The Future of Aluminium
Page 18
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ONE of the most outstanding post-war developments has been the increasing use of light alloys in the construction of goods-vehicle bodies, and many operators are reaping the benefits of the reduced unladen weight and increased payload they provide. Judging by those factors which now influence the sale of light-metal bodies, the only deterrent to the more general adoption of such material is its relatively high cost.
So far, none of the larger manufacturers has employed aluminium extensively in the, production of a standard model in quantity, but it may be incorrect to assume that this represents a settled policy. Advantages for large-scale production could outweigh the cost disadvantage compared with ferrous materials.
Basing a forecast of the more extensive use of aluminium and its alloys for vehicles on established practice in the fabrication of goods-vehicle bodies can, therefore, be misleading. If die-casting techniques were perfected, it should be possible to build a power unit mainly of die-cast components at a cost that would compare favourably with that of existing types, and although an equal production advantage cannot be envisaged with regard to bodywork pressings, the saving in machine power required might offset the higher cost, given the introduction of suitable tools.
In the case of the die-cast engine, the potential saving in machine cutting time is in the region of three to one, which would greatly reduce tooling costs and the machine-shop space required—an all-important consideration in many industrial areas. A substantial reduction in machine power for body fabrication by the use of light alloys would be possible only in the case of complicated shapes, such as pressings for integral bodies, but could apply to a large proportion of the lighter commercial vehicles. A difficult machine-tool problem in the production of the die-cast engine, particularly if full automation were achieved, would arise from the penetration of the swarf, carried by the lubricant suds, into the working parts of the machine, and a number of manufacturers are waiting with some impatience for a solution to this problem to be found. The advantage of the high cutting rate could be completely offset by accelerated wear of the machine.
Corrosion resistance of the available alloys is adequate for their use as cylinder-block materials, with the possible exception of isolated areas in this country and some districts overseas, where the quality of the mains water is such that fairly rapid corrosion of the water passages could be caused.
Production engineers are calling for improved welding and pressability properties for aluminium, and some service engineers are apprehensive with regard to the facilities that exist in garages for the repair of damaged light-alloy parts, particularly in respect of the beating-out of panels of workhardening metals.
The problems of introducing aluminium on a large scale are multiple rather than immense. That they could be solved is a certainty, provided that the light-alloy industry would match its efforts to the demand. Manufacturers, however, need an assurance that their difficulties are realized and that the supply of material would be assured at a cost keyed to realistic factors.
The demand for aluminium threatens to outstrip production, and a stable steel industry, the decisions of which have always been predictable and reasonable throughout the history of vehicle production, is not lightly to be relegated to the status of secondary supplier unless the younger industry can demonstrate that it is worthy of the trust.