3G AND 4G qualified welder can do 6G welding

By gm hdec Date 04-18-2017 08:39 Edited 04-19-2017 09:57

3G AND 4G qualified (on 25MM THICKNESS Plate) welder as per AWS D1.1, can do welding above 24'' pipe in 6G position.(its Pile joint at offshore at 70°C ). we can not weld onshore because one steel pile's pilling finish and we have to weld another pile piece.

By Joey

Date 04-19-2017 02:47

6G position? 45deg Fixed. What type of weld you have in a pipe fixed at 45deg?
Very rare to weld a splice (butt) joint on a 24"dia pipe fixed at 45deg position. Why don't you weld it on the ground (1G or 5G) before erection. 3F & 4F will be enough if you are referring to fillet welding on base plate.

By gm hdec Date 04-22-2017 06:46

By pipewelder_1999 (****)

Date 04-22-2017 09:39

Are you asking? The production weld you speak of is not 6G. 6G is a test position.

A 3G and 4G test qualifies for All positions. Which would include any position on the referenced pipe joint within the other limits imposed by the code.

By gm hdec Date 04-22-2017 10:48

thanks, dear,
We qualified welder in 3G and 4G position as per AWS D1.1. on the plate thickness 20mm.
we have 02 pile joint size 32'' thickness 19.5 mm at position 70°, so we want to use the same welder.
but our client said the welder who qualified in 3G and 4G position. he qualified in only HORIZONTAL, VERTICAL AND OVERHEAD positon.
while AWS D1.1 mention qualify range for 3G and 4G is All position.

By Are Aye (*)

Date 04-22-2017 14:24

Hello gm hdeg,

Piling Joint positioned 70 deg like this?

Attachment: Jointing.jpg - Piling pipe (129k)

By welderbrent (*****)

Date 04-22-2017 14:09

The welder qualification limitations established by taking a 3G and 4G test is ALL POSITION. That includes all angles of welding. Which means that when welding on HSS, including pipe, over 24" they can weld in any and all positions.

This is accomplished for smaller diameter HSS by using the 6G because of the difficulty of welding in a groove that is at multiple angles all at the same time. That groove in the overhead, vertical, horizontal position all at once while trying to work yourself and the electrode holder around a small object can be tricky for many a newbie.

But, once the pipe is 24" or greater it is so similar to welding plate that the all position plate tests which are accomplished with the 3G and 4G test is all that is needed to prove the welders ability to produce sound welds in all positions.

ALL MEANS ALL THAT'S ALL ALL MEANS. A very common interpretation practice to be applied when trying to understand basic commonsense application of the code.

He Is In Control, Have a Great Day, Brent