Furnace Brazing of Oxygen Free High Conductivity Copper to Silicon Steel

Abstract

Furnace brazing was carried out to produce joints between two different materials, Oxygen Free High Conductivity Copper [OFHC] type ISO C10300 and silicon steel (electric steel) type ASTM 36F145 by using two groups of filler metals were selected in this research, silver group type DIN L-Ag20Cd and copper group type AWS BCuP-1 with using flux type AWS FB3-A to remove oxide and protect the welding joint.
The brazing temperature for both filler was 790°C and 940°C respectively above liquidus temperature of them, then soaking at different time (10, 20,30,40,50, and 60min.) for each filler metal. The microstructures of cross section area of joints were revealed in optical microscope shows presence of different reaction in the brazed area.
The maximum double shear strength of dissimilar brazed joints was 47MPa by using filler metal AWS BCuP-1 at 30min. soaking time, while using filler metal DIN L-Ag20Cd give rice in double shear strength to 98MPa at 30min. soaking time due to better coalescence of the mating surfaces .The occurrence of solid solution and different types of intermetallic compounds such as Cu5Si, Fe3Zn10, FeZn10, Cu5Zn6, CuZn, CdCu2, Cd3Cd4, Cd3Cu, Cu3P,and α-Fe that is responsible for joint strength has been detected by X-ray diffraction inspection.