I do a lot of vessel and heat exchanger rerates.  Often, the flange bolts are the limiting component.  I am currently looking at a TEMA flange that would be sufficient if I change the bolts.  The problem:  Bolts made of material such as SB 637 are not only hard to find, but they are very expensive ($7000 for a set).  Does anyone know of high strength studs that are common enough to be available and cost effective?  Thanks, TEEBOOG