A572 Gr50 HSLA Steel vs A36 Structural
A572 Gr50 and A36 are both structural steels, but A572 is a high-strength low-alloy (HSLA) grade. A572 Grade 50 delivers ~345 MPa minimum yield versus A36's ~250 MPa — about 38% more — letting designers use thinner, lighter sections. A36 is the cheaper, more weldable general structural baseline. Higher strength-to-weight versus economical, forgiving general structure.
The verdict
Choose A572 Gr50 for structural buildings, bridges, and heavy fabrications where its ~345 MPa yield lets you reduce section size and weight. Choose A36 for general structural work, weldments, and parts where lower cost, easier welding, and a recognized baseline outweigh the strength advantage.
Side-by-side data
| Property | A572 Gr50 HSLA Steel | A36 Structural |
|---|---|---|
| Category | Steel | Steel |
| Density (g/cm³) | 7.85 | 7.85 |
| Tensile strength (MPa) | 450 | 400 |
| Yield strength (MPa) | 345 | 250 |
| Elongation (%) | 21 | 20 |
| Hardness | 150 HB | 120 HB |
| Max service temp (°C) | 400 | 400 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 50 | 50 |
| Typically used for | Structural buildings & bridges | Structural & weldments |
Which should you choose?
Choose A572 Gr50 HSLA Steel when…
- Designing buildings, bridges, and structures benefiting from higher yield
- Reducing weight and section size matters (~345 MPa vs A36's 250)
- Strength-to-weight efficiency lowers steel tonnage and cost
- High-strength structural plate, beams, and weldments are needed
- Microalloyed HSLA toughness and strength suit the design code
- Heavy load-bearing members where A36 would be over-thick
Choose A36 Structural when…
- General structural fabrication where standard strength suffices
- Lowest material cost is the priority (~1.0 vs A572's ~1.2 index)
- Maximum weldability and forgiving fabrication are wanted
- Sections aren't weight- or strength-critical
- A widely stocked, code-recognized baseline steel is preferred
- Simple plates, frames, and brackets at minimum cost
Key differences that matter
- Strength: A572 Gr50 ~450 MPa tensile / 345 MPa yield vs A36 ~400 MPa / 250 MPa — A572 has ~38% higher yield
- A572 is a microalloyed HSLA steel (small additions like vanadium/niobium); A36 is plain structural carbon steel
- A572's higher yield lets designers use thinner, lighter sections, reducing weight and sometimes total cost
- Both are weldable, but A36's lower strength and simpler chemistry make it the more forgiving general choice
- Ductility is comparable (A572 21%, A36 20% elongation) — HSLA strength doesn't sacrifice much ductility
- Both have poor corrosion resistance (1.5/5) and need protective coatings outdoors
- Cost: A572 (~1.2 index) is modestly higher than A36 (~1.0); the strength-to-weight gain often offsets it
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Open the Material SelectorGet a Quote →Frequently asked questions
What is the difference between A572 Gr50 and A36 steel?
A572 Grade 50 is a high-strength low-alloy (HSLA) steel with about 345 MPa minimum yield, while A36 is a plain carbon structural steel with about 250 MPa yield. A572's microalloying gives roughly 38% more yield strength, letting engineers use lighter sections. A36 is cheaper and slightly easier to weld, making it the general-purpose baseline.
Is A572 stronger than A36?
Yes. A572 Grade 50 provides about 345 MPa minimum yield and 450 MPa tensile, versus A36's roughly 250 MPa yield and 400 MPa tensile — about 38% higher yield strength. That extra strength comes from microalloying, and it allows lighter, thinner structural members carrying the same load, which can reduce overall steel weight.
Can A572 Gr50 be welded like A36?
Yes, A572 Gr50 is weldable and widely used in welded structures, though its higher strength and microalloy content can warrant attention to heat input and, in thicker sections, preheat. A36's lower strength and simpler chemistry make it marginally more forgiving to weld. Both are common structural weldment materials with established welding procedures.
Why choose A572 over A36 for buildings and bridges?
A572 Gr50's higher yield (~345 vs 250 MPa) lets engineers carry the same loads with thinner, lighter members, cutting steel tonnage and dead weight. On large structures like buildings and bridges, that weight savings can offset A572's modestly higher cost per pound, while keeping comparable ductility and weldability. A36 remains fine where strength isn't the constraint.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.