Hot Rolled v Cold Rolled Sheet

[Seano]

Not withstanding the difference in cost, hot rolled being cheaper to produce and buy than cold rolled. Is there any great difference in how stronger, more malliable, springy, either type are. I am talking of 1mm, 1.6, and 1.8 in thickness here and it ultimately will be used to form shall we say 3 sided shapes initially.

 

[Drains]

Cold rolled tends to be stronger. less malleable, more springy, than hot, as the cold working stiffens it up a little.

It's also better to weld, paint etc.

Hot rolled is more malleable, but that's about it on the positive side.

1.8mm is pretty thick for cold rolled. I'd probably have trouble finding it. At that thickness I'd probably go for the cheaper option. On 0.8-1.2, cold would invariably be my material of choice.

 

[Paul.]

Thinnest hot rolled sheet I've ever seen is 1.5mm, below that its all cold reduced, hot rolled is a bit more malleable, less likely to crack if your working it hard, cold reduced is likely to be flatter and free from surface flaws, so better for fine work, consistent bending etc,
1.8mm is not a standard thickness 2mm is the next size up to 1.5mm.

 

[Drains]

Thinnest hot rolled sheet I've ever seen is 1.5mm

We have a supplier who stocks 1mm hot rolled. I wish he didn't.

 

[Seano]

We have a supplier who stocks 1mm hot rolled. I wish he didn't.

Why is that Simon.....?

 

[Drains]

Because we get hot rolled and I prefer cold, for the reasons above.

 

[Seano]

Thanks for the info guys, very informative too, it has allowed me to come to my decision.....cold reduced it is, cheers.

Sean.

 

[aametalmaster]

Cold rolled starts out as hot rolled. Its cleaned of the mill scale (from being hot) then run thru rolls which makes it stronger and smoother...Bob

 

[Hitch]

We tend to use HR for most things down to about 1.2mm, unless theres lots of welding to do on it where the scale is a pain.
Only ever seen CR upto 3mm, next best thing then up is probably hot rolled, pickled and oiled (HRPO)

 

[Welderpaul]

We rarely do anything thinner than 2mm, so use HR for everything. Never had any problems with the scale.
Whats the price difference between HR/CR?

 

[Hotmetal]

I think CR4 is the softest? generally available.

 

[chunkolini]

Welderpaul asks the difference between hot rolled and cold reduced.
I was ordering steel a few days back and asked this. on 1.6mm sheet it is another three quid. so it is CR for me from now on, at least at this thickness.

 

[sword]

Is hot or cold rolled better for automotive chassis repairs? Sounds like cold rolled is the go?

 

[Seano]

Well for my upcoming work it will be 1.2 & 1.0mm cold reduced.

 

[candor]

Just a quick question, is most larger box section, angle, flat etc hot rolled?

 

[waddycall]

Depending on how your using it the varying tensile strength of hot rolled can cause issues. The tensile strength in cold reduced is more consistent so if the material is being folded in a press brake or punched then CR4 is more reliable. Repetitive folding of hot rolled can be a bit hit and miss as the tensile strength varies throughout the sheet/plate. We can only get CR4 up to 3mm I believe.

Most standard sections are hot rolled I believe although many are available in bright. Any "black" mild steel is.