Corrosion resistant CuZn alloy

A CuZn alloy, the alloy having a Zn content of from 15 to 55% by mass, the balance being Cu and inevitable impurities,

• the CuZn alloy consisting of
• (i) a total content of Zn and Cu is 99.995% by mass or more,
• (ii) a number of pores is 1/cm2 or less based on optical microscopic observation, and
• (iii) a content of P of 0.01 ppm or less, and
• wherein the CuZn alloy has a weight loss of less than 2 mg/cm2 after 60 minutes of feeding a 10 mm×10 mm×10 mm sized sample into 500 mL of aqueous fluonitric acid solution at 25° C., said aqueous fluonitric acid solution is a solution prepared by mixing 20 mL of 46% hydrofluoric acid, 60 mL of 65% nitric acid, and 420 mL of pure water;
• wherein the CuZn alloy is subjected to hot forging where the CuZn alloy is drawn in a longitudinal direction so as to reduce a cross sectional area of an ingot to 60 to 80% of the original cross sectional area at a temperature in a range of from 600 to 900° C.;
• wherein after the hot forging step the CuZn alloy is subjected to hot isotropic pressing at a temperature in a range of from 450 to 650° C. for 1 to 8 hours under a pressure of from 100 to 200 MP;
• wherein the CuZn alloy is subjected to the hot forging step and hot isotropic step without being subjected to extrusion;
• and
• wherein after the hot isotropic pressing step, the CuZn alloy is subjected to annealing at a temperature in a range of from 500 to 700° C. for 0.5 to 4 hours by air cooling or furnace cooling.