedule which is not usually possible in industrial rolling. iii) An investigation of some of the properties of a number of intermetallic phases found in commercial aluminium alloys helped in understanding how the hot rolled structures are formed. Also with the aid of energy curves it was possible to find a criterion which allows the division of commercial aluminium alloys into two groups. These two groups are usually called “soft” and “strong” by mill operatives depending upon their rolling characteristics. The shape of a plot of the slope of the energy curve for an alloy was found to be a good grouping criterion. The new grouping does not separate alloys purely on resistance to deformation during hot rolling but on a characteristic CHANGE in the resistance to deformation at some stage of the schedule.