A36 & A572 Material Specifications
Grades
The A572 steel H-beam specification has five different grades: Grade 42, Grade 50, Grade 55, Grade 60 and Grade 65. Each of these grades has slightly different chemical compositions and mechanical properties. The A36 steel H-beam specification, on the other hand, does not cover multiple grades.
Chemical Composition
A36 steel H-beam is considered a low-carbon, or mild, steel, containing a carbon composition of between 0.05% to 0.25%. The low carbon content of A36 makes it one of the most ductile and machinable structural steels, making it easy to form and fabricate into a wide range of structural profiles, including H-beams.
A572 is also a mild carbon steel, but with a greater addition of strengthening alloys such as phosphorus, manganese, and silicon. These alloying elements make A572 a high-strength, low-alloy (HSLA) steel, meaning it has higher strength-to-weight performance relative to A36. This makes A572 H-beams ideal for structural applications requiring higher load-bearing capacity, such as bridges, building frameworks, and transmission towers.
Chemical Composition of ASTM A36 Steel (H-Beam)
| Chemical Alloy | Up to ¾" Thick | Over ¾" to 1 ½" Thick | Over 1 ½" to 2 ½" Thick | Over 2 ½" to 4" Thick | Over 4" Thick |
|---|---|---|---|---|---|
| Carbon Max | 0.25% | 0.25% | 0.26% | 0.27% | 0.29% |
| Manganese | N/A | 0.80–1.20% | 0.80–1.20% | 0.85–1.20% | 0.85–1.20% |
| Phosphorus Max | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% |
| Sulfur Max | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% |
| Silicon | 0.40% Max | 0.40% Max | 0.15–0.40% | 0.15–0.40% | 0.15–0.40% |
| Copper Min | 0.20% | 0.20% | 0.20% | 0.20% |
0.20% |
Chemical Composition of ASTM A572 Steel (H-Beam)
| Chemical Alloy | Gr. 42 | Gr. 50 | Gr. 55 | Gr. 60 | Gr. 65 ≥ ½" | Gr. 65 Over ½"–1¼" |
|---|---|---|---|---|---|---|
| Carbon Max | 0.21% | 0.23% | 0.25% | 0.26% | 0.26% | 0.23% |
| Manganese Max | 1.35% | 1.35% | 1.35% | 1.35% | 1.35% | 1.65% |
| Phosphorus Max | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% |
| Sulfur Max | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% | 0.030% |
| Silicon | 0.15–0.40% | 0.15–0.40% | 0.15–0.40% | 0.40% | 0.40% | 0.40% |
Mechanical Properties
Because of differences in chemical composition, A36 and A572 H-beams also differ in mechanical properties such as yield strength and tensile strength.
A572 contains higher levels of strengthening alloys such as manganese and silicon, giving the steel significantly greater strength compared to A36. This allows A572 H-beams to support heavier loads and resist greater forces without failure-critical for structural applications that require high performance.
Mechanical Properties of ASTM A36 & ASTM A572 H-Beam
| Grade | Yield Point | Tensile Strength |
|---|---|---|
| A36 | 36 ksi | 58–80 ksi |
| A572 Gr. 42 | 42 ksi | 60 ksi |
| A572 Gr. 50 | 50 ksi | 65 ksi |
| A572 Gr. 55 | 55 ksi | 70 ksi |
| A572 Gr. 60 | 60 ksi | 75 ksi |
| A572 Gr. 65 | 65 ksi | 80 ksi |
Material Testing for A36 & A572 H-Beam
For colder climate applications, engineers may request Charpy impact testing to ensure A36 and A572 H-beams can absorb energy under low temperatures without brittle failure.
For heavy-section H-beams-especially thicker flanges or webs exceeding certain size limits-ultrasonic testing (UT) is often required to verify internal soundness and structural reliability.
Are A36 & A572 H-Beams Interchangeable?
Both A36 and A572 H-beams are widely used in structural applications such as buildings and bridges, but they are not interchangeable.
A572 provides higher strength and better wear resistance. For high-load or long-span applications-like transmission towers or heavy structural components-A572 is usually the more suitable choice.
A36 & A572 Cost Difference
A36 steel has a minimum yield strength of 36,000 PSI. Its strength mainly comes from carbon and manganese.
A572-such as A572 Gr. 50-has a 50,000 PSI minimum yield strength and includes additional strengthening elements like columbium or vanadium. Because of the enhanced alloying, A572 is typically 2.5%–5% more expensive than A36.
Sourcing A36 & A572 H-Beams
When selecting H-beam suppliers, consider:
Flexible purchasing options (online + sales reps)
Complete mill test reports and certification
Sufficient stock of H-beams in multiple grades/sizes
GneeSteel supplies A36 and A572 H-beams in a wide range of sizes with reliable documentation and global shipping solutions.