1. Core Definition & Standard Compliance

1.1 Fundamental Overview

DX51D+Z is a low-carbon hot-dip galvanized steel product manufactured by immersing cold-rolled or hot-rolled steel substrates in a molten zinc bath (445–465℃) to form a metallurgically bonded zinc-iron alloy coating. Its naming and classification follow global standards:

• Grade Nomenclature (EN 10346):

• "D": Indicates hot-dip galvanized (Diplomatic) process;

• "X51": Designates forming capability (X = cold-forming, 51 = moderate ductility for bending/stamping);

• "D": Denotes commercial quality grade (suitable for general applications);

• "+Z": Signifies zinc coating (Zinc); suffixes like "Z150" or "Z275" indicate zinc coating weight (g/m² per side).

• Key Aliases: HDG Steel DX51D, Galvanized Steel Sheet DX51D+Z, Zinc-Coated Steel DX51D.

• Equivalent Grades:

• European: EN 10346 DX51D+Z, DIN 17165 DC01+Z;

• American: ASTM A653 CS Type B (hot-dip galvanized);

• Chinese: GB/T 2518 SGCC (equivalent forming and coating performance);

• Japanese: JIS G 3302 SGCC.

1.2 Core Standards

• Primary Standards: EN 10346 (European core standard for coated steel), EN 10142 (zinc coating requirements), ASTM A653 (American standard), GB/T 2518 (Chinese standard), JIS G 3302 (Japanese standard);

• Quality Certifications: ISO 9001, ISO 14001, CE (for European market), and third-party certifications (SGS, BV, TÜV) for export;

• Coating Requirements: Zinc coating weight typically ranges from Z100 (100 g/m² per side) to Z275 (275 g/m² per side); minimum adhesion (no peeling during bend test) and corrosion resistance (≥500 hours salt spray test for Z275).

2. Chemical Composition

DX51D+Z’s low-carbon substrate is optimized for formability and galvanizability, with strict impurity control to ensure coating adhesion and processing stability (mass fraction, %; per EN 10346):

Key Alloy Advantage

The low-carbon, low-impurity substrate ensures excellent formability (suitable for simple to moderate cold forming) and optimal galvanizability—zinc forms a tight metallurgical bond with steel, preventing delamination and ensuring long-term corrosion protection.

3. Mechanical & Coating Properties

DX51D+Z’s performance combines the ductility of low-carbon steel with the corrosion resistance of a zinc coating—typical values for 0.3–3.0mm thick sheets (EN 10346 compliant):

Performance Note

• Substrate Thickness Impact: Thinner sheets (<0.5mm) exhibit slightly higher tensile strength (+15–20MPa); thicker sheets (>3.0mm) maintain stable ductility but may require preheating for complex forming.

• Coating Durability: Zinc coating forms a protective ZnO/Zn(OH)₂ patina over time, slowing corrosion; service life ranges from 10–15 years (Z150, rural areas) to 20–25 years (Z275, coastal areas) without additional coating.

4. Product Forms, Dimensional Range & Surface Quality

4.1 Core Product Forms

DX51D+Z is supplied in flexible configurations to meet mass production and construction needs:

• Hot-Dip Galvanized Coils: Inner diameter (ID) 508mm/20", outer diameter (OD) ≤2100mm; length up to 300m (depending on thickness); ideal for continuous stamping/rolling lines.

• Hot-Dip Galvanized Sheets: Standard sizes (1220×2440mm, 1000×2000mm); custom cut-to-length available.

• Roofing Sheets: Profiled sheets (corrugated, trapezoidal) for construction; width 600–1200mm.

• Slit Coils: Custom width slitting (50–1500mm) for specialized production.

4.2 Dimensional Range

• Thickness: Standard 0.15–6.0mm (common gauges: 0.3mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 2.0mm); customized up to 12.0mm for heavy-duty applications.

• Width: Standard 1000mm, 1250mm, 1500mm; customized 50–2000mm.

• Length: Sheets 1000–6000mm; coils up to 300m.

• Dimensional Tolerance: Thickness ±0.02mm (precision grade) to ±0.05mm (standard grade); width ±1mm (standard); length ±2mm (standard).

4.3 Surface Quality & Coating Types

DX51D+Z’s surface quality and coating variants are tailored to application requirements:

Surface Defect Control

• Common Defects Avoided: Zinc slag, peeling, blisters, scratches, and uneven coating; 100% visual inspection ensures surface quality compliance.

5. Production Process & Quality Control

DX51D+Z undergoes a precision-controlled production process to ensure coating adhesion, uniformity, and performance:

1. Substrate Preparation: Low-carbon steel coils/sheets (e.g., DC01, SPCC) are selected; chemical composition verified to meet EN 10346.

2. Pickling: Substrate is immersed in hydrochloric acid (18–22% concentration) at 60–80℃ to remove oxide scale and rust; ensures clean surface for zinc adhesion.

3. Rinsing & Fluxing: Thorough water rinsing to remove acid; fluxing (zinc ammonium chloride solution) to prevent re-oxidation.

4. Annealing: Substrate heated to 700–850℃ in a reducing atmosphere (H₂/N₂) to refine grain structure and improve ductility.

5. Hot-Dip Galvanizing: Substrate immersed in molten zinc bath (445–465℃) for 3–10 seconds; zinc-iron alloy layer (Γ, δ phases) forms at the steel-zinc interface, followed by pure zinc layer (η phase).

6. Cooling: Air or water cooling to solidify the coating; skin pass rolling (0.5–1.0% elongation) to improve flatness and surface uniformity.

7. Post-Treatment: Optional passivation (chromate-free) or oil coating for additional protection.

8. Quality Inspection:

• Chemical Testing: Spectrometric analysis of substrate and zinc bath composition.

• Mechanical Testing: Tensile, bend, and coating adhesion tests (180° bend + tape test).

• Coating Testing: Zinc coating weight (magnetic thickness gauge), salt spray test (ASTM B117), and uniformity inspection.

• Surface & Dimensional Testing: Visual inspection + laser measurement for thickness/width/flatness.

6. Core Applications

DX51D+Z’s balance of corrosion resistance, formability, and cost-effectiveness makes it indispensable across industries:

6.1 Construction & Architecture

• Roofing sheets (corrugated, trapezoidal), wall panels, door/window frames, scaffolding, and steel structures.

• Rationale: Corrosion resistance for outdoor use; long service life (15–25 years); cost-effective vs. stainless steel.

6.2 Automotive Industry

• Automotive body parts (door panels, fenders), underbody shields, chassis components, and interior brackets.

• Rationale: Lightweight, corrosion resistance to road salts; good formability for stamping.

6.3 Home Appliances & Electronics

• Refrigerator casings, washing machine cabinets, air conditioner housings, and electrical enclosures.

• Rationale: Smooth surface for painting; corrosion resistance to humidity; cost-effective for mass production.

6.4 Agricultural & Industrial Equipment

• Farm machinery (tractor bodies, grain bins), industrial containers, and HVAC ducts.

• Rationale: Severe environment resistance; durability against dust, moisture, and chemicals.

6.5 Packaging & General Manufacturing

• Metal containers, shipping pallets, brackets, and fasteners.

• Rationale: Versatile formability; low cost; rust protection for storage/transport.

7. Comparison with Similar Materials

7.1 DX51D+Z vs. Cold-Rolled Steel (SPCC)

7.2 DX51D+Z vs. Stainless Steel (304)

• DX51D+Z: 50–70% lower cost; good corrosion resistance (with zinc coating); suitable for general outdoor use.

• 304 Stainless Steel: Superior corrosion resistance (no coating needed); higher cost; ideal for coastal/severe corrosion environments.

7.3 DX51D+Z vs. Electrogalvanized Steel (DX51D+ZE)

• DX51D+Z (Hot-Dip): Thicker coating (14–49 μm); better adhesion and corrosion resistance; lower cost for thick coatings.

• DX51D+ZE (Electrogalvanized): Thinner coating (5–15 μm); smoother surface; higher cost; suitable for precision electronic components.

8. Cost & Pricing Considerations (2025 Q4 Data)

DX51D+Z pricing is influenced by steel substrate costs, zinc prices, coating weight, and order volume:

8.1 Global Price Ranges

8.2 Key Pricing Drivers

• Zinc Price Fluctuation: Accounts for 20–30% of total cost; linked to LME zinc prices (2025 Q4: ~$2,800/ton).

• Coating Weight: Z275 costs 20–30% more than Z150; Z100 is 10–15% cheaper than Z150.

• Substrate Thickness: Thin sheets (<0.5mm) cost 15–20% more than medium sheets (1.0–2.0mm) due to processing complexity.

• Order Volume: Bulk orders (≥50 tons) unlock 10–15% discounts vs. small orders (<5 tons).

• Surface Treatment: Zero spangle or passivated sheets cost 5–10% more than standard small spangle.

8.3 Cost Optimization Strategies

• Coating Weight Selection: Choose Z150 for general use (balance of cost and protection); avoid over-specifying Z275 for non-severe environments.

• Bulk Purchasing: Orders ≥50 tons reduce costs via manufacturer direct pricing.

• Standard Sizes: Opt for common dimensions (1220×2440mm, 1000×2000mm) to avoid custom cutting premiums (10–15%).

• Domestic Sourcing: Chinese-manufactured DX51D+Z offers 20–30% cost savings vs. Western suppliers with comparable quality.

9. Supply Chain & Value-Added Services

• Minimum Order Quantity (MOQ): 1 ton (standard sizes, Z150); 5 tons (custom coating / 尺寸).

• Delivery Lead Time: 7–14 days for stock products; 20–35 days for custom orders (including coating customization).

• Packaging: Seaworthy export packaging (moisture-proof plastic film + kraft paper + steel strips + wooden pallets) to prevent scratches and corrosion; roofing sheets wrapped in protective film.

• Loading Ports: Shanghai, Tianjin, Qingdao (China); Hamburg, Rotterdam (Europe); Houston, New Orleans (USA).

• Value-Added Services:

• Custom Processing: Slitting, cutting-to-length, bending, and profiling (roofing sheets).

• Surface Customization: Zero spangle, passivation, and oil coating.

• Technical Support: Coating selection and forming process optimization.

• Third-Party Testing: SGS/BV/TÜV reports for coating weight, adhesion, and corrosion resistance.

10. Conclusion

DX51D+Z hot-dip galvanized steel stands as the benchmark for cost-effective, corrosion-resistant steel, balancing formability, durability, and affordability for global industrial and construction needs. Its hot-dip zinc coating provides robust protection against rust and harsh environments, while its low-carbon substrate enables versatile forming for diverse applications—from architectural roofing to automotive components.

Compliant with EN 10346 and global equivalents, DX51D+Z is supported by a mature supply chain and flexible customization options, making it the preferred choice for mass production and large-scale projects. While it offers lower corrosion resistance than stainless steel, its cost advantage (50–70% cheaper) makes it the most economical solution for general outdoor use. For severe corrosion environments, upgrading to Z275 coating or combining with painting extends its service life further.

Backed by strict quality control, consistent performance, and global availability, DX51D+Z remains the top choice for engineers and buyers seeking a reliable, cost-effective material that delivers long-term value in corrosion-prone applications.