Hot or cold rolled plate

[bhoulis]

I'm looking to get a 1/2" thick steel plate to lay on my workbench to be used as a work surface and to do basic light sheetmetal work on. Probably 1 ft x 2 ft on the small side, but no bigger than 2ft x 3ft. Which would be better, cold rolled or hot rolled? Is one generally more expensive than the other? I have no experience buying metal stock of any kind so any advice would be helpful. Thanks.

Brian

 

[Dave Carney]

Cold rolled is more expensive and I don't see any reason to use it for what you are doing here.

 

[swampman]

Hot rolled will have mill scale and be much less expensive. Cold rolled, no mill scale. Like Dave said, no need for cold rolled for a benchtop.

 

[aka Larry]

1/2" thk for an overlay? That's a serious piece of steel.

 

[sberry]

For light work 1/4 would be plenty and bigger is better up to a point.

 

[mikegt4]

^^^ all the above.
Have you looked at the prices yet??

 

[Ilikeike]

We build work tables out of 3/8" hot rolled. I'd build a nice table if I had 1/2" !

For my tool chest and the cover for my wood work bench at home 1/4" hot is plenty beefy.

 

[matt_i]

I don't think you can buy 1/2" (sheet) in cold rolled. [I could be wrong, check locally].

A36 is typically hot rolled with mill scale. Typically that's cheapest.

If you can get HRP&O = hot rolled pickled and oiled it has the nasty mill scale removed for you, nice uniform finish like cold-rolled. More expensive but that would be my choice if its not an astronomical premium over A36.

1018 CF cold finished flat bar has some great dimensions - .001" to .002" of nominal but its also loaded with stresses from smashing it down with gigundous pressure rollers.

A large steelyard might be able to shear it to custom size for you as well.

 

[HenryAZ]

I use 3/8" hot rolled 3' x 6' for my bench top, not an overlay. It is plenty strong and stable enough. I welded the support table with braced legs (1/4" x 2" x 2" square tube legs and top rails), and a bottom shelf with 2" angle iron spreaders and expanded metal for the shelf.

 

[readhead]

More important is flat. Ask for and be sure that it is flat. Take a straight edge to be sure. You will hate it for ever if it isn’t flat.

 

[nadogail]

For the small amount of welding I do, a piece of Hardi Backer makes a decent table cover.

 

[CraigStu]

Steel is really nice though especially for tig. Most of the time I have the ground clamp on the steel frame of my 1/8" steel topped table. just set whatever I want to weld on the top and start welding. Once in a while an arc won't start. 90% of those times I slide the piece 2 inches across the table and then an arc will start.

 

[FSrepair&fabrication]

Make friends with the guys at your county roads maintenance shop. Bring them some donuts or something. When they cut a piece of plate to patch a hole in the road they usually toss the leftovers. Ive gotten some nice pieces of 1/2 and 3/4 plate this way. You can also just buy it, but if you know somebody there or are good at making friends they throw away alot of good stuff.

 

[CJDave]

What about checking at the local scrap yard? They take in all kinds of stuff. CJDave.

 

[metlmunchr]

What Matt said. HRPO is the way to go.

You wouldn't want cold rolled even if it was the same price as hot rolled. CR steel has extreme levels of compressive stress locked in near its surface due to the rolling process. Heating one surface to any appreciable degree relieves those stresses on that side. The imbalance of stress then causes the material to warp. HR doesn't have those compressive stresses because the elevated temperature of the steel during rolling allows it to remain in the annealed state.

A good while back, pickling and oiling added about 5¢/lb to the cost of HR plate. Could be as much as a dime now, but that's still cheap compared to the premium for CR which typically runs about twice the price of HR.