Steel 4615 · supply condition · default condition
Steel 4615-HR
Properties of the HR condition, compared with the other 4615 tempers.
Standard stock form for parts that will be machined and then carburized or heat treated.
What is 4615-HR?
4615-HR is 4615 supplied in the HR condition — standard stock form for parts that will be machined and then carburized or heat treated. 4615-HR has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 73% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi). 4615-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- Ductile — tolerates forming and impact — 25%, better than 76% of steel grades
4615-HR properties
Typical room-temperature values for 4615-HR — 8 properties are specific to this condition; the rest are grade-level values shared by every 4615 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
4615-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical13
4615-HR has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 73% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4615-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
4615-HR has an electrical resistivity of 2.3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4615-HR takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
4615-HR's machinability is good (58/100, better than 75% 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 4615 tempers and conditions
4615 is also supplied in 6 other conditions. The full side-by-side table is on the 4615 overview.
- HRDefaultStandard stock form for parts that will be machined and then carburized or heat treated.350 MPa yield · 163 HB
- CarburizedThe intended service condition: hard wear-resistant case over a tough Ni–Mo core for gears and cams.700 MPa yield · 60 HRC
- Q&TDirect hardening of the low-carbon core for tough, moderately strong shafts and pins where no case is required.680 MPa yield · 25 HRC
- CDChoose for as-drawn dimensional accuracy, straightness and higher yield in screw-machine work.540 MPa yield · 192 HB
- NormalizedUse to homogenize forged or hot-worked stock and give a uniform fine-grain core before carburizing.380 MPa yield · 174 HB
- AnnealedPick for maximum softness and machinability before deep cutting, cold forming or carburizing.340 MPa yield · 149 HB
Working with 4615-HR
Is 4615 easy to machine?
Machines like other 0.15 %C alloy carburizing steels (~65 % of 1212); normalized stock cuts cleaner than annealed, use sharp tools and positive rake to avoid gumming.
Can 4615 be welded?
Readily arc-welded in the soft condition with low-hydrogen consumables; preheat 100–200 °C on heavy sections and never weld after carburizing.
Can 4615 be formed, bent or molded?
Good cold formability when annealed (bending, upsetting, thread rolling); hot forge 1100–1200 °C and normalize before carburizing.
What surface finishes work on 4615?
No natural corrosion resistance — finish with black oxide, phosphate plus oil, zinc or nickel plating; grind case-hardened surfaces to size after quenching.
4615 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 | 0.13 – 0.18 | 0.16 |
| Mn | 0.45 – 0.65 | 0.55 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 1.65 – 2 | 1.82 |
| Mo | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
4615-HR — frequently asked
What is 4615-HR used for?
4615-HR is typically used for gears, forged industrial shafts and pins. In short: carburizing nickel-moly bar.
What is the yield strength of 4615-HR?
4615-HR has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 73% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4615-HR easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like other 0.15 %C alloy carburizing steels (~65 % of 1212); normalized stock cuts cleaner than annealed, use sharp tools and positive rake to avoid gumming.
Can 4615-HR be welded?
Yes — weldability is rated good (55/100). Readily arc-welded in the soft condition with low-hydrogen consumables; preheat 100–200 °C on heavy sections and never weld after carburizing.
What surface finishes work on 4615-HR?
No natural corrosion resistance — finish with black oxide, phosphate plus oil, zinc or nickel plating; grind case-hardened surfaces to size after quenching.
Can 4615-HR be formed, bent or molded?
Good cold formability when annealed (bending, upsetting, thread rolling); hot forge 1100–1200 °C and normalize before carburizing.
What is the maximum service temperature of 4615-HR?
4615-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 4615-HR and 4615-CD?
HR is the default condition — standard stock form for parts that will be machined and then carburized or heat treated. CD: choose for as-drawn dimensional accuracy, straightness and higher yield in screw-machine work. Yield strength is 350 MPa in HR versus 540 MPa in CD.
Can FabDigit make parts in 4615-HR?
Yes — 4615-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 — 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 of Ni-Mo steels) — ASM International (1991)
- ASM Handbook Vol.16 — Machining — 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.