Products Description
ASTM A572 Grade 55 belongs to the family of high-strength, low-alloy (HSLA) structural steels, designed for demanding load-bearing applications that require greater yield strength than Grade 50 while maintaining good ductility and formability. Enhanced with columbium (niobium), vanadium, and occasionally copper, this steel exhibits excellent fatigue and impact resistance.
It is frequently used in bridge decks, long-span girders, transmission towers, and offshore platforms, where strength-to-weight optimization and moderate atmospheric corrosion resistance are essential. Due to its weldable and formable characteristics, ASTM A572 Grade 55 is ideal for bolted, riveted, or welded assemblies in high-performance engineering.
ASTM A572 Gr.55 Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | ≤ 0.25 |
| Manganese (Mn) | ≤ 1.35 |
| Phosphorus (P) | ≤ 0.04 |
| Sulfur (S) | ≤ 0.05 |
| Silicon (Si) | ≤ 0.40 |
| Vanadium (V) | 0.01–0.15 |
| Columbium (Nb) | 0.005–0.05 |
| Copper (Cu, when specified) | ≥ 0.20 |
The low carbon equivalent enhances weldability, while micro-alloying elements such as vanadium and niobium refine grain size, increasing toughness and reducing crack sensitivity. Compared with lower grades, Grade 55 offers superior performance in thicker sections without sacrificing flexibility.
Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength (Min) | 380 MPa (55 ksi) |
| Tensile Strength (Min) | 485 MPa (70 ksi) |
| Elongation (in 200mm) | ≥ 17% |
| Elongation (in 50mm) | ≥ 20% |
| Charpy V-Notch Impact (0°C, optional) | ≥ 27 J |
These properties make it ideal for load-bearing and fatigue-intensive structures, offering a balanced combination of strength, ductility, and resilience suitable for bridges, cranes, and machinery frameworks.
Products Application
The versatility of ASTM A572 Grade 55 steel plate supports numerous engineering and industrial fields:
Bridge Construction: Used for girders, decks, and structural supports in long-span bridges.
High-Rise Buildings: Employed in seismic frames, columns, and load-bearing structures.
Machinery & Equipment: Applied in excavator arms, crane booms, and loaders.
Power Transmission Towers: Offers superior strength for lattice and pole structures.
Railcar and Truck Frames: Ensures stability under dynamic loading.
Offshore Platforms: Provides corrosion resistance in marine environments.
Gnee steel supplies ASTM A572 Gr.55 plates with thicknesses from 6 mm to 200 mm, widths up to 3200 mm, and lengths up to 18,000 mm, suitable for both domestic and export projects.
