Steel A572
ASTM A572
A572 is a family of niobium/vanadium microalloyed high-strength low-alloy (HSLA) structural steels graded by yield strength as 42, 50, 55, 60 and 65, with Grade 50 (345 MPa yield) the most common.
Values for the HR condition
A572 tempers and conditions
A572 is supplied in 10 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/subcritical anneal (softened) | Used only to soften for severe forming or machining; the microalloy precipitation strengthening is largely lost. | 290 | 430 | 28 | 125 HB | 9.5 % IACS |
Grade 42 | Lowest strength level, available to 150 mm thickness; pick when thick sections and easy forming matter more than strength. | 310 | 450 | 24 | 130 HB | 47 W/m·K |
HRDefault Hot rolled | Default stock condition: as-rolled A572 Gr.50 plate, beam or channel for welded structures. | 360 | 480 | 22 | 145 HB | 9 % IACS |
austenitized and air cooled | Specified for heavy plate or low-temperature service to refine grain and restore uniform toughness through thickness. | 365 | 490 | 24 | 150 HB | 9 % IACS |
Grade 50 | The industry standard HSLA structural grade — best balance of strength, weldability and availability. | 370 | 495 | 21 | 145 HB | 46 W/m·K |
Cold rolled | Thin-gauge cold-reduced HSLA sheet where flatness, tight tolerance and a clean surface matter. | 400 | 500 | 18 | 160 HB | 9 % IACS |
Grade 55 | Intermediate level used where a modest weight saving over Grade 50 is worthwhile; availability is limited. | 405 | 525 | 20 | 155 HB | 46 W/m·K |
Grade 60 | Higher-strength level limited to ~32 mm thickness; used for lighter beams, poles and equipment frames. | 440 | 560 | 18 | 165 HB | 45 W/m·K |
Cold drawn | Cold-drawn round/flat bar: highest strength and best surface finish/straightness, at the cost of ductility and residual stress. | 470 | 560 | 12 | 180 HB | 9 % IACS |
Grade 65 | Highest A572 level (≤32 mm) for maximum weight saving; needs the tightest preheat and forming-radius control. | 475 | 595 | 17 | 180 HB | 45 W/m·K |
What is A572?
A572 is a family of niobium/vanadium microalloyed high-strength low-alloy (HSLA) structural steels graded by yield strength as 42, 50, 55, 60 and 65, with Grade 50 (345 MPa yield) the most common. It keeps the cost and weldability of plain carbon structural steel such as A36 while raising yield strength by about 40%, so it is used to save weight in bridges, building beams and columns, cranes and construction equipment; plate, shapes and bar are the usual forms. Corrosion resistance is the same as ordinary carbon steel and coating is mandatory, low-temperature impact toughness and weld heat input need control on thick plate and the higher grades, and it cannot be significantly strengthened by quench and temper. A572 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 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
What is A572 used for?
- Bridge girders and gusset plates
- Building beams and columns
- Construction equipment frames
- Crane booms and runway girders
- Transmission poles and lattice towers
- Truck and trailer chassis members
- Heavy base plates and lifting lugs
Advantages
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Readily welded — 82/100, better than 81% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
A572 properties
Typical room-temperature values for A572-HR; bars are the position among steel grades.
Physical3
A572 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).
Mechanical16
A572 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A572 is rated for continuous service to 400°C (752 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
A572 conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A572 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
A572's machinability is good (55/100, better than 62% 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 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A572
Is A572 easy to machine?
Machines like a tough medium-carbon steel — roughly 55% of 1212; use rigid setups, positive-rake carbide and generous coolant, expect stringy chips and some distortion from rolling residual stress.
Can A572 be welded?
Prequalified in AWS D1.1 with E70/ER70S consumables; low carbon equivalent means little preheat below ~20 mm, but limit heat input on Gr.60/65 and use low-hydrogen practice on thick plate.
Can A572 be formed, bent or molded?
Cold bends and press-brakes well with radii ~2–3t (larger than A36 and larger still for Gr.60/65); bend transverse to the rolling direction and avoid re-bending sheared edges.
Manufacturability
The process limits FabDigit applies to A572. Every A572 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Good55 / 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 | Better82 / 100 |
| Bendable | Yes |
A572 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 |
|---|---|---|
| C0.26 max for Gr.42 shapes/bars per product form | ≤ 0.23 | 0.18 |
| Mn1.65 max for Gr.55–65 plate in some product forms | ≤ 1.35 | 1.15 |
| Si | ≤ 0.4 | 0.25 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Nbcolumbium — Type 1 and Type 3 | 0.01 – 0.05 | 0.03 |
| VType 2 and Type 3 | 0.01 – 0.15 | 0.05 |
| TiType 4/5 options | ≤ 0.05 | |
| NType 5 (V+N) only | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on A572?
No natural corrosion protection — shot blast to SA 2.5 then zinc-rich primer, paint, hot-dip galvanize (watch Si for coating thickness) or metallize; not anodizable.
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 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- Q345S355
How much does A572 cost?
A572 is a standard-cost steel ($$), cheaper than about 81% 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 — frequently asked
What is A572 used for?
A572 is typically used for bridge girders and gusset plates, building beams and columns, construction equipment frames, crane booms and runway girders, transmission poles and lattice towers and truck and trailer chassis members. In short: standard structural grade.
What is the yield strength of A572?
A572 has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 72% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is A572 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a tough medium-carbon steel — roughly 55% of 1212; use rigid setups, positive-rake carbide and generous coolant, expect stringy chips and some distortion from rolling residual stress.
Can A572 be welded?
Yes — weldability is rated very good (82/100). Prequalified in AWS D1.1 with E70/ER70S consumables; low carbon equivalent means little preheat below ~20 mm, but limit heat input on Gr.60/65 and use low-hydrogen practice on thick plate.
What surface finishes work on A572?
No natural corrosion protection — shot blast to SA 2.5 then zinc-rich primer, paint, hot-dip galvanize (watch Si for coating thickness) or metallize; not anodizable.
Can A572 be formed, bent or molded?
Cold bends and press-brakes well with radii ~2–3t (larger than A36 and larger still for Gr.60/65); bend transverse to the rolling direction and avoid re-bending sheared edges.
What is the maximum service temperature of A572?
A572 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-HR and A572-Gr65?
HR is the default condition — default stock condition: as-rolled A572 Gr.50 plate, beam or channel for welded structures. Gr65: highest A572 level (≤32 mm) for maximum weight saving; needs the tightest preheat and forming-radius control. Yield strength is 360 MPa in HR versus 475 MPa in Gr65.
How much does A572 cost?
A572 is a standard-cost steel ($$), cheaper than about 81% 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?
Yes — A572 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)
- 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)
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.