DX51D galvanized steel is a popular low-carbon steel widely used in construction, automotive, and household appliance manufacturing due to its excellent corrosion resistance, flexibility, and durability.
Its zinc coatings (Z, ZF, ZA, AZ, ZM) provide protection against rust and harsh environmental conditions, making it suitable for both structural and decorative applications.
What is DX51D?
DX51D is a hot-dip galvanized low-carbon steel grade under the EN 10346 standard. It is primarily designed for cold-forming applications, offering high plasticity, toughness, and weldability.
Designation Breakdown:
D: Cold-forming steel
X: Unspecified rolling state (hot-rolled or cold-rolled)
51: Steel grade serial number; higher numbers (52, 53, 54) indicate better formability
D: Hot-dip galvanized coating
+Z, +ZF, +ZA, +AZ, +ZM: Coating types
Comparison with DX52D
DX52D is similar to DX51D but features higher ductility and elongation, making it better suited for complex forming processes. DX51D is ideal for standard forming applications where moderate flexibility and corrosion protection are sufficient.
Equivalent Steel Grades by Region
| Region | Standard | Equivalent Grade |
|---|---|---|
| Europe | EN 10346 | DX51D |
| USA | ASTM A653 | A653/A653M Class B |
| Japan | JIS G3302 | SGCC |
| China | GB/T 2518 | Q195/Q235 |
| India | IS 277 | IS 277 |
| Germany | DIN EN 10130/1623 | 1.0322, 1.0335, DC01, DC04, DD11, DD13 |
Material Numbers:
1.0917: Based on EN 10027-2
1.0226: Most commonly used for DX51D under EN 10346
DX51D Chemical Composition
| Element | Maximum Content (%) | Notes |
|---|---|---|
| Carbon (C) | 0.18 | Ensures good formability and weldability |
| Silicon (Si) | 0.5 | Improves strength |
| Manganese (Mn) | 1.2 | Enhances toughness |
| Phosphorus (P) | 0.12 | Controlled to avoid brittleness |
| Sulfur (S) | 0.045 | Low levels maintain ductility |
| Titanium (Ti) | 0.3 | Deoxidizer and grain refiner |
Mechanical Properties
| Property | Value | Units |
|---|---|---|
| Tensile Strength (Rm) | 270–500 | MPa |
| Elongation (A%) | ≥22 | % |
| Surface Hardness | Low to moderate | HV |
Characteristics:
Excellent corrosion resistance from zinc coatings
High formability and ductility for bending, stamping, and cold forming
Long-lasting durability under harsh conditions
Good weldability with appropriate precautions for coated surfaces
Coating Types and Thickness
| Coating | Composition | Thickness (μm) | Application |
|---|---|---|---|
| Z | Pure zinc | 5–42 | Roofing, cladding, automotive parts |
| ZF | Zinc-Iron (Galvannealed) | 5–12 | Painted automotive panels, appliances |
| ZA | Zinc-Aluminum (95/5) | 5–33 | Coastal structures, cladding |
| AZ | Aluminum-Zinc (55/43.5) | 9–33 | HVAC, roofing, industrial machinery |
| ZM | Zinc-Magnesium | 4–20 | Marine structures, automotive parts |
Coating Weight Examples (g/m², both sides):
Z275: 275 g/m²
Z200: 200 g/m²
ZA130: 130 g/m²
AZ150: 150 g/m²
Surface Treatments
| Treatment | Purpose | Best For |
|---|---|---|
| Chromate (+C, +S) | Enhanced corrosion resistance | Outdoor structures, roofing, wall panels |
| Phosphate (+P, +Q, +T, +V) | Paint-ready surface | Automotive body parts, appliances |
| Oiling (+O) | Temporary rust protection | Stamping, bending, coating after delivery |
| Untreated (+M) | Custom processing | Manufacturers applying own coatings |
Surface Quality Options:
Standard: Minor imperfections, suitable for structural use
Improved: Fewer defects, better for painting/finishing
High: Nearly flawless, ideal for decorative or high-end coatings
Products Applications
Construction: Roofing, wall cladding, gutters, flashing
Automotive: Car body panels, undercarriages, painted components
Household Appliances: Washing machines, refrigerators, air conditioning units
Industrial Equipment: Ductwork, HVAC, machinery, storage containers
Product Forms and Sizes
| Form | Thickness (mm) | Width (mm) |
|---|---|---|
| Sheets | 0.3–3.0 | Up to 1520 |
| Coils (Cold-Rolled) | 0.2–6.0 | 600–1500 |
| Coils (Hot-Rolled) | 3.0–12.0 | 600–2000 |
DX51D galvanized steel is a versatile, corrosion-resistant, low-carbon steel suitable for construction, automotive, appliances, and industrial applications.
With multiple coating options and surface treatments, DX51D provides long-lasting performance, excellent formability, and reliable corrosion protection, making it a preferred choice for both standard and specialized projects.
Q1: What does the designation "DX51D+Z" mean?
A: This is a standard European (EN) designation for a hot-dip galvanized steel grade:
DX: Indicates it is a forming steel primarily for cold forming applications.
51: A numerical designator specifying a base steel with a minimum yield strength typically ≤ 280 MPa and specific mechanical properties suitable for forming.
D: Denotes the ductility level. "D" stands for "Drawing" quality, indicating good to very good ductility for deep drawing applications.
+Z: Specifies the coating: hot-dip galvanized with a zinc coating.
Q2: What are its primary mechanical properties?
A: According to EN 10346, the typical properties are:
Yield Strength (Re): Usually 140 - 300 MPa (Note: No specific minimum is mandated; it's based on the base steel chemistry for formability).
Tensile Strength (Rm): 270 - 500 MPa.
Elongation (A₈₀): Typically ≥ 22% - 26% (minimum depends on thickness). This high elongation is key for its formability.
It is not a high-strength steel. Its value lies in its excellent formability and corrosion protection.
Q3: What is the "Z" coating, and what are typical coating weights?
A: The "Z" stands for a massive zinc coating applied via the continuous hot-dip galvanizing process. The coating weight is specified by a suffix (e.g., Z140, Z275):
Example - DX51D+Z140: Minimum total coating mass of 140 g/m² (approx. 20 µm per side, 40 µm total). Common codes are Z100 (light), Z140 (standard), Z200/Z225 (heavy), and Z275 (extra heavy for severe environments).
Q4: What are the main applications for DX51D+Z?
A: It is the workhorse steel for general fabrication where corrosion resistance and formability are needed, but not high structural strength. Common uses include:
HVAC ductwork and components.
Appliance housings (washing machines, dryers, enclosures).
Light gauge building panels and profiles.
General metal cabinets, enclosures, and light furniture.
Agricultural and industrial containers.