Steel SPFC780
SPFC780 is a cold-rolled JIS dual-phase automotive sheet at the 780 MPa class (DP780), supplied at 480 MPa yield, 820 MPa tensile and 16 % elongation.
Reference datasheet — SPFC780 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the CR condition
SPFC780 tempers and conditions
SPFC780 is supplied in 4 conditions, soft to hard. CR is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Low-yield-ratio (dual-phase) type per JIS G 3135 | Specify the JIS G 3135 low-yield-ratio dual-phase type at 470 MPa yield and 820 MPa tensile for the best stamping formability and dent resistance; it is the variant normally purchased. | 470 | 820 | 17 | 21 HRC | 8.6 % IACS |
CRDefault Cold rolled | Take the bare cold-rolled, continuously annealed dual-phase coil as the default for body inner structural parts that are stamped then phosphated and e-coated; rust protection comes only from paint. | 480 | 820 | 16 | 22 HRC | 8.6 % IACS |
Skin-passed / temper-rolled, high surface quality | Order skin-passed (temper-rolled) material to remove the yield-point elongation and improve flatness and surface for appearance panels or tight springback control; yield rises to 510 MPa, elongation 15 %. | 510 | 830 | 15 | 23 HRC | 8.6 % IACS |
2 % prestrain + 170 °C/20 min paint-bake | Use the 2 % prestrain plus 170 °C/20 min paint-bake state for CAE and crash assessment: bake hardening raises yield to 570 MPa while elongation drops to 12 %. | 570 | 850 | 12 | 25 HRC | 8.6 % IACS |
Supply forms, finishes and certifications
Ways SPFC780 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EG | Electrogalvanized (electroplated zinc) coating | Coating |
GA | Galvannealed (Fe–Zn alloyed hot-dip) coating | Coating |
GI | Hot-dip galvanized (pure zinc) coating | Coating |
What is SPFC780?
SPFC780 is a cold-rolled JIS dual-phase automotive sheet at the 780 MPa class (DP780), supplied at 480 MPa yield, 820 MPa tensile and 16 % elongation. It is common in Japanese-designed body structures where a crash load path needs more strength than SPFC590 but the part must still be cold stamped; conditions on file include CR, high-yield SPFC780Y, skin-passed SK, 2PS+BH and EG, GI or GA coatings. Springback, sidewall curl and low sheared-edge flangeability are the working limits, and bare sheet has no corrosion resistance. SPFC780 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). SPFC780 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 59% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
What is SPFC780 used for?
- door rings
- cross members
- seat structures
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to machine — 35/100, worse than 84% of steel grades
SPFC780 properties
Typical room-temperature values for SPFC780-CR; bars are the position among steel grades.
Physical3
SPFC780 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).
Mechanical16
SPFC780 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 59% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
SPFC780 is rated for continuous service to 200°C (392 °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
SPFC780 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SPFC780 takes about 26 MJ of energy and emits 2.3 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 20%.
Manufacturability7
SPFC780's machinability is fair (35/100, worse than 84% of steel grades); weldability good (60/100); formability fair (45/100).
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. SPFC780 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SPFC780
Is SPFC780 easy to machine?
Very little machining is done; blanking and laser cutting dominate. Use a punching clearance of 10–14 % of sheet thickness with powder-metallurgy or coated (TiCN/CrN) tool steels for wear resistance, since burred cut edges markedly reduce flanging and fatigue performance.
Can SPFC780 be welded?
Resistance spot welding is the main process, with a narrower current window than mild steel; pulsed current plus a tempering pulse is recommended to reduce nugget martensite brittleness. Laser and MAG welding are feasible, but the softened HAZ band becomes the tensile failure site, so avoid prolonged local high heat input.
Can SPFC780 be formed, bent or molded?
Cold stamped with n ≈ 0.16 and r ≈ 0.9; springback and sidewall curl are pronounced, so use CAE springback compensation, higher blank-holder force or a stepped/variable-radius punch. Bend radius should be ≥3 t, and because sheared-edge flangeability is low, laser trim or stress-relieve after trimming.
SPFC780 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 |
|---|---|---|
| CJIS G 3135 limit ≤0.18; DP780 typically 0.09–0.15 | 0.07 – 0.18 | 0.12 |
| Sisuppresses cementite, stabilizes retained austenite | 0.1 – 0.8 | 0.35 |
| Mnmain hardenability element | 1.3 – 2.5 | 1.9 |
| P | ≤ 0.04 | 0.02 |
| Slow S improves bending and flanging | ≤ 0.02 | 0 |
| Aldeoxidizer | 0.02 – 0.08 | 0.04 |
| CrCr/Mo optional to raise martensite fraction | ≤ 0.6 | 0.25 |
| Mooptional | ≤ 0.35 | 0.1 |
| Nbmicroalloying for grain refinement (optional) | ≤ 0.06 | 0.02 |
| Tioptional | ≤ 0.06 | 0.02 |
| Boptional, increases hardenability | ≤ 0.01 | 0 |
| N | ≤ 0.01 | 0 |
| Fe | balance |
What surface finishes work on SPFC780?
Bare sheet must be protected: phosphate plus cathodic e-coat, or order EG, GI or GA coated condition. Avoid strong acid pickling and high-hydrogen plating processes to prevent hydrogen-induced delayed cracking; powder coating and structural adhesive bonding are compatible.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SPFC780 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- DP780
How much does SPFC780 cost?
SPFC780 is a budget-cost steel ($), cheaper than about 90% 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.
SPFC780 — frequently asked
What is SPFC780 used for?
SPFC780 is typically used for door rings, cross members and seat structures. In short: 780 MPa cold-stamping grade; between DP590 and DP980; springback-sensitive in dies.
What is the yield strength of SPFC780?
SPFC780 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 820 MPa (119 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SPFC780 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Very little machining is done; blanking and laser cutting dominate. Use a punching clearance of 10–14 % of sheet thickness with powder-metallurgy or coated (TiCN/CrN) tool steels for wear resistance, since burred cut edges markedly reduce flanging and fatigue performance.
Can SPFC780 be welded?
Yes — weldability is rated good (60/100). Resistance spot welding is the main process, with a narrower current window than mild steel; pulsed current plus a tempering pulse is recommended to reduce nugget martensite brittleness. Laser and MAG welding are feasible, but the softened HAZ band becomes the tensile failure site, so avoid prolonged local high heat input.
What surface finishes work on SPFC780?
Bare sheet must be protected: phosphate plus cathodic e-coat, or order EG, GI or GA coated condition. Avoid strong acid pickling and high-hydrogen plating processes to prevent hydrogen-induced delayed cracking; powder coating and structural adhesive bonding are compatible.
Can SPFC780 be formed, bent or molded?
Cold stamped with n ≈ 0.16 and r ≈ 0.9; springback and sidewall curl are pronounced, so use CAE springback compensation, higher blank-holder force or a stepped/variable-radius punch. Bend radius should be ≥3 t, and because sheared-edge flangeability is low, laser trim or stress-relieve after trimming.
What is the maximum service temperature of SPFC780?
SPFC780 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SPFC780-CR and SPFC780-SK?
CR is the default condition — take the bare cold-rolled, continuously annealed dual-phase coil as the default for body inner structural parts that are stamped then phosphated and e-coated; rust protection comes only from paint. SK: order skin-passed (temper-rolled) material to remove the yield-point elongation and improve flatness and surface for appearance panels or tight springback control; yield rises to 510 MPa, elongation 15 %. Yield strength is 480 MPa in CR versus 510 MPa in SK.
How much does SPFC780 cost?
SPFC780 is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- JIS G 3135 — Cold-reduced high strength steel sheet and strip for automobile structural uses — JISC (2018)
- Advanced High-Strength Steels Application Guidelines V7 — WorldAutoSteel (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Cold-rolled dual phase steel (DP780) product data — Nippon Steel / JFE Steel (2022)
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.