Steel HC550LA · supply condition · default condition
Steel HC550LA-HR
Properties of the HR condition, compared with the other HC550LA tempers.
Pick for thicker gauges (>3 mm) such as chassis, wheel discs and cross-members where surface finish is secondary.
What is HC550LA-HR?
HC550LA-HR is HC550LA supplied in the HR condition — pick for thicker gauges (>3 mm) such as chassis, wheel discs and cross-members where surface finish is secondary. HC550LA-HR has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 75% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi). HC550LA-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Advantages
- Readily welded — 85/100, better than 83% of steel grades
- High strength — 580 MPa (84.1 ksi), better than 75% of steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 77% of steel grades
HC550LA-HR properties
Typical room-temperature values for HC550LA-HR — 11 properties are specific to this condition; the rest are grade-level values shared by every HC550LA temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
HC550LA-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical15
HC550LA-HR has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 75% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
HC550LA-HR is rated for continuous service to 300°C (572 °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
HC550LA-HR conducts electricity at 9 % IACS, better than 70% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of HC550LA-HR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
HC550LA-HR's machinability is fair (52/100, better than 52% of steel grades); weldability excellent (85/100); formability fair (52/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other HC550LA tempers and conditions
HC550LA is also supplied in 3 other conditions. The full side-by-side table is on the HC550LA overview.
- HRDefaultPick for thicker gauges (>3 mm) such as chassis, wheel discs and cross-members where surface finish is secondary.580 MPa yield · 195 HB
- CRStandard supply condition for HC550LA sheet/coil: tight thickness and flatness for stamped automotive structural parts.600 MPa yield · 200 HB
- GalvanizedChoose for body-in-white and underbody parts needing cathodic corrosion protection straight from the coil.590 MPa yield · 198 HB
- TMCPUse where the 550 MPa yield class must be combined with fine-grain low-temperature toughness and good bendability in heavier plate.590 MPa yield · 205 HB
Working with HC550LA-HR
Is HC550LA easy to machine?
Machines like a 200 HB low-alloy steel — use coated carbide, moderate speeds and rigid clamping of thin sheet; punching needs sharp tooling and ≥15 % of thickness clearance to limit burr and edge damage.
Can HC550LA be welded?
Very good resistive spot, MAG and laser weldability thanks to low carbon equivalent; keep heat input controlled to avoid HAZ softening, and remove/allow for zinc fume on coated material.
Can HC550LA be formed, bent or molded?
Cold form with generous radii (≥2–3 t bends), high blank-holder force and springback compensation; cut edges should be laser-trimmed or deburred to avoid edge cracking at high stretch.
What surface finishes work on HC550LA?
Not anodizable; supply as hot-dip galvanized/galvannealed, or phosphate + cathodic e-coat and paint for corrosion protection.
HC550LA 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 |
|---|---|---|
| Clow carbon for weldability | ≤ 0.13 | 0.08 |
| Si | ≤ 0.5 | 0.2 |
| Mnsolid-solution strengthening | ≤ 1.8 | 1.5 |
| P | ≤ 0.03 | 0.02 |
| Slow S for bendability | ≤ 0.02 | 0.01 |
| Altotal Al, deoxidation | ≥ 0.02 | 0.04 |
| Nbgrain refinement / precipitation | ≤ 0.09 | 0.05 |
| TiNb+Ti ≤ 0.22 total | ≤ 0.15 | 0.05 |
| Fe | balance | — |
HC550LA-HR — frequently asked
What is HC550LA-HR used for?
HC550LA-HR is typically used for automotive bumper beams, stamped suspension components, door intrusion beams, chassis cross members, seat structure brackets and wheel rims. In short: high-strength HSLA sheet.
What is the yield strength of HC550LA-HR?
HC550LA-HR has a typical yield strength of 580 MPa (84.1 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 75% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is HC550LA-HR easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines like a 200 HB low-alloy steel — use coated carbide, moderate speeds and rigid clamping of thin sheet; punching needs sharp tooling and ≥15 % of thickness clearance to limit burr and edge damage.
Can HC550LA-HR be welded?
Yes — weldability is rated excellent (85/100). Very good resistive spot, MAG and laser weldability thanks to low carbon equivalent; keep heat input controlled to avoid HAZ softening, and remove/allow for zinc fume on coated material.
What surface finishes work on HC550LA-HR?
Not anodizable; supply as hot-dip galvanized/galvannealed, or phosphate + cathodic e-coat and paint for corrosion protection.
Can HC550LA-HR be formed, bent or molded?
Cold form with generous radii (≥2–3 t bends), high blank-holder force and springback compensation; cut edges should be laser-trimmed or deburred to avoid edge cracking at high stretch.
What is the maximum service temperature of HC550LA-HR?
HC550LA-HR is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between HC550LA-HR and HC550LA-CR?
HR is the default condition — pick for thicker gauges (>3 mm) such as chassis, wheel discs and cross-members where surface finish is secondary. CR: standard supply condition for HC550LA sheet/coil: tight thickness and flatness for stamped automotive structural parts. Yield strength is 580 MPa in HR versus 600 MPa in CR.
Can FabDigit make parts in HC550LA-HR?
Yes — HC550LA-HR is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10268 — Cold-rolled steel flat products with high yield strength for cold forming — CEN (2006)
- EN 10346 — Continuously hot-dip coated steel flat products for cold forming (HX...LAD grades) — CEN (2015)
- EN 10149-2 — Hot-rolled flat products of high yield strength steels for cold forming (S550MC) — CEN (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- HSLA cold-rolled and galvanized steel grade datasheets — ArcelorMittal / SSAB / Baosteel (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.