Steel HSLA
HSLA is a low-carbon manganese steel micro-alloyed with Nb, V and Ti, using grain refinement and precipitation strengthening to reach 290–550 MPa yield (quenched-and-tempered types above 690 MPa) with carbon held below 0.25 %.
Values for the HR condition
HSLA tempers and conditions
HSLA 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 |
|---|---|---|---|---|---|---|
HRDefault Hot rolled | Default stock condition for structural plate, sections and hot-rolled coil; best price per unit strength. | 345 | 490 | 21 | 150 HB | — |
Normalized | Specify when uniform fine grain and guaranteed sub-zero Charpy values are needed in thicker plate or after hot forming. | 360 | 510 | 23 | 155 HB | 46 W/m·K |
Cold rolled | Choose for thin-gauge stamped parts needing tight thickness tolerance, clean surface and higher yield than CQ steel. | 380 | 470 | 21 | 160 HB | — |
Thermomechanically controlled processed | Use for thick plate needing high strength plus low-temperature toughness and low carbon equivalent for field welding (ships, bridges, offshore). | 430 | 550 | 22 | 175 HB | — |
Quenched and tempered | Highest-strength HSLA route for naval hull, crane boom and heavy equipment plate where 550–700 MPa yield with good toughness is required. | 620 | 720 | 18 | 22 HRC | — |
Supply forms, finishes and certifications
Ways HSLA is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Galvanized | Hot-dip zinc coated HSLA sheet | Coating |
What is HSLA?
HSLA is a low-carbon manganese steel micro-alloyed with Nb, V and Ti, using grain refinement and precipitation strengthening to reach 290–550 MPa yield (quenched-and-tempered types above 690 MPa) with carbon held below 0.25 %. Engineers specify it to thin down sections and save weight against plain carbon structural steel while keeping good weldability and low-temperature toughness; stock forms include HR, CR, galvanized, TMCP, normalized and Q&T plate, sheet and sections. Strength cannot be raised much by heat treatment except in dedicated Q&T grades, and the elastic modulus equals mild steel, so stiffness does not improve. Corrosion protection still requires paint or zinc, and higher-strength grades show greater springback and sheared-edge crack sensitivity. HSLA 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). HSLA has a yield strength of 345 MPa (50 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 75% of steel grades. Elongation at break is 21% and the elastic modulus is 205 GPa (29.7 Msi).
What is HSLA used for?
- Bridge girders and plate sections
- Building and structural frames
- Crane and excavator booms
- Truck chassis frames and crossmembers
- Automotive body structural reinforcements
- Pressure vessel shells
- Ship hull plating
Advantages
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Low strength — 345 MPa (50 ksi), worse than 75% of steel grades
HSLA properties
Typical room-temperature values for HSLA-HR; bars are the position among steel grades.
Physical3
HSLA 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
HSLA has a yield strength of 345 MPa (50 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 75% of steel grades. Elongation at break is 21% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
HSLA is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
HSLA conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of HSLA takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
HSLA's machinability is good (58/100, better than 75% of steel grades); weldability very good (80/100); 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. HSLA is highlighted; hover a dot for its name, or open the interactive family chart.
Working with HSLA
Is HSLA easy to machine?
Machines like a tough medium-carbon steel — use rigid setups, positive-rake carbide, moderate speeds and generous feed; micro-alloy carbonitrides cause slightly faster tool wear than plain 1020, and Q&T grades need reduced speed.
Can HSLA be welded?
Low carbon equivalent makes most HSLA prequalified for SMAW/GMAW/SAW with matching-strength consumables; keep heat input controlled (excess input coarsens the HAZ and erodes toughness) and preheat 50–150 °C for thick or Q&T plate.
Can HSLA be formed, bent or molded?
Cold forms well but needs larger bend radii, higher press tonnage and 2–3× the springback compensation of mild steel; roll or press-brake with sheared edges deburred to avoid edge cracking, and avoid re-forming Q&T grades.
Manufacturability
The process limits FabDigit applies to HSLA. Every HSLA 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 | Excellent80 / 100 |
| Bendable | Yes |
HSLA 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 |
|---|---|---|
| C≤0.20 % typical for weldable micro-alloyed grades | ≤ 0.23 | 0.12 |
| Mn | 0.6 – 1.7 | 1.3 |
| Si | ≤ 0.55 | 0.3 |
| P | ≤ 0.04 | 0.02 |
| S≤0.010 % for Ca-treated / low-temp grades | ≤ 0.04 | 0.01 |
| Nbgrain refinement + precipitation strengthening | 0.01 – 0.11 | 0.03 |
| V | 0.01 – 0.15 | 0.05 |
| TiN fixing, grain size control | ≤ 0.15 | 0.02 |
| Alacid-soluble, deoxidation | 0.02 – 0.06 | 0.03 |
| Cuup to 1.2 % in Cu-precipitation HSLA-80/100 | ≤ 0.6 | 0.2 |
| Nihigher in Q&T naval grades | ≤ 0.9 | 0.1 |
| Cr | ≤ 0.7 | 0.1 |
| Mo | ≤ 0.3 | 0.02 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance |
What surface finishes work on HSLA?
No anodizing; specify blast + zinc-rich primer/paint, hot-dip galvanize (watch silicon/phosphorus for coating thickness), phosphate + e-coat, or use a weathering-type HSLA composition for bare patina service.
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 HSLA in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- High Strength Low AlloyHigh-Strength Low-Alloy SteelHSLA Steel
How much does HSLA cost?
HSLA is a standard-cost steel ($$), cheaper than about 61% 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.
HSLA — frequently asked
What is HSLA used for?
HSLA is typically used for bridge girders and plate sections, building and structural frames, crane and excavator booms, truck chassis frames and crossmembers, automotive body structural reinforcements and pressure vessel shells. In short: high-strength low-alloy plate.
What is the yield strength of HSLA?
HSLA has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 75% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is HSLA easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a tough medium-carbon steel — use rigid setups, positive-rake carbide, moderate speeds and generous feed; micro-alloy carbonitrides cause slightly faster tool wear than plain 1020, and Q&T grades need reduced speed.
Can HSLA be welded?
Yes — weldability is rated very good (80/100). Low carbon equivalent makes most HSLA prequalified for SMAW/GMAW/SAW with matching-strength consumables; keep heat input controlled (excess input coarsens the HAZ and erodes toughness) and preheat 50–150 °C for thick or Q&T plate.
What surface finishes work on HSLA?
No anodizing; specify blast + zinc-rich primer/paint, hot-dip galvanize (watch silicon/phosphorus for coating thickness), phosphate + e-coat, or use a weathering-type HSLA composition for bare patina service.
Can HSLA be formed, bent or molded?
Cold forms well but needs larger bend radii, higher press tonnage and 2–3× the springback compensation of mild steel; roll or press-brake with sheared edges deburred to avoid edge cracking, and avoid re-forming Q&T grades.
What is the maximum service temperature of HSLA?
HSLA 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 HSLA-HR and HSLA-QT?
HR is the default condition — default stock condition for structural plate, sections and hot-rolled coil; best price per unit strength. QT: highest-strength HSLA route for naval hull, crane boom and heavy equipment plate where 550–700 MPa yield with good toughness is required. Yield strength is 345 MPa in HR versus 620 MPa in QT.
How much does HSLA cost?
HSLA is a standard-cost steel ($$), cheaper than about 61% 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 HSLA?
Yes — HSLA 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 A1008/A1011 — Cold/Hot-Rolled Steel Sheet, HSLAS — ASTM International (2021)
- ASTM A653/A653M — Zinc-Coated (Galvanized) Sheet, SS and HSLAS — ASTM International (2020)
- EN 10025-2/-4 Hot rolled structural steels (S355, S420M/ML) — CEN (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.14A/14B — Metalworking: Forming and Sheet Metal — ASM International (2006)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- HSLA structural plate datasheets (ArcelorMittal, Nucor, Baosteel) — various producers (2023)
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.