ASTM A242 Weathering Steel for Fabrication
ASTM A242 is a high-strength, low-alloy structural steel specification with improved atmospheric-corrosion resistance. Its scope includes plates, shapes and bars for welded, bolted or riveted construction.
For exposed plate components, the material combines structural properties with the ability to develop a protective weathered surface under suitable conditions. The resulting appearance is useful in architectural steelwork, while the specified material properties remain important to the component’s design.
ASTM A242 Type 1 and Legacy Type 2
Type 1 and Type 2 are not interchangeable labels. Type 2 appears in historical A242 specifications as a lower-phosphorus material designation. A legacy Type 2 request therefore needs the edition and material requirements referenced by the original drawing.
ASC handles Type 1 plate supply and legacy Type 2 enquiries within the same A242 range. For replacement or refurbishment work, the original material basis is reviewed before an offer is agreed.
| Designation | Material context |
|---|---|
| ASTM A242 Type 1 | Structural weathering-steel plate; the chemical and tensile references below are explicitly ASTM A242-13. |
| Legacy ASTM A242 Type 2 | Historical A242 designation assessed against the referenced edition and project requirements. |
Type 1 property values are not applied to legacy Type 2 material.
A242 Type 1 reference, section 6.1.5.2 · Historical A242 types, NCHRP Report 314, section 4.2
ASTM A242 Plate and Sheet Dimensions
ASC quotes flat material by thickness, width and length for the fabrication schedule. Plate and sheet enquiries are matched to the applicable structural-product requirements, including the required testing and documentation.
The current ASTM A242/A242M-24 scope extends to 4 in [100 mm] thickness. These are independently stated standard-system limits, not a stocked-size range. The quotation confirms the available dimensional combination.
Thickness also affects the mechanical requirements. The Type 1 reference below separates the plate-thickness bands rather than applying one yield value to every plate or sheet.
ASTM A242 Plates and Sheets Supplier, Exporter and Stockist
ASC exports internationally and welcomes ASTM A242 enquiries from fabricators, contractors and distributors in the USA, the UK and Europe, including Germany and the Netherlands. We support new fabrication and replacement-material purchasing, with domestic supply also available.
We specialize in fast delivery and prioritize urgent requirements. Material specification, dimensions, quantity, availability and destination determine the delivery schedule. Bundles or wooden boxes can be selected to suit the flat products and order.
Request an ASTM A242 Plates and Sheets Export QuoteASTM A242 Type 1 Chemical Composition
The Type 1 chemistry reference identifies carbon, manganese, phosphorus and sulfur limits alongside a minimum copper content. These are heat-analysis limits; actual heat results are reported in the material documents.
| Element | Limit |
|---|---|
| Carbon, C | ≤ 0.15 |
| Manganese, Mn | ≤ 1.00 |
| Phosphorus, P | ≤ 0.15 |
| Sulfur, S | ≤ 0.05 |
| Copper, Cu | ≥ 0.20 |
ASTM A242-13 (2013) Type 1 heat-analysis reference. Product-analysis tolerances differ; the edition specified for the order governs acceptance.
A242-13 Type 1 reference, section 6.1.5.2
ASTM A242 Type 1 Mechanical Properties
Minimum yield point and tensile strength decrease across the plate-thickness bands in this reference. Elongation is reported at two gauge lengths and remains subject to the plate-width, thickness and specimen provisions stated below.
| Plate thickness, in | Yield point, minimum ksi | Tensile strength, minimum ksi | Baseline elongation, 8 in gauge | Baseline elongation, 2 in gauge |
|---|---|---|---|---|
| ≤ 0.75 | 50 | 70 | 18% | 21% |
| > 0.75–1.50 inclusive | 46 | 67 | 18% | 21% |
| > 1.50–4.00 inclusive | 42 | 63 | 18% | 21% |
For plate wider than 24 in, reduce the baseline elongation requirement by two percentage points. Below 5/16 in thickness, applicable ASTM A6 elongation adjustments apply. Specimen direction and other test provisions follow the ordered product requirements.
ASTM A242-13 (2013) Type 1 reference in the inch/ksi system. The ordered edition and applicable product-testing provisions govern acceptance.
A242-13 tensile reference, printed page 39
Applications in Architecture and Structural Fabrication
Architectural metalworkers use weathering plate in designed screens, facade elements and exposed fabricated features where both material appearance and durability matter. Structural fabricators use specified A242 material in plate components joined by welding, bolting or riveting.
Building and refurbishment work can involve a mixture of plate thicknesses and older material descriptions. Matching the product to the design is particularly important for a legacy Type 2 requirement or a component with additional impact-toughness requirements.
Welding procedures and consumables should suit the actual material, thickness and service. Tensile values alone do not establish impact performance or the load capacity of the finished assembly.
Outdoor Exposure and Protective Weathering
The protective surface develops best where the steel can become wet and then dry. Drainage, ventilation and details that avoid water or debris traps are important for exposed assemblies.
Persistent moisture and significant chloride exposure need particular assessment. Weathering run-off can also stain concrete, paving and adjacent finishes, so drainage paths matter as much as the intended surface appearance.
Material Documents and Inspection
Mill test certificates and additional inspection can be requested for ASTM A242 orders. The documentation and inspection scope are agreed with the offer, including any project-specific acceptance requirements.
For legacy Type 2 enquiries, the referenced edition and original material requirements provide the basis for assessing the proposed supply. A substitute grade is offered only against the project’s permitted alternatives.
ASTM A242 Plates and Sheets FAQs
What is the difference between ASTM A242 Type 1 and Type 2?
Type 2 is a historical lower-phosphorus A242 designation. Type 1 and legacy Type 2 requirements must be matched to their referenced editions; they are not interchangeable labels. The numerical references shown are for ASTM A242-13 Type 1 only.
Can ASC handle a legacy ASTM A242 Type 2 requirement?
Yes. ASC welcomes legacy Type 2 enquiries for assessment against the original drawing or specification. The referenced edition and material requirements are reviewed before the proposed supply is confirmed.
Does every A242 Type 1 plate have the same yield requirement?
No. The 2013 Type 1 reference gives minimum yield points of 50 ksi through 0.75 in, 46 ksi above 0.75 through 1.50 in, and 42 ksi above 1.50 through 4.00 in. The ordered edition and product requirements govern acceptance.
What sizes can be quoted for ASTM A242 plates and sheets?
ASC quotes thickness, width and length combinations for the project. The current A242 specification extends to 4 in [100 mm] thickness, but this scope limit is not a stock list. Available dimensions are confirmed with the material offer.
Can ASTM A242 steel be used without paint?
Suitable applications can use it unpainted when exposure and detailing support protective weathering. Drainage, drying, persistent moisture, chloride exposure and staining of adjacent finishes should be considered in the design.
Can ASTM A588 or Corten A replace A242 Type 1?
Only where the project accepts the proposed material after comparing its requirements. A trade name, similar appearance or overlapping strength does not establish automatic equivalence or dual compliance.
Can I request an A242 mill test certificate or additional inspection?
Yes. Mill test certificates and additional inspection can be requested. The order should identify the required specification basis and any project-specific acceptance requirements so the documentation can be agreed.
How are A242 plates packed, and what affects delivery?
Bundles or wooden boxes can be selected for the product dimensions and quantity. ASC specializes in fast delivery; the schedule depends on the material requirement, sizes, quantity, availability, inspection scope and destination.