Steel A572 Gr 42
ASTM A572 Gr 42
A572 Gr 42 is a niobium/vanadium microalloyed HSLA structural steel supplied to a minimum yield of 290 MPa (42 ksi) and minimum tensile of 415 MPa (60 ksi), as plate, shapes and bar for bridges, building frames, crane girders and towers.
Values for the HR condition
A572 Gr 42 tempers and conditions
A572 Gr 42 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, stress-free) | Choose when maximum ductility and dimensional stability for heavy forming or deep machining outweigh the loss of yield strength (may fall below the A572 spec minimum). | 260 | 420 | 30 | 120 HB | — |
HRDefault Hot rolled | Standard mill condition for structural plate, shapes, sheet piling and bar; pick this for welded structures and general fabrication. | 320 | 460 | 26 | 140 HB | — |
austenitized ~870–900 °C and air cooled | Order normalized plate when uniform fine grain and better low-temperature Charpy toughness are required (cold-climate bridges, pressure-retaining or impact-tested applications). | 330 | 470 | 28 | 145 HB | — |
Cold rolled | Use for thin sheet/strip where a smoother surface, tighter thickness tolerance and higher yield are wanted, at the cost of ductility. | 400 | 500 | 14 | 160 HB | — |
Cold drawn | Cold-finished bar for machined shafts, pins and studs where straightness, size tolerance and a strength bump matter more than ductility. | 430 | 520 | 12 | 170 HB | — |
What is A572 Gr 42?
A572 Gr 42 is a niobium/vanadium microalloyed HSLA structural steel supplied to a minimum yield of 290 MPa (42 ksi) and minimum tensile of 415 MPa (60 ksi), as plate, shapes and bar for bridges, building frames, crane girders and towers. Low carbon (≤0.21 %) and fine-grain microalloy strengthening give better weldability and cold bending than medium-carbon steel of the same strength, often with no preheat. Corrosion resistance equals plain carbon steel, so paint or galvanize; strength is not heat-treatable and impact values are not mandatory, so order impact testing or normalized material for low-temperature use. A572 Gr 42 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). A572 Gr 42 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi).
What is A572 Gr 42 used for?
- Bridge girders and gusset plates
- Industrial building framing
- Crane runway beams
- Transmission and communication towers
- Welded base plates and stiffeners
- Trailer and equipment chassis
- Machine frames and weldments
Advantages
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 85/100, better than 83% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Forms and bends easily — 65/100, 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 — 40/100, worse than 96% of steel grades
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
A572 Gr 42 properties
Typical room-temperature values for A572 Gr 42-HR; bars are the position among steel grades.
Physical3
A572 Gr 42 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
A572 Gr 42 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A572 Gr 42 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 Gr 42 conducts electricity at 10 % IACS, better than 83% 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 42 takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 40%.
Manufacturability7
A572 Gr 42's machinability is good (58/100, better than 75% of steel grades); weldability excellent (85/100); formability good (65/100).
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 42 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A572 Gr 42
Is A572 Gr 42 easy to machine?
Machines like a soft low-carbon steel — gummy chips and built-up edge; use positive rake, sharp coated carbide, high feed and coolant; normalized or cold-drawn stock gives better finish than as-rolled.
Can A572 Gr 42 be welded?
Prequalified in AWS D1.1 with E70XX/ER70S-X consumables; low carbon equivalent means little or no preheat below ~38 mm, but keep hydrogen low and avoid excessive heat input to preserve the fine-grain toughness.
Can A572 Gr 42 be formed, bent or molded?
Good cold bending and press braking if bend radii follow A6/A572 minimums (bend transverse to rolling direction, remove flame-cut hardened edges); hot forming above ~650 °C partly removes microalloy strengthening.
Manufacturability
The process limits FabDigit applies to A572 Gr 42. Every A572 Gr 42 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 | Better65 / 100 |
|---|---|
| Weldability | Excellent85 / 100 |
| Bendable | Yes |
A572 Gr 42 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 |
|---|---|---|
| CGr 42 maximum per ASTM A572 | ≤ 0.21 | 0.16 |
| Mnmax 1.35 for Gr 42 | ≤ 1.35 | 1.05 |
| Si0.40 max (plates ≤ 38 mm may be lower) | ≤ 0.4 | 0.25 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| NbType 1 (columbium) microalloy addition | 0.01 – 0.05 | 0.03 |
| VType 2; Type 3 uses Nb+V with Nb ≤0.05, V ≤0.11, total ≤0.15 | 0.01 – 0.15 | 0.05 |
| TiType 5 (Ti) option, 0.006–0.04 typical when used | ≤ 0.15 | |
| Nwhen V is used, V:N ratio ≥ 4:1 required | ≤ 0.02 | |
| Cuonly when copper-bearing steel is specified | ≥ 0.2 | 0.25 |
| Fe | balance |
What surface finishes work on A572 Gr 42?
No anodizing — protect by blast + zinc-rich or epoxy primer, hot-dip galvanizing (watch Si level for coating thickness), or metallizing; mill scale must be removed for durable paint adhesion.
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
How much does A572 Gr 42 cost?
A572 Gr 42 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 42 — frequently asked
What is A572 Gr 42 used for?
A572 Gr 42 is typically used for bridge girders and gusset plates, industrial building framing, crane runway beams, transmission and communication towers, welded base plates and stiffeners and trailer and equipment chassis. In short: HSLA structural plate.
What is the yield strength of A572 Gr 42?
A572 Gr 42 has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A572 Gr 42 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a soft low-carbon steel — gummy chips and built-up edge; use positive rake, sharp coated carbide, high feed and coolant; normalized or cold-drawn stock gives better finish than as-rolled.
Can A572 Gr 42 be welded?
Yes — weldability is rated excellent (85/100). Prequalified in AWS D1.1 with E70XX/ER70S-X consumables; low carbon equivalent means little or no preheat below ~38 mm, but keep hydrogen low and avoid excessive heat input to preserve the fine-grain toughness.
What surface finishes work on A572 Gr 42?
No anodizing — protect by blast + zinc-rich or epoxy primer, hot-dip galvanizing (watch Si level for coating thickness), or metallizing; mill scale must be removed for durable paint adhesion.
Can A572 Gr 42 be formed, bent or molded?
Good cold bending and press braking if bend radii follow A6/A572 minimums (bend transverse to rolling direction, remove flame-cut hardened edges); hot forming above ~650 °C partly removes microalloy strengthening.
What is the maximum service temperature of A572 Gr 42?
A572 Gr 42 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 42-HR and A572 Gr 42-CD?
HR is the default condition — standard mill condition for structural plate, shapes, sheet piling and bar; pick this for welded structures and general fabrication. CD: cold-finished bar for machined shafts, pins and studs where straightness, size tolerance and a strength bump matter more than ductility. Yield strength is 320 MPa in HR versus 430 MPa in CD.
How much does A572 Gr 42 cost?
A572 Gr 42 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 42?
Yes — A572 Gr 42 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 (HSLA steels) — ASM International (1990)
- Steel Construction Manual, 15th ed. — AISC (2017)
- ICE / worldsteel LCI data for structural steel — University of Bath / worldsteel (2019)
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.