Steel is the skeleton of contemporary infrastructure, equipment and industrialization. With a variety of specifications of different materials, two significant materials in the construction and the manufacturing world are ASTM A572 Grade 42 and ASTM A653M CS G90 SS Grade 33. Even though the two standards are the part of the ASTM family, they are not equals; one is a structural steel plate and the other a galvanized sheet steel.
In this article, the author examines the features and characteristics of both grades and their most common uses as well as pricing factors to buy them as a global purchaser.
Understanding ASTM Standards
The American Society for Testing and Materials (ASTM) provides internationally recognized standards that ensure steel products meet specific mechanical and chemical requirements. Two such standards relevant here are:
- ASTM A572: Covers high-strength low-alloy (HSLA) structural steel plates.
- ASTM A653M: Covers galvanized sheet steels with different coating designations, including G90.
Each standard is designed with different end uses in mind, but both are essential in modern construction, automotive, and industrial projects.
ASTM A572 Grade 42 – Overview
ASTM A572 is a specification for HSLA (High Strength Low Alloy) structural steel. The Grade 42 designation indicates a minimum yield strength of 42 ksi (290 MPa). This steel is primarily used in bridges, buildings, and other load-bearing applications where both strength and weldability are crucial.
Key Mechanical Properties of A572 Grade 42
- Yield Strength: Minimum 290 MPa (42 ksi)
- Tensile Strength: 415–550 MPa
- Elongation: 18–21% (depending on thickness)
- Weldability: Excellent, with good response to standard welding methods
- Formability: Fair, but typically used in plate rather than sheet form
Applications
- Structural components in bridges and buildings
- Cranes, construction equipment, and heavy machinery
- Pressure vessels and components requiring high toughness
- Infrastructure projects where strength-to-weight ratio is important
ASTM A653M CS G90 SS Grade 33 – Overview
ASTM A653M covers hot-dipped galvanized steel sheets. The designation CS G90 SS Grade 33 can be broken down as follows:
- CS (Commercial Steel): Indicates the intended use is general forming and moderate strength applications.
- G90: Refers to the zinc coating weight, meaning 0.90 oz/ft² (275 g/m²) of zinc coating on both sides of the sheet.
- SS Grade 33: Indicates a minimum yield strength of 33 ksi (230 MPa).
This steel is valued for its corrosion resistance due to the zinc coating, making it ideal for applications where exposure to moisture or weather is a concern.
Key Mechanical Properties of A653M CS G90 SS Grade 33
- Yield Strength: Minimum 230 MPa (33 ksi)
- Tensile Strength: Approx. 310–380 MPa
- Elongation: 20% or higher, depending on thickness
- Corrosion Resistance: Excellent due to galvanized coating
- Formability: High, suitable for bending, stamping, and shaping
Applications
- Roofing and siding panels
- Automotive panels and body parts
- HVAC ductwork and appliance housings
- Agricultural and industrial equipment
- General sheet metal fabrication
Comparison of ASTM A572 Grade 42 and ASTM A653M CS G90 SS Grade 33
| Property / Feature | ASTM A572 Grade 42 | ASTM A653M CS G90 SS Grade 33 |
| Type of Steel | HSLA structural plate | Galvanized sheet steel |
| Yield Strength | 42 ksi (290 MPa) | 33 ksi (230 MPa) |
| Tensile Strength | 415–550 MPa | 310–380 MPa |
| Coating | None | G90 (zinc coating, 275 g/m²) |
| Formability | Moderate (structural applications) | Excellent (stamping & bending) |
| Corrosion Resistance | Requires protective coatings/painting | High, due to galvanization |
| Typical Applications | Bridges, buildings, heavy machinery | Roofing, HVAC, automotive, appliances |
| Standard Thickness Range | Plates: 6–150 mm | Sheets: 0.3–3.0 mm |
Performance Considerations
Strength vs. Corrosion Resistance
- ASTM A572 Grade 42 provides higher strength, making it better suited for heavy load-bearing structures.
- ASTM A653M CS G90 prioritizes corrosion protection with its zinc coating, making it ideal for exposed sheet applications.
Fabrication
- A572 Grade 42 is widely weldable but not typically used for intricate forming.
- A653M CS G90 SS Grade 33 excels in stamping, bending, and shaping, essential for automotive and HVAC industries.
Durability
- A572 needs protective coatings or galvanization for corrosion resistance.
- A653M G90 already has superior corrosion protection built in.
Market Prices and Cost Trends (2025 Outlook)
Prices vary depending on thickness, coating, supplier, and regional availability.
- ASTM A572 Grade 42 (Structural Steel Plate):
- Average Price: $700–850 per ton
- Higher thickness and mill-certified plates can go above $900 per ton.
- Used in bulk infrastructure projects, so pricing is tied to construction demand.
- Average Price: $700–850 per ton
- ASTM A653M CS G90 SS Grade 33 (Galvanized Sheet):
- Average Price: $750–950 per ton
- Thinner coils (0.3–0.7 mm) often priced at premium due to forming applications.
- Demand is closely tied to the automotive and building industries.
- Average Price: $750–950 per ton
Price Drivers:
- Raw material fluctuations in zinc and iron ore
- Global shipping costs
- Regional demand from construction and automotive sectors
- Steel tariffs and trade policies
How Buyers Choose Between the Two Grades
- For Heavy Structural Projects – Bridges, cranes, and pressure vessels → A572 Grade 42
- For Sheet Metal and Coated Applications – Roofing, ductwork, and automotive → A653M CS G90 SS Grade 33
- For Corrosion-Prone Environments – A653M with G90 coating offers superior protection.
- For High Load-Bearing Capacity – A572 is the better choice due to higher yield strength.
Future Demand Outlook
- A572 Grade 42: Demand will remain strong in infrastructure development, especially in bridges, renewable energy towers, and urban construction projects.
- A653M CS G90: Growth will be driven by increasing use of galvanized steel in EV manufacturing, sustainable building envelopes, and HVAC systems.
As industries focus on lightweight yet durable materials, both steels will continue to play key roles, but with different markets driving their growth.
Conclusion
And there is no doubt that both ASTM A572 Grade 42 and ASTM A653M CS G90 SS Grade 33 are essential steel products with their own benefits. Whereas A572 is trademarked strong and dependable in structure, A653M CS G90 is the formability and resistant to corrosion in sheet.
To the buyers, it is a matter of the end-use requirement:
When strength and load bearing matter → make an A572 Grade 42 choice.In the event that corrosion resistance and formability are the most important → select A653M CS G90 Grade 33. Price-wise, both steels are in the range of 700-950 USD per ton, and the price varies based on coating, thickness and international market demand.
These grades will be very relevant in the world steel market with the continuous growth of construction and automotive industries in 2025.