How Many Welding Layers?

dear Wien

it is not a 3mm electrode (if you are using smaw electrode) it is 3.15mm electrode , generally in every single run it would deposit 1.5 times the electrode of material(3.15 * 1.5= 4.725 mm). (i am considering A 36 material) .

so it takes only 3 runs only .

Mahesh ,KEI

To give you a better answer, I need to know what you are using for material, the welding method you intend to employ, the filler alloy you intend to use, and what positions these weldments will be laid in. Remember that there are advantages to laying stringer beads in most materials.

Thank you for attention The plate mat'l spec is A516 gr 70 and will be welded with manual welding (SMAW) using E7016 or E7018 AWS class for electrode. There are 2 major positions of weldment I.e horizontal and vertical position. Further more there are two terms that I still in confuse, I.e LAYER and PASS. So please give me explanation how to calculate the number of welding layer or welding pass with clear definition of each. Thank you so much

Why don't you just have enough of the filler rod available to accomplish the task.

And have a competent welder on hand, who understands the difference between "LAYER and PASS"

And, have you Goggled?

First, given your base material, I would recomend that you use 9018 to match the material strength. As was previously stated, use 3.15mm for the root pass and 4mm for the filler passes. If this is to be a two-sided weld, ie; there will be weld preps to be filled from both sides, you will have the root and then two passes per side to fill. Since every boiler maker in the world welds vertical-up, you will very likely have this weld filled after root in a single pass running vertically, your procedure nothwithstanding. If the weld is all one-sided, root and four passes of staggered layers.

The difference between pass and layer is thus; envision ropes laying on the ground. you put three of them side by side. This is three passes forming one layer. Should you lay more on top of these, that would form additional passes in another layer.

Also remember that as you weld, you are melting not only your filler rod, but the material that you are depositing your alloy to. As a consequence, even though you can make a 12mm bead with 4mm rod, its accumulative effect is less because of dilution into the base material and / or other beads.

I disagree with using a 9018 which is usually a chrome-molly alloy type electrode on carbon steel plate such as 516 grade 70. While it is true that a 9018 would is a stronger electrode there is no need to use it on grade 70 material. A 7018 would be correct for this very common material.IMO

Both welds would take 3 layers normally. On the horizontal seams it would take 4 beads because of the position (2 bead cap) and on the vertical weld it would take 3 beads (1 bead cap as long as the cap is not wider than 1.5 times the size of electrode being used usually).

If your trying to asses time then look carefully at whether or not your going to have to run a bead on the inside of the tank. If your restricted to 7016 or 7018 those are "closed root" rods. Which means you will need to have access to the inside of the tank to back-gouge and weld. Most times you would use 6010 for an open root or tig the root in. This would give you the advantage of full pen. weld with back beading, Then follow up with 7018 as a filler and strength.We are dealing with a tank from hell now. The welding procedures where not spelled out in the prints that made it to the shop. They were general, as to the size of the weld and wire but left the procedure itself open. This was not what was supposed to happen we've had to gouge and weld the tank 3 times. All because of a paper shuffle. Be sure that the necessary procedures are included in your paperwork.

Hi...

You can finish this welding in 3-layers and a total of 5passes.

Use 3.15mm dia electrode for the root and 4mm dia for the filler runs. This is suitable for both 1G & 3G weld positions.

I had an acquaintance working in a ship yard. They were expected to weld 1/2" plate in one pass. I do not know any of the details except it was very challenging for the welders.

Hi...

I can be done. GMAWC process (CO₂ pure shielding gas) welding is a good option. It is widely used also much cheaper than the SMAW process which is worse as far as economics of large weld deposits are concerned. The initial question was however pertaining to SMAW.

They were probably using an iron powder electrode like 7014 or 7024 which were the closest things to wire welding before they had wire welding. These are designed as fast-fill electrodes that are meant for flat welding, though the 7014 will work by spec to 45 degrees down. I have seen 7014 used in all positions, though you lose the benefits of its fast-fill properties. And unless your skill level is high, you end up with a nasty weld.

According to aquantance of mine who worked in the shipyards during WW II, they laid keels with big three foot long, screw together electrodes of 6010. There was so much arc energy that they had to lean on the electrode holder to hold it to the work.

What I would like to know is, why have you been asked to weld any kind of tank if you don't have the necessary welding knowlege?

Spencer.

The 7018 electrodes are the correct rod for this in these positions. I would suggest using 1/8" diameter although it would be somewhat faster with a 5/32" diameter if you had experienced welders that were used to carrying that much metal and heat on the thickness you are referring to.