Steel C15R +FP
Heat-treated state
EN C15R
+FP = treated to ferrite-pearlite structure with specified hardness range
Choose when a controlled microstructure/hardness band is needed for stable machining results.
Values for the +FP condition
Other C15R tempers and conditions
C15R is listed in 8 conditions; see the grade overview at C15R.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ADefault Annealed | Standard stock condition for machining and cold forming before carburizing. | 250 | 420 | 30 | 125 HB | — |
Treated for shearability | For wire and bar that must be cold-sheared or cold-headed without cracking. | 260 | 430 | 30 | 130 HB | 10.5 % IACS |
Hot rolled | Cheapest mill condition for parts that will be normalized or carburized anyway. | 280 | 460 | 26 | 135 HB | 10.5 % IACS |
Normalized | Uniform fine ferrite-pearlite grain before carburizing; best baseline toughness. | 285 | 450 | 28 | 135 HB | — |
+FPThis page Treated to ferrite-pearlite structure with specified hardness range | Choose when a controlled microstructure/hardness band is needed for stable machining results. | 290 | 460 | 27 | 150 HB | 10.5 % IACS |
Treated to specified hardness range | Ordered when the machine shop needs a guaranteed narrow hardness band on incoming bar. | 320 | 500 | 24 | 160 HB | 10.5 % IACS |
Carburized and hardened | Final service condition: hard wear-resistant case (~0.2–0.8 mm) over a tough low-carbon core. | 400 | 650 | 13 | 60 HRC | — |
Cold drawn | Close tolerance bright bar for pins, shafts and screw-machine parts needing higher as-supplied strength. | 450 | 560 | 12 | 165 HB | — |
What is C15R +FP?
C15R +FP is C15R heat treated to +FP — choose when a controlled microstructure/hardness band is needed for stable machining results. C15R +FP has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 88% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi). C15R +FP 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). +A is the default condition FabDigit quotes; +FP is available on request or by drawing note.
Advantages
- Readily welded — 90/100, better than 90% of steel grades
- Forms and bends easily — 75/100, better than 90% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
Limitations
- Low strength — 290 MPa (42.1 ksi), worse than 88% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
C15R +FP properties
Typical room-temperature values for C15R +FP; 22 are specific to this condition. Other listed values are C15R reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C15R +FP 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
C15R +FP has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 88% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
C15R +FP is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
C15R +FP conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C15R +FP takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
C15R +FP's machinability is good (60/100, better than 83% of steel grades); weldability excellent (90/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C15R +FP
Is C15R easy to machine?
Gummy when soft-annealed — use sharp positive-rake tools, high speed and good chip control; the 0.02–0.04 % S in the R grade gives noticeably better chip breaking and finish than C15E.
Can C15R be welded?
Excellent weldability by all arc, resistance and laser processes with CE ≈ 0.25; no preheat below ~30 mm, but never weld after carburizing.
Can C15R be formed, bent or molded?
Very good cold formability in +A/+S: deep drawing, cold heading, bending to tight radii; hot forge at 1050–1200 °C, normalize afterwards.
What surface finishes work on C15R?
No natural corrosion resistance — zinc plate, phosphate + oil, black oxide or paint; case-hardened surfaces polish and grind well but must be re-passivated/oiled.
C15R 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 |
|---|---|---|
| C | 0.12 – 0.17 | 0.15 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.04 | 0.02 |
| SR = controlled sulphur range for machinability | 0.02 – 0.04 | 0.03 |
| Crresidual | ≤ 0.4 | 0.1 |
| Niresidual | ≤ 0.4 | 0.1 |
| Moresidual; Cr+Mo+Ni ≤ 0.63 typical | ≤ 0.1 | 0.03 |
| Fe | balance | — |
C15R +FP — frequently asked
What is C15R +FP used for?
C15R +FP is typically used for carburized gears, pins, cam followers and small shafts. In short: free-cutting case-hardening steel; machines better than C15E; specified hardenability band.
What is the yield strength of C15R +FP?
C15R +FP has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 88% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is C15R +FP easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Gummy when soft-annealed — use sharp positive-rake tools, high speed and good chip control; the 0.02–0.04 % S in the R grade gives noticeably better chip breaking and finish than C15E.
Can C15R +FP be welded?
Yes — weldability is rated excellent (90/100). Excellent weldability by all arc, resistance and laser processes with CE ≈ 0.25; no preheat below ~30 mm, but never weld after carburizing.
What surface finishes work on C15R +FP?
No natural corrosion resistance — zinc plate, phosphate + oil, black oxide or paint; case-hardened surfaces polish and grind well but must be re-passivated/oiled.
Can C15R +FP be formed, bent or molded?
Very good cold formability in +A/+S: deep drawing, cold heading, bending to tight radii; hot forge at 1050–1200 °C, normalize afterwards.
What is the maximum service temperature of C15R +FP?
C15R +FP is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C15R +A and C15R-CH?
+A is the default condition — standard stock condition for machining and cold forming before carburizing. CH: final service condition: hard wear-resistant case (~0.2–0.8 mm) over a tough low-carbon core. Yield strength is 250 MPa in +A versus 400 MPa in CH.
Sources
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10277 — Bright steel products — CEN (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing) — ASM International (1991)
- Stahlschlüssel / Key to Steel — 1.1140 C15R — Verlag Stahlschlüssel (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.