CR4 Cold-Rolled Steel

Plain English is a quick buyer's guide. Engineer view adds the full property tables, composition and design-for-laser figures.

Overview

CR4 is a low-carbon mild steel cold-rolled to a smooth, clean surface, supplied to BS EN 10130 (where it carries the modern designation DC01). The cold-rolling gives a tighter thickness tolerance and a far better surface than hot-rolled steel, so it takes paint, powder-coat and plating well. It is very formable and easy to weld, which makes it the everyday choice for folded brackets, enclosures and panel work — and it is the most economical sheet steel we cut. Its one real caveat is corrosion: bare CR4 will rust, so for any outdoor or damp use it must be painted, powder-coated, galvanised or plated. Where you need a ready-coated finish straight off the cut, choose galvanised steel; where appearance or hygiene rule out coatings, choose stainless steel.

Best for

Indoor brackets, frames and supports
Enclosures, cases and panels
Folded and formed parts (good bend behaviour)
Parts to be painted, powder-coated or plated
General fabrication and welded assemblies

Less ideal for

Outdoor or damp use without a protective coating
Bare, uncoated exposed parts (it will rust)
Hygienic or food-contact surfaces (use stainless)
High-strength structural members (use S355JR)

Properties

BS EN 10130:2006 · DC01

Physical

Density	7.85	g/cm³
Melting point	~1500	°C
Thermal expansion	12	×10⁻⁶/K
Modulus of elasticity	210	GPa
Thermal conductivity	~52	W/m·K
Magnetic	Yes	ferromagnetic

Mechanical

Tensile strength	270–410	MPa
Yield strength	140–280	MPa
Elongation A80	28 min	%
Hardness	~110	HB

Cold-rolled sheet (typical; figures vary with thickness)

Chemical Composition

BS EN 10130 · DC01 (1.0330)

Fe C Mn P S

Element		% present
Iron	Fe	Balance
Carbon	C	0.0 – 0.12
Manganese	Mn	0.0 – 0.60
Phosphorus	P	0.0 – 0.045
Sulphur	S	0.0 – 0.045

Formability & Fabrication

CR4 is made for forming — that is the whole point of the grade. It bends, folds and deep-draws cleanly with tight internal radii, and its smooth cold-rolled surface means folded edges stay neat. It welds readily by MIG, spot and arc, and machines reasonably for a low-carbon steel. Because it is bare steel, plan a protective finish: it takes paint, powder-coat, zinc plating and galvanising well.

Cold working

Excellent

Bending

Excellent

Deep drawing

Good

Arc / MIG

Excellent

Spot welding

Excellent

Gas welding

Good

Machinability

Good

Galvanising

Good

Recommended filler: a copper-coated mild-steel MIG wire such as ER70S-6 (A18/G3Si1) for most CR4 welds. Match consumables to plate where a coated or plated finish will follow, and clean any oil or anti-rust film from the joint before welding.

Corrosion Resistance

CR4 has no inherent corrosion resistance — bare, it is plain carbon steel and will rust in damp air. It is supplied lightly oiled to protect it in storage, but that is not a finish. For any outdoor, wet or humid use it must be sealed with paint, powder-coat, zinc plating or galvanising, all of which it accepts readily. Kept dry and indoors it stays bright for a long time; where corrosion resistance must be built in, choose galvanised or stainless steel instead.

Environment	Suitability
Dry indoor (uncoated)	Good
Painted / powder-coated	Good
Galvanised / plated	Excellent
General outdoor (uncoated)	Poor
Damp / condensation (uncoated)	Poor
Marine / coastal (uncoated)	Avoid

Typical Applications

Indoor brackets & supports Enclosures & equipment cases Control & electrical panels Folded trays & chassis parts Machine guards & covers Shelving & fixtures Powder-coated signage backs General sheet-metal fabrication

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Laser Cutting & Ordering

at Metal Parts Direct

Thicknesses we cut

0.9 mm1.2 mm1.5 mm2 mm2.5 mm3 mm

Cut tolerance

±0.25 mm up to 20 mm, ±0.5 mm above

Max part size

1000 × 1000 mm

Max part weight

No maximum

Estimated delivery if ordered today

Friday 28th August 2026 – Monday 31st August 2026

UK-made Laser cut to your spec No minimum order Material certs on request

Design-for-laser quick reference

These are the exact minimums the Part Builder enforces as you design, relative to sheet thickness — so your part and your quote never disagree.

Feature	Minimum
Min hole / bore Ø	0.7 × thickness (min 1 mm)
Min slot / opening width	0.7 × thickness (min 1 mm)
Min web / wall between cuts	0.7 × thickness (min 1 mm)
Min cut-to-edge distance	0.7 × thickness (min 1 mm)

Frequently Asked Questions

Will CR4 rust?

Yes — bare CR4 is plain mild steel with no built-in corrosion resistance, so it will rust in damp air. It is fine kept dry indoors, but for any outdoor or wet use it must be painted, powder-coated, plated or galvanised. If you need rust resistance without a coating, choose galvanised or stainless steel.

What is the difference between CR4 and hot-rolled (HR) steel?

Both are low-carbon mild steel, but CR4 is cold-rolled to a smooth, clean surface with a tighter thickness tolerance, while hot-rolled steel has a darker, scaly mill surface. CR4 is the better choice where appearance, accuracy or a paint/powder-coat finish matters; hot-rolled is used for heavier, less cosmetic work.

Is CR4 the same as DC01?

Effectively yes. CR4 is the older British designation; DC01 (material number 1.0330) is the modern BS EN 10130 grade that replaced it. We use the names interchangeably, and material is supplied to the EN standard.

Can CR4 be bent and folded?

Yes — forming is exactly what it is designed for. CR4 bends and folds cleanly with tight internal radii, and its smooth surface keeps folded edges neat, which is why it is the standard choice for brackets, enclosures and trays.

Can CR4 be powder-coated or painted?

Yes, and it takes finishes very well. Its clean cold-rolled surface is ideal for paint, powder-coat and plating. Degrease the part first to remove the protective oil film, and for the best result apply the coating reasonably soon after cutting so no surface rust forms.

Is CR4 magnetic?

Yes. CR4 is a ferromagnetic carbon steel, so magnets hold to it firmly — handy for jigs, fixtures and magnetic catches.

Equivalents

Also designated

DC01 1.0330 CR4 BS 1449 CR4 EN 10130 DC01

Cross-references are indicative and may not be exact equivalents — confirm against the certificate for critical work.

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This data is indicative and provided in good faith from recognised EN standards and industry references. It is not a substitute for the full specification or material certificate; mechanical properties in particular vary with temper, form and dimension. Material supplied will conform to the relevant applicable standards but may differ from these figures. No liability is accepted for actions taken in reliance on this guide. Confirm critical values against the certificate for your delivery.