DC05 and DC06 are the two softest formable grades of EN 10130, the European standard for cold-rolled low-carbon steel flat products for cold forming. They are specified when a part must be deep drawn or stretch-formed with the minimum risk of splitting, for example automotive inner panels, lamp housings, battery enclosures and complex appliance parts. Because the material is soft and its surface quality matters to the final part, packaging, transport, storage and inspection deserve as much attention as the grade itself. This article covers the practical side of buying DC05/DC06 coils across borders.
What DC05 and DC06 guarantee
EN 10130 limits the chemistry tightly: DC05 has a maximum carbon of 0.02% and manganese of 0.25%; DC06 also has a maximum carbon of 0.02% with manganese limited to 0.30%, and both limit phosphorus and sulphur to 0.020%. The low carbon and manganese keep the steel soft and ductile. For skin-rolled material in the common 0.4-2.0 mm range, the guaranteed yield strength Rp0.2 is at most 180 MPa for DC05 and at most 170 MPa for DC06, with tensile strength of 270-330 MPa and 270-350 MPa respectively and minimum elongation A80 of 38% and 40%. These values make DC06 the most drawable grade in the EN 10130 family, followed closely by DC05. The mill certificate should be checked for the actual values of the delivered heat, because the guaranteed limits vary slightly with thickness.
| Property | DC05 | DC06 |
|---|---|---|
| Carbon, max | 0.02% | 0.02% |
| Manganese, max | 0.25% | 0.30% |
| Phosphorus, max | 0.020% | 0.020% |
| Sulphur, max | 0.020% | 0.020% |
| Yield strength Rp0.2, max | 180 MPa | 170 MPa |
| Tensile strength | 270-330 MPa | 270-350 MPa |
| Elongation A80, min (t 0.4-2.0 mm) | 38% | 40% |
Packaging for sea freight
DC05/DC06 coils are soft and the surface is easily damaged, so export packaging follows a standard sequence. The coil is wrapped in rust-proof paper, then in a plastic film, then secured with steel strapping; the inner and outer edges are protected with end rings or edge protectors, and the outside carries labels with the grade, heat number, dimensions, coil weight and handling markings. The whole package is normally placed on a wooden or steel pallet, or into a steel frame that can be lifted by crane or forklift without touching the coil itself. Buyers should confirm the packaging specification in the order, because under-specified packaging is the most common cause of transit damage and edge corrosion.
Transport and storage
Coils are usually transported by flatbed truck with the coil axis horizontal and secured against rolling, or in containers with proper blocking. For sea freight, moisture protection is the critical point: temperature changes inside a container cause condensation, so the rust-proof paper and film must stay intact until the coil reaches a dry indoor storage area. Storage should be indoor, dry and ventilated, with the coil kept on its end or on a stand, never directly on the ground. Age hardening is a real effect: the soft steel slowly becomes less formable over time, so the practical rule is to use the material within about 3 months of delivery and to confirm the forming behaviour on a trial blank before a large production run, especially for DC06 parts that operate close to the forming limit.
What to confirm before ordering
A complete inquiry should state: thickness, width and coil weight; grade and standard, for example DC06 per EN 10130; surface quality, since the softest grades are sensitive to scratches and marks; whether the material must be skin-rolled, and on one or both sides; delivery form, coil or cut sheet; packaging level; and the required mill certificate. For deep-drawn parts, ask the mill to confirm the r-value and n-value on the actual heat if the forming operation is close to the limit, because these two values govern deep drawing behaviour better than the tensile figures alone. Third-party inspection by SGS, BV or an equivalent body before shipment, including a dimensional check, a surface check and a review of the mill certificate, is strongly recommended for the first order.
Pricing considerations
DC05 and DC06 are priced per ton, and the price reflects the tighter chemistry, the extra metallurgical control and the softer temper. The main price drivers are the base cold-rolled coil price, the ordered width and thickness, the coil weight per order, the packaging level and the delivery term. As with all steel, the effective price should be compared on the same basis: same grade, same size range, same packaging, same certificate and the same delivery point. Because the material sits at the soft end of the range, an attractive quote should be checked against the actual mechanical values on the mill certificate, since an out-of-tolerance yield strength can stop a deep-drawing line.
Frequently asked questions
1. What is the difference between DC05 and DC06?
Both are ultra-low-carbon deep-drawing grades. DC06 has the tighter yield guarantee, max 170 MPa versus 180 MPa, and the higher elongation guarantee, 40% versus 38% at A80 in the 0.4-2.0 mm range, so it is chosen for the most severe drawing operations.
2. How long can DC05/DC06 coils be stored?
The material should be used within about 3 months of delivery because of age hardening. Storage must be indoor, dry and ventilated. Before a large run, verify forming behaviour on a trial blank.
3. What packaging protects the coils in sea freight?
Rust-proof paper, plastic film, steel strapping, end rings or edge protectors, and labels, normally on a pallet or steel frame. Keep the wrapping intact until the coil reaches dry indoor storage to avoid condensation damage.
4. Do I need third-party inspection?
For the first order, yes. A pre-shipment inspection by SGS, BV or an equivalent body covers dimensions, surface quality and the mill certificate, and protects both buyer and seller against disputes at arrival.
5. Why is the coil price different from plain DC01?
DC05/DC06 cost more per ton because of tighter chemistry, extra annealing control and the softer temper. Compare quotes on the same basis: grade, size, packaging, certificate and delivery term.
6. Can DC06 be used for automotive body parts?
Yes. DC06-type formability is used for inner panels and structural parts with severe drawing. Confirm the r-value and n-value on the actual heat with the mill when the forming operation is close to the limit.