ASTM A36 vs A572 Grade 50 vs A516 Grade 70: Quick Comparison

The values above are general reference values. Mechanical requirements can vary according to plate thickness,
product form, heat-treatment condition and the applicable edition of the ASTM specification. Final acceptance
should always be based on the purchase specification and the material test certificate.

What Is ASTM A36 Carbon Steel?

ASTM A36 is a widely specified carbon structural steel used for plates, bars and structural shapes.
It is intended for riveted, bolted or welded construction, including buildings, bridges, platforms,
machine structures and general fabrication.

Its popularity is based on a practical balance of strength, ductility, weldability, availability and cost.
A36 is commonly selected when a project does not require the higher yield strength of an HSLA grade or
the specialized toughness and pressure-service controls associated with pressure-vessel plate.

Key advantages of ASTM A36

• Good weldability with commonly used structural welding processes
• Easy cutting, drilling, bending and machining
• Broad availability in standard plate sizes and thicknesses
• Competitive material and fabrication cost
• Suitable for a wide range of non-pressure structural components

For a more detailed introduction, read our

ASTM A36 carbon steel guide
.

What Is ASTM A572 Grade 50 Steel?

ASTM A572 is a high-strength, low-alloy structural steel specification. Grade 50 is one of its most commonly
used strength levels and has a minimum yield strength of approximately 345 MPa, or 50 ksi, within the applicable
product and thickness limitations.

Compared with ASTM A36, A572 Grade 50 can carry a higher design load at the same plate thickness.
Depending on the engineering design, this may allow the use of thinner or lighter structural components.
However, any reduction in thickness must be approved through proper structural calculations rather than
based only on the nominal yield-strength difference.

Key advantages of A572 Grade 50

• Higher yield strength than standard A36 structural steel
• Potential reduction in structural weight
• Good suitability for welded, bolted and riveted structures
• Efficient performance in heavy construction and equipment fabrication
• Useful where strength-to-weight performance is important

A572 Grade 50 is frequently used for structural members, bridge components, heavy machinery frames,
industrial buildings, transmission structures and load-bearing fabricated assemblies.

What Is ASTM A516 Grade 70 Steel?

ASTM A516 Grade 70 is a carbon steel plate specification developed primarily for welded pressure vessels
operating at moderate and lower temperatures. The specification places particular importance on mechanical
performance and notch-toughness capability for pressure-containing equipment.

A516 Grade 70 is not simply a stronger replacement for A36. It belongs to a different application category.
It is normally selected when a pressure vessel, boiler, separator, heat exchanger or similar component must
satisfy an applicable pressure-equipment design code.

Key advantages of A516 Grade 70

• Tensile strength commonly specified in the 485–620 MPa range
• Suitable for welded pressure-containing components
• Controlled steelmaking and fine-grain requirements
• Good balance of strength, ductility and toughness
• Availability with additional impact testing and ultrasonic examination when specified

The required delivery condition may depend on plate thickness, service temperature and project specifications.
Normalized plate, impact testing or additional inspection may be required for critical applications.

Mechanical Properties Comparison

Although A516 Grade 70 has a higher tensile-strength range than A36, its minimum yield strength is not as high
as that of A572 Grade 50. This demonstrates why steel grades should not be ranked using only one mechanical property.

Structural design, pressure design, fatigue loading, service temperature, toughness, weldability and code compliance
must all be evaluated before selecting a plate grade.

Chemical Composition and Metallurgical Differences

ASTM A36 is a conventional carbon structural steel. Its composition is controlled according to product form
and thickness, with carbon, manganese, phosphorus, sulfur, silicon and copper among the elements addressed by
the specification.

ASTM A572 Grade 50 is classified as a high-strength, low-alloy steel. Its strength is achieved through controlled
chemistry and processing, which may include microalloying elements such as niobium, vanadium or titanium.

ASTM A516 Grade 70 is a killed, fine-grain carbon steel plate intended for pressure-vessel service.
Its metallurgy and production controls support the required combination of strength, ductility and toughness.

Because chemical limits can vary with thickness and specification edition, buyers should avoid relying on a
single generic composition table. The correct procedure is to confirm the ordered standard, grade, thickness
and heat analysis shown on the mill test certificate.

Weldability and Fabrication Differences

Welding ASTM A36

ASTM A36 generally offers good weldability and is commonly welded using shielded metal arc welding,
gas metal arc welding, flux-cored arc welding and submerged arc welding.

Preheating may not be necessary for many thin, lightly restrained components, but thicker plate, low ambient
temperature, high restraint and high hydrogen risk can change the welding requirements.

Welding A572 Grade 50

A572 Grade 50 is also considered weldable, but fabrication control becomes increasingly important as plate
thickness, joint restraint and structural criticality increase.

The fabricator should evaluate carbon equivalent, heat input, filler-metal strength, hydrogen control,
preheat temperature and interpass temperature. Welding should follow an approved welding procedure specification.

Welding A516 Grade 70

A516 Grade 70 is specifically associated with welded pressure equipment, but this does not mean that all welding
conditions are automatically acceptable.

Pressure-vessel fabrication normally requires qualified welding procedures, qualified welders, suitable filler
metals and inspection in accordance with the governing construction code. Preheating, post-weld heat treatment
and impact-test requirements may apply depending on thickness, service temperature and equipment design.

Typical Applications

Common applications of ASTM A36

• Building frames and structural supports
• Base plates and connection plates
• Industrial platforms and walkways
• Machine bases and equipment frames
• Brackets, supports and general fabricated components
• Storage structures that are not classified as pressure vessels

Common applications of ASTM A572 Grade 50

• Heavy structural columns and beams
• Bridge components
• Crane and lifting-equipment structures
• Transmission towers and infrastructure projects
• Mining and construction machinery
• High-load industrial frames

Common applications of ASTM A516 Grade 70

• Pressure vessels
• Industrial boilers
• Oil and gas separators
• Heat exchangers
• Process equipment
• Pressurized storage equipment
• Petrochemical and energy-industry vessels

Corrosion Resistance

ASTM A36, A572 Grade 50 and A516 Grade 70 do not provide the inherent corrosion resistance associated with
stainless steel. When exposed to moisture, salts, industrial chemicals or aggressive outdoor conditions,
unprotected surfaces can corrode.

Common protection methods include:

• Industrial paint systems
• Epoxy or polyurethane coatings
• Hot-dip galvanizing where technically suitable
• Metal spraying
• Corrosion allowance in the engineering design
• Cathodic protection for selected installations

The coating system should be selected according to the service environment, surface preparation standard,
expected service life and maintenance strategy.

How to Select the Correct Steel Plate Grade

Choose ASTM A36 when:

• The component is a general structural or fabricated part
• Standard structural strength is sufficient
• Cost and availability are major priorities
• The component is not a code-regulated pressure boundary
• Easy cutting, bending and welding are required

Choose ASTM A572 Grade 50 when:

• Higher yield strength is required
• Structural weight reduction is beneficial
• The design involves heavy loads or long spans
• The engineer specifies HSLA structural steel
• The project requires improved strength-to-weight efficiency

Choose ASTM A516 Grade 70 when:

• The plate forms part of a welded pressure vessel
• The applicable design code specifies pressure-vessel-quality material
• Strength and notch toughness are important
• Impact testing or normalized delivery is required
• The project involves boilers, process vessels or pressurized equipment

Cost and Total Project Value

ASTM A36 is generally the most economical of the three grades because of its broad availability and straightforward
production requirements. A572 Grade 50 may carry a higher price per tonne, but its higher yield strength can reduce
the amount of steel required in an optimized structural design.

A516 Grade 70 may involve higher purchasing and inspection costs because pressure-vessel projects can require
normalized material, impact testing, ultrasonic examination, traceability and additional certification.

The lowest price per tonne does not always provide the lowest project cost. Buyers should also consider:

• Required plate thickness
• Fabrication and welding expenses
• Testing and inspection costs
• Material utilization and scrap
• Engineering-code compliance
• Service life and maintenance
• Risk of material rejection or project delay

Carbon Steel Plate Procurement Checklist

A complete purchase inquiry helps the steel supplier confirm availability, calculate an accurate quotation
and avoid technical misunderstandings.

1. ASTM designation and grade: Specify A36, A572 Grade 50 or A516 Grade 70.
2. Standard edition: Confirm the required ASTM edition or project specification.
3. Dimensions: Provide thickness, width, length and quantity.
4. Delivery condition: State as-rolled, normalized or another required condition.
5. Impact testing: Specify test temperature and acceptance criteria where required.
6. Ultrasonic testing: State the applicable UT standard and acceptance level.
7. Material certificate: Request the required mill test certificate or inspection certificate.
8. Surface condition: Specify mill finish, shot blasting, priming or another treatment.
9. Dimensional tolerances: Identify any special flatness or thickness requirements.
10. Processing services: Include cutting, beveling, drilling, bending or machining requirements.
11. Destination: Provide the delivery port or final destination for freight calculation.
12. Third-party inspection: Identify SGS, BV, TÜV or another required inspection organization.

JUDE Steel supplies carbon and alloy steel plate for structural, machinery, energy and industrial applications.
Explore our

carbon and alloy steel plate range
, review our

quality-control procedures
, or

contact our team
for a project-specific quotation.

Frequently Asked Questions

Is ASTM A572 Grade 50 stronger than ASTM A36?

Yes. A572 Grade 50 generally has a minimum yield strength of approximately 345 MPa, compared with approximately
250 MPa for A36. This higher yield strength can support heavier loads or allow lighter structural designs when
approved by the engineer.

Is A516 Grade 70 stronger than A36?

A516 Grade 70 normally has a higher tensile-strength range than A36, but the two materials serve different purposes.
A36 is a general structural steel, while A516 Grade 70 is designed primarily for welded pressure-vessel applications.

Can A572 Grade 50 replace A36?

A572 Grade 50 may replace A36 in some structural applications after engineering review. The designer must evaluate
strength, ductility, welding procedure, connection design, availability and the applicable construction standard.

Can ASTM A36 be used for pressure vessels?

ASTM A36 should not automatically be used as pressure-vessel plate. Pressure-containing equipment normally requires
materials recognized by the governing pressure-equipment code. The responsible engineer must approve the material
specification.

What is the main difference between A572 Grade 50 and A516 Grade 70?

A572 Grade 50 is an HSLA structural steel focused on higher yield strength. A516 Grade 70 is a carbon steel plate
intended primarily for welded pressure vessels where pressure-service performance and toughness are important.

Are these steel grades corrosion resistant?

No. All three grades require suitable corrosion protection when exposed to moisture or aggressive environments.
Painting, coating, galvanizing where appropriate, corrosion allowance and other protection systems may be used.

Does A516 Grade 70 always require normalization?

Not in every case. The required heat-treatment condition depends on plate thickness, specification requirements,
service conditions and the purchaser’s order. Critical pressure-vessel projects may specify normalized plate.

What information should be included in a steel plate inquiry?

The inquiry should include the standard, grade, dimensions, quantity, delivery condition, inspection requirements,
material certificate, surface condition, processing requirements and delivery destination.

Conclusion

ASTM A36, A572 Grade 50 and A516 Grade 70 are important steel plate grades, but they are not interchangeable
general-purpose materials.

ASTM A36 is a reliable and economical choice for standard structural fabrication. ASTM A572 Grade 50 provides
higher yield strength for demanding structural applications and weight-efficient designs. ASTM A516 Grade 70 is
the appropriate category for many welded pressure-vessel applications where strength, toughness and code compliance
must be carefully controlled.

The correct material should be selected by considering the complete engineering requirement rather than only
price or nominal tensile strength. Buyers should confirm the applicable standard edition, dimensions, mechanical
requirements, delivery condition, impact testing, ultrasonic inspection and certification before placing an order.

For technical support, material availability or a detailed quotation,

contact JUDE Steel
.