Steel HC550LA · supply condition
Steel HC550LA-CR
Properties of the CR condition, compared with the other HC550LA tempers.
Standard supply condition for HC550LA sheet/coil: tight thickness and flatness for stamped automotive structural parts.
What is HC550LA-CR?
HC550LA-CR is HC550LA supplied in the CR condition — standard supply condition for HC550LA sheet/coil: tight thickness and flatness for stamped automotive structural parts. HC550LA-CR has a yield strength of 600 MPa (87 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 77% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). HC550LA-CR 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). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 83% of steel grades
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
Limitations
- Limited ductility — 13%, worse than 78% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 77% of steel grades
HC550LA-CR properties
Typical room-temperature values for HC550LA-CR — 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-CR 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-CR has a yield strength of 600 MPa (87 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 77% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
HC550LA-CR 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-CR conducts electricity at 9 % IACS, better than 70% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of HC550LA-CR 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-CR's machinability is fair (50/100, worse than 53% of steel grades); weldability excellent (85/100); formability fair (50/100).
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-CR
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-CR — frequently asked
What is HC550LA-CR used for?
HC550LA-CR 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-CR?
HC550LA-CR has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 77% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is HC550LA-CR easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% 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-CR 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-CR?
Not anodizable; supply as hot-dip galvanized/galvannealed, or phosphate + cathodic e-coat and paint for corrosion protection.
Can HC550LA-CR 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-CR?
HC550LA-CR 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-CR?
Yes — HC550LA-CR 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.