Define "Root Pass"

By Michael Baker Date 07-28-2008 19:45

Hello
My students and I, are trying to define the term, Root Pass, and where it is used. AWS, says, The first weld made into the root of the joint. I agree, How-ever, Define "Root of the joint", that comes back, Root Opening. My old school thinking, says, there must be a root opening, with or without, backup bar, such as Pipe test or Plate test. My students,claim, Root pass, is the first weld made of any multi-pass weld, to include T-joints. I disagree, and they would love to prove me wrong.
Michael SVC

By ssbn727 (*****)

Date 07-28-2008 20:53 Edited 07-28-2008 21:12

Hi Michael!!!

Page 32, right column, AWS A3.0:2001 - "Standard Welding Terms and Definitions" states: "ROOT PASS: A weld made to produce a root bead." which then leads us to go define root bead which is found on the same page, same column...

"ROOT BEAD: A weld bead that extends into or includes part or all of the Joint Root." which leads us to go define Joint Root...

"JOINT ROOT" found on page 22, right column: " That portion of a joint to be welded where the members approach closest to each other. In cross section, the joint root may be either a point, a line, or an area. See figure 4 on page 50. I'm not going to post it without permission from the AWS so, I cannot help you there but if you have a copy of AWS A3.0 2001, you can find it in the pages referenced.

Also, on page 44, right column, you'll find the definition for "Weld Root" which was also referenced in the term "Root" on page 32...
"Weld Root: The points, shown in cross section, at which the weld metal intersects the base metal and extends furthest into the weld joint. See figures 24 (B)-(E), 24 (H)-(K), 24 (M)-(P).

I hope this info helps out in the clarification of the differences between standard & non-standard terms and definitions.

Respectfully,
Henry

By Goose-em (**)

Date 07-29-2008 00:41

Root pass is the first pass made in the joint.

Fillet welds requiring only one pass. This pass would technically be considered the root pass.

If a T-joint requires more than one pass the root pass would be the first pass. Your students are correct in their thinking.