Steel SPFH780-FB (FB/Y type)
Grade
Pick when the part has punched holes or sheared flanges — much higher hole-expansion ratio than the DP type at the same 780 MPa class.
Values for the FB condition
Other SPFH780 tempers and conditions
SPFH780 is listed in 4 conditions; see the grade overview at SPFH780.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
DP type | Choose for deep/stretch formed parts needing high work hardening, high crash energy absorption and good bake hardening. | 490 | 830 | 21 | 23 HRC | 8.6 % IACS |
P&ODefault Hot rolled, pickled and oiled coil/sheet | Standard stocked condition for stamped chassis parts — scale-free surface ready for forming, welding and e-coat. | 520 | 820 | 20 | 23 HRC | 8.6 % IACS |
Hot rolled | Cheapest supply form for parts that will be shot-blasted or machined; scale must be removed before forming or coating. | 520 | 820 | 20 | 23 HRC | 8.6 % IACS |
FBThis page FB/Y type | Pick when the part has punched holes or sheared flanges — much higher hole-expansion ratio than the DP type at the same 780 MPa class. | 690 | 810 | 17 | 23 HRC | 8.6 % IACS |
What is SPFH780-FB?
SPFH780-FB is SPFH780 in the FB grade — pick when the part has punched holes or sheared flanges — much higher hole-expansion ratio than the DP type at the same 780 MPa class. SPFH780-FB has a yield strength of 690 MPa (100 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 80% of steel grades. Elongation at break is 17% and the elastic modulus is 207 GPa (30 Msi). SPFH780-FB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). P&O is the default condition FabDigit quotes; FB is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 80% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to machine — 35/100, worse than 84% of steel grades
SPFH780-FB properties
Typical room-temperature values for SPFH780-FB; 22 are specific to this condition. Other listed values are SPFH780 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SPFH780-FB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
SPFH780-FB has a yield strength of 690 MPa (100 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 80% of steel grades. Elongation at break is 17% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
SPFH780-FB 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
SPFH780-FB 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 SPFH780-FB takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability6
SPFH780-FB's machinability is fair (35/100, worse than 84% of steel grades); weldability good (68/100); formability fair (42/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SPFH780-FB
Is SPFH780 easy to machine?
Rarely machined as sheet; when drilled or trimmed use rigid setups, coated carbide and reduced feed — work hardening at cut edges is significant.
Can SPFH780 be welded?
Resistance spot welding is the primary joint; use extended/pulsed schedules and larger electrode force, expect some HAZ softening — for arc/laser welding keep heat input low and use matching or slightly overmatched filler.
Can SPFH780 be formed, bent or molded?
Design for high springback (compensated dies, extra restrike), generous bend radii (≥2.5–3 t), and avoid sheared-edge stretching — laser or fine-blanked holes greatly improve flange cracking resistance.
What surface finishes work on SPFH780?
Supplied bare or Zn-coated; parts must be phosphated and e-coated/painted, or hot-dip/electro-galvanized, for any exposed automotive service.
SPFH780 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 |
|---|---|---|
| Ckept low for weldability | 0.06 – 0.15 | 0.1 |
| Sihigher in DP/TRIP-assisted variants | 0.1 – 1.2 | 0.4 |
| Mnhardenability for martensite/bainite | 1.2 – 2.5 | 1.9 |
| P | ≤ 0.03 | 0.02 |
| Slow S + Ca treatment for hole expansion | ≤ 0.01 | 0 |
| Alkilled steel | 0.02 – 0.07 | 0.04 |
| Timicroalloy, optional | ≤ 0.15 | 0.03 |
| Nbmicroalloy, optional | ≤ 0.1 | 0.03 |
| Croptional | ≤ 0.6 | 0.25 |
| Mooptional, suppresses pearlite | ≤ 0.4 | 0.1 |
| Boptional | ≤ 0 | 8×10⁻⁴ |
| Fe | balance | — |
SPFH780-FB — frequently asked
What is SPFH780-FB used for?
SPFH780-FB is typically used for chassis rails, suspension parts and wheel discs. In short: hot-rolled DP780 equivalent; chassis strength upgrade; enables gauge reduction.
What is the yield strength of SPFH780-FB?
SPFH780-FB has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SPFH780-FB easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Rarely machined as sheet; when drilled or trimmed use rigid setups, coated carbide and reduced feed — work hardening at cut edges is significant.
Can SPFH780-FB be welded?
Yes — weldability is rated good (68/100). Resistance spot welding is the primary joint; use extended/pulsed schedules and larger electrode force, expect some HAZ softening — for arc/laser welding keep heat input low and use matching or slightly overmatched filler.
What surface finishes work on SPFH780-FB?
Supplied bare or Zn-coated; parts must be phosphated and e-coated/painted, or hot-dip/electro-galvanized, for any exposed automotive service.
Can SPFH780-FB be formed, bent or molded?
Design for high springback (compensated dies, extra restrike), generous bend radii (≥2.5–3 t), and avoid sheared-edge stretching — laser or fine-blanked holes greatly improve flange cracking resistance.
What is the maximum service temperature of SPFH780-FB?
SPFH780-FB 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 SPFH780 P&O and SPFH780-FB?
P&O is the default condition — standard stocked condition for stamped chassis parts — scale-free surface ready for forming, welding and e-coat. FB: pick when the part has punched holes or sheared flanges — much higher hole-expansion ratio than the DP type at the same 780 MPa class. Yield strength is 520 MPa in P&O versus 690 MPa in FB.
Sources
- JIS G 3134 — Hot-rolled high strength steel sheet and strip for automobile structural uses — JSA (2018)
- Hot-rolled high strength steel sheets for automotive use (590–980 MPa class) — JFE Steel / Nippon Steel (2022)
- 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)
- Steel LCI methodology report (hot rolled coil) — worldsteel (2021)
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.