Steel T5 HT-63
Heat-treated state
AISI/SAE T5 · UNS T12005
HT-63 = hardened & tempered 63–65 HRC
Standard working hardness for general heavy-duty cutting tools in T5; best balance of red-hardness and residual toughness.
Values for the HT-63 condition
Other T5 tempers and conditions
T5 is listed in 5 conditions; see the grade overview at T5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hardened & tempered 60–62 HRC | Softer, tougher setting for interrupted cuts, large-section tools and hot-work punches prone to chipping. | — | — | — | 61 HRC | — |
ANNDefault Annealed | The as-supplied machinable condition for cutting blanks, forgings and dies before hardening. | 590 | 900 | 12 | 255 HB | 22 W/m·K |
HT-63This page Hardened & tempered 63–65 HRC | Standard working hardness for general heavy-duty cutting tools in T5; best balance of red-hardness and residual toughness. | 1,950 | 2,100 | 0.5 | 64 HRC | 20 W/m·K |
Hardened & tempered 65–66 HRC | Maximum-hardness condition for abrasive hot cutting and hogging where edge wear, not chipping, controls tool life. | 1,950 | 2,050 | 0.3 | 66 HRC | 2.9 % IACS |
Hardened + deep cryogenic treated + tempered | Adds a −80 to −196 °C sub-zero step to convert retained austenite; used for dimensional stability and extra wear life on precision tooling. | 1,950 | 2,050 | 0.3 | 65 HRC | 2.9 % IACS |
What is T5 HT-63?
T5 HT-63 is T5 heat treated to HT-63 — standard working hardness for general heavy-duty cutting tools in T5; best balance of red-hardness and residual toughness. T5 HT-63 has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 223 GPa (32.3 Msi). T5 HT-63 has a density of 8.75 g/cm³ (0.316 lb/in³), heavier than 100% of steel grades. It melts at 1,400°C (2,552 °F). ANN is the default condition FabDigit quotes; HT-63 is available on request or by drawing note.
Advantages
- High strength — 1,950 MPa (283 ksi), better than 100% of steel grades
- High service temperature — 580°C (1,076 °F), better than 97% of steel grades
Limitations
- Limited ductility — 0.5%, worse than 100% of steel grades
- Low fracture toughness — 15 MPa·√m (13.7 ksi·√in), worse than 100% of steel grades
- Difficult to machine — 6/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Difficult to weld — 8/100, worse than 99% of steel grades
T5 HT-63 properties
Typical room-temperature values for T5 HT-63; 18 are specific to this condition. Other listed values are T5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
T5 HT-63 has a density of 8.75 g/cm³ (0.316 lb/in³), heavier than 100% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
T5 HT-63 has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 223 GPa (32.3 Msi).
Thermal6
T5 HT-63 is rated for continuous service to 580°C (1,076 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
T5 HT-63 conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of T5 HT-63 takes about 100 MJ of energy and emits 7 kg of CO₂ — more than 99% of steel grades. Typical recycled content is 35%.
Manufacturability7
T5 HT-63's machinability is not recommended (6/100, worse than 100% of steel grades); weldability not recommended (8/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with T5 HT-63
Is T5 easy to machine?
Machine only in the annealed state with rigid setups, low speeds and positive-rake carbide or cobalt-HSS tooling; hardened T5 is finished by CBN/alumina grinding, and its high V + Co content makes grindability poor (burn and wheel wear).
Can T5 be welded?
Essentially a repair-only operation: preheat 500–550 °C, use matched HSS or Co-HSS filler, weld hot, cool slowly and immediately re-temper at the original tempering temperature to avoid quench cracks.
Can T5 be formed, bent or molded?
No cold forming; hot forge from 1050–1150 °C, stop above 950 °C, cool slowly and always full-anneal (860–900 °C, slow cool) after forging.
What surface finishes work on T5?
Not anodizable; protect with oil, black oxide, steam oxide or phosphate, or apply TiN/TiAlN/AlCrN PVD coatings below the tempering temperature for cutting tools.
T5 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 |
|---|---|---|
| C | 0.75 – 0.85 | 0.8 |
| Mn | 0.2 – 0.4 | 0.3 |
| Si | 0.2 – 0.4 | 0.3 |
| Cr | 3.75 – 5 | 4.2 |
| W | 17.5 – 19 | 18.25 |
| V | 1.8 – 2.4 | 2 |
| Cohigh-cobalt for red hardness | 7 – 9.5 | 8 |
| Mo | 0.5 – 1.25 | 0.8 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
T5 HT-63 — frequently asked
What is T5 HT-63 used for?
T5 HT-63 is typically used for heavy roughing tools, hot-hardness cutting tools, broaches and high-temperature turning tools. In short: high-cobalt tungsten HSS; red-hardness roughing grade; poor grindability.
What is the yield strength of T5 HT-63?
T5 HT-63 has a typical yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is T5 HT-63 easy to machine?
Not especially — machinability is rated not recommended (6/100, worse than 100% of steel grades). Machine only in the annealed state with rigid setups, low speeds and positive-rake carbide or cobalt-HSS tooling; hardened T5 is finished by CBN/alumina grinding, and its high V + Co content makes grindability poor (burn and wheel wear).
Can T5 HT-63 be welded?
Not readily — weldability is rated not recommended (8/100). Essentially a repair-only operation: preheat 500–550 °C, use matched HSS or Co-HSS filler, weld hot, cool slowly and immediately re-temper at the original tempering temperature to avoid quench cracks.
What surface finishes work on T5 HT-63?
Not anodizable; protect with oil, black oxide, steam oxide or phosphate, or apply TiN/TiAlN/AlCrN PVD coatings below the tempering temperature for cutting tools.
Can T5 HT-63 be formed, bent or molded?
No cold forming; hot forge from 1050–1150 °C, stop above 950 °C, cool slowly and always full-anneal (860–900 °C, slow cool) after forging.
What is the maximum service temperature of T5 HT-63?
T5 HT-63 is rated for continuous use to about 580°C (1,076 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between T5-ANN and T5 HT-63?
ANN is the default condition — the as-supplied machinable condition for cutting blanks, forgings and dies before hardening. HT-63: standard working hardness for general heavy-duty cutting tools in T5; best balance of red-hardness and residual toughness. Yield strength is 590 MPa in ANN versus 1,950 MPa in HT-63.
Sources
- ASTM A600 — Standard Specification for Tool Steel High Speed — ASTM International (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- High-speed steel grade datasheets (T-series, Co-bearing) — Erasteel / Böhler-Uddeholm (2022)
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.