Analysis of Stress Corrosion Cracking of Beryllium Bronze Spring Flake

The spring flake of a sensitive switch cracked during working. Appearance observation, energy spectrum analysis, microstructure inspection and hardness testing were performed. Then simulated testing for intact spring flake was carried out. The results show that the crack of spring flake is stress corrosion crack. The corrosion medium derived from the remaining flux containing NH4Cl at the welding point belween long contact flake and socket. By using ZnCl2 and glycerin to substitute as flux containing NH4Cl, the cracking of the spring flake has been effectively prevented.