Steel 4815 · heat-treated state
Steel 4815 Carburized
Properties of the Carburized condition, compared with the other 4815 tempers.
The intended service condition: hard wear- and pitting-resistant case on a tough Ni-Mo core for gears, pinions and bearing races.
What is 4815 Carburized?
4815 Carburized is 4815 heat treated to Carburized — the intended service condition: hard wear- and pitting-resistant case on a tough Ni-Mo core for gears, pinions and bearing races. 4815 Carburized has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 4815 Carburized has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,425°C (2,597 °F). HR is the default condition FabDigit quotes; Carburized is available on request or by drawing note.
Advantages
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
4815 Carburized properties
Typical room-temperature values for 4815 Carburized — 9 properties are specific to this condition; the rest are grade-level values shared by every 4815 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
4815 Carburized has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 91% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical13
4815 Carburized has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4815 Carburized is rated for continuous service to 180°C (356 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 74% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
4815 Carburized has an electrical resistivity of 2.2×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4815 Carburized takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
4815 Carburized's machinability is fair (50/100, worse than 53% of steel grades); weldability good (55/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 4815 tempers and conditions
4815 is also supplied in 6 other conditions. The full side-by-side table is on the 4815 overview.
- HRDefaultStandard mill stock condition for bar and billet intended for machining and subsequent carburizing.420 MPa yield · 200 HB
- CarburizedThe intended service condition: hard wear- and pitting-resistant case on a tough Ni-Mo core for gears, pinions and bearing races.800 MPa yield · 61 HRC
- Q&TDirect-quench-and-temper condition used where a tough, moderately strong through-hardened core is required without a carburized case.780 MPa yield · 31 HRC
- CDChoose for tighter size tolerance, better surface and higher as-supplied strength on small-diameter bar.655 MPa yield · 223 HB
- NormalizedUse to homogenize structure and refine grain in forgings before carburizing or final machining.455 MPa yield · 212 HB
- AnnealedPick for maximum machinability and cold-forming ability before case hardening.415 MPa yield · 187 HB
Working with 4815 Carburized
Is 4815 easy to machine?
Machines like a tough 200 HB alloy steel — gummy in the annealed state; use sharp positive-rake carbide, generous feed and coolant, and finish-machine before carburizing since the case is nearly unmachinable.
Can 4815 be welded?
Weldable at 0.15 % C but the 3.5 % Ni raises hardenability: preheat 150–250 °C, use low-hydrogen or Ni-bearing filler and post-weld stress relief; avoid welding carburized surfaces.
Can 4815 be formed, bent or molded?
Cold forms and cold heads reasonably in the annealed condition; hot work 1100–1200 °C and normalize afterwards to break up the coarse as-forged grain.
What surface finishes work on 4815?
No inherent corrosion resistance — protect with oil, black oxide, manganese phosphate, zinc or chrome plating; grind/hone after carburizing for gear-quality surface finish.
4815 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 |
|---|---|---|
| Ccarburizing carbon level | 0.13 – 0.18 | 0.16 |
| Mn | 0.4 – 0.6 | 0.5 |
| Si | 0.15 – 0.35 | 0.25 |
| Nicore toughness and hardenability | 3.25 – 3.75 | 3.5 |
| Mo | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.04 | — |
| Smax (0.15–0.35 for resulfurized 4815H variants not standard) | ≤ 0.04 | — |
| Fe | balance | — |
4815 Carburized — frequently asked
What is 4815 Carburized used for?
4815 Carburized is typically used for gears, pins and camshafts. In short: carburizing nickel-moly bar.
What is the yield strength of 4815 Carburized?
4815 Carburized has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4815 Carburized easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like a tough 200 HB alloy steel — gummy in the annealed state; use sharp positive-rake carbide, generous feed and coolant, and finish-machine before carburizing since the case is nearly unmachinable.
Can 4815 Carburized be welded?
Yes — weldability is rated good (55/100). Weldable at 0.15 % C but the 3.5 % Ni raises hardenability: preheat 150–250 °C, use low-hydrogen or Ni-bearing filler and post-weld stress relief; avoid welding carburized surfaces.
What surface finishes work on 4815 Carburized?
No inherent corrosion resistance — protect with oil, black oxide, manganese phosphate, zinc or chrome plating; grind/hone after carburizing for gear-quality surface finish.
Can 4815 Carburized be formed, bent or molded?
Cold forms and cold heads reasonably in the annealed condition; hot work 1100–1200 °C and normalize afterwards to break up the coarse as-forged grain.
What is the maximum service temperature of 4815 Carburized?
4815 Carburized is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4815-HR and 4815-CD?
HR is the default condition — standard mill stock condition for bar and billet intended for machining and subsequent carburizing. CD: choose for tighter size tolerance, better surface and higher as-supplied strength on small-diameter bar. Yield strength is 420 MPa in HR versus 655 MPa in CD.
Can FabDigit make parts in 4815 Carburized?
Yes — 4815 Carburized is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — ASTM (2020)
- ASTM A322 — Steel Bars, Alloy, Standard Grades — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing steels) — ASM International (1991)
- ASM Handbook Vol.16 — Machining (machinability ratings) — ASM International (1989)
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.