ASTM A572 Grade 50 vs ASTM A588 (Corten): Same yield strength — A588 adds weathering corrosion resistance
ASTM A572 Grade 50 vs ASTM A588 (Corten)
Side-by-side chemical composition and mechanical property comparison.
Overview
ASTM A572 Grade 50
The most widely used structural steel grade in the United States. 345 MPa (50 ksi) yield strength HSLA steel. Has largely replaced A36 for structural applications due to higher strength-to-weight ratio. Used for building frames, bridges, heavy equipment, and general structural fabrication.
ASTM A588 (Corten)
High-strength low-alloy weathering steel. Forms a stable protective rust patina eliminating the need for paint. Cu-Cr-Ni-V composition provides 4-8x atmospheric corrosion resistance vs carbon steel. Used for unpainted bridges, architectural facades, sculptures, outdoor structures, and freight cars.
| ASTM A572 Grade 50 | ASTM A588 (Corten) | |
|---|---|---|
| Material Number | — | — |
| Category | Carbon Steel | Carbon Steel |
| Standard | ASTM A572 | ASTM A588 |
Chemical composition (wt%)
| Element | ASTM A572 Grade 50 | ASTM A588 (Corten) | Overlap |
|---|---|---|---|
| C | 0–0.23% | 0–0.19% | OK |
| Si | 0–0.4% | 0.3–0.65% | Partial |
| Mn | 0–1.35% | 0.8–1.25% | OK |
| P | 0–0.04% | 0–0.04% | OK |
Mechanical properties
| Property | ASTM A572 Grade 50 | ASTM A588 (Corten) | Unit |
|---|---|---|---|
| tensile_strength | ≥ 450 | ≥ 485 | MPa |
| yield_strength | ≥ 345 | ≥ 345 | MPa |
| elongation | ≥ 18 | ≥ 18 | % |
Compatibility Assessment
Both have 345 MPa yield. A588 adds Cu/Cr/Ni/V for a protective patina that eliminates painting. A572-50 is ~15% cheaper. Choose A588 for unpainted outdoor structures; A572-50 for painted/indoor.
Frequently Asked Questions
Is ASTM A572 Grade 50 the same as ASTM A588 (Corten)?
ASTM A572 Grade 50 and ASTM A588 (Corten) have a 75% composition overlap. Same yield strength — A588 adds weathering corrosion resistance
Can I replace ASTM A572 Grade 50 with ASTM A588 (Corten)?
In many cases, yes. The compositions overlap significantly (75%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between ASTM A572 Grade 50 and ASTM A588 (Corten)?
The main differences are in the following elements: Si. ASTM A572 Grade 50 is a Carbon Steel grade, while ASTM A588 (Corten) is a Carbon Steel grade.
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