Thanks for all the suggestions.

I am of the school of thought that says that it is better to weld first then roll rather than rolling first, except in the case of titanium to titanium which, of course, is not welded with filler wire. This is because gasses build up behind the weld, and with a un-rolled tube they can escape along the tube toward the rear of the tubesheet, while with a rolled tube, they have nowhere to go and build up pressure, which will push out through the molten weld metal causing a pinhole. Now, that said, there are those who swear by rolling first then welding, and cite years of experience with a variety of metallurgies using that procedure, so who am I to argue with their success. I wanted to present the other side of the arguement for the original poster's consideration. rmw