Steel 8617 Carbonitrided
Heat-treated state
AISI/SAE 8617 · UNS G86170
Lower-temperature alternative to carburizing for small pins, washers and light gears where distortion must be minimized.
Values for the Carbonitrided condition
Other 8617 tempers and conditions
8617 is listed in 8 conditions; see the grade overview at 8617.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
for cold heading / cold extrusion | Pick when parts are cold-formed (headed, extruded) before carburizing; lowest hardness and best cold ductility. | 330 | 480 | 34 | 137 HB | 7.8 % IACS |
as-rolled bar | Cheapest mill condition for large forging/gear blanks that will be normalized or annealed before machining. | 340 | 560 | 27 | 163 HB | 7.8 % IACS |
AnnealedDefault full anneal, soft machinable bar | Standard stock condition for gear blanks: softest, most machinable, ready for carburizing after rough machining. | 360 | 515 | 31 | 149 HB | — |
900–925 °C air cool | Use to homogenize forgings and refine grain before carburizing; best combination of core strength and machinability. | 375 | 610 | 27 | 179 HB | — |
annealed and cold finished bar | Choose for small shafts and pins needing tight tolerance and good surface straight from bar, with higher as-supplied strength. | 500 | 600 | 18 | 179 HB | — |
Through-hardened | Direct oil quench and high temper when a tough uniform core is wanted without a case (shafts, arbors, fixtures). | 750 | 950 | 18 | 30 HRC | — |
CarbonitridedThis page thin hard case on small parts | Lower-temperature alternative to carburizing for small pins, washers and light gears where distortion must be minimized. | 780 | 1,000 | 13 | 59 HRC | 7.5 % IACS |
case 58–62 HRC / core ~30–40 HRC | The service condition for gears and pins: hard wear/pitting-resistant case with high compressive residual stress over a tough core. | 850 | 1,100 | 12 | 60 HRC | — |
What is 8617 Carbonitrided?
8617 Carbonitrided is 8617 heat treated to Carbonitrided — lower-temperature alternative to carburizing for small pins, washers and light gears where distortion must be minimized. 8617 Carbonitrided has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 8617 Carbonitrided has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Carbonitrided is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 780 MPa (113 ksi), better than 86% of steel grades
Limitations
- Difficult to machine — 10/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
8617 Carbonitrided properties
Typical room-temperature values for 8617 Carbonitrided; 21 are specific to this condition. Other listed values are 8617 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8617 Carbonitrided has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
8617 Carbonitrided has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8617 Carbonitrided is rated for continuous service to 180°C (356 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
8617 Carbonitrided conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 8617 Carbonitrided takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
8617 Carbonitrided's machinability is not recommended (10/100, worse than 99% of steel grades); weldability not recommended (10/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8617 Carbonitrided
Is 8617 easy to machine?
Machine in the annealed or normalized state (≈65 % of 1212) with carbide at ~120–170 m/min; leave 0.2–0.5 mm grind stock for post-carburizing distortion.
Can 8617 be welded?
Weldable with low-hydrogen consumables at 150–250 °C preheat and post-weld stress relief; do not weld after carburizing.
Can 8617 be formed, bent or molded?
Good hot forgeability at 1100–1200 °C and acceptable cold heading when spheroidize annealed; normalize forgings before case hardening.
What surface finishes work on 8617?
Gas carburize 900–930 °C, oil quench, temper 150–200 °C, then grind; protect uncarburized surfaces with copper plate or stop-off paint and finish with black oxide, phosphate or zinc plating.
8617 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 |
|---|---|---|
| CSAE J404 heat analysis | 0.15 – 0.2 | 0.17 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.6 | 0.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | — |
| Smax; 8617H/resulfurized variants differ | ≤ 0.04 | — |
| Fe | balance | — |
8617 Carbonitrided — frequently asked
What is 8617 Carbonitrided used for?
8617 Carbonitrided is typically used for gears, shafts, bushings and camshafts. In short: deeper case than 8615; medium-duty gear steel; tough Ni-Cr-Mo core.
What is the yield strength of 8617 Carbonitrided?
8617 Carbonitrided has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 8617 Carbonitrided easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machine in the annealed or normalized state (≈65 % of 1212) with carbide at ~120–170 m/min; leave 0.2–0.5 mm grind stock for post-carburizing distortion.
Can 8617 Carbonitrided be welded?
Not readily — weldability is rated not recommended (10/100). Weldable with low-hydrogen consumables at 150–250 °C preheat and post-weld stress relief; do not weld after carburizing.
What surface finishes work on 8617 Carbonitrided?
Gas carburize 900–930 °C, oil quench, temper 150–200 °C, then grind; protect uncarburized surfaces with copper plate or stop-off paint and finish with black oxide, phosphate or zinc plating.
Can 8617 Carbonitrided be formed, bent or molded?
Good hot forgeability at 1100–1200 °C and acceptable cold heading when spheroidize annealed; normalize forgings before case hardening.
What is the maximum service temperature of 8617 Carbonitrided?
8617 Carbonitrided 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.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — 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) — ASM International (1991)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels (8617H) — SAE International (2019)
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.