A Study of Erosion-Corrosion in Aluminum Radiator Alloys 720009
The frequent occurrence of erosion-corrosion attack in service failures of aluminum radiators suggests the need for a rapid test which will predict erosion-corrosion susceptibility in aluminum alloys under conditions simulating those in an actual radiator. This paper describes a multijet test apparatus which has been used to compare the erosion-corrosion resistance of aluminum alloys in antifreeze solutions at 200 F. Impingement velocities of up to 130 ft/s have been used.
The effect of short-term jet impingement has been found to produce a mode of erosion-corrosion attack similar to that found in a 6951 alloy radiator after 40,000 miles of service. Attack appears to progress through several distinct stages starting with the development of a high density of pits which eventually become coalesced together at points of very high impingement velocity. The rate of attack has been found to be dependent on alloy composition and properties, jet velocity, and metal surface condition.
The test would indicate that the susceptibility of aluminum radiator alloys to erosion-corrosion failure can be predicted by the effects of high-speed antifreeze jets produced with the equipment described.