Historically, Korea had to import steam and gas turbine bolting increasing costs and incurring long lead times.
Turbine housings are in 2 parts and bolted together using highly engineered fasteners.
In many applications these require to accommodate elevated temperatures and high pressures.
Typical fasteners used are THRU STUDS, TAP STUDS, COUPLING SETS AND DOWEL PINS.
These are applied to various turbine models by manufacturers like GE, SIEMENS, MITSUBISHI etc.