WELD JOINT QUALIFICATION BASED ON THE GAP

By 803056

Date 02-04-2020 18:01

What code and what the hell is gap?

Al

By rakshithegde5 Date 02-04-2020 18:22

Clearance between the edges of the components or space between two components?

By 803056

Date 02-04-2020 19:22

And the code?

By SWN1158 (***)

Date 02-04-2020 19:25 Edited 02-04-2020 19:28

This space you speak of is commonly referred to as the root opening. You didn’t mention a code, but in the structural welding code, the gap (root opening) can’t exceed 3/16 “ except in cases involving either shapes or plates 3” or greater in thickness if, after straightening and in assembly, the root opening can’t be closed sufficiently to meet this tolerance. In such cases, a maximum root opening of 5/16” may be used, provided suitable backing is used. If the separation is greater than 1/16”, the legs of the fillet weld must be increased by the amount of the root opening, or the Contractor must demonstrate that the required effective throat has been obtained. At the beginning of your post, you mentioned a butt weld, but at the end, your question was about fillet welds.

By rakshithegde5 Date 02-04-2020 20:03

I am a rookie, just entered the Design field after my graduation.

Steel plates, i think welding code isD1.1? If not correct me and let me know what exactly is the welding code, To make the question more clear, i will be attaching a small drawing depicting what i wanted to say.

Plate thickness are 1.5".

Attachment: Capture.PNG (7k)

By 803056

Date 02-04-2020 20:26 Edited 02-05-2020 01:27

Who are you working for? Either the employer, if they are a design firm designing equipment, or the customer is responsible for determining what welding standard meets their needs.

If you have limited experience, you may not be in a position to specify what code is appropriate. We are by not means in a position to say what standard applies. We have no idea what the application is.

Al

By Jim Hughes (***)

Date 02-05-2020 17:42

rak****hegde5,
First, gap is an appropriate term used in all AWS and ASME codes. If it is D1.1 and you have a copy of that code you have two choices. Either your joint comes under a pre-qualified or qualified by testing. Since we don't know materials or application it's going to hard to help beyond this. If you can find out some more information, such as materials, thicknesses, code of construction, which can be narrowed down by telling us what this component is being used for, e.g. structural, bridge, or?? Bottom line? Once you know the COC (code of construction) then you will need to get a copy of it and read it. Your answers to your questions are in there. BTW welcome to the forum.

By SWN1158 (***)

Date 02-05-2020 19:49

To the best of my knowledge, the word “gap” is only mentioned in Section 9 Tubular Structures in D1.1. The poster said he thinks the code is D1.1, and mentions the “plate thickness are 1.5”, and the sketch provided doesn’t indicate that tubing is involved. As has been said, knowing the applicable code would be helpful.

By jwright650 (*****)

Date 02-05-2020 20:13 Edited 02-06-2020 11:56

I wonder if Plate #2 can be shifted to the left a couple thousandths (.0025") to get to a .1875" root? Then he could add the 3/16" to the required fillet weld size and all would be good.
Must not be structural steel if it's held to that close of a tolerance. (.0025") That's like building watches in the structural steel world.

Edit: .002 is half the thickness of a sheet of notebook paper

By welderbrent (*****)

Date 02-06-2020 00:14

WELDCOME TO THE ORIGINAL AWS WELDING FORUM!!! THE GREATEST WELDING FORUM IN THE WORLD...BAR NONE!!!

Where to start??

Having some hind sight as you now have posted an attachment so we can view what you have and being part of the latter end of this discussion, lets approach it this way:

1) 'Gap' is a non-standard term and as such has broad interpretations and applications that could easily confuse the discussion. One would need to know exactly what it is that is being termed a 'gap' and what code is being referenced in order to understand what you are asking. In some cases it is a valid description and in other cases it is totally incorrect and does not lend itself to being a proper adjective.

2) You can't expect us to tell you what the code is. That should be in your job specs and you should know it before you started work on the project. We are just needing to know what code you are working to to better understand your situation and how to assist you with your question.

3) In many cases, the measurement you give of 0.190 is over 0.188 (3/16") so it is unacceptable as a opening between faying surfaces. Sure, it is close, but the minimum standard of the code would say that it is unacceptable and needs to be brought into tighter tolerance. And again, we need to know which code as while this is true of D1.1:2015 it may not be true in other codes.

4) IF you can get that opening closer than 3/16" then you have a valid/compliant opening that will still need to have the fillet weld upsized in order to be of the correct strength value. If the weld were specified as 1/4" then you would have to add 3/16" to that and the resultant fillet weld would need to be 7/16". For engineering/design purposes you can not count any suspected weld fusion in the afore mentioned 'gap' and that weld where there is no fusion from the side is obviously not doing you any good so it is upsized to get a weld of the size that will have the strength to accomplish the load requirements that will be on the parts.

As I am not able to view all other posts from this screen, I will have to stop there for now.

Have a Great Day, Brent

By Tyrone

Date 02-07-2020 12:13

Poster said he just entered the field as a Designer.
I would think that would mean that he's the Customer creating the drawings and will call out which weld code.

As a new Designer, I suggest you familiarize yourself with the different codes, talk to your peers, understand the nuances of the codes and how they would affect the performance of your product.

Tyrone