Analysis of Stress Corrosion of Brass Tube on Heat Exchangers

U shape brass tube bundle on heat exchanger cracked when it was having ammonia leak test. Sample was made from brass tube fragment, polished the surface of the sample, eroded it with solution of 5% iron trichloride (FeCl3) and 10% hydrochloric acid (HCl), then took photos with Nicon-300 metallographic microscope. The fracture is a kind of stress corrosion cracking, the reason of cracking was analyzed. The technology of test was improved, the method should be paid attention to during brass tube exchanger manufacture was given out too.