G300 Steel Grades
High-Performance Structural Steel with Excellent Strength, Formability, and Corrosion Resistance
- Technical Support
G300 Steel Technical Specifications & Applications
G300 Steel is a structural steel grade with a minimum yield strength of 300 MPa, offering an excellent balance of strength, toughness, and formability. It is widely used in roofing, cladding, general manufacturing, roll-formed profiles, and load-bearing components.
With excellent weldability and cold-forming performance, G300 Steel is ideal for bending, cutting, stamping, and roll-forming applications. Manufactured under strict quality control, it meets international standards and ensures consistent performance in various structural and galvanized steel applications.
As a key product of Hengze Steel Group, G300 Steel is trusted worldwide for high-performance galvanized structural steel solutions in construction, engineering, and manufacturing.
Table of Contents
1. Typical Uses & Selection Guidance
- Structural Applications
G300 steel combines a higher yield strength (300 MPa) with excellent ductility, making it suitable for cold-formed structural sections such as purlins, channels, and framing components where greater strength and formability are required. - Corrosion Protection
When hot-dip galvanized or metallic-coated (Zinc, Zinc-Aluminium), G300 provides reliable corrosion resistance for roofing, wall cladding, gutters, and general building applications, particularly in mild to moderate environments. - Forming Advantages
The higher yield strength of G300 allows for easier bending, tighter radii, and reduced risk of cracking, making it ideal for complex profiles, detailed fabrication, and applications requiring superior formability.
2. Technical Specifications Table
1. Chemical Composition Requirements (Maximum %)
| Steel Grade | Carbon (C) | Manganese (Mn) | Phosphorus (P) | Sulfur (S) | Silicon (Si) | Aluminum (Al) |
|---|---|---|---|---|---|---|
| G300 | 0.30 | 1.60 | 0.10 | 0.035 | 0.60 | 0.07 |
2. Mechanical Property Requirements (Maximum Values)
| Steel Grade | Min. Yield Strength (MPa) | Min. Tensile Strength (MPa) | Min. Elongation (%) Lo=50mm | Min. Elongation (%) Lo=80mm | Bend Angle (°) | Mandrel Diameter (× Thickness t) |
|---|---|---|---|---|---|---|
| G300 | 300 | 340 | 20 | 18 | 180 | 1t |
3. Coating Adhesion (180° Bend Test) Requirements
| Coating Class | Mandrel Diameter (× Thickness t) |
|---|---|
| Z100, Z200 | 0t |
| Z275, Z350, Z450, AZ150, AZ200, AM100, AM125, AM150, AM175, AM200, AM225 | 1t |
| Z600 | 2t |
4. Applicable Hot-Dip Metallic Coating Types
| Coating Class | Composition | Key Features |
|---|---|---|
| Z (Zinc) | 100% Zinc | Basic corrosion protection; suitable for general use. |
| ZA (Zinc-Aluminium) | 95% Zn, 5% Al | Improved corrosion resistance over pure zinc. |
| ZF (Zinc-Iron) | Zn with iron alloy | Enhanced hardness and wear resistance. |
| ZM (Zinc-Magnesium) | Zn with 2–4% Mg, 5–13% Al | Superior corrosion resistance in harsh environments. |
| AZ (Aluminium-Zinc) | 55% Al, 43.5% Zn, 1.5% Si | Excellent corrosion resistance and heat reflectivity. |
| AM (Aluminium-Magnesium) | Al with Mg alloy | High corrosion resistance; suitable for high-temperature applications. |
3. G300 vs G350 — What’s the Difference?
| Property | G250 Steel | G350 Steel |
|---|---|---|
| Yield Strength | 250 MPa | 350 MPa |
| Tensile Strength | 420 MPa | 450 MPa |
| Elongation | ≥15% (50 mm gauge length) | ≥15% (50 mm gauge length) |
| Formability | Excellent; ideal for bending and forming | Good; suitable for structural applications |
| Weldability | High | High |
| Applications | Roofing, wall cladding, gutters, light structures | Structural beams, frames, bridges, high-rise buildings |
G300 Steel FAQ：
G300 steel is a structural grade with a minimum yield strength of 300 MPa, conforming to the Australian Standard AS 1397. It combines high formability and moderate strength, making it ideal for roofing, wall cladding, gutters, purlins, and light structural components. G300 steel is often supplied with hot-dip metallic coatings such as ZINCALUME® or galvanized finishes for enhanced corrosion resistance.
G300 steel is widely used in construction and structural projects due to its balance of strength and flexibility. Common applications include:
Roofing and wall cladding
Structural framing and cold-formed purlins
Gutters and downpipes
Roll-formed sections and light structural components
Its combination of durability, formability, and corrosion protection makes it a preferred choice for both residential and commercial projects.
The primary difference lies in yield strength and application suitability:
G250: 250 MPa yield strength; excellent formability for light-duty applications.
G300: 300 MPa yield strength; ideal for applications needing a balance of strength and fabrication ease.
G350: 350 MPa yield strength; suitable for higher load-bearing structural applications.
Selecting the correct grade ensures optimal performance and safety in construction projects.
G300 steel can be supplied with various protective coatings to enhance corrosion resistance:
ZINCALUME® (Aluminium-Zinc Alloy): Provides superior corrosion protection and heat reflectivity.
Galvanized (Zinc Coating): Offers basic corrosion protection for general use.
These coatings improve durability, lifespan, and suitability of G300 steel in diverse environmental conditions.
