Products Description
DX51D and S250GD are the two most widely used aluzinc steel grades under EN 10346; DX51D is a forming grade for bending, deep drawing and complex shaped parts, while S250GD is a structural grade designed for load-bearing, wind resistance and pressure-bearing infrastructure components. Choosing the right grade directly affects structural safety, processing yield and long-term service life of aluzinc steel projects.
The global aluzinc steel market maintains a steady 5.2% CAGR from 2024 to 2030, with building envelope, light steel structure and renewable energy support systems accounting for over 60% of total consumption. Most project buyers and processors often confuse DX51D and S250GD aluzinc steel, leading to improper material selection-either insufficient forming performance or inadequate structural strength. This article clearly differentiates the two grades and explains exactly when you need to upgrade to structural grade aluzinc steel.
1. Core Definition: What Are DX51D and S250GD Aluzinc Steel?
DX51D is a commercial drawing-grade aluzinc steel focused on excellent ductility for cold forming; S250GD is a structural-grade aluzinc steel with fixed minimum yield strength for load-bearing engineering use.
DX51D belongs to non-structural forming grade, optimized for bending, rolling, deep drawing and profiling. It has low yield strength, high elongation and superb flexibility, with no strict requirement for structural load-bearing capacity. It is the standard choice for non-load-bearing shaped components made from aluzinc steel coils.
S250GD is typical structural grade aluzinc steel. The letter S stands for structural, 250 refers to minimum yield strength ≥250MPa, and GD means galvalume hot-dip coated grade. It maintains balanced formability while providing stable mechanical strength to withstand wind load, snow load and static building pressure.
Both grades adopt standard 55% Al-Zn-Si aluzinc coating, with the same corrosion resistance, surface spangle quality and coating weight options such as AZ70, AZ100, AZ150. The essential difference lies in substrate mechanical properties and application positioning.
2. Mechanical Property Comparison: DX51D vs S250GD
S250GD has much higher yield strength than DX51D for structural bearing; DX51D owns better elongation and formability for complex shaping.
| Grade | Minimum Yield Strength | Tensile Strength | Elongation | Core Advantage |
|---|---|---|---|---|
| DX51D | No fixed structural requirement | 270–350 MPa | ≥30% | Superior bending, deep drawing, complex profiling |
| S250GD | ≥250 MPa | 320–440 MPa | ≥26% | High strength, wind-resistant, pressure-bearing, stable structure |
DX51D sacrifices structural strength for better ductility; S250GD properly reduces partial formability to ensure reliable load-bearing performance for engineering structures.
3. When to Use DX51D Aluzinc Steel?
Choose DX51D if your production requires bending, stretching, deep drawing or making irregular complex shapes with no load-bearing requirements.
DX51D aluzinc steel is the preferred option for all non-structural, shaped and decorative components:
Rain gutters, downpipes and drainage system parts
Architectural decorative wall panels and shaped facade profiles
Small stamped parts, deep drawing accessories and curved components
Simple corrugated roof sheets without large-span wind pressure demand
Household appliance shell parts and light industrial non-bearing casings
Household appliance
In all scenarios that need repeated bending, rolling into special arcs or deep stamping, DX51D avoids cracking and deformation, delivering a higher processing yield rate compared with structural grade aluzinc steel.
4. When Should You Use S250GD Structural Grade Aluzinc Steel?
Choose S250GD or higher S280GD grade once the component needs to bear weight, resist wind, withstand pressure or serve as main load-bearing structural parts.
S250GD structural aluzinc steel is mandatory for all load-bearing engineering applications:
Industrial factory main roof structures, C/Z purlins and light steel keels
Solar PV mounting brackets and wind power auxiliary support structures
Large-span warehouse steel structures and logistics park building frames
Highway guardrail base parts and municipal infrastructure supporting components
Coastal high-wind area buildings and heavy snow load region structural components
Solar PV mounting brackets
Using DX51D instead of S250GD in these scenarios will lead to hidden dangers such as structural deformation, wind pressure collapse and shortened service life, increasing later maintenance and replacement costs by over 35%.
5. DX51D vs S250GD: Quick Selection Rule
Shape and no load → DX51D; Bear load, resist wind and pressure → S250GD / S280GD.
Pick DX51D: Need bending, stretching, deep drawing, complex curved shapes, decoration and non-load-bearing parts.
Pick S250GD: Need load bearing, wind resistance, compression, large-span buildings, purlins, solar brackets and main structural components.
Pick S280GD: For higher wind pressure, large-span heavy load and extreme weather environment structural projects.
Frequently Asked Questions (FAQ)
1. What is the main difference between DX51D and S250GD aluzinc steel?
DX51D is a forming grade for bending and complex shaping; S250GD is a structural grade with fixed yield strength for load-bearing, wind-resistant and pressure-bearing applications.
2. Can DX51D replace S250GD for purlins and solar brackets?
Not recommended. DX51D lacks stable structural yield strength, easily causing deformation and safety risks under wind load and long-term bearing.
3. Can S250GD be used to make gutters and decorative curved parts?
It supports conventional simple bending, but for ultra-deep drawing and complex special-shaped profiling, DX51D has better ductility and lower cracking risk.
4. Do DX51D and S250GD have the same corrosion resistance?
Yes. Both adopt standard 55% Al-Zn aluzinc coating, with identical salt spray resistance and outdoor service life under the same coating weight.
5. What standards do DX51D and S250GD comply with?
Both fully conform to EN 10346 European standard, available for global engineering export and construction project use.
6. Is S250GD stronger than DX51D?
Yes. S250GD has a defined minimum yield strength ≥250MPa, far exceeding the non-structural strength level of DX51D, ideal for structural stress-bearing.
7. What coating weights are available for these two grades?
Common coating weights include AZ50, AZ70, AZ100, AZ120, AZ150; customized aluzinc coating thickness can be produced according to project requirements.
8. What are the standard supply forms?
Both DX51D and S250GD aluzinc steel are supplied in coils, sheets, cut-to-length plates and slit strips, with customizable thickness and width for processing and construction needs.
