How Does S280GD Perform In Extreme Temperatures?

If you are specifying S280GD (material number 1.0244) for a desert roof, a cold-store cladding, a chimney casing or an industrial mezzanine, the question is not whether the steel "can handle heat" - it is where the coating stops protecting the substrate, and whether the guaranteed mechanical values still apply at your service temperature. This article gives you the verified numbers, the coating limits and the ordering checklist, based on EN 10346:2015 and industry guidance from the American Galvanizers Association (AGA) and the Galvanizers Association of Australia (GAA).

Gnee Steel (Tianjin) Co., Ltd supplies S280GD in coil, sheet and strip with Z, AZ and ZM coatings, and every shipment carries a mill test certificate (EN 10204 Type 3.1) so you can verify the actual heat values against your project specification.

S280GD galvanized steel

S280GD is a strong, low-alloy structural steel that's widely used in construction and manufacturing. With a minimum yield strength of 280 MPa, it's tough enough for demanding structural tasks. The hot-dip zinc coating provides superior protection against corrosion, guaranteeing extended durability. Thanks to this blend of strength and protection, the S280GD is perfect for structural frames, roofing systems, and other heavy-duty applications.

The name S280GD is derived from European standard EN 10346 and stands for:

S: Structural grade steel.
280: Minimum yield strength of 280 MPa.
GD: Suitable for continuous hot-dip galvanization.

GNEE STEEL offers S280GD galvanized steel in various forms, including coils, sheets, and strips. Each product supports a range of metal coatings such as Z275, Z100, and AZ150, meeting rigorous quality standards.

GNEE STEEL S280GD galvanized steel, especially the version with +AZ (aluminum zinc) coating, performs well in high temperature environments and maintains structural integrity. Our products are precisely controlled to ensure reliable performance in extreme temperatures.

S280GD galvanized steel

What Actually Limits S280GD at High Temperature

Three layers matter: the steel substrate, the metallic coating, and - if the product is pre-painted (PPGI) - the organic paint film.

1 Steel substrate

The low-carbon substrate keeps useful strength well above 300°C, but EN 10346 verifies mechanical properties at room temperature only. There is no elevated-temperature yield table in the standard; if your design temperature exceeds about 150-200°C, have a structural engineer apply the relevant reduction factors for carbon steel (and verify with the mill).

2 Hot-dip zinc coating (Z) - the limiting layer above ~200°C

Industry guidance (AGA; GAA design manual) recommends a maximum continuous service temperature of about 200°C (392°F) for hot-dip zinc coatings, with occasional excursions up to about 275°C acceptable without immediate failure. Above 200°C the zinc-iron intermetallic layer grows rapidly: the coating loses ductility, becomes more prone to cracking on forming, and its sacrificial corrosion protection is consumed faster. At 419.5°C the zinc itself melts. For applications above 200°C, do not rely on a Z coating.

3 Aluminium-zinc coating (AZ / 55% Al-Zn) - the high-temperature option

The 55% aluminium-zinc coating (AZ, often called Galvalume) can be used continuously at roughly 315°C (600°F), which is why S280GD+AZ is preferred for hot-climate roofs, solar mounting and heat-reflective building envelopes. It also reflects more radiant heat than pure zinc. Above ~315°C the aluminium-iron alloy layer degrades and the coating's barrier protection drops; for sustained service beyond that, consider a dedicated heat-resistant product (e.g. aluminium-silicon AS coating - confirm ratings with the supplier).

4 Pre-painted (PPGI) variants

If the coil is pre-painted, the organic topcoat - not the steel or zinc - becomes the weakest link: most polyester and PVDF systems are rated for continuous service around 100-120°C before noticeable colour and gloss change. Confirm the paint system's rating (per EN 10169) with the coil coater before using PPGI in a high-heat application. Verify with supplier.

5 Low temperature

Zinc and Al-Zn coatings do not become brittle at low temperature, and thin S280GD sheet is generally used down to -40°C in roofing applications. However, EN 10346 places no Charpy impact requirement on S280GD. If the structure carries dynamic or impact loads below about -30°C, request impact test data or select a grade with guaranteed notch toughness. Verify with supplier.

Verified Mechanical Properties (EN 10346:2015)

Property	EN 10346 value	Notes
Yield strength (ReH / Rp0.2), min	280 MPa	Guaranteed minimum
Tensile strength (Rm)	≥ 360 MPa	Expected span ~140 MPa (typically 360-500 MPa)
Elongation A80, min (t > 0.7 mm)	18%	0.5-0.7 mm: 16%; 0.35-0.5 mm: 14%; t < 0.35 mm: 11%
Hardness	Not specified	EN 10346 sets no hardness requirement - verify actual values on the MTC

Verified Chemical Composition (heat analysis, max %)

Element	C	Si	Mn	P	S
Maximum (%)	0.20	0.60	1.70	0.10	0.045

EN 10346 also allows micro-alloying elements (Ti, Nb) where agreed. Nitrogen and aluminium are not specified for S280GD in EN 10346 - if a supplier lists them, ask whether they are internal control values. Always compare the actual heat values on the EN 10204 3.1 mill certificate, not the nominal grade limits.

Practical Guidance by Application

Desert / hot-climate roofing and wall cladding: S280GD+AZ150 or +AZ185 with high-heat-reflective finish; radiant heat on a dark roof can approach 90-110°C surface temperature, comfortably within AZ limits.

Cold storage and freezer buildings: Z coatings are fine down to very low temperatures; ensure profiles allow thermal movement and condensation drainage.

Industrial chimneys, flue casings and furnace screens: keep continuous metal temperature below 200°C (Z) or 315°C (AZ); above that, AS-coated or aluminized products. Verify with supplier.

Fire exposure: zinc melts at 419.5°C. S280GD has no fire-resistance rating; in fire-rated assemblies use a system engineered for the required rating.

Chemical Composition of S280GD Steel

Element	Content (%)
Iron, Fe	98-99
Carbon, C	0.1-0.2
Manganese, Mn	≤ 1.2
Phosphorus, P	≤ 0.12
Sulfur, S	≤ 0.045
Silicon, Si	≤ 0.5
Nitrogen, N	≤ 0.012
Aluminum, Al	≤ 0.015

Mechanical Properties of S280GD Steel

Property	Metric	Imperial
Tensile Strength	360-440 MPa	52-64 ksi
Yield Strength	≥ 280 MPa	≥ 40.6 ksi
Brinell Hardness	110-140 HB	110-140 HB
Rockwell Hardness	65-75 HRB	65-75 HRB
Vickers Hardness	120-140 HV	120-140 HV
Elongation	20-26%	20-26%
Elastic Modulus	210 GPa	30,500 ksi
Fracture Elongation (≤ 0.7mm)	≥ 16%	≥ 16%
Fracture Elongation (> 0.7mm)	≥ 18%	≥ 18%
Coating Adhesion (Bend Radius)	0T-2T (0-2x thickness)	0T-2T (0-2x thickness)

S280GD Steel Properties

High Corrosion Resistance:

The hot-dip galvanizing process creates a durable zinc coating that effectively prevents rust, ensuring the steel can withstand prolonged exposure to humidity and wet conditions.

Enhanced Structural Stability:

S280GD maintains its mechanical performance under both static and dynamic loads, making it reliable for load-bearing frameworks and dynamic structures like bridges and cranes.

Excellent Formability:

This steel grade can be easily shaped into complex components such as roofing profiles, wall cladding, and structural panels without cracking or losing surface quality.

Strong Coating Adhesion:

The zinc coating is tightly bonded to the steel surface, ensuring long-term corrosion protection even after cutting, bending, or forming.

Outstanding Weather Resistance:

S280GD resists environmental wear in harsh climates, including prolonged exposure to rain, snow, and temperature fluctuations, ensuring a consistent performance over time.

High Heat Reflectivity and Insulation Capability:

Its surface can reflect a significant amount of radiant heat, helping to maintain stable interior temperatures in structures and making it an effective material for energy-efficient roofing or insulation.

What to Specify When You Order

1.Standard and grade: EN 10346:2015, S280GD (1.0244).

2.Coating type and class: e.g. +Z275 (zinc) or +AZ150 (55% Al-Zn), both sides.

3.Substrate thickness range 0.35-3.0 mm (thinner/thicker by agreement).

4.Surface quality and finish (e.g. regular spangle / zero spangle for painting).

5.Forming requirement: state the bending radius so the supplier confirms the EN 10346 bend test result for your thickness.

6.Documentation: EN 10204 Type 3.1 mill certificate, and third-party inspection (SGS/BV) if your contract requires it.

Available Steel Grade

Standard	Grade	C	Si	Mn	P	S	Ti
Forcold Forming Chinese Standard	DX51D+Z	0.12	0.50	0.60	0.100	0.045	0.30
	DX52D+Z	0.12	0.50	0.60	0.100	0.045	0.30
	DX53D+Z	0.12	0.50	0.60	0.100	0.045	0.30
	DX54D+Z	0.12	0.50	0.60	0.100	0.045	0.30
	DX56D+Z	0.12	0.50	0.60	0.100	0.045	0.30
	DX57D+Z	0.12	0.50	0.60	0.100	0.045	0.30
Forcold Forming Japanese Standard	SGCC	0.15	0.50	0.80	0.050	0.030	0.025
	SGCD1 SGCD2	0.12 0.10	0.50 0.50	0.60 0.45	0.040 0.030	0.030 0.030	0.025 0.025
	SGCD3	0.08	0.50	0.45	0.030	0.030	0.025
	SGCD4	0.06	0.50	0.45	0.030	0.030	0.025
For Structure Japanese Standard	SGC340	0.25	0.50	1.70	0.200	0.035	0.025
	SGC400 SGC440	0.25 0.25	0.50 0.50	1.70 2.00	0.200 0.200	0.035 0.035	0.150 0.150
	SGC490	0.30	0.50	2.00	0.200	0.035	0.025
	SGC510	0.30	0.50	2.50	0.200	0.035	0.025
For Structure AISI Standard	S220GD+Z	0.20	0.60	0.70	0.100	0.045	0.025
	S250GD+Z	0.20	0.60	0.70	0.100	0.045	0.025
	S280GD+Z	0.20	0.60	0.70	0.100	0.045	0.025
	S320GD+Z	0.20	0.60	0.70	0.100	0.045	0.025
	S350GD+Z	0.20	0.60	0.70	0.100	0.045	0.150
	S550GD+Z	0.20	0.60	0.70	0.100	0.045	0.150

Mechanical Properties

Grade	Yield Strength MPa≥	Tensile Strength MPa≥	Elongation A%≥
DX51D Z/ZM/AZ/AM	240-380	270-500	22
DX52D Z/ZM/AZ/AM	140-300	270-420	26
DX53D Z/ZM/AZ/AM	140-260	270-380	30
DX54D Z/ZM/AZ/AM	120-220	260-350	36
S220GD Z/ZM/AM	220	300	20
S250GD Z/ZM/AZ/AM	250	330	19
S280GD Z/ZM/AM	280	360	18
S300GD A/AM	300	380	18
S320GD Z/ZM/AM	320	390	17
S350GD Z/ZM/AZ/AM	350	420	16
S450GD A/AM	450	480	15
S550GD Z/ZM/AZ/AM	550	550	-

FAQ

What is the minimum yield strength of S280GD?
Minimum yield strength (Rp0.2) is 280 MPa.

What is the typical tensile strength?
Minimum tensile strength is around 360 MPa.

What is the minimum elongation?
Minimum elongation A80 is typically 18 % (varies slightly with thickness).

What thicknesses are available for S280GD sheet/coils?
Thickness can range from about 0.12 mm up to 6.0 mm or more upon request.

Can S280GD be supplied with customized widths and lengths?
Yes - widths (e.g., 600–2000 mm) and lengths/coils can be customized.

What types of galvanization processes are used?
It supports hot-dip galvanizing, electro-galvanizing, and pre-galvanizing.

How thick can the zinc coating be?
Zinc coating weights typically range from Z30 to Z600 g/m² double-sided.

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Knowledge

S280GD galvanized steel

What Actually Limits S280GD at High Temperature

Verified Mechanical Properties (EN 10346:2015)

Verified Chemical Composition (heat analysis, max %)

Practical Guidance by Application

Chemical Composition of S280GD Steel

Mechanical Properties of S280GD Steel

S280GD Steel Properties

What to Specify When You Order

Available Steel Grade

Mechanical Properties

FAQ

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