Steel 9SiCr
GB 9SiCr
9SiCr is a silicon–chromium oil-hardening cold-work tool steel cross-referenced to AISI O2, combining good wear resistance with deep hardenability in small sections.
Reference datasheet — 9SiCr is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the A condition
9SiCr tempers and conditions
9SiCr is supplied in 9 conditions, soft to hard. A is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
9SiCr is a silicon–chromium oil-hardening cold-work tool steel cross-referenced to AISI O2, combining good wear resistance with deep hardenability in small sections. Annealed stock (≤241 HB) is about 450 MPa yield, 760 MPa tensile, 18 % elongation and 220 HB; hardening at 860–880 °C with a 180–250 °C temper produces working hardness bands from 48–52 up to 60–62 HRC, and an isothermal (ISOT) route is on file for distortion control. Tempering resistance is limited — treat 300 °C as the service ceiling — machinability is 45 and corrosion resistance is nil; use D2 or SKD1 for higher-abrasion die work. 9SiCr 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). 9SiCr has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 52% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
What is 9SiCr used for?
- taps
- dies
- woodworking tools
- cutting tools
Advantages
- Polishes to a fine finish — 75/100, better than 94% of steel grades
Limitations
- Difficult to weld — 12/100, worse than 96% of steel grades
- Poor heat conductor — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades
- Low electrical conductivity — 5.7 % IACS, worse than 80% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
9SiCr properties
Typical room-temperature values for 9SiCr-A; bars are the position among steel grades.
Physical3
9SiCr 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 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 52% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
9SiCr is rated for continuous service to 300°C (572 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
9SiCr conducts electricity at 5.7 % IACS, worse than 80% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 9SiCr 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's machinability is fair (45/100, worse than 65% of steel grades); weldability not recommended (12/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 9SiCr is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 9SiCr
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 9SiCr in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- O2
How much does 9SiCr cost?
9SiCr is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
9SiCr — frequently asked
What is 9SiCr used for?
9SiCr 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?
9SiCr has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 9SiCr easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% 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 be welded?
Not readily — weldability is rated not recommended (12/100). 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?
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 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?
9SiCr is rated for continuous use to about 300°C (572 °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.
How much does 9SiCr cost?
9SiCr is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.