Brazing Technology for Bimetallic (Ti64 & SS321) Glandless Valves
Glandless valves are special type of compact valves without glands / packing which are meant for service in submarines and ships having zero leakage. The valve is a special angle valve with titanium body and stainless steel adaptor. The body of the valve should be joined to the adaptor so that the joint is leak proof, easy to fabricate and should have adequate strength. Joining of titanium alloys to steels by conventional arc welding procedures and advanced solid‐state joining procedures is not successful due to the formation of brittle intermetallic phases FeTi and FeTi2.
The technology developed at DMRL involves development of sound joint between Ti64 titanium alloy and SS321 steel components with thread joint configuration which provides strength and metallic sealing by vacuum brazing using a suitable brazing alloy. The brazing procedure has been optimized with respect to the microstructure and bond strength of the joint with Ag‐Cu as brazing alloy. The valves have subsequently undergone the requisite tests and have been installed onboard.
Brazed Components
The novelty of the technology lies in selecting the suitable brazing filler material, brazing temperature and time. The knowledge can be adapted for any other application as well.
Other Applications
- Vacuum systems made of dissimilar metals for cryogenic engineering applications
- Transition joints between titanium alloy and stainless steel in chemical and nuclear industries
There is a huge market potential for production of valves with different configurations and supply to Indian defence programmes as well as is for various industrial applications
