Abstract:

From the actual production of brazed electrical contacts in the field of low voltage electrical apparatus,the principle is analyzed for the frequently unqualified products combined with the ultrasonic testing and metallographic diagrams.It’s determined that the major reason for the unqualified product brazing rate is that the contact grid-like welding surface structure is not conducive to the spreading,wetting and interaction of the liquid solder to the base metal.The four different welding surface structure design contacts for brazing used.After welding,the appearance,brazing rate,metallographic structure and shear strength of the electrical contacts are compared and analyzed.The results show that the welding effect of striped contacts on welding surface is better than that of flat contacts and grid contacts.The shear strength range is (140.1±3.6) MPa,and the brazing rate range is (95.11±3.66)%.

Key words: electrical contact, brazing, shear strength, striped welding surface