Steel 12NiCr3-2 +CH (Carburized and hardened)
Heat-treated state
EN 12NiCr3-2
Final in-service condition: carburized 0.3–1.2 mm, quenched and tempered ~180 °C — pick for gear teeth, cams and pins needing wear and contact fatigue resistance.
Values for the +CH condition
Other 12NiCr3-2 tempers and conditions
12NiCr3-2 is listed in 8 conditions; see the grade overview at 12NiCr3-2.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACDefault Spheroidize annealed | Softest stocked condition with spheroidal carbides — pick for heavy machining, cold forming or upsetting of gear blanks before carburizing. | 295 | 500 | 25 | 150 HB | — |
Treated for shearability | Hardness-capped delivery condition for coil and bar that must be cold sheared or cropped into blanks. | 310 | 520 | 24 | 160 HB | 7.8 % IACS |
Normalized | Normalized bar or forging with refined uniform grain — pick to reset structure after hot forging and before carburizing. | 330 | 540 | 24 | 165 HB | 7.8 % IACS |
Treated to ferrite-pearlite structure and hardness range | Controlled ferrite-pearlite delivery condition — pick for consistent chip formation and surface finish on automatic lathes and gear cutting. | 340 | 550 | 22 | 170 HB | — |
Spheroidize annealed and cold drawn | Cold-drawn bright bar with close tolerance and smooth surface — pick for small pins, bushings and screw-machine parts made near-net before carburizing. | 500 | 620 | 12 | 190 HB | — |
Cold drawn | Straight cold-drawn bar without prior spheroidizing — pick for cheapest close-tolerance bright stock where cold formability is not needed. | 540 | 660 | 10 | 14 HRC | 7.8 % IACS |
Hardened | Quenched-and-low-tempered condition giving the tough martensitic core strength quoted for case-hardened parts — pick when core load capacity, not just case wear, governs. | 640 | 880 | 12 | 27 HRC | — |
+CHThis page Carburized and hardened | Final in-service condition: carburized 0.3–1.2 mm, quenched and tempered ~180 °C — pick for gear teeth, cams and pins needing wear and contact fatigue resistance. | 650 | 900 | 11 | 61 HRC | — |
What is 12NiCr3-2 +CH?
12NiCr3-2 +CH is 12NiCr3-2 heat treated to +CH — final in-service condition: carburized 0.3–1.2 mm, quenched and tempered ~180 °C — pick for gear teeth, cams and pins needing wear and contact fatigue resistance. 12NiCr3-2 +CH has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Elongation at break is 11% and the elastic modulus is 207 GPa (30 Msi). 12NiCr3-2 +CH 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). +AC is the default condition FabDigit quotes; +CH is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 79% of steel grades
Limitations
- 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
- Difficult to machine — 15/100, worse than 98% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
12NiCr3-2 +CH properties
Typical room-temperature values for 12NiCr3-2 +CH; 11 are specific to this condition. Other listed values are 12NiCr3-2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
12NiCr3-2 +CH 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).
Mechanical13
12NiCr3-2 +CH has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Elongation at break is 11% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
12NiCr3-2 +CH is rated for continuous service to 180°C (356 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
12NiCr3-2 +CH conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 12NiCr3-2 +CH takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability6
12NiCr3-2 +CH's machinability is poor (15/100, worse than 98% 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 12NiCr3-2 +CH
Is 12NiCr3-2 easy to machine?
Machine fully in the +AC/+FP condition with sharp positive-rake carbide and generous coolant; annealed material is gummy, so a normalized or cold-drawn condition gives better chip break, and hard finishing after carburizing must be done by grinding.
Can 12NiCr3-2 be welded?
Weldable before carburizing with low-hydrogen electrodes and 150–200 °C preheat; welding after case hardening is not recommended because the case cracks and decarburizes.
Can 12NiCr3-2 be formed, bent or molded?
Hot forge at 1050–1150 °C then normalize at 880–920 °C; cold heading and upsetting are practical in the spheroidized (+AC) condition.
What surface finishes work on 12NiCr3-2?
Carburize 900–930 °C, quench in oil and temper 150–200 °C; unhardened surfaces need oil, phosphate, zinc or nickel plating since the steel has no inherent corrosion resistance — bake plated parts to avoid hydrogen embrittlement.
12NiCr3-2 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 |
|---|---|---|
| Clow carbon for tough core; case is enriched to ~0.8 % C | 0.09 – 0.15 | 0.12 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.04 | — |
| Sresulphurized (S-suffix) versions run 0.020–0.040 % | ≤ 0.04 | — |
| Crper EN designation digit 2 (≈0.5 %) | 0.4 – 0.7 | 0.55 |
| Niper EN designation digit 3 (≈0.75 %); older DIN 1.5732 tables list higher Ni — confirm with mill certificate | 0.6 – 0.9 | 0.75 |
| Fe | balance | — |
12NiCr3-2 +CH — frequently asked
What is 12NiCr3-2 +CH used for?
12NiCr3-2 +CH is typically used for gears, pins and case-hardened shafts. In short: entry-level Ni-Cr case-hardening steel; tough core, hard case; good cold-heading formability.
What is the yield strength of 12NiCr3-2 +CH?
12NiCr3-2 +CH has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 12NiCr3-2 +CH easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Machine fully in the +AC/+FP condition with sharp positive-rake carbide and generous coolant; annealed material is gummy, so a normalized or cold-drawn condition gives better chip break, and hard finishing after carburizing must be done by grinding.
Can 12NiCr3-2 +CH be welded?
Not readily — weldability is rated not recommended (10/100). Weldable before carburizing with low-hydrogen electrodes and 150–200 °C preheat; welding after case hardening is not recommended because the case cracks and decarburizes.
What surface finishes work on 12NiCr3-2 +CH?
Carburize 900–930 °C, quench in oil and temper 150–200 °C; unhardened surfaces need oil, phosphate, zinc or nickel plating since the steel has no inherent corrosion resistance — bake plated parts to avoid hydrogen embrittlement.
Can 12NiCr3-2 +CH be formed, bent or molded?
Hot forge at 1050–1150 °C then normalize at 880–920 °C; cold heading and upsetting are practical in the spheroidized (+AC) condition.
What is the maximum service temperature of 12NiCr3-2 +CH?
12NiCr3-2 +CH 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
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10027-1/-2 — Designation systems for steels (name and number) — CEN (2016)
- Key to Steel / Stahlschlüssel — Verlag Stahlschlüssel Wegst (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes (carburizing) — ASM International (2013)
- GB/T 3077 — Alloy structural steels (comparison grades 12CrNi2 / 20CrNi) — SAC (2015)
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.