Heat Exchanger
This power utility replaced ten existing studs and nuts on one of their high pressure feed water heaters.
The old studs had problems with thread galling and nut seizure, partly due to the material not being suitable for the 850° conditions. The old 4” diameter studs were made from a carbon steel only good for low temperature service. Superbolt® replaced the studs and recommended using a more common material for high temperature service. The old hex nuts were replaced with stainless, high temperature, Superbolt® tensioners.
The Superbolt® Multi-Jackbolt tensioners eliminate the risk of thread galling and seizing because there are no twisting forces acting on the threads.
Previous stud and hex nut used in this application. You can see the thread galling on the stud. |