SPCC and SPHC: Rolling Temperature Sets the Grade Family
SPCC and SPHC are both designations of JIS G 3141 for carbon steel sheet delivered in coil, and the difference between them begins at the rolling mill. SPHC is hot rolled commercial quality, produced above the recrystallisation temperature and pickled when a clean surface is required, so it keeps a rougher surface and a slightly wider thickness tolerance. SPCC is cold rolled commercial quality, produced by pickling a hot rolled coil and then reducing it between work rolls at ambient temperature, followed by annealing and a light skin pass. The cold reduction is what delivers the smooth surface, the tight thickness control and the uniform mechanical properties that a coated coil needs.
| Feature | SPCC (cold rolled) | SPHC (hot rolled) |
|---|---|---|
| Standard | JIS G 3141 | JIS G 3131 / JIS G 3141 |
| Process | Pickled, cold reduced, annealed, skin passed | Hot rolled, optionally pickled |
| Typical thickness | 0.30 mm to 3.00 mm | 1.20 mm to 6.00 mm and above |
| Surface | Smooth, uniform, suitable for painting | Rougher, may retain mill scale |
| Thickness tolerance | Tight | Wider |
| Formability | Good, elongation above 28% | Lower elongation, thicker sections |
| Typical use | Coated and painted parts, appliances, casings | Structural sections, tubes, brackets |
What SPCD Adds and Where the Equivalents Sit
SPCD is the drawing quality version of the same cold rolled family, supplied with lower yield strength, higher elongation and tighter chemistry so that it can be pressed into deep housings without cracking. Buyers working across standards commonly find SPCC treated as equivalent to DC01 to EN 10130 and to Q195 or Q215A to the Chinese cold rolled standard, while SPCD aligns with the DC03 and DC04 drawing grades. The equivalence is a practical starting point for substitution rather than a formal identity.
SPCC: commercial quality, bending, roll forming, lock seaming, shallow drawing.
SPCD: drawing quality, deeper cups and panels, tighter thickness and flatness.
Bare equivalents: DC01 and DC03 to EN 10130, Q195, Q215A and Q235B to the Chinese standard.
Coated product: the same base steel is offered with a hot dip aluminium-zinc or zinc coating.
ASTM A792 AZ150 Coating on a 1 mm SPCC Base
When the base coil is coated, ASTM A792 governs the coated product. The standard covers sheet coated by the hot dip process with an alloy of about 55% aluminium, 43.4% zinc and 1.6% silicon, and the coating designation AZ150 states a coating mass of 150 g/m2 measured over both surfaces. That is roughly 75 g/m2 per side, or about 20 micrometres of coating per side on a 1 mm base. The aluminium rich layer resists oxidation better than a plain zinc coating, while the zinc fraction protects sheared edges by galvanic action for about 1 to 2 mm.
Formability, Joining and Corrosion Behaviour
A 1 mm SPCC base with an AZ150 coating roll forms and bends readily, and a minimum inside bend radius of one times the thickness is a practical starting point for transverse bends, with the radius opened slightly if the coating must remain free of fine cracking at the fold. Laser and arc welding are straightforward provided the joint design allows the coating to be displaced, and resistance spot welding needs higher electrode force and more frequent tip dressing than bare steel. Sheared edges are left unpainted in most roofing work because the coating protects them, but welds and deep scores should be touched up. Coated coil is stored indoors on dry bearers.
Applications Where SPCC Replaces SPHC or SPHD
SPCC and SPCD are chosen whenever a smooth, paintable, tightly toleranced surface matters: appliance side and back panels, air conditioner housings, refrigerator and freezer liners, electrical cabinets, control panels, computer and server chassis, cable trays, light fittings, and the substrate for prepainted colour coated roofing and cladding. Hot wider sections such as purlins, truck frames and tube blanks stay with SPHC or SPHD.
Frequently Asked Questions
Q: What material is SPCC?
SPCC is a cold rolled carbon steel sheet grade defined in JIS G 3141. It is a low carbon, fully processed steel with a smooth surface and is also described as commercial quality cold rolled steel.
Q: What is the difference between SPCC and SPHC?
SPHC is hot rolled commercial quality coil with a rougher surface and wider tolerances, while SPCC is cold rolled commercial quality with a smooth surface, tight thickness tolerance and better surface appearance.
Q: Is SPCC stainless steel?
No. SPCC is a carbon steel. It contains far less than the 10.5% chromium needed to form the passive layer that defines stainless steel, so it must be painted or metallic coated to resist corrosion.
Q: What is SPCC equivalent to in other standards?
It is treated as equivalent to DC01 to EN 10130 and to Q195 or Q215A in the Chinese cold rolled system, and it is also close to the older German grade St12.
Q: What are cold rolled coils used for?
They are used for appliance and electrical cabinets, automotive inner panels, furniture, drums, general containers, and as the base metal for galvanised, aluminium-zinc coated and prepainted products.
Q: How does AZ150 compare with a plain zinc coating?
AZ150 combines the heat and oxidation resistance of an aluminium rich coating with the sacrificial edge protection of zinc, which suits roofing and cladding.