ASTM A572 Grade 50 carbon steel plate is the most widely used high-strength low-alloy (HSLA) structural plate in North American construction. It bridges the gap between ordinary A36 plate and high-strength quenched-and-tempered grades like A514, delivering a 50 ksi (345 MPa) minimum yield strength with excellent weldability and formability. It is the reference material for bridges, transmission towers, building columns, heavy equipment frames, and mining / earthmoving machinery.
Huaxia-Steel supplies A572 Gr.50 plate direct from ISO-certified Chinese mills, with full ASTM A6 / A572 / A36 dual compliance on request, EN 10204 3.1 mill certification, third-party inspection (SGS / BV / TUV), and global ocean shipping.
Product Overview
A572 Grade 50 is a high-strength low-alloy (HSLA) structural plate standardized under ASTM A572/A572M-21. The specification covers five grades (42, 50, 55, 60, 65) with progressively higher yield strengths. Grade 50 is by far the most specified — it provides 50 ksi (345 MPa) minimum yield at thicknesses up to 4 inches (100 mm), with excellent notch toughness and welding characteristics derived from its low-carbon, micro-alloyed chemistry (typically Nb, V, or Ti additions).
Specifications
Standard & Grade
- Standard: ASTM A572/A572M-21 (Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel)
- Grade: Grade 50 (50 ksi / 345 MPa minimum yield)
- Product form: Hot-rolled plate; structural shapes also available as A572 Gr.50 per ASTM A6
- Delivery condition: As-rolled (+AR), with optional normalizing (+N) for thickness over 50 mm
- Equivalents: EN 10025-2 S355JR / S355J0 / S355J2, JIS G3101 SS490 (older), GB/T Q355B (most direct), DIN St52-3 (legacy)
Dimensional Range
| Parameter | Range |
|---|---|
| Thickness | 5 mm – 100 mm (standard); 5 – 200 mm (special order) |
| Width | 1,500 mm – 3,500 mm |
| Length | 3,000 mm – 18,000 mm |
| Plate weight (10 mm) | ~78.5 kg/m² |
| Maximum plate weight | ~15 – 20 tonnes per plate |
Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength (ReH, ≤100 mm) | ≥345 MPa (50 ksi) |
| Yield Strength (100 – 150 mm) | ≥325 MPa |
| Tensile Strength (Rm) | ≥450 MPa (65 ksi min) |
| Elongation (A200, ≥200 mm gauge) | ≥18% (typical 21 – 25%) |
| Elongation (A50, 50 mm gauge) | ≥21% (typical) |
| Brinell Hardness (typical) | 140 – 180 HBW |
| Charpy Impact (default per A572) | Not required (by agreement can be specified) |
Chemical Composition (Heat Analysis, max %)
| C | Mn | P | S | Si | Nb | V | Ti |
|---|---|---|---|---|---|---|---|
| 0.23 | 1.35 (typically 0.80 – 1.35) | 0.040 | 0.050 (≤0.040 for shapes) | 0.40 (typical 0.15 – 0.40) | 0.005 – 0.05 | 0.01 – 0.15 | 0.01 – 0.05 |
The micro-alloying with Nb (columbium), V (vanadium), or Ti produces a fine-grain microstructure that delivers the 50 ksi yield without requiring higher carbon content (which would compromise weldability). The typical CEV for A572 Gr.50 is 0.38 – 0.45, allowing welding without preheating for thin sections up to 25 mm.
Subgrades and Supplementary Requirements
| Subgrade / Designation | Description |
|---|---|
| A572 Gr.50 (default) | Standard 345 MPa minimum yield, no impact requirement |
| A572 Gr.50 + Charpy 27J @ 0°C | By agreement between buyer and producer |
| A572 Gr.50 + Charpy 27J @ -20°C | Cold-climate applications |
| A572 Gr.50 Type 1 | Columbium (Nb) micro-alloyed |
| A572 Gr.50 Type 2 | Vanadium micro-alloyed |
| A572 Gr.50 Type 3 | Columbium + Vanadium |
| A572 Gr.50 Type 4 | Vanadium + Nitrogen |
| A572 Gr.50 Type 5 | Titanium + Nitrogen |
For atmospheric corrosion resistance (“weathering steel”), A572 is not the appropriate specification — use ASTM A242 or ASTM A588 instead.
Manufacturing Standards
- ASTM A572/A572M-21: Chemistry and mechanical properties
- ASTM A6/A6M: General requirements for plate, shapes, and bars (dimensional tolerances, marking, testing)
- ASTM A370: Mechanical testing methods
- ASTM E415 / OES: Chemistry verification by optical emission spectroscopy
- EN 10204 3.1: Mill test certificate supplied with every plate
- ASTM A578/A578M: Ultrasonic examination (optional, by agreement)
Typical Applications
Construction & Infrastructure
- Steel building columns and beams (multi-story commercial and industrial)
- Bridge girders and cross-frames (highway, rail, pedestrian)
- Transmission towers and substations
- Industrial building frames, crane girders
- Stadium roof structures, long-span trusses
Heavy Equipment & Machinery
- Mining truck bodies and excavator booms
- Crane jibs and outrigger pads
- Agricultural machinery frames
- Heavy haul trailer chassis
- Offshore platform secondary structures
Energy Sector
- Wind turbine tower flanges and base plates
- Solar tracker structural supports
- Hydroelectric turbine housings
- Power plant ducting and bunker structures
Transportation
- Rail car bodies (high-strength hopper, tank car shell)
- Truck frame rails and cross members
- Ship hull secondary structures
- Container chassis
Welding and Fabrication Notes
A572 Gr.50 is readily weldable by all standard arc-welding processes:
- SMAW (stick): E7018, E7018-1 (low-hydrogen)
- GMAW (MIG): ER70S-6, ER80S-G (for matching strength)
- FCAW: E71T-1, E81T1 (for higher deposition)
- GTAW (TIG): ER70S-2, ER80S-G
Preheat is generally not required for sections up to 25 mm thickness. For thicker sections or high-restraint joints, preheat to 100 – 150 °C and use low-hydrogen consumables to avoid HAZ cracking. The combined effect of micro-alloying and controlled CEV makes A572 Gr.50 one of the easier high-strength structural plates to weld in field conditions.
Quality Assurance
- MTC EN 10204 3.1: Independent of manufacturing source, listing heat chemistry, mechanical results, and dimensional verification.
- Optional Charpy impact testing: Per agreement at 0°C or -20°C, full-size specimens.
- Optional ultrasonic testing: Per ASTM A578 Level I, II, or III.
- Third-party inspection: SGS, BV, TUV, or Intertek at mill before shipment.
- Traceability: Each plate marked with heat number, plate number, dimensions, weight, and ASTM marking per A6.
Packaging & Shipping
- Plate bundles: 4 – 10 plates per bundle, secured with 4 – 6 steel bands, edge protectors on corners
- Markings: Heat number, plate number, grade (e.g., “A572 / GR50”), dimensions, weight per bundle
- Surface protection: Optional mill primer, desiccants, or VCI paper for long voyages
- Container / bulk: Plates up to 12 m in 40′ open-top or flat-rack containers; larger plates on break-bulk ships
- Lead time: Stock grades ship in 2 – 4 weeks; special thickness / impact testing 6 – 10 weeks
Order Information
To receive an accurate quotation, please provide:
- Standard and grade: ASTM A572 Gr.50 (or dual cert with A36 / EN 10025 S355)
- Dimensions: Thickness, width, length, quantity
- Mechanical requirements: Yield, tensile, elongation (default per A572), impact (if any)
- Dimensional tolerances: Standard A6 or tighter per agreement
- Surface condition: Mill scale, shot-blasted, primer-coated
- Inspection requirements: MTC, third-party inspection, ultrasonic
- Delivery terms: FOB / CIF / DDP to project port
A572 Gr.50 plate is widely available in most major steel-producing countries. The most consistent sources:
- North America (USA, Canada, Mexico): Nucor, SSAB Americas, ArcelorMittal USA, EVRAZ (now Oregon Steel), Commercial Metals Company (CMC). All produce to ASTM A572/A572M-21 with full A6 dimensional compliance.
- Europe (Germany, France, Italy, Spain, Turkey):
- East Asia (China, Korea, Japan): Baosteel, HBIS, Shougang, Ansteel, POSCO, Hyundai Steel, Nippon Steel. Strong dual-cert capability (Q355 / SS400 / A572 / S355J2 all in one heat).
- India: Tata Steel, SAIL, JSW Steel. Excellent for medium-to-heavy plate.
- Brazil and Turkey: Growing exporters with ASTM-certified capacity.
SSAB Europe, ArcelorMittal Europe, Salzgitter, Voestalpine, Dillinger, and Turkish mills (Tosyalı, Borçelik, İlhanlı). Most produce to EN 10025 S355JR / S355J2 with ASTM A572 available as a dual-cert.
Engineering Design Notes for A572 Gr.50
When designing with A572 Gr.50, structural engineers use widely-available international design standards:
| Design Code | Region | Reference Standard |
|---|---|---|
| AISC 360 / 341 | USA / international | ASTM A572 Gr.50 (preferred for W-shapes) |
| AASHTO LRFD | USA bridges | ASTM A572 Gr.50 (typical for short spans); AASHTO M270 / M270M for bridges |
| CAN/CSA S16 | Canada | CSA G40.21 Gr.350W (Canadian equivalent) |
| EN 1993 (Eurocode 3) | Europe | EN 10025 S355JR / S355J0 / S355J2 (European equivalent) |
| GB 50017 | China | GB/T 1591 Q355B / C / D (Chinese equivalent) |
| AIJ | Japan | JIS G3106 SM490YA / YB (Japanese equivalent) |
While A572 Gr.50 and these equivalents have similar yield strengths, they differ in:
- Charpy impact (S355J2 has mandatory 27J at -20°C; A572 default no Charpy)
- Maximum thickness (A572 to 100 mm; EN S355 commonly to 150 mm; GB Q355 to 250 mm)
- Through-thickness Z-quality (separate from base chemistry, but related to inclusion control)
For projects crossing design codes, verify with the engineer of record which property governs — often a 27J @ -20°C Charpy requirement is added to A572 by agreement.
Cost Drivers for A572 Gr.50 Plate
The price of A572 Gr.50 plate is influenced by:
- Base steel price: Driven by global iron ore, scrap, and coking coal markets. Volatile; can swing 10 – 25% in a 6-month period.
- Thickness premium: Thin plate (≤16 mm) is the cheapest because it rolls fast. Plate ≥50 mm is priced 5 – 15% higher due to slow rolling and special handling.
- Quantity: Bulk order (over 100 tonnes per heat) typically gets price discount.
- Testing premium: Charpy at -20 °C adds 3 – 8%; ultrasonic per A578 adds 5 – 10%.
- Surface treatment: Shot-blasting and priming add cost per ton.
- Mill certification premium: Dual-cert (e.g., A572 + A36 + S355) adds small premium over single-cert.
- Shipping and currency: For export, ocean freight, insurance, and USD/RMB/CNY rate fluctuations.
For project budget planning, request a price quotation valid for 30 – 60 days. Large-volume projects (over 1,000 t) often get annual price contracts that fix the price for repeated monthly deliveries.
Comparable and Substitutable Grades
| Standard | Closest Grade | Yield (MPa min) | Notes |
|---|---|---|---|
| ASTM A572 Gr.50 | (baseline) | 345 | — |
| ASTM A36 | Approximately equivalent in MTC for thin sections | 250 | A36 is lower yield; specifier must upgrade thickness for equivalent strength |
| ASTM A992 | Equivalent for W-shapes (columns, beams) | 345 – 450 | For structural W-shapes only |
| ASTM A529 Gr.50 | Carbon-manganese bar / plate | 345 | Similar yield; A529 often has slightly different chemistry |
| EN 10025 S355JR / J0 / J2 | European equivalent | 345 | Cross-cert commonly available |
| JIS G3106 SM490YA / YB | Japanese welded structural | 365 | Slightly higher yield; compatible |
| GB/T 1591 Q355B / C / D | Chinese equivalent | 355 | Most direct Chinese equivalent; widely dual-cert |
| IS 2062 E350 | Indian structural | 350 | Yield essentially identical; cross-cert possible |
Get a Quote
Need ASTM A572 Grade 50 plate for bridges, buildings, towers, or heavy equipment? Huaxia-Steel supplies A572 Gr.50 plate in thicknesses from 5 to 100 mm, with 50 ksi minimum yield, full ASTM A572/A572M compliance, EN 10204 3.1 mill certificate, third-party inspection on request, and global shipping. Send your specification to [email protected] for a quotation.
