Cold rolled is thinner, tighter tolerance and smoother; hot rolled is thicker, cheaper and available in heavier gauges. The practical dividing line is around 3 mm. Below it you almost always want cold rolled; above it, hot rolled — with some important exceptions covered below.
At a glance
| Hot rolled (No.1) | Cold rolled (2B / BA) | |
|---|---|---|
| Typical thickness | 3 – 200 mm | 0.3 – 3.0 mm |
| Thickness tolerance | ±0.3 mm and up | ±0.02 mm |
| Surface | Scaled, pickled, dull grey | Smooth, bright, uniform |
| Flatness | Good but less precise | Excellent, ≤ 3 mm/m |
| Strength | Same alloy, slightly lower from annealing | Can be temper-rolled harder |
| Width | Up to 2000 mm | Typically 1000–1500 mm |
| Relative price (per kg) | Lower | Higher (extra rolling passes) |
| Lead time | Stock sizes fast, custom heavier | Stock fast, custom slit/cut fast |
| Best for | Tanks, structural, heavy plate, machined parts | Precision sheet, appliances, architectural, deep drawing |
Why the difference exists
Hot rolling happens above the recrystallisation temperature — the steel is soft and is rolled to thickness in a few passes. That is why it can reach 200 mm, and why the surface carries scale that must be pickled off.
Cold rolling happens at room temperature. The steel work-hardens, so it is rolled in several passes with annealing in between. That costs more energy, but it delivers tight thickness tolerance and a smooth surface that hot rolling cannot match.
How to choose
- Under 3 mm? Cold rolled. Hot rolled is not normally produced that thin, and where it is, tolerance is poor.
- Over 3 mm and appearance does not matter? Hot rolled, pickled. It is the economical choice for tanks, bases and structural parts.
- Over 3 mm but the surface will be visible? Hot rolled, then ground or polished. Specify the finish after processing.
- Need ±0.02 mm? Cold rolled only.
- Deep drawing or bending? Cold rolled with the right temper — and tell us the forming operation so we match it.
Two things that trip up buyers
"Thickness" is not always what you measure. Cold rolled sheet is specified as nominal thickness. Your micrometer may read slightly under, because the mill rolls to the low side of tolerance to save material. If your process needs a guaranteed minimum, say so on the order — it is a different (and slightly more expensive) specification.
Hot rolled is not always rougher. Hot rolled plate that has been pickled and then ground can look close to cold rolled. What you cannot get is the same tolerance and flatness.
Bottom line
Thickness decides it in 90% of cases. Below 3 mm: cold rolled. Above 3 mm: hot rolled, unless the surface is visible or the tolerance is tight — in which case specify grinding or polishing on top of hot rolled.
Both are stocked here: cold rolled sheet and coil 0.3–3.0 mm, hot rolled plate 3–200 mm. See the sheet and plate range or send your thickness and tolerance.
Have a question about stainless steel?
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