Weld Metal Thickness Question

You don't state what configuration you are welding. Is it butt welding 2 pieces side by side, 2 pieces in a "T" shape, are you chamfering the edges, etc.?

2.4mm only represents the diameter of the filler rod. You can build the weld up to whatever thickness you want. If I have 1/8" filler rod I can keep on adding it onto itself to whatever thickness I want it to be such as 1", 1-1/2", 2", etc. It will be ugly and nonfunctional but it can be done. YOU determine what thickness you want it. Thats one of the great things about welding. Same with both both GTAW and SMAW.

For your final capping it is most often of the same dimension that makes the total weld thickness the same thickness as the metal piece. But again, it is whatever you want it to be.

Old Salt

There are many missing links in your query. However we assume the following factors.

1. The joint is a single V groove butt joint with 30-35⁰ bevel angle per side

2. The root gap is 2.0 mm min. since U are using 2.4 mm filler wire for root pass.

3. The root land is app. 1.50 mm since it is a TIG process.

4. The position of the joint is down /flat.

5. The material used is Carbon Steel.

6. The Current selected and travel speeds are normal.

Since all above factors contribute to the thickness of the bead, The bead thickness may vary and need not be the same of filler metal thickness. It could be less or bit more after weld completion.

For example the 2.40mm thick filler rod need not necessarily give the same 2.40 mm thick weld bead . IT may be less (2.00 mm) or more also depending upon your travel speed and current selection. On same basis the 3.20 mm electrode may give around 3.00 to 3.50 mm thick bead thickness.

Further you have forgotten to add the Root penetration and Face reinforcement requirements. We assume the penetration will be app. 1.00 to 1.50 mm and reinforcement on the face side be app. 1.50 to 2.00 mm.

Considering all above factors, the total thickness of the weld metal could be {7.11 plate (+) 1 to 1.50 mm root (+) 1.50 to 2.00 mm reinforcement} 9.50 to 10.50 mm and not 7.11 mm as you assume.

Hence you may get,

1. root with 2.40 mm thick filler rod (+)

2. first filler pass with 3.20 mm size electrode and (you should use bit slower travel speeds to increase the bead thickness to 3.00 mm or so) - to eliminate the 4th pass

3. final cap pass again with 3.20 mm and not with 2.40 mm electrode. A slower pass speed with weaving pattern will help to increase the bead thickness and also cover up the toes to avoid undercuts.

4. If your find it difficult to complete the welding in 3 passes, then you can use 2.40 electrode for 1st and 2nd filler passes (with faster travel speeds) and 3.20 for final cap pass.

5. If it is SS then the root gap could be 3.00 mm and first filler pass to be done with 2.40 mm and balance 2 passes with 3.2. mm electrode.

Trust above details are clear.

Sridhar

Dear Sridhar and Old Salt,

Thank you very much for your detailed reply. Base on the conditions stated as above, during the PQR i will need to draw a diagram showing the groove and beads and indicate the weld thickness of each layer of beads.

For the root pass, what should my deposited weld thickness be? For each intermediate pass what should my deposited weld thickness be? For the capping, what should my deposited weld thickness be?

To sum it up, what is the deposited weld thickness of my GTAW and my SMAW? How should i take such readings?

Thank you very much

REgards,

Jess

It is not required to show the bead thickness for each and every pass of the weld while doing PQR. You have to show only the root penetration, (+) base metal thickness (+) reinforcement.

But if you are very particular, then you can show it as:

1. For root bead with TIG, the bead thickness is 1.00 mm and show the root penetration as 1.50 mm

2. For first filler pass as 4.00 mm

3. For cap pass 2.20 mm and show the reinforcement as 1.50 mm

4.Show thickness tolerances as ± 0.50 for root and face reinforcement.

sridhar.

Dear Sir,

I would like to ask if there is any rule to define width of passes of weld. I mean to say that is it like root pass shall be 2% or 10% or any part of total weld width. If it is so then what is the rule?

If not, then can any thickness of each pass will do?

Regards,

Gautam