ASTM A572 Grade 50 vs P355NL: 70% composition overlap. Some similarities but notable differences in alloying elements.
ASTM A572 Grade 50 vs P355NL
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.
P355NL
1.0566
Normalized pressure vessel steel with low-temperature toughness — ReH >=355 MPa, Charpy at -40°C (KV >=27J). "NL" = Normalized + Low-temperature. Used for pressure vessels, storage tanks, and process equipment operating in cold environments (LPG, cryogenic). EN 10028-3 + PED compliant.
| ASTM A572 Grade 50 | P355NL | |
|---|---|---|
| Material Number | — | 1.0566 |
| Category | Carbon Steel | Carbon Steel |
| Standard | ASTM A572 | EN 10028-3 |
Chemical composition (wt%)
| Element | ASTM A572 Grade 50 | P355NL | Overlap |
|---|---|---|---|
| C | 0–0.23% | 0–0.18% | OK |
| Si | 0–0.4% | 0–0.5% | OK |
| Mn | 0–1.35% | 1–1.7% | Partial |
| P | 0–0.04% | — | — |
Mechanical properties
| Property | ASTM A572 Grade 50 | P355NL | Unit |
|---|---|---|---|
| tensile_strength | ≥ 450 | 490–630 | MPa |
| yield_strength | ≥ 345 | ≥ 355 | MPa |
| elongation | ≥ 18 | ≥ 20 | % |
Compatibility Assessment
ASTM A572 Grade 50 and P355NL share some characteristics (70% overlap) but have notable differences. They may be substitutable in some applications but not all. Verify suitability carefully.
Automated assessment based on composition analysis
Frequently Asked Questions
Is ASTM A572 Grade 50 the same as P355NL?
ASTM A572 Grade 50 and P355NL have a 70% composition overlap. For most purposes, they can be considered similar.
Can I replace ASTM A572 Grade 50 with P355NL?
In many cases, yes. The compositions overlap significantly (70%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between ASTM A572 Grade 50 and P355NL?
The main differences are in the following elements: Mn. ASTM A572 Grade 50 is a Carbon Steel grade, while P355NL is a Carbon Steel grade.
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.