Steel 4815 · supply condition · default condition
Steel 4815-HR
Properties of the HR condition, compared with the other 4815 tempers.
Standard mill stock condition for bar and billet intended for machining and subsequent carburizing.
What is 4815-HR?
4815-HR is 4815 supplied in the HR condition — standard mill stock condition for bar and billet intended for machining and subsequent carburizing. 4815-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi). 4815-HR 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).
4815-HR properties
Typical room-temperature values for 4815-HR — 8 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-HR 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-HR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 53% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4815-HR is rated for continuous service to 400°C (752 °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-HR 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-HR 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-HR's machinability is fair (50/100, worse than 53% of steel grades); weldability good (55/100); formability good (55/100).
Common Calculations5
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-HR
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-HR — frequently asked
What is 4815-HR used for?
4815-HR is typically used for gears, pins and camshafts. In short: carburizing nickel-moly bar.
What is the yield strength of 4815-HR?
4815-HR has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4815-HR 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-HR 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-HR?
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-HR 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-HR?
4815-HR 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 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-HR?
Yes — 4815-HR 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.