Products Description
DX51D+AZ and DC51D+AZ are both hot-dip galvalume steel grades with a 55%Al-43.4%Zn-1.6%Si coating, but they differ in substrate origin, applicable standards, and forming consistency-DX51D+AZ follows EN 10346 with versatile substrate options, while DC51D+AZ adheres to Chinese Q/BQB 425 and uses a fixed cold-rolled DC01 substrate. As a leading galvalume steel supplier, GNEE STEEL clarifies these critical distinctions to help you select the optimal grade for your project.
- DX51D+AZ: A European-standard galvalume steel grade for cold forming, where "D" = flat steel for cold forming, "X" = indefinite rolling state (compatible with both hot-rolled DD11 and cold-rolled DC01 substrates), "51" = grade series number, the second "D" = hot-dip coated, and "+AZ" = Al-Zn alloy coating.
- DC51D+AZ: A Chinese-standard galvalume steel grade for cold forming, where "C" = cold-rolled substrate only (fixed DC01 low-carbon cold-rolled steel base), with the same coating (+AZ) and mechanical property requirements as DX51D+AZ.
Key Standard & Substrate Differences
The most fundamental difference lies in governing standards and substrate consistency, directly impacting material stability and global applicability.
| Comparison Item | DX51D+AZ | DC51D+AZ |
|---|---|---|
| Applicable Standard | EN 10346 (EU, 2015) | Q/BQB 425 (Chinese domestic) |
| Substrate Type | Optional: Hot-rolled (DD11) or Cold-rolled (DC01) | Fixed: Cold-rolled DC01 only |
| Substrate Carbon Content | 0.06–0.12% (variable by substrate) | 0.08–0.12% (fixed low-carbon) |
| Global Acceptance | High (widely used in EU, Southeast Asia, Middle East) | Regional (primarily for Chinese domestic projects) |
| Dimensional Tolerance | ±0.02mm (EN 10346 strict tolerance) | ±0.03mm (Q/BQB 425 standard tolerance) |
Mechanical Property Performance
Both grades meet the same mechanical property thresholds per EN 10346, but DC51D+AZ offers more consistent performance due to its fixed cold-rolled substrate.
Core Mechanical Properties (Typical Values):
Yield Strength (Re): 140–220MPa (≤220MPa standard limit)
Tensile Strength (Rm): 270–350MPa
Elongation (A80): ≥22% (minimum for cold forming)
Hardness: HRB 50–65
Performance Difference Note:DX51D+AZ with a hot-rolled DD11 substrate has 5–8% lower elongation than DC51D+AZ, making DC51D+AZ more suitable for complex bending or stamping processes.
Galvalume Coating Characteristics
Both grades feature the same high-performance AZ coating (55%Al-43.4%Zn-1.6%Si), the industry's gold standard for corrosion resistance.
Coating Core Parameters:
Coating Weight: AZ30–AZ150 g/m² (double-sided; customizable up to AZ275)
Corrosion Resistance: 1,000+ hours of neutral salt spray testing without red rust (3–5× longer than conventional galvanized steel)
Heat Resistance: Continuous use up to 315°C (short-term up to 400°C) with no coating discoloration or peeling
Surface Appearance: Bright silver matte finish (reflectivity ≥75% for visible light)
Application Scenarios: Which to Choose?
DX51D+AZ: Best for Global Projects & Cost-Effective General Use
Export construction: Roofing, wall panels, corrugated sheets for EU, Southeast Asian, or Middle Eastern projects
General cold-formed parts: Ventilation ducts, culverts, and low-stress components
Cost-sensitive applications: Hot-rolled substrate option reduces material costs by 8–12%
DC51D+AZ: Best for High-Precision Forming & Chinese Domestic Projects
Complex stamping: Home appliance shells (refrigerator back panels, air conditioner casings), electrical cabinet components
High-precision construction: Curtain wall panels, solar mounting brackets requiring tight dimensional control
Automotive parts: Exhaust heat shields, battery trays (high temperature and corrosion resistance)
GNEE STEEL's Galvalume Steel Advantage
At GNEE STEEL, we supply both DX51D+AZ and DC51D+AZ galvalume steel coils/sheets with strict quality control:
Thickness: 0.2–2.0mm, width: 1,000–1,500mm (customizable)
Certified to EN 10346 and Q/BQB 425, with full mill test certificates (MTC)
Surface options: Chromium-free passivated, fingerprint-resistant, oiled/unoiled
Global delivery: EXW, FOB, CIF terms, with 10-ton MOQ and standard export packaging
Frequently Asked Questions (FAQ)
Q1: Are DX51D+AZ and DC51D+AZ interchangeable?
A1: Partially interchangeable for simple cold forming, but DC51D+AZ is preferred for complex stamping due to its fixed cold-rolled substrate and consistent elongation. DX51D+AZ is better for global export projects requiring EN 10346 compliance.
Q2: What is the price difference between the two grades?
A2: DC51D+AZ is typically 3–5% more expensive than DX51D+AZ (hot-rolled substrate) due to its fixed cold-rolled DC01 base. DX51D+AZ (cold-rolled substrate) is priced nearly the same as DC51D+AZ.
Q3: Can DX51D+AZ be used in high-temperature environments?
A3: Yes. Both grades have the same 315°C continuous heat resistance (short-term up to 400°C) due to the identical 55%Al-Zn-Si coating, suitable for oven shells, exhaust components, and high-temperature ducting.
Q4: Which grade is better for coastal construction projects?
A4: Both offer excellent corrosion resistance (1,000+ hours salt spray), but DX51D+AZ is preferred for coastal export projects due to EN 10346 global recognition. For Chinese coastal domestic projects, DC51D+AZ is a reliable choice.
Q5: What substrate does GNEE STEEL use for DX51D+AZ?
A5: GNEE STEEL provides two substrate options for DX51D+AZ: hot-rolled DD11 (cost-effective) and cold-rolled DC01 (consistent performance), matching DC51D+AZ's substrate quality for high-demand applications.
Q6: Do both grades have the same surface treatment options?
A6: Yes. GNEE STEEL offers identical surface treatments for both grades: chromium-free passivation (eco-friendly), fingerprint-resistant (AFP), oiled, or unoiled, meeting diverse application needs.
Q7: What is the typical delivery time for GNEE STEEL's galvalume steel?
A7: Standard delivery time is 15–20 days after order confirmation, with expedited 7–10 day delivery available for urgent orders. We provide full MTC and third-party test reports (SGS/BV) upon request.
Q8: How to distinguish between DX51D+AZ and DC51D+AZ in actual products?
A8: Check the mill certificate and product marking: DX51D+AZ is marked with EN 10346, while DC51D+AZ uses Q/BQB 425. GNEE STEEL labels all products with clear grade, standard, substrate type, and coating weight for easy identification.
