Vacuum Brazing is widely employed in joining incompatible materials such as Ti alloy and stainless steel. In the present work connector joint is proposed to be achieved by combining thread joint configuration which provides strength and metallic sealing by vacuum brazing using suitable braze alloy.

Initially brazing alloy and parameters were optimized by evaluating microstructure and shear strength properties. Active metal braze alloys as 72Ag–28Cu(Bag8 ) and 63Ag–35.25Cu 1.75Ti(Cusil ABA ) in wt.%, were selected as filler metals in the present study.

Ti base braze alloy (TiCuNiZr) which has melting point lower than 8500 C is also chosen for comparative study. The microstructure of joints showed that all the filler metals interact with steel and titanium, forming different kinds of intermetallic compounds such as CuTi, Cu2Ti, Cu4Ti3, and FeTi.

The presence of intermetallic compounds at the interfacial regions strongly affects the shear strength of the joints.

Based on these results, BAg8 has been selected for carrying out joining trials of threaded component. Brazing trials were conducted for evaluating spreading and flow of braze alloy in the entire threaded area. Furthermore, these brazed components were subjected to pressure test.

This article is shared by Amit Kumar Singh and G Madhusudhan Reddy from Defence Metallurgical Research Laboratory, Hyderabad.