HR (hot rolled) and CR (cold rolled) sheets are both mild steel, but they are made differently and they suit different jobs. Picking the right one saves money and avoids rework.
How they are made
HR sheets are rolled from a heated slab at high temperature, above about 900 °C, and cooled in air. This leaves a dark blue-grey surface layer called mill scale and slightly rounded edges.
CR sheets start as HR coil. The coil is pickled to remove the scale, then rolled again at room temperature to a thinner, more accurate size. Most CR sheet is then annealed to make it soft enough to bend and press. That is why it is often called CRCA (cold rolled close annealed).
Side by side
| HR Sheet | CR Sheet | |
|---|---|---|
| Surface | Dark, mill scale, slightly rough | Bright, smooth, oiled |
| Common thickness | About 1.6 mm and above | About 0.3 mm to 3 mm |
| Tolerance | Wider | Tighter, flatter |
| Bending and pressing | Good for simple bends | Excellent; drawing grades for deep pressing |
| Painting and powder coating | Needs descaling first | Paints well after cleaning |
| Price per kg | Lower | Higher (extra processing) |
| Common Indian standards | IS 2062, IS 1079, IS 10748 | IS 513 |
Where each one is used
- HR sheets: fabrication, tanks, chassis and frames, base plates, brackets, machine bodies, general engineering. Pickled and oiled HR (HRPO) is a middle option with the scale removed.
- CR sheets: electrical panels and enclosures, steel furniture, almirahs, appliances, auto parts, ducting and anything that will be painted or powder coated and needs a neat finish.
Quick rule of thumb
If the part is thicker than about 2 mm, will be welded, and appearance does not matter, HR is usually the economical choice. If the part is thin, needs accurate bends, or must look good after painting, choose CR.
Not sure? Tell us the job and the thickness, and we will suggest the right material and grade.