1. What Is ST12 Cold Rolled Steel Sheet?
ST12 is the designation for a cold-rolled low-carbon steel sheet and strip in the former German standard DIN 1623 Part 1:1983 ("cold rolled low carbon steel sheet and strip"). In practice, ST12 is a commercial-quality (general forming) cold-rolled steel, equivalent to DC01 under the current European standard EN 10130, and comparable to SPCC in JIS G3141. Many buyers still use the ST12 name in specifications and drawings, and suppliers routinely deliver DC01 to satisfy an "ST12" order - but the certificate should always state the governing standard.
Note: DIN 1623-1 has been withdrawn and superseded by EN 10130. For new contracts, specify DC01 per EN 10130 (or the applicable national standard) and use ST12 only as a familiar reference term.
2. How Cold Rolling Improves the Product
Cold-rolled steel is essentially hot-rolled steel that has been pickled and re-rolled at ambient temperature to achieve tighter dimensions and better surface quality. Compared with hot-rolled material, cold-rolled sheet offers:
Closer thickness tolerances and more consistent gauge across width and length.
Superior surface finish - smoother, cleaner surfaces that are often slightly oily to the touch, ready for painting or plating.
Better flatness and straightness, with well-defined edges and corners for accurate cutting and blanking.
Good consistency for forming - ideal for stamping, bending and drawing of general parts.
3. Chemical Composition and Grade Equivalence
Indicative composition limits (commercial-quality cold-rolled grades):
| Grade (standard) | C max (%) | Mn max (%) | P max (%) | S max (%) |
|---|---|---|---|---|
| DC01 / ST12 (EN 10130 / DIN 1623) | 0.10 | 0.50 | 0.035 | 0.035 |
| SPCC (JIS G3141) | 0.12 | 0.50 | 0.035 | 0.035 |
| DC03 / ST13 (EN 10130 / DIN 1623) | 0.08 | 0.45 | 0.030 | 0.025 |
| DC04 / ST14 (EN 10130 / DIN 1623) | 0.08 | 0.40 | 0.025 | 0.020 |
Use-based grade selection:
| Application | Recommended grade |
|---|---|
| Normal use (general forming) | DC01 (St12), SPCC |
| Drawing quality | DC03 (St13), SPCD |
| Deep drawing | DC04 (St14, St15), SPCE/SPCEN |
| Extra/ultra-deep drawing | DC05, DC06, DC07 (EN 10130) |
Values above are typical published limits; the authoritative values for a specific shipment are those on the mill test certificate. For deep drawing applications, also compare yield strength, elongation and r-value, not chemistry alone.
4. Typical Applications of ST12 / DC01 Sheet
General stamping and blanking parts - brackets, covers, enclosures.
Furniture components and office equipment.
Automotive non-structural parts (with specified surface class).
Base material for subsequent surface treatment: painting, powder coating, electroplating.
Substrate for galvanizing or other metallic coatings where a smooth cold-rolled surface is required.
5. Supply Range and Ordering Notes
Thickness: 0.3 - 3.5 mm standard (wider range on request).
Width: 120 - 1850 mm, including slit strips.
Form: coil, sheet (cut-to-length), strip, or blanks.
Surface finish: specify the surface class and oiling level; a skin-passed (smooth) finish is recommended for painting.
Edge: mill edge or slit edge as required by your processing line.
Documentation: mill test certificate per EN 10204; state DC01/EN 10130 (or your reference to ST12) clearly on the order.
Frequently Asked Questions
Is ST12 the same as DC01? Functionally yes: ST12 (DIN 1623) and DC01 (EN 10130) are both commercial-quality cold-rolled low-carbon grades with comparable chemistry and properties, and DC01 is the modern designation that replaced ST12 when DIN 1623-1 was withdrawn. Confirm the standard on the certificate for contractual clarity.
What is the difference between ST12 and SPCC? ST12 (DC01) follows the German/European standard system; SPCC follows JIS G3141. Chemistry and properties are close (SPCC allows slightly higher carbon, 0.12% vs 0.10%). Either can be specified for general forming; pick the standard used in your market or drawing.
Can ST12 be deep drawn? Only for shallow-to-moderate draws. For deep drawing, specify DC04 (St14) or higher (DC05-DC07) per EN 10130 - they have lower yield strength and better elongation, which prevents splitting in severe draws.
Why is cold-rolled sheet slightly oily? The oil is a rust-preventive film applied at the mill (oiled finish). It protects the surface during transport and storage and is normally removed by degreasing before painting or welding. Dry (unoiled) finishes are available for applications that cannot tolerate oil.
Does cold-rolled sheet rust? Yes, if unprotected. The bare steel surface corrodes in humid conditions - that is why the oil film matters and why many buyers galvanize or paint cold-rolled parts. Store coils and sheets indoors, dry and ventilated.
What dimensions are available for ST12/DC01 coil and sheet? Cold-rolled coil is commonly supplied in thicknesses from 0.3 mm to 3.5 mm and widths from 120 mm to 1850 mm, slit or cut to length as required. Confirm thickness, width, quantity and surface finish in the purchase order.
