Bought some round bar stock from Lowes yesterday - Boy! That steel is high!  Every time I do that I kick myself in the rear again.

 

But my point and question:   They have round solid steel in both hot rolled and cold rolled.  Best I can tell there are two differences:  The color paint on the end of the rod, and the price.  Ok - a third would be the finishing process.  Does anyone know of any other differences in the two that a smith might consider or be concerned about as for choosing hot rolled verses cold rolled round bar stock for forging?  Why would anyone ever care, for any use, if it's hot rolled or cold rolled?  Does the cold roll strain harden the bar any?

 

BTW, in the big box stores, you can purchase a tool steel crow bar for about the same price you can buy similar sized mild steel piece of plain rod.

I'll be interested to hear from others but for forging purposes I'd go with the hot rolled and only buy from a metal supply store, not HD or Lowes way overpriced.  And usually you can pick up mild steel in the drop zone for 40 cents a lb at a metal supply, or whatever the going scrap rate is now.  The only time I buy cold rolled is if I need something to be the exact dimensions and normally that would be a welding project.

Cold rolled looses it's work hardening and descaled surface as soon as you heat it in the forge.  So you pay extra for it and then throw that extra away.  It used to be that cold rolled was often a cleaner alloy, 1018 vs A36 and so forged softer; but nowadays it is often all A36.

 

I have used CR a time or two when I wanted the sharp corners for ornamental twists; but usually I only pick it up when I can find it at the scrap yard for US$00.20 a pound.

 

My local steel dealer swears that they don't make 1/4" sq stock in hot rolled and tries to sell me 12' CR for a high price.  So I wait till I visit my parents and pick up 20' sticks of 1/4" HR at the steel place where they live for about the same price as the 12' stick of CR.

 

One trick:  I try to buy an extra stick of steel when I'm buying steel and put it on the rack so I have it if I make a mistake or when I go to make a small project I don't have to go into town to buy just a tad of steel.

Don't know about the US, but here in the UK,  cold rolled is made to much tighter specifications, both steel grade wise, and tolerance on dimensions, shape and size.

 

It also gives a better finish and is easier to cut if machined. More suited to engineering situations than 'smithing.

I've noticed cold rolled is more brittle then hot rolled. Also cold rolled has a much higher tensile strength then hot rolled. So whenever I make something with bends or I'm working the metal real thin I use hot from all of my trial and errors.

Cold rolled 1018 will be softer after forging than hot rolled A-36, making for easier filing.