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Up Topic American Welding Society Services / Technical Standards & Publications / Question about AWS D1.1 Table 3.7 Layer Width!
- - By playboy1898 (*) Date 01-18-2012 11:13 Edited 01-19-2012 00:31
Dear All :

Happy New Year to You!

I have some question about AWS D1.1 Table 3.7 Layer Width:
I can not find the difinition for 'Layer Width' on AWS A 3.0. Also can not find in AWS D1.1.
1.Which width is the 'layer width'?
2.How to measure it?
When the Singel pass layer width is exceed the limitation(for example:5/8 in). we must split the layer!
3.When the layer width is 1 5/8 in, How to split it?
We only need to split this layer into 2  pass?  In this way the singel should over 1 in.
or 3 pass? the pass weld width also over 5/8 in. Becaus of the Overlap in each pass.
Should split it in 5 pass? Pls see the drawing!

Thank you Very much!
Parent - - By PWCameron (**) Date 01-18-2012 13:40
See "*layer" in Annex K
Parent - By 803056 (*****) Date 01-18-2012 14:07
The width of the layer is dependent on the welding process and the position in which the welding is performed.

In the case of SMAW, the width of the bead, i.e., layer, isn't restricted.

Al
Parent - By playboy1898 (*) Date 01-19-2012 06:46
Thank you very much!
I know the Layer.
But I do know  the difinition of layer With!
Parent - - By ozniek (***) Date 01-19-2012 12:30
Hi

Keep in mind that the variable is "maximum single pass layer width", so within this context, any of your sketches regarding the layer width that includes more than one pass would not be covered by this variable. Also note that there is an additional requirement for the bead cross section to not be any wider than it is at the top of the bead, (3.7.2) so any reference in your sketches to a width that is wider than the top of the bead is also not valid.

I think we should not get too complicated here. If the width you can measure on the surface of a layer, if it was to be made in a single pass, exceeds that specified in table 3.7, then you need to make it a multi pass layer. I don't think there is anything more to it than that. If the issue was supposed to be revolving around the maximum bead width, then surely they would simply have termed this variable "maximum bead width".

If this matter is very important to you, you could look through the interpretations to see if there is a more definitive answer.

Regards
Niekie
Parent - - By playboy1898 (*) Date 01-20-2012 00:39 Edited 01-20-2012 00:50
Hi Diekie:

Thank you very much.

Ok. I agree with you. When we welding the single pass layer, we measure the surface width of the bead, not the other place.
But it is very hard to forecast the bead width before doing the welding work! 
Especially for surface layer! Because of the extending of the two edges.

I still have some question.
If we do the multi pass layer, each pass or bead width is not restricted by this table 3.7!
We can weld the bead width exceed limitation of the Table 3.7?
You can see the drawing, can we welding the 2 3/8 in weld by 2 beads(pass)(:lol: theoretic only!!!!)?

Best regards!
David
Parent - - By ozniek (***) Date 01-20-2012 10:36
Hi

My interpretation is that theoretically there is not a limitation on the width of the weld beads once you are welding multi-pass. Practically there will be a limitation, because once you are welding an assymetrical bead, it will run all over the place if the weld pool is too fluid, restricting your ability to "place" it where it is needed. Visually it will be obvious that it is a poor weld.

It may be worth your while to look at the interpretations to see if this question has been asked.

Regards
Niekie
Parent - - By 803056 (*****) Date 01-20-2012 19:16 Edited 01-20-2012 19:40
D1.1, Table 3.7 lists the restrictions that apply to prequalified WPSs. The restrictions are based on the specific welding process used.

The table does not place limitations or restrictions on the width of an individual weld bead (or pass), only the thickness of the layer of each pass (or bead). The table does require a split layer technique when the width of the root opening or previous layer exceeds some value. Again, the limitations is dependent on the welding process and position employed. So, while the width of an individual weld bead is not addressed, the limitation on the thickness of a layer does so in an indirect way. However, the width of the individual bead is not tied to a specific value.

The attached sketch may better explain the intent of Table 3.7 as I understand it.

Best regards - Al
Parent - - By playboy1898 (*) Date 01-30-2012 01:23
Dear Al:

Thank you very much!

I am much more clear now!

But I still have some question:

1.When we do the PQR, we don't need to control or record the width of the singel pass layer!
If we use this PQR, we don't need to limit this layer width?

2. Why the code do not place limitations or restrictions on the width of an individual weld bead? But for single pass layer?  They want to limit the heat input? or others?
Parent - - By 803056 (*****) Date 01-30-2012 02:04 Edited 01-30-2012 02:13
The PQR is the "proof" or demonstration that what was done to weld the test coupon produced acceptable results, i.e., a sound weld with the appropriate mechanical properties. As such, you are establishing the parameters of what will and will not work.

The requirements of Table 3.7 only apply to a prequalified WPS. Any restrictions or limitations apply if the procedure is prequalified and no test sample is welded and subjected to testing.

You can do whatever you want if you are qualifying the WPS by testing as required by Clause 4. The limitations of Table 4.5 apply to the type of range of groove types,, groove details, welding parameters, e.g., voltage range, amperage range, etc. that is qualified by the test that passed. Even if you violate a restriction listed in Table 3.7, no big deal, they don't apply to a WPS qualified by testing. If you weld in the vertical position using a 4 inch wide weave, 3/4 inch thick, you have proven it works. You are then free to use it in production.

As for what information is recorded, the codes list the minimum information that must be recorded on the PQR. Personally, I record all the code required information plus anything I believe is germane to what I am trying to demonstrate. If my goal is to demonstrate I can deposit a 4 inch wide weave, I better record that on my PQR. If I'm demonstrating I can deposit a layer that is 3/4 inch thick, I will be well served to record the thickness of each weld layer. If I want to demonstrate I can weld with water soaked electrode, I better record how long the electrode was submerged underwater before being used to weld the test sample.

I typically record the welding parameters for each weld bead deposited, the number of beads per layer, which side of the joint they were deposited on, the heat input, the interpass temperature of each bead just before initiating the arc, etc. Is it all required to meet the minimum code requirements? No, not all the information is required. Some people might consider it to be overkill, but at the end of the day I can tell you exactly what was done, bead by bead, layer by layer and the results can be reproduced if challenged.

Best regards - Al
Parent - By playboy1898 (*) Date 01-30-2012 09:47 Edited 01-31-2012 00:18
Dear Al:

Thank you very much!

1. We also can do 4 inch width weave without the PQR. Only if we do the split layer welds and the total width is 5 inch or more! :twisted:

2. If we have finished the single pass layer welds exceed the max. limited width in table 3.7. How to deal with it? Scrap it? Remove it and reweld it? ( the more weld times the less strength, the quality of the welds are poor than the before). or other way? such as do a welding test?

3. How to restrict the weave width for welding technic? Weave width and bead witdh is the same things? We can not find the definitions on AWS Code also.  Is it related to the layer width?  or limited by layer width?

4. The AWS D1.1 have no figures. and have no difinitions about the layer width.  Put you drawings on it may be more clearly:lol::lol:!

5. According to your opinion, We only care/measure the layer width before the welding work. We don't need to foreseen the finished layer width?  so the width of the finished single layer welds may biger than 5/8 inch! It's right? But the Table 3.7 requires if the width is biger than 5/8 we shall spilte the layer! The code did not mentioned that this 5/8 inch is before welding or after welding work!

Best regards

David
Up Topic American Welding Society Services / Technical Standards & Publications / Question about AWS D1.1 Table 3.7 Layer Width!

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