GL

Types and uses
Manufacturing process

Lightweight Trusses

Hvac System

Wall Cladding

Metal Roofing

Ceiling Panels

Rolling Door

Substrate For Pre-Painted Steel

High-strength Al-Zn alloy coated steel (G550) is the core material for Smart Truss systems. With a minimum yield strength of $550 \text{ MPa}$, this material enables the fabrication of ultra-lightweight yet superior load-bearing C-trusses and Battens (Topspan), perfectly replacing traditional black steel and timber. The Aluminium-Zinc alloy coating (AZ100 - AZ200), combined with a resin (Anti-fingerprint) finish, provides lifetime protection for the roof structure, completely eliminating the need for painting and maintenance, while ensuring corrosion resistance even in humid tropical environments.

Main uses Technical data Add to quote basket

Produced via a continuous hot-dip process at 600°C, this product features a metallic coating structure optimized for superior corrosion resistance.

The coating composition is precisely controlled to maximize durability:

55% Aluminium (Al): Provides a passive barrier against oxidation and offers excellent heat resistance.

43.5% Zinc (Zn): Provides sacrificial (galvanic) protection, self-healing cut edges and scratches.

1.5% Silicon (Si): Ensures strong adhesion between the coating and the steel base, preventing peeling during forming.

Specification

GL
Lightweight Trusses
DESCRIPTION

PRODUCT SPECIFICATIONS

Specification	Specicfic Document Number	Steel GRADE	AL%	Zn%	Si%	YS [N/mm2] [Min]	TS [N/mm2] [Min]	E [%] [Min] L0=50mm	Primary Applications
JIS	JIS G 3321	SGLCC	55.0%	43.5%	1.5%	–	≥270 (Ref)	–	HVAC Ductwork, General Bending, Shutter Body.
JIS	JIS G 3321	SGLCD	55%	43.5%	1.5%	–	≥270	≥36	Deep Drawing, Appliance Casings.
JIS	JIS G 3321	SGLC400	55%	43.5%	1.5%	≥295	≥400	≥18	General Structural, Purlins.
JIS	JIS G 3321	SGLC440	55%	43.5%	1.5%	≥335	≥440	≥18	Pre-Engineered Buildings (PEB).
JIS	JIS G 3321	SGLC490	55%	43.5%	1.5%	≥365	≥490	≥16	High Strength Purlins.
JIS	JIS G 3321	SGLC570	55%	43.5%	1.5%	≥560	≥570	–	Roofing, Decking, High Strength Cladding.
ASTM	ASTM A792M	CS Type B	55%	43.5%	1.5%	205−380	–	≥20	General Fabrication, Ductwork.
ASTM	ASTM A792M	FS	55%	43.5%	1.5%	170−310	–	≥24	Drawing Applications.
ASTM	ASTM A792M	SS Grade 33	55%	43.5%	1.5%	≥230	≥310	≥20	Light Structural, Roofing.
ASTM	ASTM A792M	SS Grade 37	55%	43.5%	1.5%	≥255	≥360	≥18	Purlins, Trusses.
ASTM	ASTM A792M	SS Grade 40	55%	43.5%	1.5%	≥275	≥380	≥16	Structural Framing.
ASTM	ASTM A792M	SS Grade 50	55%	43.5%	1.5%	≥345	≥450	≥12	High Strength Purlins, PEB Members.
ASTM	ASTM A792M	SS Grade 80	55%	43.5%	1.5%	≥550	≥570	–	Industrial Roofing, Decking (Full Hard).
AS	AS 1397	G2	55%	43.5%	1.5%	–	≥270	≥27	Lock-seam Ducting, Curve Forming.
AS	AS 1397	G300	55%	43.5%	1.5%	≥300	≥340	≥18	Residential Framing, Battens.
AS	AS 1397	G350	55%	43.5%	1.5%	≥350	≥420	≥14	Purlins (C/Z sections), Trusses.
AS	AS 1397	G450	55%	43.5%	1.5%	≥450	≥480	≥9	High Strength Purlins, PEB.
AS	AS 1397	G500	55%	43.5%	1.5%	≥500	≥520	≥8	Light Gauge Steel Framing.
AS	AS 1397	G550	55%	43.5%	1.5%	≥550	≥550	≥2	Roofing, Decking, Smart Truss (Lath).
EN	EN 10346	DX51D+AZ	55%	43.5%	1.5%	–	270−500	≥22	HVAC, Cable Trays, General Forming.
EN	EN 10346	DX52D+AZ	55%	43.5%	1.5%	140−300	270−420	≥26	Forming, Shallow Drawing.
EN	EN 10346	DX53D+AZ	55%	43.5%	1.5%	140−260	270−380	≥30	Complex Components.
EN	EN 10346	S220GD+AZ	55%	43.5%	1.5%	≥220	≥300	≥20	Light Partitioning.
EN	EN 10346	S250GD+AZ	55%	43.5%	1.5%	≥250	≥330	≥19	Structural Frames.
EN	EN 10346	S280GD+AZ	55%	43.5%	1.5%	≥280	≥360	≥18	Purlins, Trusses.
EN	EN 10346	S320GD+AZ	55%	43.5%	1.5%	≥320	≥390	≥17	Structural Members.
EN	EN 10346	S350GD+AZ	55%	43.5%	1.5%	≥350	≥420	≥16	Heavy Duty Purlins, PEB.
EN	EN 10346	S550GD+AZ	55%	43.5%	1.5%	≥550	≥560	–	Roofing, Composite Floor Decking.

MRM Steel specializes in supplying high-quality Galvalume Coated Steel (GL), ensuring consistent material properties and strict adherence to international standards. For detailed consultation on specific grades and quotations, please contact our Sales Department directly.

Please find the detailed technical specifications below:

Specification

GL
Lightweight Trusses
ORDERING INFORMATION

Technical Specification

No.	Item	Specification
1	Standards	JIS G3321, AS 1397, ASTM A792/ A792M, EN 10346
2	Base Metal Thickness	0.18 – 2.0 mm
3	Coating mass	40 – 200g / m² / both side
4	Width	860 – 2000 mm
5	Coil Weight	Up to 4 MT
6	Surface processing	Skin-pass, Non-Skin-pass
7	MOQ	40 MT
8	Inspection	MTC, SGS / BV / TUV

Packaging & Delivery

Export seaworthy packaging
Delivery time: 20–35 days
Shipment: bulk vessel or container

Catalog

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Galvannealing

The surface of steel sheet can be coated with a zinc compound prior to reheating in an annealing process. Zn atoms diffuse into the Fe to create a Zn-Fe series alloy. This process is referred to as Galvanealing.

SPM & Chemical Treatment

In order to achieve a ﬂat surface and elegant ﬁnish, the steel sheet is processed with a skin pass mill. In order to prevent the white rust, which often forms on the surface of activated zinc, and to improve corrosion resistance, the surface is coated with a Cr-free resin.

Inspection & Coiling

Located at the line’s exit section are a side trimmer, inspection table and oil coating equipment. At this station all products are inspected and judged relative to material speciﬁcations required by the client.

Electrolytic Cleaning

Some rolling oil and other contaminants remain on the surface of cold-rolled steel sheets following processing. These are removed by passing the electrically charged sheet through an alkaline solution which induces an electro-chemical reaction.

Annealing

The material properties of pre-treated steel sheet can be altered and improved through re-crystallization during the annealing process.

How GL Steel is Made (Pohang Steelworks)