ASTM A242 is a standard specification for high-strength low-alloy structural steel with enhanced atmospheric corrosion resistance (weathering steel). Its closest equivalents come from major international standards, primarily ISO and European (EN) standards. Direct equivalence is complex due to differences in categorization and specific requirements, but these are the primary counterparts:
ISO 5952: Weathering Steels:
WR350A: This is the closest ISO equivalent to ASTM A242 Type 1 (the most common grade). They share:
Similar high-strength properties (minimum yield strength around 345 MPa / 50 ksi).
Comparable corrosion resistance based on alloying elements like Cu, Cr, and Ni.
The "WR" prefix indicates "Weathering Resistance."
EN 10025-5: Structural Steels with Improved Atmospheric Corrosion Resistance:
S355J0W: This is the most common European equivalent grade.
S355 denotes a minimum yield strength of 355 MPa at ≤16mm thickness (close to A242's 50 ksi/345 MPa).
J0 indicates impact toughness (27 J) at 0°C (EN specs often mandate impact testing, which is supplementary in ASTM A242).
W signifies "Weathering steel".
Other Similar EN Grades: S355J2W (impact at -20°C), S355K2G1W ("G1" indicates similar use/properties as S355J0W/J2W but can have slight chemical/physical differences).
Key Difference: EN standards define steel grades based on bothmechanical properties (like yield strength) and specific impact toughness categories (like J0, J2). ASTM A242 primarily focuses on chemistry and tensile properties, with toughness often a supplementary requirement.
JIS G 3114: Hot-Rolled Atmospheric Corrosion Resisting Steels for Welded Structure (Japanese Standard):
SPA-H: This JIS grade is a widely used weathering steel with properties similar to ASTM A242 and Corten A.
Important Considerations Regarding Equivalents:
No Perfect 1:1 Match: Different standards have different underlying philosophies, testing requirements (especially impact toughness), and certification processes. "Equivalence" refers to similar intended purpose (weathering steel), strength level, and chemical composition targets.
Chemical Composition: The core reason for atmospheric corrosion resistance in all these standards is the similar alloying, primarily higher Copper (Cu), Chromium (Cr), and sometimes Nickel (Ni).
Mechanical Properties: They offer similar yield and tensile strengths, providing high-strength advantages.
Verification is Crucial: When selecting an equivalent for a specific application (especially a critical structural one), ALWAYS consult the detailed specifications of the standards involved and potentially the project engineer. Do not assume direct substitutability without thorough verification against the application requirements (thickness, temperature, fabrication method, required properties).
In summary:
The primary ISO equivalent is WR350A (ISO 5952).
The most common European equivalent is S355J0W (EN 10025-5).
A key Japanese equivalent is SPA-H (JIS G 3114).
Remember that ASTM A242 Type 1 is the specific grade most often referenced when talking about these equivalents.
Just like you, 70% customers choose long-term cooperation with BBN steel not only for our good product and service quality, good reputation in the international market, but also for our experienced one-stop raw material supply and further steel processing!
