ANALYSIS FOR LEAKAGE OF HEAT EXCHANGERS USING IN CENTRAL AIR-CONDITIONING UNITS WITH LITHIUM BROMIDE
溴化锂中央空调换热管泄漏原因分析

Absorbers of central air-conditioning units used by clients in factory A and factory B are made of pure copper tubes.After running for more than one year or even before formal usage,many cracks were found on the surfaces of these exchanger tubes.The reason for cracking was investigated by using optical microscope,scanning microscope and Energy-Dispersive X-ray spectroscopy(EDX).Results revealed that the cracks on the tubes was caused by stress corrosion cracking,which was the result of joint action of residual stress and lithium bromide solution containing oxygen.Under the condition of existence of oxygen,bromine ion can induce pitting and promote stress corrosion cracking.Validating tests reproduced the appearance of cracks.