High-Strength Friction Grip Bolt is called HSFG for short. 

It can be seen that the  high-strength bolts mentioned in our Chinese construction are short for high-strength friction pre-tightening bolts.

Bolts that are made of high-strength steel or require greater pretension can be called high-strength bolts. High-strength bolts are mostly used for the connection of bridges, steel rails, high-pressure and ultra-high pressure equipment. High-strength bolts applied to ultra-high pressure equipment need to be pre-stressed in order to ensure the sealing of the container.

The processing technology of high-strength bolts is: hot-rolled wire rod → (cold drawing) → spheroidizing (softening) annealing → mechanical descaling → pickling → cold drawing → cold forging forming → thread processing → heat treatment → inspection.

It seems very complicated, right? Yes, so high-Strength Friction Grip Bolt is relatively expensive.

So when your supplier gives you the quotation of it, please be more tolerant to them.