What manufacturing processes were applied to SS Forged Fittings?

There are four processes of manufacturing a SS forged fittings. First is Mandrel method, as the name suggests a curved mandrel is inserted into a length of pipe. Extrusion Method consists of a machine that has the mould of the fitting into which the pipe inserted and come out in the shape of a fittings.

Next is the UO method in which a piece of sheet is cut out and then it is pressed on an anvil that has the inverted shape of a fittings. Hot Forming Method is somewhat similar to Extrusion Method, here a piece of pipe goes through a mould of the fittings and come out in the needed shape.