Qualification summary
Cold-rolled product forms and delivery conditions
Cold-rolled steel must be specified by grade, condition, dimensions, surface, tolerance and forming requirement. Cold reduction work-hardens the strip; annealing restores formability and temper rolling controls surface, shape and yield-point behaviour.
| Delivery concept | Technical condition | Typical buyer concern |
|---|---|---|
| Batch annealed | Coil annealed in batch furnaces | Grain size, consistency, surface and forming response |
| Continuously annealed | Strip annealed in a continuous line | Uniformity, fine structure, surface quality and stable forming |
| Skin passed / temper rolled | Light reduction after annealing | Flatness, surface texture and stretcher-strain or coil-break control |
| Full hard (FH) | Cold reduced but not annealed | Very high strength, very low elongation and limited formability |
| Slit coil | Coil cut to narrower widths | Width tolerance, burr, camber, edge condition and coil build |
| Cut-to-length sheet | Leveled and cut from coil | Length tolerance, squareness, flatness and surface protection |
The five-second specification should state product form, standard and grade, annealed/skin-passed/full-hard condition, dimensions, surface class, oiling, edge, tolerance, test direction, certificate and downstream process.
Standards
Standards map for cold-rolled steel
State the required edition in the RFQ. “Commercial quality cold rolled” does not define forming performance, surface, tolerance or inspection evidence.
| Standard | Technical scope | Common grades or topics |
|---|---|---|
| EN 10130 | Cold-rolled uncoated low-carbon flat products for cold forming | DC01, DC03, DC04, DC05, DC06 |
| EN 10131 | Dimensional and shape tolerances | Thickness, width, length, flatness and shape |
| EN 10268 | Cold-rolled flat products with high yield strength for cold forming | HC220Y/HC260Y and HC260LA-HC500LA |
| ASTM A1008/A1008M | Cold-rolled carbon, structural, HSLA and related sheet | CS, DS, DDS, EDDS and high-strength families |
| ASTM A370 | Mechanical testing of steel products | Tensile-test methods and specimen requirements |
| JIS G 3141 | Cold-reduced carbon steel sheet and strip | SPCC/SPCCT and drawing families |
| EN 10209 | Cold-rolled low-carbon flat products for vitreous enamelling | DC01EK-DC06ED |
| EN 10204 | Inspection documents for metallic products | Types 2.2, 3.1 and 3.2 |
Forming grades
EN 10130 DC01-DC06 grades and forming indicators
| Grade | Typical selection | Re max. (MPa) | Rm (MPa) | A80 min. | r90 min. | n90 min. |
|---|---|---|---|---|---|---|
| DC01 | General forming | 280 | 270-410 | 28% | — | — |
| DC03 | Drawing | 240 | 270-370 | 34% | 1.3 | — |
| DC04 | Deep drawing | 210 | 270-350 | 38% | 1.6 | 0.18 |
| DC05 | Extra-deep drawing | 180 | 270-330 | 40% | 1.9 | 0.20 |
| DC06 | Ultra-deep drawing | 170 | 270-330 | 41% | 2.1 | 0.22 |
The source applies the grade values to transverse specimens and states thin-gauge corrections below 0.7 mm. Confirm the exact corrections in the ordered edition.
| Indicator | Buyer-relevant meaning |
|---|---|
| Re or Rp0.2 | Yield or proof strength; lower values generally reduce forming load and springback |
| Rm | Tensile strength |
| A80 | Elongation measured on an 80 mm gauge length |
| r value | Plastic strain ratio; higher values generally support resistance to thinning in deep drawing |
| n value | Strain-hardening exponent; higher values generally support more uniform strain distribution |
| FLC | Forming Limit Curve for a particular grade, thickness and condition |
Grade name alone is not sufficient for die approval. Use lot-specific data and forming simulation or trials where failure risk is high.
Higher strength
EN 10268 cold-rolled HSLA grades
Cold-rolled HSLA grades use fine grains and microalloy precipitation to provide higher strength while retaining a usable forming window.
| Grade | Transverse Rp0.2/ReL (MPa) | Transverse Rm (MPa) | Transverse A80 min. | Longitudinal Rp0.2/ReL (MPa) | Longitudinal Rm (MPa) | Longitudinal A80 min. |
|---|---|---|---|---|---|---|
| HC260LA | 260-330 | 350-430 | 26% | 240-310 | 340-420 | 27% |
| HC300LA | 300-380 | 380-480 | 23% | 280-360 | 370-470 | 24% |
| HC340LA | 340-420 | 410-510 | 21% | 320-410 | 400-500 | 22% |
| HC380LA | 380-480 | 440-580 | 19% | 350-450 | 430-550 | 20% |
| HC420LA | 420-520 | 470-600 | 17% | 390-500 | 460-580 | 18% |
| HC460LA | 460-580 | 510-660 | 13% | 420-560 | 480-630 | 14% |
| HC500LA | 500-620 | 550-710 | 12% | 460-600 | 520-690 | 13% |
The source uses transverse testing as the default and permits longitudinal values by agreement. As strength increases, the forming limit generally decreases. Automotive structural parts also require fatigue, deformation and edge-quality review.
Surface and shape
Surface quality, texture and tolerances
| Requirement | Technical advisory point |
|---|---|
| Surface class A | Used where minor imperfections are acceptable within the governing standard |
| Surface class B | Prefer for visible or surface-sensitive use; define inspected side and acceptance criteria |
| Thickness tolerance | State EN 10131 class and whether a narrowed tolerance is required |
| Narrowed tolerance | Contract the exact limit rather than relying on an informal special-tolerance label |
| Protective oil | Define type, amount, cleaning/coating compatibility and expected storage duration |
| Surface texture | State roughness range and measurement method when paint, adhesion or forming depends on texture |
| Flatness | State product form, sheet dimensions and class; coil shape and cut-sheet flatness are not interchangeable |
| Slit edge | State width tolerance, burr, camber and coil-build expectations |
Surface class and finish are not the same as grade. A buyer may need DC04 for forming and a defined surface/roughness condition for a visible or painted part.
Special conditions
Full-hard and vitreous-enamelling steel
Full-hard steel is cold reduced but not annealed. Its elongated grain structure and internal stress produce high strength and hardness, elongation commonly below 2% and very limited forming capacity. Do not apply annealed EN 10130 property tables to full-hard material.
| Full-hard use or requirement | Advisory point |
|---|---|
| Final product such as straps or buckles | Validate bend performance and edge cracking because forming is limited |
| Feedstock for re-rolling, annealing or coating | Final properties develop in the downstream process |
| Mechanical-property guarantee | Some FH routes may be chemistry-only; define required properties explicitly |
| Flatness | Normal flatness rules may not apply; contract an agreed shape requirement if critical |
| Surface | Rolling oil remains unless another condition is agreed |
Full-hard material requires a separate delivery-condition specification.
| Enamelling topic | EK grades | ED grades |
|---|---|---|
| Enamelling route | Conventional enamelling | Direct and conventional enamelling |
| Typical process | Ground coat plus firing, or two coats/two firings | Two coats/one firing may be possible |
| Surface use | More suited to parts enamelled on one side | Can suit both surfaces |
| Gas/hydrogen management | Gas can escape through the opposite surface | Hydrogen-trap structures reduce post-firing outgassing |
| Procurement fields | Grade, coating side, frit and firing route | Grade, one-/two-side coating, firing route and fish-scale requirement |
For enamelled products, define forming sequence, frit system, firing cycle, adhesion, coating thickness and fish-scale resistance.
Decision aid
Grade selection and quality evidence
The quality package may include the governing product standard, tolerance standard, MTC, processing records, surface or roughness measurements and method-specific laboratory evidence. ISO 9001 and ISO/IEC 17025 documents have different roles.
| Buyer need | Starting family | Confirm before recommendation |
|---|---|---|
| General bending and shallow forming | DC01 | Surface, thickness, bend radius and ageing requirement |
| Drawing | DC03 | Draw ratio, lubrication, r/n values and surface |
| Deep drawing | DC04 | Tool geometry, thickness, FLC and stretcher-strain guarantee |
| Extra-/ultra-deep drawing | DC05/DC06 | IF requirement, ageing guarantee, r/n values and simulation |
| Higher yield with forming | HC-Y or HC-LA under EN 10268 | Strength, bend/edge performance, weldability and fatigue |
| Vitreous enamel | DCxxEK or DCxxED | Coating sides, firing route, fish-scale resistance and formability |
| Very high hardness or semi-finished feedstock | Full hard | Chemistry, reduction, downstream annealing and shape |
| Visible painted or appliance surface | EN 10130 surface class B or agreed equivalent | Inspected side, roughness, oil, defect limits and packing |
Buyer checklist
Cold-rolled steel RFQ checklist
Send the product form; standard, grade and edition; annealing or full-hard condition; dimensions and quantity; coil ID/OD and maximum mass; edge, burr and camber; surface class and inspected side; roughness; oiling; dimensional and flatness tolerances; mechanical properties and test direction; forming, welding, painting or enamelling requirements; ageing guarantee; EN 10204 type; packing, destination and Incoterm.
SteelFromTurkey supplies cold-rolled sheet and coil against order-defined grade, condition, surface, tolerance and documentation requirements.
FAQ
Cold-rolled steel technical questions
Is DC06 always the best cold-rolled grade?
No. DC06 is intended for severe forming, but the correct choice depends on the part, thickness, tooling, surface, joining, cost and required properties.
Is DC04 enough to guarantee deep drawing?
No. Grade designation must be supported by lot properties, thickness, test direction, ageing condition, surface, lubrication, tooling and process validation.
Can full-hard steel use the same property table as annealed CRC?
No. Full-hard material has not undergone recrystallization annealing and has very limited elongation. Define its chemistry, reduction, shape and downstream route separately.
What is the difference between surface class and roughness?
Surface class defines allowable surface quality within the standard, while roughness is a measured texture parameter. Visible or painted parts may require both.
Which certificate should accompany cold-rolled coil?
The purchase order defines the inspection document. State the EN 10204 type or other document requirement and maintain heat, master-coil and child-coil identity through processing.