What gets welded at 800 amps?

[Iron Beaver]

Hey everyone. Just curious, why do 800 amp welding machines exist? What gets welded at that current? I'm guessing super thick steel with super expensive electrodes?

Just trying to satisfy my curiosity...

 

[dffay]

YouTube has a vid on guys welding a 3/4”diameter stick electrode (5 feet long) on steel at 1000 amps.
I’m thinking steel bridge supports.

 

[unslow1]

Pretty much everything.



Maybe commercial equipment. The ones I've seen them use on implements and construction equipment seems pretty stout.

 

[quickfarms]

800 amp is not that big

a lot of the structural guys are using 600 amp machines in the field

in the shop it is not uncommon to find 1000 to 1500 amp machines

the shipyards probably have even larger machines. I wonder how many amps it takes to weld the flight deck or hull plates on an aircraft carrier?

 

[macgyver37]

I have a 600 amp machine that I bought from Western plow, it welded up snow plows for 30+ years before I got it.

I did an internship at the Case skid steer plant in the weld shop and some of the buckets were out of 5/8-3/4" thick material, I know they had some larger amp machines in most of the welding cells. 1/16" solid core mig wire was the norm. That was in '97 I think, idk what they are doing now..

 

[cvairwerks]

Takes a bit more than 800 amps to make passes on 11 inch walls of high temp pressure vessels.....

 

[king nero]

A standard SAW installation (sub arc welding) has a 1000 Amp power source and is used at 600 - 1000 amps.
This is used for the everyday, albeit a bit thicker than standard, steel construction industry.

As mentioned before, heavy walled pressure vessels and other installations can be welded with even higher currents but everything up to a 1000 amps is fairly common.

 

[cvairwerks]

For S’s and G’s, pull up any of the videos out there with guys striking an arc with 3/4” rods....

 

[BigMike782]

Locomotive engine cases. Twin torch, sub arc powered by twin 1000 amp power sources.

 

[MBeaty]

Using submerged arc strip cladding, the filler is not limited to round wire, but instead can be wide strips of material. This can easily be used to add a cladding of inconel, chemical, or wear resistant material to steel, sometimes in "beads" 2-3 inches wide. This used a tremendous amount of power and sometimes has multiple machines linked together.

 

[welder4956]

^^^What he said. Submerged arc welding with 3/32" diameter wire is usually done at 500-600 amps. Also, each machine has a 100% duty cycle rating that is usually less than the maximum nameplate rating. Submerged arc welding is also usually a mechanized process and runs for long periods of time, so you want a machine that has a high enough amp rating that it's not going to overheat and trip the thermal overload or fail prematurely.

 

[gearhead1]

Nuclear containment vessels are like 10” thick or something like that. I bet those are high amp machines to make those vessels.

 

[The Cobbler]

 

[Iron Beaver]

Maybe I could run that sweet 3/4" electrode one of these days now

 

[king nero]

Using submerged arc strip cladding, the filler is not limited to round wire, but instead can be wide strips of material. This can easily be used to add a cladding of inconel, chemical, or wear resistant material to steel, sometimes in "beads" 2-3 inches wide. This used a tremendous amount of power and sometimes has multiple machines linked together.

Both SAW (submerged arc) and ESW (elektro slag welding) strip cladding is typically done around 1000 amps (with strips up to 90 mm or 3 1/2" wide).

 

[dr_clyde]

There's a whole 'nother world out there beyond the brackets and frames welded up in a typical garage shop. Ships, large pressure vessels, bridges and large civil construction, heavy equipment, all kinds of things take a fair bit of current to weld. Typically this is automated, or at the very least mechanized. It is rare to have a guy running those big 3/4" stick electrodes, they aren't very efficient vs wire. Not to mention the mess. Sub arc is much cleaner.

I run a small fab shop and our biggest machine goes to 600 amps fully maxed out.

When you start talking pounds per minute deposition rate, you need some horsepower to put weld down. Big stuff gets welded with big wire.

Not to mention you need duty cycle and capacity. If you want to run at 400 amps all day long, you'd best be running a 800 amp machine. It's not good for a machine to be up near it's limit all day every day. You get more life out of your tools if you size them appropriately.

 

[Nomex]

I've used Dynasty 800s to TIG weld solid copper crucibles used in electron beam furnaces at a Titanium foundry.

1/4" tungsten, baseball bat size torch.

Tungsten weight is recorded daily, before and after sharpening. Tungsten inclusion in a crucible for titanium meant for aerospace and DoD use is not a good situation.

Fun stuff.

 

[PugetDude]

Started my career in a tank/pressure vessel shop; we also did a lot of hydroelectric penstock and turbine components- saw a lot of 4-6” plate.

It wasn’t uncommon for us to weld circumferential seams in a positioner with dual head SMAW at well over 1500 amps and iron powder pouring into the bead.
The slag would peel off in a continuous bead over an inch wide and the thickness of your thumb. It went back to the supplier for recycling.

100% x-ray quality welds.

 

[danski0224]

That would be cool to see.

 

[JimDon]

The flip side of this coin is your garage version of o/a torch for demo work, and then it’s industrial counterpart, the thermal lance. Once you see one of these in operation, you will never ever forget it. Think taking apart a Great Lakes ore carrier.

 

[readhead]

I used to hire a guy out of Denver to come down and install headed anchor studs, Nelson studs, on bridge beams. 800 amps was his small machine.