Steel P3 CARB-HT
Heat-treated state
AISI/SAE P3 · UNS T51603
CARB-HT = carburized, hardened and low-temperature tempered
Final working condition: hard wear-resistant case on a tough, low-carbon core for production mold cavities.
Values for the CARB-HT condition
Other P3 tempers and conditions
P3 is listed in 3 conditions; see the grade overview at P3.
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 | — |
CARB-HTThis page 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 CARB-HT?
P3 CARB-HT is P3 heat treated to CARB-HT — final working condition: hard wear-resistant case on a tough, low-carbon core for production mold cavities. P3 CARB-HT has a yield strength of 760 MPa (110 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 85% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). P3 CARB-HT 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). ANN is the default condition FabDigit quotes; CARB-HT is available on request or by drawing note.
Advantages
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
- Polishes to a fine finish — 68/100, better than 83% of steel grades
Limitations
- 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
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
P3 CARB-HT properties
Typical room-temperature values for P3 CARB-HT; 20 are specific to this condition. Other listed values are P3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P3 CARB-HT 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 CARB-HT has a yield strength of 760 MPa (110 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 85% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
P3 CARB-HT is rated for continuous service to 180°C (356 °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 CARB-HT 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 CARB-HT 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 CARB-HT's machinability is poor (15/100, worse than 98% 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 P3 CARB-HT
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.
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.
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 | — |
P3 CARB-HT — frequently asked
What is P3 CARB-HT used for?
P3 CARB-HT 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 CARB-HT?
P3 CARB-HT has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is P3 CARB-HT easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% 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 CARB-HT be welded?
Not readily — weldability is rated poor (20/100). 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 CARB-HT?
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 CARB-HT 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 CARB-HT?
P3 CARB-HT 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.
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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.