Steel P2
AISI/SAE P2 · UNS T51602
P2 (T51602) is a very low-carbon, low-alloy Ni-Mo plastic mold steel supplied annealed or normalized for carburizing, giving a hard wear-resistant case over a tough, ductile core.
Reference datasheet — P2 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
P2 tempers and conditions
P2 is supplied in 4 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
P2 (T51602) is a very low-carbon, low-alloy Ni-Mo plastic mold steel supplied annealed or normalized for carburizing, giving a hard wear-resistant case over a tough, ductile core. It is used as plate and blocks for cold-hobbed cavities and small mold cores; annealed values are about 330 MPa yield, 510 MPa tensile, 27% elongation, 110 HB, 40 W/m·K thermal conductivity and service to 400 °C. Corrosion resistance is low (score 12), so cavities are plated or kept oiled, and all finish machining must precede case hardening. P20 suits work that needs pre-hardened plate instead. P2 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). P2 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
What is P2 used for?
- carburized cavity inserts
- small precision mold cores
- plastic injection mold components requiring case hardening
Advantages
- Easy to machine — 70/100, better than 96% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
Limitations
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
P2 properties
Typical room-temperature values for P2-ANN; bars are the position among steel grades.
Physical3
P2 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 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
P2 is rated for continuous service to 400°C (752 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
P2 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 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's machinability is very good (70/100, better than 96% of steel grades); weldability good (60/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. P2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P2
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel P2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T51602
How much does P2 cost?
P2 is a premium-cost steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
P2 — frequently asked
What is P2 used for?
P2 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?
P2 has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is P2 easy to machine?
Yes — machinability is rated very good (70/100, better than 96% 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 be welded?
Yes — weldability is rated good (60/100). 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?
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 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?
P2 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 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.
How much does P2 cost?
P2 is a premium-cost steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.