Hi guys,

I'm new to this welding stuff, I noticed some welds from full race that have a nice weld inside a sch 40 pipe. I tried purging with argon and it didn't get the penetration needed to look like that. Do they leave a little gap then weld it? or is it just a but joint with some trick to it? Also you know the color that they get from every three or four beads, how is that done? I looked through a lot of old post but couldn't find anything. help please....i want to get a little better

 

You need to bevel the pipe with a 1/16" land so that you can get full penetration without burning the metal. An argon purge will work fine once you get the puddle to go to the backside of the weld. You want to aim for a gold color to the welds for stainless and a small heat affected zone (HAZ) around the weld.

 

And, although it's commonly thought of otherwise, you don't have to weld the entire thickness in one pass. In fact, in every industrial welding job I've ever had, they'd be rather upset if we welded it in one pass. Military weld specs require 2 passes, at least. On sch10 pipe, I'd probably make 2 passes. One would just be focused on getting the inside root pass to look nice. The other would fill the bevel and put a nice final pass on the outside.

Notice in the weld below, this is the "root pass." There was no effort made to fill the bevel, only to put a nice bead on the inside. (this is carbon steel)

 

Engloid...On my second pass when welding sch 40 pipe i notice alot of time i have trouble keeping a nice color like the initial pass...any tips or advice? Gas/Amps are all kept the same..