Cutting thick (2") Steel

[bdog]

I have to do some cutting on some 2" thick plate. I have never worked with anything remotely this thick before. I have been welding and cutting 20 years but have never messed with anything over 3/4" thick. Any tips or ideas on what I am going to need to do it?

It is going to be a one time thing cutting this thick material but I don't mind spending whatever I need to on the equipment to get it done. I am guessing I will need to make about 20 linear feet of cuts in total.

 

[mjncad]

Is the plate part of an existing piece of equipment? If so, plasma or cutting torches come to mind; but a plasma capable of slogging through 2" plate is going to be BIG $$$$$$.

Or is this a piece of plate at the steel yard? If so, I suggest having it cut with a waterjet.

A little more info on what you have in mind for this plate would be helpful.

 

[Shield Arc]

Over the years I've had steady diets of thick plate, up to 8-inch. With 20-feet to cut, if you can rent or borrow a tractor torch, they make that kind of cutting a breeze.

Hooper Welding Supply - Tip Charts

 

[weldermike]

Over the years I've had steady diets of thick plate, up to 8-inch. With 20-feet to cut, if you can rent or borrow a tractor torch, they make that kind of cutting a breeze.

Hooper Welding Supply - Tip Charts

We use these as well at work, ShieldArc is right, if you can rent one it would really make that job a breeze!

 

[deereman75]

Is the 20ft one long cut, or many short ones. If it is a long one, a track torch would be best. If it was a bunch of short ones, probably a hand torch and a straight edge.

 

[longevity]

That is a super thick cut. One of our customers has done it in the past, its slow, ugly, but can be done. Maybe using an Oxy torch will be a better idea for that thickness.

[ame=http://www.youtube.com/watch?v=sd24YrvlC8U]Longevity ForceCut LP-80 PLASMA CUTTER Cutting 2" Thick Steel Slab - YouTube[/ame]

You will need to turn the pressure up if you are going to use a plasma cutter.

 

[monckywrench]

I'd track torch it. You can make a guide long enough for your longest cut and save serious money over buying a track torch.

Anyone made a homemade torch guide? - WeldingWeb™ - Welding forum for pros and enthusiasts

If I didn't have a track torch I'd make one of these simple units. Mute the audio on this video since it adds nothing.

[ame=http://www.youtube.com/watch?v=qpCMmCDdFkw]Cutting a perfectly straight edge with an OA torch - YouTube[/ame]

PREHEAT is your friend. I make at least one slow preheat pass on any material 3/8" or above, then reverse direction for the cut.

Ask on weldingweb (since there are lots of folks there who cut serious plate on the job) for advice and post very specific details about what you are cutting.

 

[Shield Arc]

I carried one of these in my bucket for years.

 

[jake98]

M/W, That was great to see, thanks! :thumbsup:

Shield, does that square elevate the tip for you?

 

[monckywrench]

I like the combo square with a brass blade! :thumbsup:

 

[Shield Arc]

I added the aluminum angle for when using the plasma.

 

[yomax4]

I would call this an Oxyfuel application but if it's not an option; Borrow or rent a Thermal Dynamics Cut Master 152 Plasma. 120 Amps..Air Cooled. Cuts 2" like a dream. The only 120 Amp Air Cooled unit out there. Google it.

 

[CJONE]

If you use O/A the biggest thing that I found is the tip, mainly the cutting jet [center hole] has to be CLEAN and drilled accurate. I have tips that are huge and I never use them. I have a small tip that is my favorite one that will cut 2" cleanly. Adjust the Oxy pressure to the manufacturers rec or by trial. Most of my tips are in the 40-60 psi range. Like was stated preheat is your friend. You have to move slow and keep the torch head angles the same, if you move them at all you will screw up the cut. Cutting slag is not fun. A magnetic cutting guide is a huge help with thick plate if you don't have a track cutter. CJ

 

[Shield Arc]

I'm a real hack when it comes to O/A burning. I've worked with a few guys over the years that could burn better free hand than I could with a tractor torch.
When I set up a torch to burn I like to get the cutting cone as long as possible. 99 times out of 100 I only need to press the cutting lever an 1/8 inch or so. When I do find the sweet spot the flame sounds like a small jet engine.

 

[monckywrench]

I added the aluminum angle for when using the plasma.

I'll be copying that as soon as I score some angle. That's slicker than the proverbial deer guts on a door knob.

 

[Shield Arc]

That's slicker than the proverbial deer guts on a door knob.

That's a new one on me!:laughing:



If you get a magnetic burning square with brass bar, don't loan it out! Years ago I was working with some guys who weren't the sharpest tools in the shed. One of them go the bright idea to use my burning square to carbon arc a straight line. He forgot that a carbon arc would arc on the brass bar!!!!!!!!!!!!

 

[CJONE]

I'm a real hack when it comes to O/A burning. I've worked with a few guys over the years that could burn better free hand than I could with a tractor torch.
When I set up a torch to burn I like to get the cutting cone as long as possible. 99 times out of 100 I only need to press the cutting lever an 1/8 inch or so. When I do find the sweet spot the flame sounds like a small jet engine.

+1 My little tip that I was referring to will literally split the flame for 2' and it sounds just as you describe. It was a cheepy from US tip company I believe. I wish I would have bought more of them. CJ

 

[CJONE]

That's a new one on me!:laughing:



If you get a magnetic burning square with brass bar, don't loan it out! Years ago I was working with some guys who weren't the sharpest tools in the shed. One of them go the bright idea to use my burning square to carbon arc a straight line. He forgot that a carbon arc would arc on the brass bar!!!!!!!!!!!!

Sounds like the same ones who always used my tri square for a chipping hammer!! CJ

 

[yomax4]

I'm a real hack when it comes to O/A burning. I've worked with a few guys over the years that could burn better free hand than I could with a tractor torch.
When I set up a torch to burn I like to get the cutting cone as long as possible. 99 times out of 100 I only need to press the cutting lever an 1/8 inch or so. When I do find the sweet spot the flame sounds like a small jet engine.

Nice Spike. I like your choice of Torches too.:thumbsup:

 

[bdog]

Is the plate part of an existing piece of equipment? If so, plasma or cutting torches come to mind; but a plasma capable of slogging through 2" plate is going to be BIG $$$$$$.

Or is this a piece of plate at the steel yard? If so, I suggest having it cut with a waterjet.

A little more info on what you have in mind for this plate would be helpful.

Actually it is a truck bed on an International truck. The truck has some specialty equipment mounted on it. The bed is made of 2" thick plate and the plate weighs about 6,000lb. It is a long story but when they built the truck they thought the more it weighed the better. I am wanting to reduce the weight of the truck to get it under CDL requirements (26,000lb) by selectively cutting out portions of the bed that are not critical to the structure. For example cut holes in the bed under the tool boxes, auxillary diesel tanks, etc.