Steel A572 Gr 50
ASTM A572 Gr 50
A572 Grade 50 is the most widely used grade of the ASTM A572 high-strength low-alloy structural steel family, microalloyed with vanadium and/or niobium to a 50 ksi minimum yield, with typical values of 380 MPa yield, 485 MPa tensile, 21 % elongation and 150 HB.
Values for the HR condition
A572 Gr 50 tempers and conditions
A572 Gr 50 is supplied in 5 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/subcritical anneal (softened for machining or severe forming) | Use when maximum ductility and lowest hardness are needed for deep forming or heavy machining; yield falls below the 345 MPa structural minimum. | 300 | 450 | 30 | 130 HB | — |
austenitized and air cooled (supplementary requirement, heavy plate) | Pick for thick plate or low-temperature service where uniform fine grain and higher Charpy energy are required. | 370 | 500 | 24 | 150 HB | — |
HRDefault Hot rolled | Default mill condition for A572 Gr 50 plate, structural shapes and HSS-type sections; meets 345 MPa min yield as-rolled. | 380 | 485 | 21 | 150 HB | — |
Cold rolled | Thin sheet/strip form with better flatness and surface finish; strength raised and ductility reduced by cold reduction. | 450 | 550 | 14 | 170 HB | 8.6 % IACS |
Cold drawn | Choose for dimensionally accurate bar stock, machined shafts and pins where the higher yield from drawing is a bonus; residual stress may cause distortion on machining. | 470 | 570 | 13 | 175 HB | — |
What is A572 Gr 50?
A572 Grade 50 is the most widely used grade of the ASTM A572 high-strength low-alloy structural steel family, microalloyed with vanadium and/or niobium to a 50 ksi minimum yield, with typical values of 380 MPa yield, 485 MPa tensile, 21 % elongation and 150 HB. It is specified for welded structural members needing better strength-to-weight than mild carbon structural steel, and is supplied hot-rolled as plate, shapes, bar and sheet, plus cold-rolled, cold-drawn, annealed and normalized stock. It has no inherent corrosion resistance and must be coated, and cold forming needs larger radii and more tonnage than A36. Q345B and S355J2 are the close international equivalents. A572 Gr 50 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). A572 Gr 50 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 68% of steel grades. Elongation at break is 21% and the elastic modulus is 200 GPa (29 Msi).
What is A572 Gr 50 used for?
- Bridges
- Crane structures
- Building frames
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- Readily welded — 82/100, better than 81% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
A572 Gr 50 properties
Typical room-temperature values for A572 Gr 50-HR; bars are the position among steel grades.
Physical3
A572 Gr 50 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
A572 Gr 50 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 68% of steel grades. Elongation at break is 21% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A572 Gr 50 is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
A572 Gr 50 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A572 Gr 50 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 40%.
Manufacturability7
A572 Gr 50's machinability is good (58/100, better than 75% of steel grades); weldability very good (82/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A572 Gr 50 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A572 Gr 50
Is A572 Gr 50 easy to machine?
Machines like a 1020–1025 carbon steel at ~58 % of 1212; use rigid setups and positive-rake carbide, expect gummy chips and moderate built-up edge without a free-machining sulfur addition.
Can A572 Gr 50 be welded?
Prequalified in AWS D1.1 (Group II); weld with E70XX/ER70S-6 or matching 480 MPa consumables, preheat 10–110 °C depending on thickness and CE, and avoid excessive heat input to keep HAZ toughness.
Can A572 Gr 50 be formed, bent or molded?
Cold bends readily but needs larger bend radii and more press tonnage than A36 (springback higher); hot forming above ~650 °C on V/Nb grades can coarsen grain and lose the microalloy strengthening.
Manufacturability
The process limits FabDigit applies to A572 Gr 50. Every A572 Gr 50 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better58 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better60 / 100 |
|---|---|
| Weldability | Excellent82 / 100 |
| Bendable | Yes |
A572 Gr 50 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C0.23 max for Gr 50; often ≤0.20 for good weldability | ≤ 0.23 | 0.18 |
| Mn1.35 max (plate/shapes); 1.65 max allowed for some Gr 60/65 forms | ≤ 1.35 | 1.15 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Si0.40 max for plate/bar; 0.15–0.40 for some shapes | ≤ 0.4 | 0.25 |
| NbType 1 microalloying (columbium) | 0.01 – 0.05 | 0.03 |
| VType 2 microalloying; Type 3 = Nb + V combined | 0.01 – 0.15 | 0.05 |
| TiType 5 (titanium) option | ≤ 0.05 | 0.02 |
| NV:N ratio ≥ 4:1 when nitrogen intentionally added | ≤ 0.02 | 0.01 |
| Fe | balance |
What surface finishes work on A572 Gr 50?
No natural corrosion resistance — specify shot blast to SA 2.5 plus zinc-rich or epoxy primer, hot-dip galvanizing (watch Si level for coating thickness), or metallizing; anodizing is not applicable.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A572 Gr 50 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does A572 Gr 50 cost?
A572 Gr 50 is a budget-cost steel ($), cheaper than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A572 Gr 50 — frequently asked
What is A572 Gr 50 used for?
A572 Gr 50 is typically used for bridges, crane structures and building frames. In short: workhorse HSLA plate.
What is the yield strength of A572 Gr 50?
A572 Gr 50 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 485 MPa (70.3 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A572 Gr 50 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a 1020–1025 carbon steel at ~58 % of 1212; use rigid setups and positive-rake carbide, expect gummy chips and moderate built-up edge without a free-machining sulfur addition.
Can A572 Gr 50 be welded?
Yes — weldability is rated very good (82/100). Prequalified in AWS D1.1 (Group II); weld with E70XX/ER70S-6 or matching 480 MPa consumables, preheat 10–110 °C depending on thickness and CE, and avoid excessive heat input to keep HAZ toughness.
What surface finishes work on A572 Gr 50?
No natural corrosion resistance — specify shot blast to SA 2.5 plus zinc-rich or epoxy primer, hot-dip galvanizing (watch Si level for coating thickness), or metallizing; anodizing is not applicable.
Can A572 Gr 50 be formed, bent or molded?
Cold bends readily but needs larger bend radii and more press tonnage than A36 (springback higher); hot forming above ~650 °C on V/Nb grades can coarsen grain and lose the microalloy strengthening.
What is the maximum service temperature of A572 Gr 50?
A572 Gr 50 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A572 Gr 50-HR and A572 Gr 50-CD?
HR is the default condition — default mill condition for A572 Gr 50 plate, structural shapes and HSS-type sections; meets 345 MPa min yield as-rolled. CD: choose for dimensionally accurate bar stock, machined shafts and pins where the higher yield from drawing is a bonus; residual stress may cause distortion on machining. Yield strength is 380 MPa in HR versus 470 MPa in CD.
How much does A572 Gr 50 cost?
A572 Gr 50 is a budget-cost steel ($), cheaper than about 99% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in A572 Gr 50?
Yes — A572 Gr 50 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A572/A572M — High-Strength Low-Alloy Columbium-Vanadium Structural Steel — ASTM International (2021)
- ASTM A6/A6M — General Requirements for Rolled Structural Steel Bars, Plates, Shapes and Sheet Piling — ASTM International (2019)
- AWS D1.1/D1.1M Structural Welding Code — Steel — American Welding Society (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Construction Manual, 15th ed. — AISC (2017)
- GB/T 1591 (Q345/Q355 comparison grade) — SAC (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.