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Steel P5 Carburized-HT

Heat-treated state

AISI/SAE P5 · UNS T51605

Final service condition: pack/gas carburize 900–925 °C, quench from ~790–830 °C, temper 175–260 °C for a hard wear-resistant case over a tough low-carbon core.

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Values for the Carburized-HT condition

Other P5 tempers and conditions

P5 is listed in 4 conditions; see the grade overview at P5.

Compare all 4 conditionsHide
Condition · open for datasheetBest forYield MPaTensile MPaElong. %HardnessConductivity
AnnealedDefault
soft, as-supplied condition for machining and cold hubbing
Standard stock condition: maximum softness (105–116 HB) for cavity hubbing, machining and engraving before carburizing.29049030110 HB—
Normalized
900–925 °C air cool, grain refinement before final machining
Used after heavy forging or hubbing to refine grain and homogenize structure before the sub-critical anneal.34056026150 HB35 W/m·K
Carburized-HTThis page
case 58–64 HRC
Final service condition: pack/gas carburize 900–925 °C, quench from ~790–830 °C, temper 175–260 °C for a hard wear-resistant case over a tough low-carbon core.7501,0001262 HRC—
Carburized-HT-Cr
Carburized, hardened and hard-chrome plated cavity
Choose when molding corrosive resins (PVC, FR grades) or when extra cavity wear life and release are needed.7609501466 HRC7.5 % IACS

What is P5 Carburized-HT?

P5 Carburized-HT is P5 heat treated to Carburized-HT — final service condition: pack/gas carburize 900–925 °C, quench from ~790–830 °C, temper 175–260 °C for a hard wear-resistant case over a tough low-carbon core. P5 Carburized-HT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). P5 Carburized-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). Annealed is the default condition FabDigit quotes; Carburized-HT is available on request or by drawing note.

Advantages

  • Polishes to a fine finish — 80/100, better than 97% of steel grades
  • High strength — 750 MPa (109 ksi), better than 84% 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
  • Limited ductility — 12%, worse than 84% of steel grades
  • Difficult to weld — 20/100, worse than 84% of steel grades

P5 Carburized-HT properties

Typical room-temperature values for P5 Carburized-HT; 20 are specific to this condition. Other listed values are P5 reference data and may not represent this condition. Bars are the position among steel grades.

Physical3

P5 Carburized-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).

Density7.85 g/cm³0.28 lb/in³
Melting Point (Solidus)1,425°C2,597 °F
Liquidus Temperature1,500°C2,732 °F

Mechanical15

P5 Carburized-HT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).

Elastic (Young's) Modulus205 GPa29.7 Msi
Shear Modulus80 GPa11.6 Msi
Bulk Modulus160 GPa23.2 Msi
Poisson's Ratio0.29
Tensile Strength (Ultimate)1,000 MPa145 ksi
Yield Strength (0.2% offset)750 MPa109 ksi
Elongation at Break12%
Reduction in Area40%
Compressive Strength2,200 MPa319 ksi
Shear Strength650 MPa94.3 ksi
Fatigue Strength (Endurance Limit)480 MPa69.6 ksi
Charpy V-Notch Impact (RT)25 J18.4 ft·lbf
Hardness, Brinell610 HB
Hardness, Rockwell B62 HRB
Hardness, Vickers750 HV

Thermal6

P5 Carburized-HT is rated for continuous service to 200°C (392 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).

Thermal Conductivity36 W/m·K20.8 BTU/hr·ft·°F
Specific Heat Capacity460 J/kg·K0.11 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)12.4 µm/m·K6.9 µin/in·°F
Latent Heat of Fusion250 J/g107 BTU/lb
Max Service Temperature (continuous)200°C392 °F
Min Service Temperature-30°C-22 °F

Electrical3

P5 Carburized-HT conducts electricity at 8 % IACS, better than 55% of steel grades.

Electrical Conductivity8 % IACS
Electrical Resistivity2.2×10⁻⁷ Ω·m8.66 µΩ·in
Magnetic Responseferromagnetic

Chemical & Environmental3

Corrosion resistance is poor (16/100), better than 79% of steel grades.

Galvanic Potential (seawater, vs SCE)-0.6 V
Corrosion ResistancePoor16/100
Chemical Resistance SummaryRusts readily in humid air and with water-based coolants; attacked by acids and by corrosive plastic off-gases (PVC, flame-retarded resins) — requires oiling in storage and hard chrome or nickel plating for aggressive resins.

Sustainability4

Producing a kilogram of P5 Carburized-HT takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 40%.

Embodied Energy (primary production)32 MJ/kg13,758 BTU/lb
Embodied Carbon (primary production)2.3 kg CO₂/kg
Embodied Water65 L/kg7.8 gal/lb
Typical Recycled Content40%

Manufacturability5

P5 Carburized-HT's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (20/100); formability not recommended (5/100).

MachinabilityNot recommended12/100
Machinability Rating (AISI 1212 = 100 %)10%
WeldabilityPoor20/100
Formability (cold)Not recommended5/100
PolishabilityVery good80/100

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with P5 Carburized-HT

Is P5 easy to machine?

Very easy to machine and engrave in the annealed state (~70% of AISI 1212), but the soft low-carbon matrix tends to smear — use sharp positive-rake tools and finish before carburizing; after case hardening only grinding/EDM apply.

Can P5 be welded?

Low carbon makes repair welding practical with matching low-alloy or Ni-based filler; preheat 200–300 °C, and re-carburize or at least re-temper the repaired area.

Can P5 be formed, bent or molded?

Designed for cold hubbing (hobbing) of cavities — the master hub is pressed into the annealed blank, with stress-relief anneals between passes; hot forge 1050–1150 °C, finish above 900 °C.

What surface finishes work on P5?

Carburized case takes a high polish and texture well; hard chrome or electroless nickel plating is common for corrosive resins and added wear life; keep oiled or plated as the alloy rusts freely.

P5 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.

ElementSpec limit (wt %)Nominal
Clow carbon for carburizing / cold hubbing≤ 0.10.1
Mn0.2 – 0.60.4
Si0.1 – 0.40.25
Crgives the harder, more wear-resistant case vs P2/P32 – 2.52.25
Nioptional residual/addition≤ 0.350.2
P≤ 0.03—
S≤ 0.03—
Febalance—

P5 Carburized-HT — frequently asked

What is P5 Carburized-HT used for?

P5 Carburized-HT is typically used for carburized mold inserts, die components requiring hard cases and small precision molds. In short: easiest P-series to hob; higher-chromium case; best formability in family.

What is the yield strength of P5 Carburized-HT?

P5 Carburized-HT has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 4 listed tempers.

Is P5 Carburized-HT easy to machine?

Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Very easy to machine and engrave in the annealed state (~70% of AISI 1212), but the soft low-carbon matrix tends to smear — use sharp positive-rake tools and finish before carburizing; after case hardening only grinding/EDM apply.

Can P5 Carburized-HT be welded?

Not readily — weldability is rated poor (20/100). Low carbon makes repair welding practical with matching low-alloy or Ni-based filler; preheat 200–300 °C, and re-carburize or at least re-temper the repaired area.

What surface finishes work on P5 Carburized-HT?

Carburized case takes a high polish and texture well; hard chrome or electroless nickel plating is common for corrosive resins and added wear life; keep oiled or plated as the alloy rusts freely.

Can P5 Carburized-HT be formed, bent or molded?

Designed for cold hubbing (hobbing) of cavities — the master hub is pressed into the annealed blank, with stress-relief anneals between passes; hot forge 1050–1150 °C, finish above 900 °C.

What is the maximum service temperature of P5 Carburized-HT?

P5 Carburized-HT 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.

Sources

  1. ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
  2. ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (Tool Steels: P-type mold steels) — ASM International (1990)
  3. ASM Handbook Vol. 4: Heat Treating — Heat Treating of Tool Steels — ASM International (1991)
  4. Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
  5. UNS T51605 alloy data — SAE/ASTM Unified Numbering System (2017)

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.