Steel 12CrNi3-HR (Hot rolled)
Supply condition
EN 12CrNi3
Cheapest stock form for rough machining or forging blanks before final carburizing.
Values for the HR condition
Other 12CrNi3 tempers and conditions
12CrNi3 is listed in 8 conditions; see the grade overview at 12CrNi3.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose for best machinability and dimensional stability before carburizing or final hardening. | 420 | 660 | 22 | 200 HB | — |
HRThis page Hot rolled | Cheapest stock form for rough machining or forging blanks before final carburizing. | 450 | 720 | 18 | 18 HRC | 7 % IACS |
Normalized | Grain refinement and uniform structure for forgings prior to carburizing; better than as-rolled toughness. | 520 | 780 | 18 | 22 HRC | 6.9 % IACS |
Cold drawn | Small-diameter bright bar with tight tolerance for pins and small shafts machined with little stock removal. | 650 | 800 | 10 | 24 HRC | 6.8 % IACS |
quenched and high tempered (through-hardened shaft condition) | Pick for through-hardened shafts/couplings that will not be carburized but need good machinability after heat treatment. | 780 | 950 | 16 | 30 HRC | — |
QTDefault Quenched and tempered | Reference condition of the standard; gives the quoted 930 MPa class strength with high toughness for through-hardened shafts and gear blanks. | 790 | 990 | 14 | 31 HRC | — |
Carburized and hardened | The intended service condition: hard wear- and pitting-resistant case over a tough Ni-Cr core for gears, gear shafts and worms. | 820 | 1,050 | 11 | 60 HRC | — |
quenched and medium tempered | Higher-strength through-hardened option for heavily loaded shafts where surface carburizing is not applied. | 980 | 1,180 | 12 | 38 HRC | — |
What is 12CrNi3-HR?
12CrNi3-HR is 12CrNi3 supplied in the HR condition — cheapest stock form for rough machining or forging blanks before final carburizing. 12CrNi3-HR has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 52% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi). 12CrNi3-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). QT is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
12CrNi3-HR properties
Typical room-temperature values for 12CrNi3-HR; 23 are specific to this condition. Other listed values are 12CrNi3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
12CrNi3-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).
Mechanical16
12CrNi3-HR has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 52% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
12CrNi3-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
12CrNi3-HR conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 12CrNi3-HR takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability7
12CrNi3-HR's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (45/100); formability fair (42/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 12CrNi3-HR
Is 12CrNi3 easy to machine?
Machine in the annealed/high-tempered state (≤269 HB) with coated carbide, moderate speed and generous coolant; the Ni-rich structure is gummy and work-hardens, so finish grind after case hardening.
Can 12CrNi3 be welded?
Weldable only with care — preheat 150–250 °C, low-hydrogen Ni-alloy filler, and post-weld temper/stress relief; never weld after carburizing.
Can 12CrNi3 be formed, bent or molded?
Forge at 1150–850 °C followed by slow cooling plus normalizing/annealing; cold forming is limited and heavy bends should be hot-formed.
What surface finishes work on 12CrNi3?
No anodizing; protect with phosphating, black oxide, zinc or Ni plating (bake for hydrogen), or oil after grinding — case-hardened surfaces polish and hone well.
12CrNi3 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 |
|---|---|---|
| CGB/T 3077-2015 | 0.1 – 0.17 | 0.13 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.3 – 0.6 | 0.45 |
| Cr | 0.6 – 0.9 | 0.75 |
| Ni | 2.75 – 3.25 | 3 |
| Pmax, high-grade steel | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Curesidual max | ≤ 0.25 | — |
| Moresidual max, not intentionally added | ≤ 0.15 | — |
| Fe | balance | — |
12CrNi3-HR — frequently asked
What is 12CrNi3-HR used for?
12CrNi3-HR is typically used for gears, shafts and pins. In short: high core toughness; ni-rich carburizing steel; difficult to machine.
What is the yield strength of 12CrNi3-HR?
12CrNi3-HR has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 12CrNi3-HR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed/high-tempered state (≤269 HB) with coated carbide, moderate speed and generous coolant; the Ni-rich structure is gummy and work-hardens, so finish grind after case hardening.
Can 12CrNi3-HR be welded?
With care — weldability is rated fair (45/100). Weldable only with care — preheat 150–250 °C, low-hydrogen Ni-alloy filler, and post-weld temper/stress relief; never weld after carburizing.
What surface finishes work on 12CrNi3-HR?
No anodizing; protect with phosphating, black oxide, zinc or Ni plating (bake for hydrogen), or oil after grinding — case-hardened surfaces polish and hone well.
Can 12CrNi3-HR be formed, bent or molded?
Forge at 1150–850 °C followed by slow cooling plus normalizing/annealing; cold forming is limited and heavy bends should be hot-formed.
What is the maximum service temperature of 12CrNi3-HR?
12CrNi3-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 12CrNi3-QT and 12CrNi3-A?
QT is the default condition — reference condition of the standard; gives the quoted 930 MPa class strength with high toughness for through-hardened shafts and gear blanks. A: choose for best machinability and dimensional stability before carburizing or final hardening. Yield strength is 790 MPa in QT versus 420 MPa in A.
Sources
- 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 steels) — ASM International (1991)
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.