ASTM A992 is the standard grade for hot-rolled structural steel shapes in the United States. A572 Grade 50 is an older high-strength low-alloy grade that is still used for plate, angles, channels and other shapes. Both give 50 ksi minimum yield strength, but A992 adds limits that make shapes more predictable to weld and better behaved in earthquakes.
A992 vs A572 Grade 50 at a Glance
| Property | ASTM A992 | ASTM A572 Grade 50 |
|---|---|---|
| Minimum yield strength | 50 ksi (345 MPa) | 50 ksi (345 MPa) |
| Maximum yield strength | 65 ksi | Not specified |
| Minimum tensile strength | 65 ksi (450 MPa) | 65 ksi (448 MPa) |
| Maximum yield-to-tensile ratio | 0.85 | Not specified |
| Elongation, 8 in specimen | 18% | 18% |
| Elongation, 2 in specimen | 21% | Not specified in the same way |
| Maximum carbon equivalent | 0.45 (0.47 for Group 4 and 5 shapes) | Not specified |
| Scope | Rolled structural shapes | Plate, bars, shapes and sheet piling |
| Typical use | W shapes for building frames | Plate, channels, angles, HP and built-up members |
Values for A992 are from the published summary of ASTM A992/A992M (ASTM A992) and for A572 from the published summary of ASTM A572 (A572 steel). Buy the current ASTM standards for design or purchasing work.
Why A992 Exists
Before A992, W shapes were ordered as A36 or A572 Grade 50 and the actual strength varied a lot. Mills using scrap could deliver steel far stronger than the minimum. That is fine for strength but bad for two things: welding, because richer chemistry needs more care, and seismic design, which relies on the beam yielding before the connection fails. A992 keeps the yield strength inside a band, caps the yield-to-tensile ratio at 0.85 so there is real ductility after yield, and caps the carbon equivalent so weldability is predictable.
Which One Do You Specify?
W shapes: A992. It is the default grade US mills roll and what service centers stock, so it is usually also the cheapest option.
Channels, angles and other shapes: A992 does not cover them. A36 is common, with A572 Grade 50 where you need the higher strength.
HP piles: A572 Grade 50 is common; check what the supplier stocks.
Plate for base plates, stiffeners and built-up members: A36 or A572 Grade 50.
HSS tube: a different family again, usually A500 Grade C or A1085. See the HSS sizes chart.
Dual Certification
Plenty of material arrives dual certified, for example A992 and A572-50 on the same mill certificate, because the steel meets both. That is normal and acceptable as long as the certificate covers every grade your drawings call for. Keep the mill test report: it is the evidence that the steel meets what was specified.
Welding and Carbon Equivalent
Carbon equivalent turns the chemistry into a single number that predicts how hard the heat-affected zone will get, and therefore how much preheat a weld needs. Capping it at 0.45, or 0.47 for the heaviest shape groups, is what makes A992 shapes reliably weldable. With A572 Grade 50 the chemistry can vary more, so ask for the mill certificate before setting a welding procedure. Welding follows AWS D1.1 either way.
Strength in Practice
Because both grades have the same 50 ksi minimum yield, a beam designed for one is designed for the other as far as the calculation goes. What changes is consistency, weldability and, for seismic work, the ductility requirements. Sizes and section properties do not change with grade: a W16x26 is the same shape whatever it is rolled from.
A992 vs A36
A36 has 36 ksi minimum yield and remains common for plate, angles and light fabrication. For the same W shape, A992 gives roughly 39% more yield strength, which is why it replaced A36 as the standard for beams. A36 is still specified where strength is not the governing issue and cost or availability is.
A992 FAQ
Is A992 the same as A572 Grade 50?
Not quite. They share 50 ksi minimum yield and 65 ksi minimum tensile, but A992 also caps maximum yield at 65 ksi, caps the yield-to-tensile ratio at 0.85, and caps the carbon equivalent. A992 applies only to rolled shapes.
What grade are wide flange beams?
In the US, almost always A992, often dual certified to A572 Grade 50. Ask the supplier for the mill certificate if the grade matters to your design.
Can I weld A992?
Yes. That is one of its advantages: the capped carbon equivalent makes weldability predictable. Follow AWS D1.1 for the procedure, preheat and inspection.
Does A992 cost more than A36?
For W shapes, usually not. A992 is what mills roll by default, so it is generally the standard-priced option, while asking for A36 shapes can cost more or take longer.
Which grade do I use for a residential beam?
Your engineer specifies it. In practice the beam will be an A992 W shape from stock. Get sizes from the wide flange beam sizes chart and prices from the steel I-beam cost guide.
This page is reference information only and is not engineering advice. Sizing, rigging and load capacity decisions need a qualified engineer. Full disclaimer.