When you’re buying galvanized steel, one of the most important specifications you’ll encounter is the coating weight. For steel buyers, terms like G60 galvanized steel and G90 galvanized steel are more than just labels. They define performance, durability, and suitability for your application. Knowing the difference ensures you’re not over- or under-specifying material, which affects both cost and long-term performance.
At Hascall Steel, we stock and process galvanized steel across coating weights, providing the knowledge and inventory needed to support a wide range of industries. Whether you need the everyday reliability of G60 or the added protection of G90, we deliver galvanized steel across a wide range of specifications so you can purchase with confidence.
Why Coating Weight Matters
Galvanizing protects steel by applying a layer of zinc, which acts as a barrier against corrosion. The thicker the zinc coating, the longer the steel can withstand environmental exposure before rusting.
Coating weight is expressed as the total amount of zinc applied to both sides of the steel sheet, measured in ounces per square foot (oz/ft²) or grams per square meter (g/m²). This isn’t just an abstract measurement; it directly translates into performance.
- Higher coating weight equals a thicker zinc layer and greater corrosion resistance
- Lower coating weight equals a thinner zinc layer and cost savings when less protection is required
The key is matching the coating weight to the environment and service life expectations of the end product.
What Is G60 Galvanized Steel?
G60 galvanized steel has a total zinc coating weight of 0.60 oz/ft², split across both sides of the sheet. That equals about 0.30 oz/ft² per side.
- Typical thickness of zinc layer: roughly 0.3 mils per side
- Corrosion resistance: adequate for indoor environments and many controlled outdoor conditions
- Common applications: HVAC ductwork, interior building products, office furniture, and general manufacturing where exposure to moisture and weather is limited
G60 strikes a balance between protection and cost, making it a practical choice for buyers who don’t require the maximum lifespan of a heavier coating.
What Is G90 Galvanized Steel?
G90 galvanized steel carries a total zinc coating weight of 0.90 oz/ft², or about 0.45 oz/ft² per side.
- Typical thickness of zinc layer: about 0.6 mils per side
- Corrosion resistance: stronger than G60, especially in environments with higher humidity, outdoor exposure, or frequent condensation
- Common applications: roofing, siding, outdoor panels, structural components, agricultural equipment, and other uses where long-term durability is critical
The heavier zinc coating provides added insurance against rust, which is why G90 is often specified in construction and outdoor applications.
ASTM Standards: Assurance for Buyers
Both G60 and G90 galvanized steel are produced in accordance with ASTM A653/A653M, the standard specification for coated flat rolled steel coil and sheet, zinc-coated (galvanized) or zinc-iron alloy-coated (galvannealed).
ASTM standards define:
- Minimum coating weight requirements
- Coating adherence and quality
- Surface condition and finish
- Mechanical properties such as yield strength and elongation
By purchasing galvanized steel to ASTM specifications, buyers ensure that material is tested, verified, and consistent across suppliers. At Hascall Steel, we guarantee our galvanized steel meets ASTM requirements so you can rely on consistent performance and certification.
Comparing G60 and G90: Key Considerations
When deciding between G60 galvanized steel and G90 galvanized steel, think in terms of exposure, cost, and service life.
1. Exposure Conditions
- G60 works well indoors or in controlled environments
- G90 is better suited for exterior or semi-exposed settings where moisture and weather accelerate corrosion
2. Service Life Expectation
- G90 lasts longer due to its thicker zinc layer
- If your customer requires extended warranties, G90 is often the safer choice
3. Cost Balance
- G60 typically costs less, since it uses less zinc
- G90, while more expensive, may save on long-term replacement or maintenance costs
4. Industry Standards and Codes
- Certain building codes and OEM specifications mandate G90
- Other sectors may allow or prefer G60 for cost efficiency
Industries and Applications
Industry / Sector | G60 Applications | G90 Applications |
Automotive and Transportation | Interior panels, non-exposed components | Exterior parts requiring enhanced corrosion resistance |
Construction and Building Products | Interior framing, studs, ceiling grids | Roofing panels, siding, flashing, gutters |
HVAC and Ductwork | Standard ducts, indoor systems | Rooftop units, ductwork exposed to outdoor air |
Appliances and Furniture | Washers, dryers, shelving, office furniture | Outdoor enclosures, toolboxes, storage products |
Agriculture and Industrial Equipment | Indoor machinery housings | Fencing, silos, irrigation systems, exposed equipment |
Beyond G60 and G90: Other Coating Weights
While G60 and G90 are the most common for many applications, other coating weights are still very prevalent, including G30, G40, and G185. At Hascall Steel we carry a wide range of galvanized steels across all coating weights to meet diverse requirements.
This means we can help you:
- Optimize specifications for cost vs. performance
- Stock the right material for your production schedule
- Provide technical guidance on selecting the most effective coating weight
Why Choose Hascall?
At Hascall Steel, we know that choosing the right galvanized steel is about more than just inventory. It is about expertise, standards, and service.
- Wide inventory: We stock Galvanized steel from G30 up to G185
- Specification conformance: Every order meets your specification, whether it is domestic or foreign ensuring quality and consistency
- Processing capabilities: From slitting and shearing to blanking and leveling, we process steel to your exact dimensions
- Industry knowledge: With a collective 150+ years of experience in the industry, our sales team understands the demands of manufacturing, industrial, and many more applications and how to meet them.
At Hascall Steel, we’re here to help you navigate coating weights, meet your specifications, and keep your production running smoothly.
Contact us to learn more about our G60, G90, and other coating weight options.