What is the difference between A516 70 and A572 50?

Confused between ASTM A516 Grade 70 and ASTM A572 Grade 50 steel? This in-depth guide explains the key differences in chemistry, mechanical properties, and applications. You can learn how to choose the right material for your project to ensure safety, compliance, and cost-effectiveness.

As engineers, designers, and procurement specialists, selecting the right material is one of the most critical decisions we make. The choice directly impacts safety, performance, and budget. Two of the most commonly specified carbon steel plates are ASTM A516 Grade 70 and ASTM A572 Grade 50.

At a glance, their mechanical properties can seem similar, but they are not interchangeable. Using the wrong one can lead to catastrophic failure or non-compliance with codes. So, what exactly is the difference between A516 Grade 70 and A572 Grade 50?

This article will break down the key differences to help you make an informed decision for your next project.

This is the most crucial distinction and the starting point for selection.

ASTM A516 Grade 70: This steel is governed by the ASME Boiler and Pressure Vessel Code (BPVC). Its primary application is in the fabrication of pressure vessels. The "70" denotes a minimum tensile strength of 70 ksi. It is designed specifically to withstand internal pressure and has excellent notch toughness, especially at moderate and lower temperatures. You will often find it in welded boilers, storage tanks, and other pressure-containing structures.

ASTM A572 Grade 50: This is a high-strength, low-alloy (HSLA) structural steel. The "50" denotes a minimum yield strength of 50 ksi. It is governed by standards like AISC for structural applications. Its primary use is in bridges, buildings, and other structural frameworks where high strength-to-weight ratio is valuable. It offers good weldability and greater strength than standard carbon steel like A36.

The difference in application stems from their chemical makeup.

A516 Gr 70 is a carbon-silicon steel. The chemistry is carefully controlled, with limits on elements like manganese, phosphorus, and sulfur to ensure weldability and notch toughness. It may also have supplemental Charpy V-Notch impact testing requirements (e.g., A516 Gr 70N).

A572 Gr 50 is a High-Strength Low-Alloy (HSLA) Columbium-Vanadium steel. It contains small, intentional additions of alloying elements like columbium (niobium) and/or vanadium. These elements provide strengthening through grain refinement and precipitation hardening, allowing it to achieve higher strength with less weight.

While both are strong, their strength profiles are defined differently.

Notice that A572 Gr 50 has a higher yield strength than A516 Gr 70, which is often the governing factor in structural design to prevent permanent deformation.

Generally, A572 Grade 50 is more cost-effective than A516 Grade 70. The stringent manufacturing process, testing requirements (especially impact testing), and certification needed for pressure vessel applications make A516 a premium product. For non-pressure applications, using A516 where A572 would suffice is an unnecessary expense.

Making the right choice is straightforward if you follow this logic:

Choose ASTM A516 Grade 70 if: Your component is a pressure vessel, boiler, or any equipment governed by the ASME BPVC that must contain internal pressure. Safety and notch toughness are your top priorities.

Choose ASTM A572 Grade 50 if: Your project is a bridge, building, or structural frame where the primary goal is to support loads with a high-strength, lightweight material. Cost-effectiveness for structural applications is key.

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Always consult the governing design code (ASME for pressure equipment, AISC for structures) and involve a certified materials engineer when in doubt. Using the correct material is not just a recommendation-it's a requirement for safety and reliability.

If you want to learn more about GNEE's products, you can send an email to alloy@gneesteelgroup.com. We are more than happy to assist you.

What is ASTM A572 GR 50 standard?

ASTM A572 GR 50 is a high strength low alloy steel. Grade 50 is difficult to form since it contains more alloying elements than plain steel but offers more strength per unit of weight. Owing to its high strength ASTM A572 Grade 50 Plates requires less material to satisfy strength requirements than plain carbon steel.

What is the difference between A36 and A572 gr 50?

As mentioned earlier, A36 is steel that has a minimum yield strength of 36,000 PSI. This grade derives its strength from a combination of carbon and manganese. On the other hand, A572-50, for example, is a type of steel with a minimum yield strength of 50,000 PSI.

What is equivalent to A572 50?

S355JR

S355JR, S355J0, S355J2, S355K2 under EN 10025-2 are comparable to ASTM A572 Grade 50

Can you bend A572 grade 50 steel?

We utilize both CNC roll bending equipment as well as press brakes that generate from 250-1,500 tons of force to bend A36 and A572 Grade 50 plate steel as well as heat treated quench and tempered plate. The fully automatic process creates close tolerance, repeatable profiles with exceptional precision and quality.

What is A516 grade 70 material?

carbon-manganese steels

ASTM A516-70 and ASME SA516-70 steel plate products are made from carbon-manganese steels and produced to pressure vessel quality(PVQ) standards as delineated in ASTM A20/ASME SA20.

What is the difference between A36 and A516 gr 70?

ASTM A516 Gr 70 VS A36, ASTM A516 steel and A36 steel actually belong to different steel types. ASTM A516 steel is pressure vessel and boiler steel. ASTM A36 steel is mild steel. For the chemical content of carbon, ASTM A516 steel and A36 steel are also called carbon steel.

What is the difference between A516 70 and A572 50?

A516 Grade 70 is a pressure-vessel carbon steel plate chosen for welded vessels that require good notch toughness; A572 Grade 50 is a high-strength, low-alloy structural plate optimized for weight-sensitive structural builds.

What is the difference between A516 GR 70 and A105?

ASME SA 516 GR 70 is a carbon steel plate for pressure vessels, offering high tensile strength and HIC resistance, while ASTM A105 is a forged carbon steel for piping components. Gangsteel's ASME SA 516 GR 70 plates complement A105 forgings, providing reliable solutions for high-pressure systems.

What is the difference between SA515 grade 70 and SA516 70?

SA-516-70 typically has higher tensile strength compared to SA515 GR 70. Applications: SA-516-70 is commonly used for pressure vessels where moderate and lower temperature service is required. SA515 GR 70 is used for intermediate and higher temperature service applications