Steel 4815
AISI/SAE 4815 · UNS G48150
4815 (G48150) is a nickel-molybdenum carburizing alloy steel with about 3.25–3.75% Ni, supplied hot-rolled, cold-rolled, cold-drawn, annealed, normalized, quenched and tempered, or carburized.
Values for the HR condition
4815 tempers and conditions
4815 is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/subcritical anneal, softest machining condition | Pick for maximum machinability and cold-forming ability before case hardening. | 415 | 640 | 27 | 187 HB | 8 % IACS |
HRDefault Hot rolled | Standard mill stock condition for bar and billet intended for machining and subsequent carburizing. | 420 | 690 | 22 | 200 HB | 7.8 % IACS |
austenitize ≈ 900 °C, air cool | Use to homogenize structure and refine grain in forgings before carburizing or final machining. | 455 | 730 | 24 | 212 HB | 7.8 % IACS |
Cold rolled | Sheet/strip form for stamped and formed parts that will later be carburized; limited availability in this grade. | 600 | 740 | 16 | 217 HB | 7.8 % IACS |
Cold drawn | Choose for tighter size tolerance, better surface and higher as-supplied strength on small-diameter bar. | 655 | 760 | 15 | 223 HB | 7.8 % IACS |
Quenched and tempered | Direct-quench-and-temper condition used where a tough, moderately strong through-hardened core is required without a carburized case. | 780 | 1,000 | 16 | 31 HRC | — |
case 58–63 HRC, tempered ≈ 150–180 °C | The intended service condition: hard wear- and pitting-resistant case on a tough Ni-Mo core for gears, pinions and bearing races. | 800 | 1,050 | 13 | 61 HRC | 7.2 % IACS |
What is 4815?
4815 (G48150) is a nickel-molybdenum carburizing alloy steel with about 3.25–3.75% Ni, supplied hot-rolled, cold-rolled, cold-drawn, annealed, normalized, quenched and tempered, or carburized. The high nickel content gives outstanding core toughness under impact loading, so it is chosen for heavily loaded gears, pins and camshafts; the base condition is around 420 MPa yield, 690 MPa tensile, 22% elongation and 200 HB. It has no corrosion resistance, costs more than 8620 because of the nickel content, and must be finish-ground after carburizing; 4820 and 9310 are the higher-alloy alternatives. 4815 has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,425°C (2,597 °F). 4815 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).
What is 4815 used for?
- Gears
- Pins
- Camshafts
Limitations
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 75% of steel grades
4815 properties
Typical room-temperature values for 4815-HR; bars are the position among steel grades.
Physical3
4815 has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
4815 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 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 75% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
4815 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4815 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'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.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 4815 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4815
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.
Manufacturability
The process limits FabDigit applies to 4815. Every 4815 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better50 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better55 / 100 |
|---|---|
| Weldability | Better55 / 100 |
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 |
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.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 4815 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G48150
How much does 4815 cost?
4815 is a standard-cost steel ($$), cheaper than about 71% 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.
4815 — frequently asked
What is 4815 used for?
4815 is typically used for gears, pins and camshafts. In short: carburizing nickel-moly bar.
What is the yield strength of 4815?
4815 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 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 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?
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 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?
4815 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.
How much does 4815 cost?
4815 is a standard-cost steel ($$), cheaper than about 71% 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.
Can FabDigit make parts in 4815?
Yes — 4815 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. 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; 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.