DX51D and DX52D are the two most frequently compared galvanized coil grades in EN 10346, and the comparison matters because they are priced differently and behave differently in the press. The difference is not cosmetic: it is written into the chemistry limits and the mechanical guarantees of the standard.
Chemical Composition
| Element, max | DX51D | DX52D |
|---|---|---|
| Carbon | 0.18% | 0.12% |
| Manganese | 1.20% | 0.60% |
| Phosphorus | 0.12% | 0.10% |
| Sulphur | 0.045% | 0.045% |
DX52D carries lower carbon, manganese and phosphorus, which directly improves ductility and deep-drawing behaviour while slightly lowering the strength ceiling.
Mechanical Properties
| Property | DX51D | DX52D |
|---|---|---|
| Yield strength | Not specified | 140-300 MPa |
| Tensile strength | 270-500 MPa | 270-420 MPa |
| Elongation A80 | Min 22% | Min 26% |
DX52D has higher guaranteed elongation and a defined yield range, which makes it predictable for stamping and deeper bending. DX51D keeps a wider strength envelope, which suits parts where stiffness matters more than deep forming.
Thickness Range
Both grades are supplied as coated strip typically from 0.30 mm to 3.00 mm, with DX51D also available in very light gauges for certain applications. The governing standard covers a broader range; the practical supply window depends on the mill, the coating line and the ordered coating class.
Application Focus
Because DX51D offers relatively high strength with simpler guarantees, it is the default for building profiles, roof sheet substrate, purlins, keels and general ducts. DX52D, with its better plasticity, suits parts that need complex bending and stamping, such as appliance housings, control-cabinet components and automotive body panels where a balance of strength and formability is required.
Galvanized Grades for Automotive Body Panels
For automotive body panels, the EN 10346 family continues beyond DX52D: DX52D+Z covers moderate stamping, DX54D+Z is the deep-drawing coated grade with a minimum elongation of 36%, and higher members of the series serve the most complex panels. The coating is selected separately, typically Z100 to Z140 for visible panels, with ZF (zinc-iron alloy) where paint adhesion and weldability dominate.
Frequently Asked Questions
1. Which grade is stronger, DX51D or DX52D?
In tensile terms DX51D can reach 500 MPa while DX52D tops out at 420 MPa, but yield strength is only guaranteed for DX52D. For bending strength applications DX51D is usually sufficient; for stamping predictability DX52D is specified.
2. Why is DX51D's yield strength not specified?
EN 10346 defines DX51D as a forming grade where the minimum elongation and tensile range are the governing criteria; yield is left free so the mill can optimise the product for its rolling practice.
3. Can DX52D replace DX51D?
Yes, for most applications, at a small price premium, and it improves stamping margins. The reverse substitution is risky when the part depends on DX52D's elongation guarantee.
4. What coating classes are available?
Both grades take the full Z (pure zinc), ZF, ZA, AZ and ZM coating families, with classes from Z80 up to Z600 in the standard; Z100-Z275 covers most building and appliance orders.
5. Is DX51D suitable for roofing profiles?
Yes, it is the standard forming grade for roof sheet substrate; pair it with an adequate coating class (Z200-Z275 or AZ) for the environment.
6. How do I choose between DX51D and DX52D on an order?
Choose DX51D for bending, profiles and general forming; choose DX52D when the drawing shows deep stamping, tight radii or surface-critical forming, and state the required elongation in the order.