Steel 16NiCrMo16-5 CarbQT
Heat-treated state
EN 16NiCrMo16-5
CarbQT = carburized, hardened and low-temperature tempered
The in-service condition for bearing rings, rollers and gears: hard wear-resistant case over a strong, impact-tolerant nickel-alloy core.
Values for the CarbQT condition
Other 16NiCrMo16-5 tempers and conditions
16NiCrMo16-5 is listed in 9 conditions; see the grade overview at 16NiCrMo16-5.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACDefault Spheroidize annealed | Standard stock condition for bar and tube: softest, best for deep machining, cold extrusion and pre-carburizing turning. | 400 | 620 | 20 | 200 HB | — |
Supplied to a specified hardenability (Jominy) band | Order this when the carburizing shop must guarantee core hardness in thick rings/gears; bar is delivered soft (+A/+AC) but with a certified end-quench band. | 410 | 630 | 19 | 42 HRC | 6 % IACS |
Treated to a specified hardness range | Bar delivered inside a contract hardness window (typically 179–229 HB) for automatic-machining lines with tight tool-life control. | 415 | 640 | 18 | 15 HRC | 6 % IACS |
Annealed | General soft-annealed delivery for forging stock and rough-machined blanks where full spheroidization is not required. | 420 | 650 | 18 | 16 HRC | 6 % IACS |
Treated for improved shearability | Pick when bar is cold-sheared into slugs for forging or cold-formed rings; structure tuned for clean shear faces without cracking. | 430 | 660 | 17 | 17 HRC | 6 % IACS |
Normalized | Used after hot forging to homogenize grain size before final annealing and carburizing; harder and less machinable than +AC. | 540 | 800 | 15 | 23 HRC | — |
Cold drawn | Choose for close-tolerance bright bar and small pins/rollers machined on sliding-head lathes; higher strength, lower ductility, residual stresses present. | 650 | 820 | 10 | 24 HRC | 6 % IACS |
CarbQTThis page Carburized, hardened and low-temperature tempered | The in-service condition for bearing rings, rollers and gears: hard wear-resistant case over a strong, impact-tolerant nickel-alloy core. | 1,000 | 1,250 | 12 | 60 HRC | — |
Direct quenched + tempered ~200 °C | Reference condition for core-property verification and for uncarburized shafts/pins made from the same heat. | 1,050 | 1,300 | 11 | 40 HRC | — |
What is 16NiCrMo16-5 CarbQT?
16NiCrMo16-5 CarbQT is 16NiCrMo16-5 heat treated to CarbQT — the in-service condition for bearing rings, rollers and gears: hard wear-resistant case over a strong, impact-tolerant nickel-alloy core. 16NiCrMo16-5 CarbQT has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi). 16NiCrMo16-5 CarbQT 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). +AC is the default condition FabDigit quotes; CarbQT is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- High strength — 1,000 MPa (145 ksi), better than 92% of steel grades
Limitations
- Difficult to weld — 5/100, worse than 100% 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
- Difficult to machine — 15/100, worse than 98% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
16NiCrMo16-5 CarbQT properties
Typical room-temperature values for 16NiCrMo16-5 CarbQT; 17 are specific to this condition. Other listed values are 16NiCrMo16-5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
16NiCrMo16-5 CarbQT 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).
Mechanical14
16NiCrMo16-5 CarbQT has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
16NiCrMo16-5 CarbQT is rated for continuous service to 180°C (356 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
16NiCrMo16-5 CarbQT conducts electricity at 6 % IACS, worse than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 16NiCrMo16-5 CarbQT takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 25%.
Manufacturability8
16NiCrMo16-5 CarbQT's machinability is poor (15/100, worse than 98% of steel grades); weldability not recommended (5/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 16NiCrMo16-5 CarbQT
Is 16NiCrMo16-5 easy to machine?
Machine in the +AC spheroidized state with sharp, positive-rake carbide and generous coolant — the tough nickel matrix work-hardens and produces stringy chips; finish-grind after carburizing.
Can 16NiCrMo16-5 be welded?
Essentially a non-welding grade: high carbon-equivalent demands 250–350 °C preheat, low-hydrogen or matching Ni-Cr-Mo filler and immediate stress relief; never weld carburized surfaces.
Can 16NiCrMo16-5 be formed, bent or molded?
Hot forge 1100–1180 °C with slow cooling and post-forge normalize + spheroidize anneal; cold extrusion/upsetting only from the +AC or +S condition with phosphate-soap lubrication.
What surface finishes work on 16NiCrMo16-5?
Not anodizable; protect with oil, black oxide or manganese phosphate, and superfinish/hone raceways to Ra ≤0.05 µm — avoid electroplating without baking due to hydrogen-embrittlement risk in the hard case.
16NiCrMo16-5 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 – 0.19 | 0.16 |
| Sisome bearing specifications restrict to ≤0.30 | ≤ 0.4 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| Pbearing quality often ≤0.020 | ≤ 0.03 | — |
| Slow-S for cleanliness / fatigue life | ≤ 0.02 | — |
| Cr | 1.1 – 1.4 | 1.25 |
| Mo | 0.2 – 0.35 | 0.28 |
| Ni | 3.8 – 4.3 | 4.05 |
| Curesidual | ≤ 0.3 | — |
| Ovacuum-degassed bearing quality, 15 ppm max typical | ≤ 0 | — |
| Fe | balance | — |
16NiCrMo16-5 CarbQT — frequently asked
What is 16NiCrMo16-5 CarbQT used for?
16NiCrMo16-5 CarbQT is typically used for aerospace and gearbox bearing rings, heavy-duty carburized gears, helicopter and turbine accessory drive gears, planet pinions and gear shafts, high-load spline shafts and aircraft bearing races. In short: deepest-hardening case grade; aerospace 9310 equivalent; highest core toughness.
What is the yield strength of 16NiCrMo16-5 CarbQT?
16NiCrMo16-5 CarbQT has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 16NiCrMo16-5 CarbQT easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Machine in the +AC spheroidized state with sharp, positive-rake carbide and generous coolant — the tough nickel matrix work-hardens and produces stringy chips; finish-grind after carburizing.
Can 16NiCrMo16-5 CarbQT be welded?
Not readily — weldability is rated not recommended (5/100). Essentially a non-welding grade: high carbon-equivalent demands 250–350 °C preheat, low-hydrogen or matching Ni-Cr-Mo filler and immediate stress relief; never weld carburized surfaces.
What surface finishes work on 16NiCrMo16-5 CarbQT?
Not anodizable; protect with oil, black oxide or manganese phosphate, and superfinish/hone raceways to Ra ≤0.05 µm — avoid electroplating without baking due to hydrogen-embrittlement risk in the hard case.
Can 16NiCrMo16-5 CarbQT be formed, bent or molded?
Hot forge 1100–1180 °C with slow cooling and post-forge normalize + spheroidize anneal; cold extrusion/upsetting only from the +AC or +S condition with phosphate-soap lubrication.
What is the maximum service temperature of 16NiCrMo16-5 CarbQT?
16NiCrMo16-5 CarbQT 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 16NiCrMo16-5 +AC and 16NiCrMo16-5-QT200?
+AC is the default condition — standard stock condition for bar and tube: softest, best for deep machining, cold extrusion and pre-carburizing turning. QT200: reference condition for core-property verification and for uncarburized shafts/pins made from the same heat. Yield strength is 400 MPa in +AC versus 1,050 MPa in QT200.
Sources
- ISO 683-17 — Heat-treatable steels, alloy steels: ball and roller bearing steels — ISO (2014)
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10027-2 / Werkstoff 1.3532 designation — CEN (2015)
- 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-Cr-Mo steels) — ASM International (1991)
- MMPDS typical properties for AISI 9310 carburized steel — Battelle/FAA (2021)
- Case-hardening bearing steel bar datasheets (Ovako / Böhler / Aubert & Duval equivalents) — various producers (2023)
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.