EFFECT OF STRAIN RATE ON CORROSION OF SOME SHEET METALS.

Investigations have been carried out to evalaute the corrosion rates of hydraulically bulged and explosively formed products deformed to failure and as annealed sheets of 0. 11%C steel, 65 : 35 brass, commercial copper and aluminum in sodium chloride medium. A hydraulic bulge testing apparatus has been designed and developed for deforming blanks of thin sheets under balanced biaxial loading at a low strain rate. The corrosion rate of hydraulicaly bulged specimens have intermediate range of values, higher than the as-annealed materials but lower than the explosively formed products. The results are comparable with the data reported by other investigators. It is concluded that the corrosion susceptibility of these materials is markedly increased with the strain rate of cold working. It is recommended that this enhancement of corrosion susceptibility of the products can be economically eliminated by normalizing.