Learn About the Latest ASTM A709 Steel Plate/Sheet Price, Specifications and Dimensions.
ASTM A709 Grade 70 Steel Plate | High-Strength Bridge Steel for Girders
ASTM A709 Grade 70 steel plate is a high‑performance structural steel engineered for challenging bridge and infrastructure builds. Produced to the ASTM A709/A709M specification, this grade delivers enhanced strength compared to ordinary bridge‑grade structural steel. It is well‑suited for projects prioritizing structural efficiency and heavy load‑bearing performance.
A709 Grade 70 reaches a minimum yield strength of 485 MPa, with tensile strength spanning 620 MPa to 760 MPa. Thanks to these mechanical properties, it is widely specified for high‑capacity bridge girders, heavy‑duty structural components and other transportation‑related infrastructure works.
Royal Steel Group stocks A709 Grade 70 steel plates in standard sizes, and also supports custom‑cut dimensions to meet bridge fabrication and large‑scale structural project demands.
| Steel Grade | A709 Gr70 |
| Applicable Standard | ASTM A709 / A709M |
| Minimum Yield Strength | ≥485 MPa |
| Tensile Strength | 620–760 MPa |
| Standard Thickness | 3/8"–1" (9.53–25.40 mm) |
| Standard Width | 48"–120" (1220–3048 mm) |
| Standard Length | 96"–480" (2438–12192 mm) |
| Maximum Length | Up to 1020" (25,910 mm) |
| Product Type | High-Strength Structural Steel Plate |
| Typical Application | High-Performance Bridge Girders |
High Yield Performance
Featuring a 485 MPa minimum yield strength, A709 Grade 70 is engineered for structural parts that must sustain extreme load‑bearing conditions.
Superior Tensile Properties
Its tensile strength sits between 620 MPa and 760 MPa, delivering robust mechanical performance for heavy‑load structural assemblies.
Optimized for Bridge Construction
A709 Grade 70 is an excellent fit for high‑performance bridge girders, where strength‑to‑weight ratio and reliable structural behaviour are critical design factors.
Fit for Demanding Infrastructure Works
This steel grade is widely selected for rigorous transportation and infrastructure projects that call for high‑strength structural steel materials.
Broad Large‑Size Plate Options
Standard plate widths run from 48 to 120 inches, with standard lengths covering 96 to 480 inches. Extra‑long plates are also achievable subject to production capacity and project needs.
Tailored Project Solutions
We offer custom‑sized plates along with cutting and secondary processing services, fully aligned with client engineering drawings and purchasing requirements.
| Mechanical Property | A709 Grade 70 |
| Minimum Yield Strength | ≥485 MPa |
| Tensile Strength | 620–760 MPa |
| Strength Level | High-Strength Structural Steel |
| Main Structural Application | Bridge Girders |
The high yield and tensile strength of Grade 70 allow engineers to consider it for structural components subjected to significant loads. For bridge projects, the complete material requirements should always be checked against the applicable ASTM specification and project design documents.
ASTM A709 Steel Plate/Sheet Sizes
| Parameter | Range |
| Thickness | 2 mm – 200 mm |
| Width | 1,000 mm – 2,500 mm |
| Length | 6,000 mm – 12,000 mm (custom sizes available) |
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A709 Grade 70 is an option for bridge projects where higher structural strength is required.
Key advantages include:
≥485 MPa minimum yield strength
620–760 MPa tensile strength
ASTM A709/A709M specification
Suitable for high-performance bridge girders
High-strength structural performance
Standard and customized plate dimensions
Suitable for large-scale infrastructure projects
Cutting and fabrication options available
Material inspection and certification support
Royal Steel Group adheres to a standardized, strictly controlled production workflow for all structural steel plates to ensure stable and consistent product quality.
Our complete manufacturing process covers the full production chain: Steelmaking → Continuous Casting → Slab Processing → Reheating → Hot Rolling → Controlled Cooling → Plate Cutting → Surface Quality Inspection → Dimensional Calibration → Mechanical Performance Testing → Final Comprehensive Quality Check → Packaging → Delivery
Throughout the entire manufacturing cycle, all production parameters are precisely regulated to fully comply with customer purchase standards and designated material technical specifications.
For large-scale bridge engineering projects with stringent quality standards, we can also customize additional testing and inspection procedures in advance before formal production starts, to meet high-end project quality requirements.
A709 Grade 70 steel plates can be offered with value‑added processing tailored to individual project needs.
Our available processing scope covers:
Cut‑to‑length service
CNC cutting
Flame cutting
Edge beveling & preparation
Non‑standard custom sizes
Steel plate marking
Specified surface finishing
Drawing‑based fabricated parts
For bridge‑building applications, clients may submit engineering drawings or detailed cutting schedules for our technical team to carry out a full review.
1. High‑Performance Bridge Girders
A709 Grade 70 is most commonly utilized for high‑performance bridge girders. Its high‑strength properties meet strict design criteria and cope with severe service loads.
2. Highway Bridge Projects
This grade works well for structural components within highway bridges, whenever project specifications call for enhanced material strength.
3. Long‑Span Bridge Constructions
It is a practical choice for major bridge structural members in long‑span designs. Engineers often select this steel to cut overall structure weight without compromising necessary load‑bearing capacity.
4. Viaducts and Elevated Road Systems
The steel can be adopted for key structural parts of viaducts, overpasses and other elevated transport infrastructure.
5. Heavy‑Duty Transport Infrastructure
A709 Grade 70 fits heavy‑use infrastructure projects that mandate high‑strength structural steel complying with ASTM standards.
Royal Steel Group supplies ASTM structural steel products for bridge construction, infrastructure, industrial and engineering applications.
For A709 Grade 70 steel plate, we can support customers with material confirmation, dimensions, processing, inspection, documentation and international transportation.
Our Supply Process
Inquiry → Technical Specification Confirmation → Quotation → Order Confirmation → Production → Quality Inspection → Documentation → Packing → Shipment
For an accurate quotation, customers can provide:
Grade + Thickness + Width + Length + Quantity + Delivery Port + Inspection Requirements
1) Branch Office - Spanish-speaking support, customs clearance assistance, etc.
2) Over 5,000 tons of stock in stock, with a wide variety of sizes
3) Inspected by authoritative organizations such as CCIC, SGS, BV, and TUV, with standard seaworthy packaging
Quality consistency is critical when steel plate is used in bridge girders and other load-bearing infrastructure.
Depending on the order requirements, inspection may include:
Chemical composition analysis
Yield strength testing
Tensile strength testing
Elongation testing
Thickness inspection
Width and length inspection
Surface quality inspection
Ultrasonic testing when specified
Mill Test Certificate (MTC)
Third-party inspection when required
Inspection requirements should be confirmed before production to ensure that the delivered material matches the project specification.
A709 Grade 70 steel plates are export‑packed for overseas shipment, taking plate dimensions, weight, on‑site handling conditions and destination location into full account.
Standard export packing features:
Bundled or stacked steel plate packs
Steel band strapping for secure fastening
Moisture‑proof waterproof wrapping
Supplementary protective materials as necessary
Export‑compliant product marking
Custom stowage and loading solutions
Shipping Options
Based on plate sizes and overall order volume, we arrange transport via:
Containerized shipment
Breakbulk cargo
Bulk carrier
Truck delivery
Combined multimodal transport
We select the most suitable packing and shipping solution according to plate measurements, total cargo weight, destination port and agreed delivery terms.
1. What is ASTM A709 Grade 70 steel?
ASTM A709 Grade 70 falls under the ASTM A709/A709M standard. It is a high‑strength structural steel developed for heavy‑duty structural works and bridge construction.
2. What is the yield strength of A709 Grade 70?
Per the official standard, its minimum yield strength reaches 485 MPa.
3. What is the tensile strength of A709 Grade 70?
Its tensile strength runs from 620 MPa to 760 MPa.
4. What is A709 Grade 70 used for?
It is widely adopted for high‑performance bridge girders. Common scenarios also cover highway bridges, viaducts and other heavy‑load transport infrastructure projects.
5. Is A709 Grade 70 suitable for bridge girders?
Absolutely. This grade is well‑matched for bridge components needing high‑strength structural steel, and bridge girders are one of its core use cases.
6. What thicknesses are available?
Our standard supply thickness covers 3/8"‑1" (9.53‑25.40 mm). Alternative thickness options are negotiable, subject to production feasibility and project specifications.
7. What are the standard widths?
Standard available widths range from 48" up to 120" (1220‑3048 mm).
8. Can A709 Grade 70 steel plate be cut to custom sizes?
Yes. We offer custom cutting and dimension processing services based on your fabrication drawings, cutting lists and actual project demands.
9. What documents can be supplied?
We furnish a full set of paperwork tailored to each order, including material test certificates (MTC), Certificate of Origin, packing list, commercial invoice and third‑party inspection reports.
10. How can I get a quotation for A709 Grade 70?
Kindly share key details: steel grade, required thickness, width, length, total quantity, destination port and any special inspection needs. With this information, we can work out accurate technical and commercial terms for your reference.
ROYAL STEEL GROUP
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Kangsheng development industry zone,
Wuqing district, Tianjin city, China.
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