AWS D1.1-2004: Ref 3.6.1

By tab_1999 (**)

Date 01-03-2005 17:08

Hi Pedro,
Study the Essential Variables to get you on the right track.
You may need to use larger wires, amperages or finish a weld with another process.
Maybe your required to put the root pass in using the shielded metal arc welding process and finish the groove with a semi-automatic process. e.g. FCAW / SAW
GTAW / SMAW

By Pedro Coloma Date 01-03-2005 20:22

Ok, Let me try to propose an example:

A contractor uses two Prequalified WPS:

1. Process: FCAW, Filler metal classification: E71T-11,Type of joint:B-U2-GF, Position:V,Base Metal Classification: ASTM A572 Grade 50, BM Thickness: 1/2" ( permitted by Table 3.1),Minimun Preheat Temp.:20 ºF

2. Process: SMAW, Filler metal classification: E7018,Type of joint:B-U2, Position:V,Base Metal Classification: ASTM A572 Grade 50, BM Thickness: 1",Minimun Preheat Temp.:80 ºF

Now, this contractor is asking me for authorization in order to use:

3. Process: SMAW+FCAW, Filler metal classification: E7018+E71T-11,Type of joint:B-U2-GF ( or B-U2, it`s exactly the same), Position:V,Base Metal Classification: ASTM A572 Grade 50, BM Thickness: 1 1/2" ,Minimun Preheat Temp.:100 ºF

This is my opinion:
-B-U2 and B-U2-GF require the same joint design tolerances: NO PROBLEM
-There is a restriction in "Base Metal Thicness" with E71T-11 ( How does D1.1 deals with the " Weld metal thickness deposit" concept established in ASME IX? D1.1 establishes the " Base metal thickness" concept apparently); So I`d accept only the following combination: 1" E7018 + 1/2" E71T-11. But , because of productivity, maybe, it does not make sense to use it.
-Minimun Preheat Temp.:100 ºF : NO PROBLEM

What do you think about it?

Pedro

By DGXL

Date 01-03-2005 21:14

Pedro:
Didn't you try this one in the Forum recently?

1.) Where are you finding the 1/2" thickness limitation for the FCAW? To my knowledge there is no stated thickness limitation other than the code minimum (1/8").

2.) There are maximum prequalified weld bead/pass thicknesses and bead and layer widths specified in Table 3.7 of the D1.1 code.

3.) Prequalified SMAW details may be used for FCAW and GMAW in accordance with 3.11.1 of the D1.1 code.

By tab_1999 (**)

Date 02-04-2005 04:10

The 1/2" must be limited by the procedure they submitted.
I'm thinking that if you stay with in the thickness ranges of the WPS you will be ok.

By MBSims

Date 02-04-2005 04:34

Dave,

The 1/2" limit is in Table 3.1 and applies to the "-T11" classification. I would say that E71T-11 is not prequalified for use on base metal thicknesses greater than 1/2", even in combination with another process. The word "thickness" in Table 3.1 refers to base metal thickness, not weld deposit thickness. It would not be permissible to weld 1" with SMAW and 1/2" with E71T-11 in a 1-1/2" thick base metal.

By DGXL

Date 02-04-2005 06:00

MBSims/Pedro:
Good call by both. Never noticed the "fine print" for those classifications in T 3.1.

I have never used or qualified procedures/personnel w/-11 electrodes as here in CA we require 20 ft-lbs. @ -20*F. The A5.20 spec. denotes it may be used up to 3/4" and thicker with preheat/interpass temp. control. -11 has no impact requirements.

Maybe I should start drinking coffee again.