Steel P3
AISI/SAE P3 · UNS T51603
P3 (T51603) is a low-carbon Cr-Ni carburizing mold steel with a tough core and a hardenable case, used for smaller mold components needing moderate wear resistance.
Reference datasheet — P3 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
P3 tempers and conditions
P3 is supplied in 3 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Stock condition for machining cavities or cold-hobbing them before carburizing. | 340 | 540 | 28 | 160 HB | — |
Normalized | Use to refine grain and homogenize forged or hobbed blanks before carburizing. | 400 | 620 | 24 | 190 HB | — |
Carburized, hardened and low-temperature tempered | Final working condition: hard wear-resistant case on a tough, low-carbon core for production mold cavities. | 760 | 1,000 | 12 | 61 HRC | — |
What is P3?
P3 (T51603) is a low-carbon Cr-Ni carburizing mold steel with a tough core and a hardenable case, used for smaller mold components needing moderate wear resistance. It ships annealed or normalized for hobbing and machining, then is carburized and hardened; annealed values are about 340 MPa yield, 540 MPa tensile, 28% elongation, 160 HB and service to 400 °C. The soft matrix cuts gummy (machinability 62) and corrosion resistance is minimal (score 12). P5 gives a harder case from higher chromium, and P20 is the choice when pre-hardened plate avoids case hardening altogether. P3 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). P3 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 76% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
What is P3 used for?
- carburized mold inserts
- small cavity blocks
- die components needing case hardening
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
Limitations
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
P3 properties
Typical room-temperature values for P3-ANN; bars are the position among steel grades.
Physical3
P3 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).
Mechanical15
P3 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 76% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
P3 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 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
P3 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 P3 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability8
P3's machinability is good (62/100, better than 89% of steel grades); weldability good (65/100); 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. P3 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P3
Is P3 easy to machine?
Very soft and gummy in the annealed state — use sharp positive-rake tools, high speed and good chip evacuation to avoid built-up edge; all finish machining must be done before carburizing.
Can P3 be welded?
Low carbon makes TIG repair of annealed blanks straightforward with matching low-alloy filler; welds on carburized parts need 200–300 °C preheat and re-carburizing/tempering of the repaired zone.
Can P3 be formed, bent or molded?
Designed to be cold hobbed — cavity impressions can be pressed into the annealed blank, with stress-relief anneals between hobbing passes.
P3 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 cold hobbing; case carbon raised by carburizing | ≤ 0.1 | 0.08 |
| Mn | 0.2 – 0.6 | 0.4 |
| Si | ≤ 0.4 | 0.25 |
| Cr | 0.4 – 0.75 | 0.6 |
| Nicore toughness | 1 – 1.5 | 1.25 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on P3?
Polish and texture before or after carburizing depending on depth allowance; hard chrome or electroless nickel plate for corrosion and release, and keep oiled 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 P3 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T51603
How much does P3 cost?
P3 is a standard-cost steel ($$), cheaper than about 71% 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.
P3 — frequently asked
What is P3 used for?
P3 is typically used for carburized mold inserts, small cavity blocks and die components needing case hardening. In short: cr-Ni carburizing mold steel; hobbable soft blank; hard case, tough core.
What is the yield strength of P3?
P3 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is P3 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Very soft and gummy in the annealed state — use sharp positive-rake tools, high speed and good chip evacuation to avoid built-up edge; all finish machining must be done before carburizing.
Can P3 be welded?
Yes — weldability is rated good (65/100). Low carbon makes TIG repair of annealed blanks straightforward with matching low-alloy filler; welds on carburized parts need 200–300 °C preheat and re-carburizing/tempering of the repaired zone.
What surface finishes work on P3?
Polish and texture before or after carburizing depending on depth allowance; hard chrome or electroless nickel plate for corrosion and release, and keep oiled in storage.
Can P3 be formed, bent or molded?
Designed to be cold hobbed — cavity impressions can be pressed into the annealed blank, with stress-relief anneals between hobbing passes.
What is the maximum service temperature of P3?
P3 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 P3-ANN and P3 CARB-HT?
ANN is the default condition — stock condition for machining cavities or cold-hobbing them before carburizing. CARB-HT: final working condition: hard wear-resistant case on a tough, low-carbon core for production mold cavities. Yield strength is 340 MPa in ANN versus 760 MPa in CARB-HT.
How much does P3 cost?
P3 is a standard-cost steel ($$), cheaper than about 71% 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 — ASTM International (2022)
- 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)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
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.