What is the ASTM equivalent of S420n steel?

What is the ASTM Equivalent of S420N Steel?

As a premier exporter and manufacturer of high-quality structural steel plates, Gangsteel specializes in producing EN 10025-3 compliant materials, including the high-strength S420N steel grade.

S420N is a normalized fine-grain structural steel with a minimum yield strength of 420 MPa and excellent impact toughness at -20°C, making it ideal for welded constructions in bridges, cranes, offshore structures, and heavy machinery.

When sourcing for projects requiring ASTM standards, understanding the ASTM equivalent of S420N is crucial for compliance and performance. The closest ASTM equivalent is A572 Grade 65 (ASTM A572/A572M), a high-strength low-alloy columbium-vanadium structural steel with a minimum yield strength of 450 MPa, which is slightly higher but comparable in application. Other close matches include A572 Grade 60 (415 MPa yield) for a better strength alignment or A633 Grade E for enhanced low-temperature properties.

Gangsteel supplies S420N and ASTM-equivalent plates with dual certifications, ensuring seamless integration for international projects. For related grades, see our en 10025 3 normalized steel plate offerings or en 10025 3 s420nl normalized structural steel plate.

Understanding S420N Steel

S420N, designated as 1.8902 under EN 10025-3, is part of the family of weldable fine-grain structural steels. The "S" stands for structural steel, "420" indicates the minimum yield strength, and "N" denotes normalized delivery with impact testing at -20°C (40 J longitudinal). This grade is optimized for environments requiring high ductility and resistance to brittle fracture in cold conditions, distinguishing it from milder variants like S355N.

Under EN 10025-3, S420N is supplied in thicknesses from 6 mm to 250 mm, with controlled alloying for a maximum Carbon Equivalent Value (CEV) of 0.48 to enhance weldability. Gangsteel ensures plates meet all inspection requirements, including ultrasonic testing and Charpy impact verification, for reliable performance in global projects.

Chemical Composition of S420N Steel

The chemical makeup of S420N is carefully balanced to provide excellent strength, ductility, and resistance to brittle fracture. Below is the ladle analysis for nominal thicknesses ≤ 100 mm, with a maximum Carbon Equivalent Value (CEV) of 0.48.

*Note: Low P and S levels improve toughness; CEV ensures minimal weld cracking.

ASTM Equivalent to S420N Steel

The ASTM equivalent to S420N is A572 Grade 65 (ASTM A572/A572M), a high-strength low-alloy structural steel with a minimum yield strength of 450 MPa and good weldability. This grade is often used in similar applications, such as bridges and buildings, and can be supplied in normalized condition to match S420N's fine-grain structure.

Another close equivalent is A572 Grade 60 (415 MPa yield) for a more precise strength match, or A633 Grade E (415 MPa yield) for enhanced low-temperature performance. However, no ASTM grade is an exact replica, as EN 10025-3 emphasizes fine-grain normalization and specific impact testing at -20°C, which may require additional specifications in ASTM grades.

From industry tables, S420N is sometimes listed alongside ASTM A255 Gr. D, but this is likely a typographical error, as A255 is a test method for hardenability, not a steel grade. Always verify with mill certificates for substitution.

Equivalent Grades to S420N

Why Choose Gangsteel for S420N Steel?

Gangsteel delivers ISO-certified S420N plates with custom sizes and worldwide export. Visit our en 10025 3 s420n normalized structural steel plate page for specs and quotes, or en 10025 3 s420nl normalized structural steel plate for the low-temperature variant.

Summary

The ASTM equivalent to S420N steel is A572 Grade 65, offering similar high-strength low-alloy properties with a 450 MPa yield. While not identical, it serves as a reliable substitute for welded structural applications when normalized and impact-tested appropriately. S420N's fine-grain normalization and -20°C toughness make it a preferred choice in European standards for demanding environments.

FAQ

What is the closest ASTM equivalent to S420N steel?

A572 Grade 65 (ASTM A572/A572M), with 450 MPa yield strength, normalized delivery, and comparable weldability. A572 Grade 60 (415 MPa) is also close for strength alignment.

How does A572 Grade 65 compare to S420N in chemistry?

Both have low carbon (0.23% max for A572 Gr. 65 vs 0.20% for S420N) and CEV around 0.48, but S420N has tighter phosphorus (0.025% vs 0.040%) and sulfur (0.020% vs 0.050%) for better toughness.

Are the mechanical properties of S420N and its ASTM equivalent identical?

A572 Gr. 65 has higher yield (450 MPa vs 420 MPa) and tensile strength (550–690 MPa vs 520–680 MPa), with similar elongation (17% vs 19%). Impact testing must be specified for -20°C to match S420N's 40 J.

Can A572 Grade 65 replace S420N without changes?

Yes, if normalized and tested for 40 J at -20°C, A572 Gr. 65 matches S420N for applications like bridges or offshore in moderate cold.

What if I need an equivalent for S420NL ( -50°C)?

Use A572 Gr. 65 with supplemental -50°C impact testing, or A633 Grade E (415 MPa yield, -40°C standard).