Steel DP780-HR (Hot rolled)
Supply condition
Use for chassis, control arms and wheel discs where gauge above ~2.5 mm is needed and surface finish is secondary.
Values for the HR condition
Other DP780 tempers and conditions
DP780 is listed in 2 conditions; see the grade overview at DP780.
- CR
- HR
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CRDefault Cold rolled | Standard uncoated cold-rolled DP780 sheet for painted/e-coated interior structural stampings. | 500 | 830 | 16 | 245 HB | — |
HRThis page Hot rolled | Use for chassis, control arms and wheel discs where gauge above ~2.5 mm is needed and surface finish is secondary. | 520 | 840 | 15 | 25 HRC | 8.6 % IACS |
What is DP780-HR?
DP780-HR is DP780 supplied in the HR condition — use for chassis, control arms and wheel discs where gauge above ~2.5 mm is needed and surface finish is secondary. DP780-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 207 GPa (30 Msi). DP780-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). CR is the default condition FabDigit quotes; HR is available on request or by drawing note.
Limitations
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
DP780-HR properties
Typical room-temperature values for DP780-HR; 23 are specific to this condition. Other listed values are DP780 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
DP780-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical14
DP780-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
DP780-HR is rated for continuous service to 250°C (482 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
DP780-HR conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of DP780-HR takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability6
DP780-HR's machinability is fair (40/100, worse than 77% of steel grades); weldability good (68/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with DP780-HR
Is DP780 easy to machine?
Rarely machined; drilling/trimming needs sharp carbide or laser cutting — trimmed edges are notch-sensitive and should be deburred to avoid edge cracking.
Can DP780 be welded?
Good resistance spot weldability with reduced current and longer hold/post-pulse to limit HAZ softening and interfacial fracture; laser and MAG welding fine, avoid heavy heat input that tempers the martensite.
Can DP780 be formed, bent or molded?
High n-value gives good stretch forming but expect 2–3× the springback of mild steel — compensate dies, use over-crown/post-stretch, and keep generous bend radii (≥3–4 t) with burr-free blanks.
What surface finishes work on DP780?
Zinc coating (GI/GA/EG) plus phosphate and e-coat is the standard protection route; bare CR must be oiled in storage and painted in service, no anodizing applies.
DP780 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 |
|---|---|---|
| Ccontrols martensite hardness | 0.08 – 0.18 | 0.13 |
| Mnhardenability | 1.2 – 2.5 | 1.9 |
| Si | 0.1 – 0.8 | 0.35 |
| CrCr+Mo typically ≤1.0 combined | 0 – 0.8 | 0.25 |
| Mosuppresses pearlite on cooling | 0 – 0.4 | 0.15 |
| Aldeoxidation | 0.02 – 0.1 | 0.04 |
| Nbgrain refinement (optional) | 0 – 0.1 | 0.02 |
| Tioptional microalloy | 0 – 0.15 | 0.02 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Boptional | 0 – 0.01 | 0 |
| Fe | balance | — |
DP780-HR — frequently asked
What is DP780-HR used for?
DP780-HR is typically used for B-pillar reinforcements, bumper beams and bumper beam brackets, longitudinal frame rails, seat frames, body cross members and door impact beams. In short: workhorse dual-phase sheet.
What is the yield strength of DP780-HR?
DP780-HR has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is DP780-HR easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Rarely machined; drilling/trimming needs sharp carbide or laser cutting — trimmed edges are notch-sensitive and should be deburred to avoid edge cracking.
Can DP780-HR be welded?
Yes — weldability is rated good (68/100). Good resistance spot weldability with reduced current and longer hold/post-pulse to limit HAZ softening and interfacial fracture; laser and MAG welding fine, avoid heavy heat input that tempers the martensite.
What surface finishes work on DP780-HR?
Zinc coating (GI/GA/EG) plus phosphate and e-coat is the standard protection route; bare CR must be oiled in storage and painted in service, no anodizing applies.
Can DP780-HR be formed, bent or molded?
High n-value gives good stretch forming but expect 2–3× the springback of mild steel — compensate dies, use over-crown/post-stretch, and keep generous bend radii (≥3–4 t) with burr-free blanks.
What is the maximum service temperature of DP780-HR?
DP780-HR is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between DP780-CR and DP780-HR?
CR is the default condition — standard uncoated cold-rolled DP780 sheet for painted/e-coated interior structural stampings. HR: use for chassis, control arms and wheel discs where gauge above ~2.5 mm is needed and surface finish is secondary. Yield strength is 500 MPa in CR versus 520 MPa in HR.
Can FabDigit make parts in DP780-HR?
Yes — DP780-HR is available for 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
- EN 10346 — Continuously hot-dip coated steel flat products (HCT780X) — CEN (2015)
- SAE J2745 — Steel, High Strength, Dual Phase, Cold Rolled and Coated Sheet — SAE International (2018)
- GB/T 20564.2 — Cold rolled dual phase steel sheet for automobile — SAC (2017)
- Advanced High-Strength Steels Application Guidelines V7 — WorldAutoSteel (2021)
- Dual phase steel DP780 / DP800 cold rolled and coated data sheets — ArcelorMittal / Baosteel / voestalpine (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
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.