Steel T9A
Grade
AISI/SAE T9
T9A = high-grade quality
Specify the high-grade quality variant with lower phosphorus and sulphur and tighter control of inclusions and carbide non-uniformity for precision dies and cutting tools.
Values for the T9A condition
Other T9 tempers and conditions
T9 is listed in 8 conditions; see the grade overview at T9.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
T9AThis page High-grade quality | Specify the high-grade quality variant with lower phosphorus and sulphur and tighter control of inclusions and carbide non-uniformity for precision dies and cutting tools. | 395 | 650 | 22 | 62 HRC | 9.8 % IACS |
ADefault Solution annealed | Choose the spheroidize annealed as-supplied bar or plate for the lowest hardness (180 HB) and easiest turning, milling, drilling and cold working before final quench hardening. | 400 | 660 | 20 | 180 HB | — |
Hot rolled | Take hot rolled or hot forged untreated stock only as a blank; its network carbides require spheroidize annealing before machining or hardening. | 450 | 790 | 12 | 21 HRC | 9.4 % IACS |
Normalized | Normalize at 800–840 °C with air cooling to break up forging carbide networks and refine the structure in preparation for spheroidize annealing or quenching, not as a final state. | 470 | 830 | 10 | 25 HRC | 9.3 % IACS |
Cold drawn | Pick annealed-then-cold-drawn bar or cold rolled strip for tight size tolerance and smooth surface in small sections; hardness rises to 230 HB while elongation drops to 8%. | 620 | 800 | 8 | 20 HRC | 9.5 % IACS |
Q&T 45–52 HRC | Temper at 300–400 °C to 45–52 HRC when chisels, punches and spring parts see heavy impact; wear resistance is sacrificed for 1400 MPa yield and 4% elongation. | 1,400 | 1,650 | 4 | 49 HRC | — |
Q&T 56–60 HRC | Choose tempering at 200–250 °C to 56–60 HRC when blanking dies, shear blades and hand tools must absorb some impact, trading peak wear resistance for toughness. | 1,750 | 1,950 | 1 | 58 HRC | 8.6 % IACS |
Q&T 60–63 HRC | Use water quenching from 760–780 °C with 150–180 °C tempering for maximum hardness (60–63 HRC) and wear resistance in punches, chisels and woodworking blades; toughness is minimal. | — | 2,100 | 1 | 62 HRC | — |
What is T9A?
T9A is T9 in the T9A grade — specify the high-grade quality variant with lower phosphorus and sulphur and tighter control of inclusions and carbide non-uniformity for precision dies and cutting tools. T9A has a yield strength of 395 MPa (57.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 63% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi). T9A has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F). A is the default condition FabDigit quotes; T9A is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- High electrical conductivity — 9.8 % IACS, better than 78% of steel grades
Limitations
- Difficult to weld — 13/100, worse than 94% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
T9A properties
Typical room-temperature values for T9A; 24 are specific to this condition. Other listed values are T9 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
T9A has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
T9A has a yield strength of 395 MPa (57.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 63% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
T9A is rated for continuous service to 200°C (392 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
T9A conducts electricity at 9.8 % IACS, better than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of T9A takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
T9A's machinability is fair (47/100, worse than 58% of steel grades); weldability not recommended (13/100); formability fair (38/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with T9A
Is T9 easy to machine?
Turning, milling, drilling and tapping are all practical in the spheroidize-annealed condition (≤192 HB) using HSS or coated carbide with ample coolant; after hardening only grinding or EDM is possible.
Can T9 be welded?
Poor weldability — at about 0.9 % C martensite and cracking are almost unavoidable, so T9 is normally not welded. If repair is unavoidable, preheat 250–350 °C, use low-hydrogen consumables and temper immediately.
Can T9 be formed, bent or molded?
The annealed condition allows light cold bending and blanking, but formability is limited. Forge from 1050–1100 °C with a finishing temperature no lower than 800 °C, then slow-cool and spheroidize-anneal; harden from 760–780 °C in water or brine, noting the shallow hardening depth and high distortion and cracking risk.
What surface finishes work on T9?
No corrosion resistance: specify black oxide (alkaline blackening), phosphating, chrome plating or rust-preventive oil. Hardened parts can be ground and polished to a mirror finish, but watch for grinding burn and temper softening.
T9 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 |
|---|---|---|
| CGB/T 1298 | 0.85 – 0.94 | 0.9 |
| Si | ≤ 0.35 | 0.22 |
| Mn | ≤ 0.4 | 0.25 |
| PT9A ≤0.030 | ≤ 0.04 | — |
| ST9A ≤0.020 | ≤ 0.03 | — |
| Crresidual element | ≤ 0.25 | — |
| Niresidual element | ≤ 0.2 | — |
| Curesidual element | ≤ 0.3 | — |
| Fe | balance | — |
T9A — frequently asked
What is T9A used for?
T9A is typically used for punches, dies, cutting tools and woodworking tools. In short: mid-carbon T-series tool steel; balanced wear and toughness; water-hardening, shallow case.
What is the yield strength of T9A?
T9A has a typical yield strength of 395 MPa (57.3 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 63% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is T9A easy to machine?
Reasonably — machinability is rated fair (47/100, worse than 58% of steel grades). Turning, milling, drilling and tapping are all practical in the spheroidize-annealed condition (≤192 HB) using HSS or coated carbide with ample coolant; after hardening only grinding or EDM is possible.
Can T9A be welded?
Not readily — weldability is rated not recommended (13/100). Poor weldability — at about 0.9 % C martensite and cracking are almost unavoidable, so T9 is normally not welded. If repair is unavoidable, preheat 250–350 °C, use low-hydrogen consumables and temper immediately.
What surface finishes work on T9A?
No corrosion resistance: specify black oxide (alkaline blackening), phosphating, chrome plating or rust-preventive oil. Hardened parts can be ground and polished to a mirror finish, but watch for grinding burn and temper softening.
Can T9A be formed, bent or molded?
The annealed condition allows light cold bending and blanking, but formability is limited. Forge from 1050–1100 °C with a finishing temperature no lower than 800 °C, then slow-cool and spheroidize-anneal; harden from 760–780 °C in water or brine, noting the shallow hardening depth and high distortion and cracking risk.
What is the maximum service temperature of T9A?
T9A 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.
What is the difference between T9-A and T9 QT-58?
A is the default condition — choose the spheroidize annealed as-supplied bar or plate for the lowest hardness (180 HB) and easiest turning, milling, drilling and cold working before final quench hardening. QT-58: choose tempering at 200–250 °C to 56–60 HRC when blanking dies, shear blades and hand tools must absorb some impact, trading peak wear resistance for toughness. Yield strength is 400 MPa in A versus 1,750 MPa in QT-58.
Sources
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (water-hardening tool steels, W1) — ASM International (1991)
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.