Steel P2-CH (Carburized and hardened)
Heat-treated state
AISI/SAE P2 · UNS T51602
Working condition for finished mold cavities: carburize 900–925 °C, oil quench from 790–830 °C, temper 175–200 °C for a hard wear surface on a tough core.
Values for the CH condition
Other P2 tempers and conditions
P2 is listed in 4 conditions; see the grade overview at P2.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stock condition: soft enough for cold hobbing of cavities and easy machining before carburizing. | 330 | 510 | 27 | 110 HB | 40 W/m·K |
Normalized | Used to refine grain and homogenize forged or heavily machined blocks before carburizing; slightly stronger and harder than annealed. | 400 | 600 | 22 | 150 HB | — |
Quenched and tempered | Direct hardening without carburizing, or the core condition of a case-hardened part; low carbon limits hardness to roughly 20–30 HRC. | 620 | 830 | 17 | 25 HRC | — |
CHThis page Carburized and hardened | Working condition for finished mold cavities: carburize 900–925 °C, oil quench from 790–830 °C, temper 175–200 °C for a hard wear surface on a tough core. | 720 | 950 | 13 | 61 HRC | 38 W/m·K |
What is P2-CH?
P2-CH is P2 heat treated to CH — working condition for finished mold cavities: carburize 900–925 °C, oil quench from 790–830 °C, temper 175–200 °C for a hard wear surface on a tough core. P2-CH has a yield strength of 720 MPa (104 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 82% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). P2-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). ANN is the default condition FabDigit quotes; CH is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- High strength — 720 MPa (104 ksi), better than 82% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
P2-CH properties
Typical room-temperature values for P2-CH; 21 are specific to this condition. Other listed values are P2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P2-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).
Mechanical16
P2-CH has a yield strength of 720 MPa (104 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 82% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
P2-CH is rated for continuous service to 200°C (392 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
P2-CH conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P2-CH takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 35%.
Manufacturability8
P2-CH's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (20/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with P2-CH
Is P2 easy to machine?
Machine in the annealed state with sharp, positive-rake tools and generous coolant — the soft low-carbon matrix tends to smear and build up on edges; finish grind after case hardening.
Can P2 be welded?
Repair-weldable with matching low-alloy or Ni-based filler at 200–300 °C preheat, followed by re-annealing or re-carburizing; welding after case hardening risks case cracking.
Can P2 be formed, bent or molded?
Its main advantage is cold hobbing/hubbing of cavity detail in the annealed state, with intermediate anneals between hobbing passes.
What surface finishes work on P2?
Carburized surfaces take a fine mold polish or texture; hard chrome or electroless nickel plating is normal for corrosive resins and rust protection in storage.
P2 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 |
|---|---|---|
| Cvery low carbon for hobbing and carburizing | ≤ 0.1 | 0.07 |
| Mn | 0.1 – 0.4 | 0.25 |
| Si | 0.1 – 0.4 | 0.25 |
| Cr | 0.75 – 1.25 | 1 |
| Ni | 0.1 – 0.5 | 0.3 |
| Mo | 0.15 – 0.4 | 0.25 |
| Pimpurity limit | ≤ 0.03 | — |
| Simpurity limit | ≤ 0.03 | — |
| Fe | balance | — |
P2-CH — frequently asked
What is P2-CH used for?
P2-CH is typically used for carburized cavity inserts, small precision mold cores and plastic injection mold components requiring case hardening. In short: carburizing mold steel; cold-hobbable cavity blank; tough core, hard case.
What is the yield strength of P2-CH?
P2-CH has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 82% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is P2-CH easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed state with sharp, positive-rake tools and generous coolant — the soft low-carbon matrix tends to smear and build up on edges; finish grind after case hardening.
Can P2-CH be welded?
Not readily — weldability is rated poor (20/100). Repair-weldable with matching low-alloy or Ni-based filler at 200–300 °C preheat, followed by re-annealing or re-carburizing; welding after case hardening risks case cracking.
What surface finishes work on P2-CH?
Carburized surfaces take a fine mold polish or texture; hard chrome or electroless nickel plating is normal for corrosive resins and rust protection in storage.
Can P2-CH be formed, bent or molded?
Its main advantage is cold hobbing/hubbing of cavity detail in the annealed state, with intermediate anneals between hobbing passes.
What is the maximum service temperature of P2-CH?
P2-CH is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between P2-ANN and P2-CH?
ANN is the default condition — standard stock condition: soft enough for cold hobbing of cavities and easy machining before carburizing. CH: working condition for finished mold cavities: carburize 900–925 °C, oil quench from 790–830 °C, temper 175–200 °C for a hard wear surface on a tough core. Yield strength is 330 MPa in ANN versus 720 MPa in CH.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy (P-type mold steels) — ASTM International (2015)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (Tool Steels, Carburizing) — ASM International (1991)
- ASM Handbook Vol.16: Machining — ASM International (1989)
- Tool Steels, 5th edition — ASM International (Roberts, Krauss, Kennedy) (1998)
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.