Steel T9A QT-56-58
Hardness band
GB T9A
QT-56-58 = q&T 56–58 HRC
Pick as the general-purpose working hardness for small cold-blanking dies, shear blades and woodworking tools, where the ~220 °C temper balances hardness and toughness.
Values for the QT-56-58 condition
Other T9A tempers and conditions
T9A is listed in 9 conditions; see the grade overview at T9A.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Choose as the standard stock condition at 190 HB (=207 HB max): spheroidized pearlite turns, mills, drills and cold-blanks well before quench hardening. | 410 | 700 | 22 | 190 HB | — |
Stress relieved | Apply after rough machining to remove residual stress at 600-650 °C and limit quench distortion in long thin sections and precision punches. | 420 | 710 | 20 | 195 HB | 9.8 % IACS |
Hot rolled | Pick as the lowest-cost as-rolled blank; hardness around 240 HB and uneven structure normally require spheroidize annealing before machining. | 470 | 830 | 12 | 22 HRC | 9.6 % IACS |
Normalized | Apply after forging to break up coarse structure and carbide networks by air cooling from 800-830 °C, preparing the microstructure for spheroidize annealing or hardening. | 500 | 880 | 12 | 25 HRC | 9.5 % IACS |
Cold drawn | Use for small-section bar and strip needing tight tolerances and good surface; cold drawing lifts yield to 620 MPa but leaves residual stress, so stress relieve before finishing. | 620 | 800 | 10 | 21 HRC | 9.6 % IACS |
Q&T 54–56 HRC | Choose for punches, rivet sets and air chisels under heavy impact; the ~250 °C temper after water quenching gives the toughest working hardness at some loss of wear resistance. | 1,600 | 1,900 | 2 | 55 HRC | — |
QT-56-58This page Q&T 56–58 HRC | Pick as the general-purpose working hardness for small cold-blanking dies, shear blades and woodworking tools, where the ~220 °C temper balances hardness and toughness. | 1,750 | 2,050 | 1.5 | 57 HRC | — |
Q&T 58–60 HRC | Use for wear-dominated punches, center punches and small blades; the ~180 °C temper leaves only 1% elongation, so avoid sharp corners and stress concentrations. | 1,900 | 2,200 | 1 | 59 HRC | — |
Q&T 60–62 HRC | Specify only for thin, small cutting edges and gauges with almost no impact; the 150-170 °C stress-relief temper retains maximum wear hardness (GB quenched hardness =62 HRC). | — | 2,350 | 0.5 | 61 HRC | — |
What is T9A QT-56-58?
T9A QT-56-58 is T9A heat treated to QT-56-58 — pick as the general-purpose working hardness for small cold-blanking dies, shear blades and woodworking tools, where the ~220 °C temper balances hardness and toughness. T9A QT-56-58 has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,050 MPa (297 ksi) — stronger than 99% of steel grades. Elongation at break is 1.5% and the elastic modulus is 210 GPa (30.5 Msi). T9A QT-56-58 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). A is the default condition FabDigit quotes; QT-56-58 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 100% of steel grades
- High strength — 1,750 MPa (254 ksi), better than 99% 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 — 9.6 % IACS, better than 78% of steel grades
Limitations
- Difficult to machine — 6/100, worse than 100% of steel grades
- Limited ductility — 1.5%, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
T9A QT-56-58 properties
Typical room-temperature values for T9A QT-56-58; 12 are specific to this condition. Other listed values are T9A reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
T9A QT-56-58 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
T9A QT-56-58 has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,050 MPa (297 ksi) — stronger than 99% of steel grades. Elongation at break is 1.5% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
T9A QT-56-58 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 QT-56-58 conducts electricity at 9.6 % IACS, better than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of T9A QT-56-58 takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability8
T9A QT-56-58's machinability is not recommended (6/100, worse than 100% of steel grades); weldability poor (15/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with T9A QT-56-58
Is T9A easy to machine?
In the spheroidize-annealed condition (≤207 HB) machinability is good with either HSS or coated carbide tooling. Once hardened, only grinding or EDM is practical.
Can T9A be welded?
At about 0.9 %C weldability is poor and hardening cracks form readily. If repair welding is unavoidable, preheat to 250–350 °C, use a matching high-carbon filler and temper immediately.
Can T9A be formed, bent or molded?
Annealed material can be cold blanked, bent and lightly cold headed. Hot work at approximately 1050–850 °C, cool slowly after forging and spheroidize anneal promptly to break up network carbides.
What surface finishes work on T9A?
After hardening it can be finish ground and polished to a mirror surface. Corrosion protection relies on black oxide, phosphating, chrome plating or oiling; it cannot be anodized, and plated parts should be baked at 190 °C for hydrogen relief.
T9A 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 | 0.85 – 0.94 | 0.9 |
| Si | ≤ 0.35 | 0.25 |
| Mn | ≤ 0.4 | 0.3 |
| Phigh-quality (A) grade limit | ≤ 0.03 | — |
| Shigh-quality (A) grade limit | ≤ 0.02 | — |
| Crresidual element | ≤ 0.1 | — |
| Niresidual element | ≤ 0.12 | — |
| Curesidual element | ≤ 0.2 | — |
| Fe | balance | — |
T9A QT-56-58 — frequently asked
What is T9A QT-56-58 used for?
T9A QT-56-58 is typically used for punches, scribers and stamping dies. In short: balanced hardness and toughness; low-cost punch steel; shallow-hardening carbon grade.
What is the yield strength of T9A QT-56-58?
T9A QT-56-58 has a typical yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,050 MPa (297 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is T9A QT-56-58 easy to machine?
Not especially — machinability is rated not recommended (6/100, worse than 100% of steel grades). In the spheroidize-annealed condition (≤207 HB) machinability is good with either HSS or coated carbide tooling. Once hardened, only grinding or EDM is practical.
Can T9A QT-56-58 be welded?
Not readily — weldability is rated poor (15/100). At about 0.9 %C weldability is poor and hardening cracks form readily. If repair welding is unavoidable, preheat to 250–350 °C, use a matching high-carbon filler and temper immediately.
What surface finishes work on T9A QT-56-58?
After hardening it can be finish ground and polished to a mirror surface. Corrosion protection relies on black oxide, phosphating, chrome plating or oiling; it cannot be anodized, and plated parts should be baked at 190 °C for hydrogen relief.
Can T9A QT-56-58 be formed, bent or molded?
Annealed material can be cold blanked, bent and lightly cold headed. Hot work at approximately 1050–850 °C, cool slowly after forging and spheroidize anneal promptly to break up network carbides.
What is the maximum service temperature of T9A QT-56-58?
T9A QT-56-58 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 T9A-A and T9A-CD?
A is the default condition — choose as the standard stock condition at 190 HB (=207 HB max): spheroidized pearlite turns, mills, drills and cold-blanks well before quench hardening. CD: use for small-section bar and strip needing tight tolerances and good surface; cold drawing lifts yield to 620 MPa but leaves residual stress, so stress relieve before finishing. Yield strength is 410 MPa in A versus 620 MPa in CD.
Sources
- ASTM A686 Standard Specification for Tool Steel, Carbon (W1 ) — ASTM International (2020)
- JIS G 4401 (SK95/SK4 ) — JISC (2009)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (Water-hardening tool steels) — 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.