Backing with or without

Date 02-20-2012 19:23

Hello guys!

Everything good?

Can you help me in this interpretation:

Welding pipe -

OD: 100 mm
Joint design: Single-V-groove
Retainers: None
Groove angle (deg.): 75°
Root opening (mm): 0
Root face (mm): 1,5
GAS BACKING - YES - Argon

The question is as follows:

This welding is considered with backing or without backing, since there was a complete penetration.

Thanks for the help.

By TimGary (****)

Date 02-20-2012 20:10

The gas inside the pipe is called a "Back Purge".

The joint has backing if material is placed inside the pipe at the groove area with intent for it to catch or shape weld excess penetration.
This backing can be either permant or temporary, but cannot be gas.
Your weld sounds like it is without backing.

Tim

By GIOVANILOPES (*)

Date 02-20-2012 20:27

Thanks for the reply!

"Without backing" with opening root of the "0" mm?

The base metal in this case is not considered "backing"

Thanks.

By TimGary (****)

Date 02-20-2012 21:03

Nope.
Backing would have to be additional material, placed behind and to "back up" the weld joint.
Backing is primarily used with a root opening.
Joints without backing usually have little to no root opening and have a root face or "land" in order to help control penetration.

Tim

By ozniek

Date 02-21-2012 13:47

Hi

It will only be considered "with backing" if your weld in this instance was partial penetration. Given that the landing was only 1.5mm, this is not likely.

Regards
Niekie

By GIOVANILOPES (*)

Date 02-22-2012 22:02

Exactly.

Thank you all for the answers posted.

Giovani :grin:

By Solluz

Date 02-23-2012 22:53

Hi, There are different types of backing. AWS Standard Terms and Definitions defines backing as "a material or device placed against the back side of the joint adjacent to the joint root to support and shield molten weld metal. The material may be partially fused or remain unfused during welding and may be either metal or nonmetal. " Terms and Definitions defines "backing gas" as "backing in the form of a shielding gas employed primarily to provide a protective atmosphere." Example: ASME Section IX differentiates the two types of backing on their Suggested Format WPS form: The standard ASME Section IX form lists "backing" under the "joint" section (refering to metallic backing) and lists "backing" in the "shielding gas" section (refering to gas backing). What you have described is "inert gas backing", and yes it is a backing (in one of the two senses).

Best Regards,

Sol