ASTM A588 Grade A and ASTM A633 Grade A are High-Strength Low-Alloy (HSLA) structural steels, but A588 is a weathering steel for corrosion resistance (like bridges, corten), while A633 is a normalized steel for good low-temperature toughness (like auto frames, offshore structures), differing in composition and processing for their specific outdoor/toughness needs, though both offer good strength.
Chemical Composition of A588 Grade A
ASTM A588 Chemical Composition | |||||||
Grade | The Element Max (%) | ||||||
C | Si | Mn | P | S | Ni | Nb | |
A588 | 0.19 | 0.30-0.65 | 0.80-1.25 | 0.04 | 0.05 | 0.40 | .. |
Cu | Cr | Mo | N | V |
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0.25-0.40 | 0.40-0.65 | … | 0.01 | 0.02-0.10 |
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Chemical Composition of A633 Grade A
C | Si | Mn | P | S | Al(min) | N |
0.18 | 0.15-0.50 | 1.00-1.35 | 0.035 | 0.04 |
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Cr | Cu | Mo | Nb | Ni | Ti | V |
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| 0.05 |
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Mechanical properties of A588 Grade A
Mechanical Property of A588 Grade A steel plate | A588 Grade A |
Tensile strength, kis [MPa] | Tensile strength, kis [MPa] |
100mm or under | [485] |
100mm-125mm | [460] |
125mm-200mm | [435] |
Yield strength, min, kis [MPa] | Yield strength, min, kis [MPa] |
100mm or under | [345] |
100mm-125mm | [315] |
125mm-200mm | [290] |
Elongation in under. [50 mm], min, % | 21 |
Elongation in under. [50 mm-200mm], min, % | 18 |
Mechanical properties of A633 Grade A
Temperature | -35 | -20 | 0 | 25 |
Notch impact test. Min. absorbed energy J | 41 | 54 | 61 | 68 |
Nominal thickness (mm) | to 65 | 65 - 100 | 100 - 150 |
ReH - Minimum yield strength (MPa) | 290 | 290 |
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Nominal thickness (mm) | To 65 | 65- 100 | 100-150 |
Rm -Tensile strength (MPa) | 430-570 | 430-570 |
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Gauge Length (mm) | 200 | 50 |
A - Minimum elongation Lo = 5,65 √ So (%) Longitudinal |
18 |
23 |
ASTM A588 Grade A (Weathering Steel)
Purpose: Designed for atmospheric corrosion resistance, forming a stable, rust-like protective layer (patina) when exposed to weather.
Key Feature: Contains copper, chromium, and nickel for enhanced corrosion protection; often used unpainted (Corten steel).
Applications: Bridges, utility poles, guardrails, buildings.
ASTM A633 Grade A (Normalized Steel)
Purpose: Offers good notch toughness at low temperatures.
Key Feature: Normalized heat treatment for refined grain structure, improving impact strength.
Applications: Automotive frames, general structural use where toughness at cold temperatures is crucial.
Key Differences Summarized
A588 (Weathering): Corrosion-focused, forms patina, for exposed structures.
A633 (Normalized): Toughness-focused, especially in cold, for vehicles/marine.
Both offer high strength, but their specific alloying and treatment tailor them for different performance demands in harsh environments.
