65-35黄銅の引張強さにおよぼす予腐食の影響

Abstract

The effect of pre-exposure on the apparent tensile strength of annealed and/or cold rolled specimens of 65%Cu-35%Zn brass, which were pre-exposed to 2.5N ammoniacal solutions containing 0-40g/l Cu for 3hr at room temperature, was examined as the parameters with respect to chemical composition of solutions, pre-strain, grain size and cold reduction.The results obtained are as follows;(1) The decrease of tensile strength of both annealed and cold rolled specimens due to preexposure depended largely on the chemical composition of solutions, and the maximum decrease was found when thick black tarnished layer was formed.(2) The apparent tensile strength of annealed specimen was exceedingly decreased when the specimen was pre-strained at yield point.(3) The apparent tensile strength of cold rolled specimen increased with pre-straining.(4) The decrease of apparent tensile strength due to pre-exposure was nearly proportional to depth of corrosion penetration.