Steel 9SiCr Q_OIL
Heat-treated state
GB 9SiCr
Q_OIL = oil quenched, untempered
Intermediate as-quenched state only — must be tempered immediately; used to verify hardenability (≥62 HRC).
Values for the Q_OIL condition
Other 9SiCr tempers and conditions
9SiCr is listed in 9 conditions; see the grade overview at 9SiCr.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Isothermally annealed / stress-relieved machining stock | Uniform low-hardness structure with reduced residual stress for precision blanks that must stay dimensionally stable through hardening. | 430 | 730 | 20 | 14 HRC | 5.7 % IACS |
ADefault Solution annealed | Standard stocked condition for machining tool blanks before hardening. | 450 | 760 | 18 | 220 HB | — |
Hot rolled | Cheapest mill condition for stock that will be spheroidise-annealed or hot-formed by the customer. | 550 | 900 | 10 | 29 HRC | 5.7 % IACS |
Cold drawn | Precision-size bright bar or wire for small taps, drills and springs where close tolerance and good surface are needed before hardening. | 700 | 900 | 8 | 26 HRC | 5.7 % IACS |
Q&T 48–52 HRC | Tough, shock-resistant setting for spring-type tooling, collets, guide bushings and heavily loaded punch bodies. | 1,450 | 1,700 | 6 | 50 HRC | — |
Q_OILThis page Oil quenched, untempered | Intermediate as-quenched state only — must be tempered immediately; used to verify hardenability (≥62 HRC). | 1,900 | 2,200 | 0 | 64 HRC | 4.7 % IACS |
Q&T 55–58 HRC | Chosen when impact loading or heavier sections make 60+ HRC too brittle (blanking dies, cold chisels, mandrels). | — | 1,950 | 3 | 56 HRC | — |
Q&T 58–60 HRC | Balanced wear/toughness setting for cold-forming dies, shear blades and thread-rolling dies. | — | 2,100 | 2 | 59 HRC | — |
Q&T 60–62 HRC | Maximum-wear condition for taps, reamers, thread chasers and cold punches with light impact. | — | 2,250 | 1 | 61 HRC | — |
What is 9SiCr Q_OIL?
9SiCr Q_OIL is 9SiCr heat treated to Q_OIL — intermediate as-quenched state only — must be tempered immediately; used to verify hardenability (≥62 HRC). 9SiCr Q_OIL has a yield strength of 1,900 MPa (276 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Elongation at break is 0% and the elastic modulus is 210 GPa (30.5 Msi). 9SiCr Q_OIL has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,420°C (2,588 °F). A is the default condition FabDigit quotes; Q_OIL is available on request or by drawing note.
Advantages
- High strength — 1,900 MPa (276 ksi), better than 100% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
Limitations
- Limited ductility — 0%, worse than 100% of steel grades
- Difficult to machine — 5/100, worse than 100% of steel grades
- Difficult to weld — 3/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
9SiCr Q_OIL properties
Typical room-temperature values for 9SiCr Q_OIL; 21 are specific to this condition. Other listed values are 9SiCr reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
9SiCr Q_OIL has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
9SiCr Q_OIL has a yield strength of 1,900 MPa (276 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Elongation at break is 0% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
9SiCr Q_OIL is rated for continuous service to 150°C (302 °F). It conducts heat at 29 W/m·K (16.8 BTU/hr·ft·°F), worse than 84% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
9SiCr Q_OIL conducts electricity at 4.7 % IACS, worse than 82% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 9SiCr Q_OIL takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
9SiCr Q_OIL's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (3/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 9SiCr Q_OIL
Is 9SiCr easy to machine?
Machine in the annealed (≤241 HB) condition with sharp carbide or HSS-Co tooling and generous coolant; after hardening only grinding, EDM or honing are practical.
Can 9SiCr be welded?
Essentially not weldable for structural purposes — only local repair with matching/tool-steel electrode at 300–400 °C preheat followed by immediate re-temper.
Can 9SiCr be formed, bent or molded?
Hot forge 1100→850 °C then slow cool and spheroidise anneal at 780–800 °C; cold forming limited to gentle bending of annealed thin stock.
What surface finishes work on 9SiCr?
Harden 860–880 °C in oil (or salt/vacuum), temper 180–250 °C; finish by grinding and polishing, then protect with black oxide, phosphate or oil — PVD TiN and nitriding are common on cutting tools.
9SiCr 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 – 0.95 | 0.9 |
| Siraises tempering resistance and hardenability | 1.2 – 1.6 | 1.4 |
| Mn | 0.3 – 0.6 | 0.45 |
| Cr | 0.95 – 1.25 | 1.1 |
| Moresidual limit | ≤ 0.3 | — |
| Wresidual limit | ≤ 0.2 | — |
| Vresidual limit | ≤ 0.1 | — |
| Niresidual limit | ≤ 0.25 | — |
| Curesidual limit | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
9SiCr Q_OIL — frequently asked
What is 9SiCr Q_OIL used for?
9SiCr Q_OIL is typically used for taps, dies, woodworking tools and cutting tools. In short: deep-hardening O2-class steel; common cutting-tool tool steel; 300 °C service ceiling.
What is the yield strength of 9SiCr Q_OIL?
9SiCr Q_OIL has a typical yield strength of 1,900 MPa (276 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 9SiCr Q_OIL easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine in the annealed (≤241 HB) condition with sharp carbide or HSS-Co tooling and generous coolant; after hardening only grinding, EDM or honing are practical.
Can 9SiCr Q_OIL be welded?
Not readily — weldability is rated not recommended (3/100). Essentially not weldable for structural purposes — only local repair with matching/tool-steel electrode at 300–400 °C preheat followed by immediate re-temper.
What surface finishes work on 9SiCr Q_OIL?
Harden 860–880 °C in oil (or salt/vacuum), temper 180–250 °C; finish by grinding and polishing, then protect with black oxide, phosphate or oil — PVD TiN and nitriding are common on cutting tools.
Can 9SiCr Q_OIL be formed, bent or molded?
Hot forge 1100→850 °C then slow cool and spheroidise anneal at 780–800 °C; cold forming limited to gentle bending of annealed thin stock.
What is the maximum service temperature of 9SiCr Q_OIL?
9SiCr Q_OIL is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 9SiCr-A and 9SiCr QT48-52?
A is the default condition — standard stocked condition for machining tool blanks before hardening. QT48-52: tough, shock-resistant setting for spring-type tooling, collets, guide bushings and heavily loaded punch bodies. Yield strength is 450 MPa in A versus 1,450 MPa in QT48-52.
Sources
- GB/T 1299 Tool and Die Steels ( 9SiCr) — SAC / Standardization Administration of China (2014)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (tool steels) — ASM International (1990)
- ASM Handbook Vol. 16 — Machining (machinability of tool steels) — ASM International (1989)
- Tool Steels, 5th ed. (O-type oil-hardening grades) — ASM International (1998)
- 9SiCr / 90CrSi5 cold-work tool steel datasheets (Chinese special-steel mills) — various mills (2023)
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.