Talking flat sheet hot roll pickled and oiled versus cold roll here. Other than the obvious of how they are made what is the difference? Is one better than the other for carbon content therefore strength or are they the same? Which would be better for forming a door skin?
in my experience, sheet is usually cold rolled and plate bigger than .125" is usually hot rolled. cold rolled is harder and stronger whereas hot rolled is a little softer. anything sheet is most likely going to be cold rolled so just go with that.
Sorry, but I'm not wrong. Like I said, in my experience... my local steel supply place has nothing but cold rolled sheet and nothing but hot rolled plate. Guess that makes me right.
"anything sheet is most likely going to be cold rolled so just go with that." You may be correct in "your experience" but blanket statements based on what your local steel supply place has does not necessarily reflect what is available to others.... P & O and hot rolled in the gages shown are readily available from multiple sources here.
For sheet metal...I guess it depends on how you're going to work it, I'll defer to those with more sheetmetal experience. For structural applications the thing to consider is that most hot-rolled steel plate, bar, etc. is A36 and the most common cold-rolled alloy is 1018. 1018 is considerably stronger and the composition tolerances tighter than for A36, and while with materials sourcing what it is today it's often uncomfortable to ***ume that all that steel proudly labeled 'MADE IN EAST BUM****ISTAN' is really what it claims to be, 1018 is reputed to be more consistent than A36. Of course, 1018 is also pricier and for many applications the parts aren't heavily-enough stressed for it to matter.
The steel is hot rolled before being cold rolled. Hot rolling can only take the thickness down so far. After it has been coiled and cooled it goes to a seperate rolling mill that reduces the thickness down to final gauge.
You probably won't find HR P&O thinner then 16 ga. Every time I've asked for it, they say "can't get it" CRS is better for door skin anyways. .
Kevin, use cold rolled 18 gauge. Metal Supermarkets (Calgary) carries it and priced good also. They are even open Saturdays.
As a old tinbender, HR is too soft, and hard to find, CR is the only thing I would use for door skin.
Hot rolled is covered with mill scale and doesn't run as true to size as cold rolled. It also has a tendency to be more brittle. I don't know that I have ever seen hot rolled sheet and I've been around for quite a while but if by some freak of the imagination you would fine hot rolled in say 18 gauge or so it would not make a good door skin.
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