ASTM A709 Steel Plate for Bridges: High-Strength, Low-Alloy Structural Steel

ASTM A709 Overview

ASTM A709 steel plate is a high-strength, low-alloy structural steel developed specifically for bridge construction and other critical load-bearing structures. It is widely specified for highway bridges, railway bridges, and long-span bridge projects where strength, fracture toughness, and weldability are essential.

As an experienced ASTM A709 steel plate supplier, CJM provides A709 heavy steel plate in multiple grades and thicknesses up to 200 mm, suitable for major load-bearing bridge components such as girders, gusset plates, and cross beams. Plates are supplied in as-rolled, normalized, or TMCP delivery conditions according to project specifications and fabrication requirements.

The ASTM A709 standard includes several grades designed for different bridge engineering needs, such as Grade 36, Grade 50, Grade 50W weathering steel, and HPS 70W high-performance steel.

Available Grades of ASTM A709 Steel Plate

• ASTM A709 Grade 36
• ASTM A709 Grade 50
• ASTM A709 Grade 50W
• ASTM A709 Grade HPS 50W
• ASTM A709 Grade HPS 70W

Among these grades:

• ASTM A709 Grade 50 is commonly used for standard bridge structures requiring higher yield strength than Grade 36.
• ASTM A709 Grade 50W weathering steel is preferred for exposed bridge environments where reduced maintenance is required.
• ASTM A709 HPS 70W is designed for large-span bridges and heavily loaded structures requiring higher strength and improved toughness.

For guidance on selecting the right grade for corrosion resistance and long-term performance, you may refer to our article: Choosing the Right ASTM A709 Steel Plate for Bridge Construction and Weathering Performance

ASTM A709 Steel Plate Dimensions and Delivery Conditions

Specification	Range
Thickness	6 mm – 200 mm
Width	1500 mm – 3200 mm
Length	6000 mm – 18000 mm
Delivery Condition	Hot Rolled, Normalized, TMCP
Standard	ASTM A709 / ASME SA709

CJM maintains inventory of ASTM A709 heavy steel plate for bridge fabrication, including thick plates for large-span and heavy-load structures.

Mechanical Properties of ASTM A709 Steel Plate

Grade	Yield Strength (MPa)	Tensile Strength (MPa)	Elongation (%)	Charpy Impact
A709 Gr. 36	≥ 250	400–550	≥ 20	Optional
A709 Gr. 50	≥ 345	485–620	≥ 21	Optional
A709 Gr. 50W	≥ 345	485–620	≥ 21	Improved CVN
HPS 50W	≥ 345	485–620	≥ 21	-23°C
HPS 70W	≥ 485	585–760	≥ 18	-23°C

Note: Mechanical property requirements are defined by ASTM A709. Detailed performance comparison between standard and weathering grades is explained in our ASTM A709 selection guide.

Chemical Composition of ASTM A709 Steel (% by Weight)

Grade	C	Mn	Si	P (max)	S (max)	Cu	Cr	Ni
A709 Gr. 50	≤0.23	0.85–1.35	≤0.40	0.035	0.045	—	—	—
A709 Gr. 50W	≤0.19	0.85–1.35	0.15–0.50	0.035	0.045	0.25–0.40	0.40–0.65	≤0.40
HPS 50W	≤0.11	1.20–1.60	0.15–0.50	0.020	0.010	0.25–0.40	0.40–0.70	0.40–0.75
HPS 70W	≤0.14	1.35–1.65	0.15–0.50	0.020	0.010	0.25–0.40	0.40–0.70	0.40–0.75

Applications of ASTM A709 Bridge Steel Plate

ASTM A709 bridge steel plates are widely used in:

• Highway and railway bridges
• Pedestrian bridges and overpasses
• Heavy-load structural supports
• Long-span and cable-stayed bridges
• Marine and coastal bridge structures (using A709 Grade 50W weathering steel)

ASTM A709 is one of the most commonly specified bridge steel plates for structures exposed to dynamic loads, temperature variation, and harsh environmental conditions.

Explore our full range of bridge steel plates for different load conditions and corrosion environments.

Processing and Supply Capabilities

• CJM provides cutting, beveling, drilling, and surface preparation for all bridge plate grades.
• For urgent bridge projects, we maintain stock of A709 heavy steel plates and offer fast delivery to global markets, including Southeast Asia, the Middle East, Europe, and the Americas.

Why Choose CJM as Your A709 Steel Plate Supplier

CJM is an experienced ASTM A709 steel plate supplier, offering:

• Full grade coverage from Grade 36 to HPS 70W
• Heavy plate supply up to 200 mm thickness
• As-rolled, normalized, and TMCP delivery options
• Customized cutting, packing, and logistics solutions
• Long-term export experience for bridge and infrastructure projects

Packaging & Shipping for ASTM A709 Bridge Steel Plate

• Plates: Wrapped with protective layers to avoid surface damage
• Coils: Strapped and covered with waterproof, corrosion-resistant film
• Features: Reinforced pallets · Moisture-proof wrapping · Custom packaging on request
• Logistics: Reliable global shipping partners with optimized delivery schedules

Export packaging is designed to protect ASTM A709 bridge steel plates during long-distance transportation.

Contact Us

Looking for a reliable ASTM A709 steel plate supplier for bridge construction projects?
Please send us your required grade, thickness, dimensions, and quantity for a fast and accurate quotation.

WhatsApp: +8618191906640
Email: info@cjmstainlesssteel.com

Frequently Asked Questions

• Q1: What’s the difference between A709 Gr.50 and HPS 50W?
  A709 Gr.50 is a standard carbon steel bridge plate, while HPS 50W adds weathering resistance and is optimized for long-term performance with fewer maintenance cycles.
• Q2: Can A709 steel plates be used in marine environments?
  Yes—especially HPS 50W and HPS 70W grades, which provide strong corrosion resistance in coastal or high-humidity areas.
• Q3: Can ASTM A709 steel plates be supplied in heavy thickness?
  Yes. CJM supplies ASTM A709 heavy steel plate with thickness up to 200 mm for large-span and heavy-load bridge applications.
• Q4: Is ASTM A709 equivalent to AASHTO M270?
  Yes, ASTM A709 and AASHTO M270 share the same chemical and mechanical requirements, differing mainly in certification format.
• Q5: Do you supply as-rolled ASTM A709 steel plate?
  Yes. We supply as-rolled ASTM A709 steel plate, as well as normalized and TMCP plates based on project specifications.

Q: What is your company’s main products/services?

A: We are a professional manufacturer for Carbon Steel, Alloy Steel and Profile products. We have the experience of steel business for more than 10 years and our products are exported to Mid East,South America,Southeast Asia,Africa,South and East Asia etc.

Q: Can I go to your factory for a visit?

A: Of course, we welcome customers from all over the world to visit our factory.

Q: What are your terms of payment?

A: 30% T/T deposite and 70% balance before shipment.

Q: What is your delivery time?

A: For stocks,we could transport the goods to loading port within 7 days after we received the deposit; For production,it usually takes about 15-30 days after receiving the deposit.

Q: Do you provide samples? Are they free or paid?

A: Samples are available for free,but the courier freight will be covered by customer account.

Q: Do you accept the third party inspection?

A:Yes, we fully accept ‌third-party inspections.

Q: Why should I buy from you not from other suppliers?

A: Integrating the superior resources of China’s steel industry, we provide customers with high-quality steel products at preferential prices, and can ensure that the goods are delivered to customers in a timely manner.

Q:How can you guarantee quality?

A: Always a pre-production sample before mass production;Always 100% inspected before shipment