Controlling Distortion When Joining 25mm Plate By Arc Welding

Dear Steve

Try scallop welding butt end of the joint, turn over the plate same scalloping to be carried out on this end .

After scalloping is over, weld first pass on the same side. After completion of first pass, flip over and finish the other side with first pass.

Scalloping is tack welding but having longer distance of weld i.e 75mm of weld, then gap of 125 mm, again weld of 75mm.

Kindly revert with outcome.

Thanks

NDT

As guest says scallop [ stich ] weld & clamp down to a nice thick steel table. If v groove w/low H rod is like arc gouging, find a less heat intensive method. when laying down the stiches alternate, from end to end so the heat can dissipate.

" ...clamp down to a nice thick steel table..."

How thick must a table be when the plate is 25mm thick? 50 mm??

Try pre-heating the whole assembly then welding hot.

My in-house fabricators commonly weld large plates of 25mm or thicker, Grade 50D and RQT 701 steel as well and pre heat to 100 degrees C and hold it for 1 hour before welding. They do not have any problems with distortion.

jig it.

set the plates up on a three sixteenths plate that can be angled in a vise or clamps. clamp the plates to be welded to the 3/16 " with 3/16" on both plates as close to the weld area as possible butt the top end open the botton apx. 2mm. We will be going down hill. Keep a 90 degree rod to work, slight long arc. Run in and out and skater in. Let cool. Turn work over and bottom up, repeat above proceedure. If you need more filler then remember to travel in opposite direction. Walla...

.y

Sounds like a perfect situation for Submerged Arc welding! Or possibly eutectic metal sprayy welding.

Can you weld from both sides at the same time?

Can you weld from both sides at the same time? Handling is a major saftey issue when trying to weld from both side considering the size and weight.

Are you asking this question in regards to your first post "low hydrogen electrode" ?

MIG/MAG Butt WELD from both ends of 4m- with 2 machines

500 or 630 Amp machines will complete the job in 1 pass.

2mm wires fed from 2 reels on this MIG/MAG setup with Butt joint and only a 3mm Gap at start. No VEE preparation needed.

And if you can organize 4 Mig/Mag machines 630 Amps you can bothend 2x630Amps SAW ,with 2 Submerged arc powder flux feed/retrieve carts--then you have even less distortion than 2 MIG/MAGs'.

You will be surprised at the high efficiency of China's new IGBT MIG/MAG machines.

I just bought 2 NBC630 amps machines from Beiyung Century at Tianjin @ $1050!

IGBT Inverter Designs make these light --only 66Kg + WIRE-feeder=12KG

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OoPS!

THAT SHOULD HAVE BEEN $1510 @ ---- not 1050