Is there a specification, controlled process, or company who can do Pressure Welding?

We have a drawing which joins 4130 tubing to a 4130 forging, which calls for either flash weld or pressure weld. I understand this is a form of upset welding. Problem is, the drawing is fairly old and we don't know which process was actually used or how it was originally done. We have been advised that flash welding is impractical because there isn't enough room for the collar to fit on the forging side.

Any information would be appreciated.

Thanks