Stainless Steel 1.4911 +QT900
Heat-treated state · default condition
EN 1.4911
+QT900 = quenched (≈1040–1070 °C) and tempered, Rm ≈ 900–1050 MPa
Standard commercial delivery condition for turbine bolting, blades and rotor parts — balanced creep strength, toughness and machinability.
Values for the +QT900 condition
Other 1.4911 tempers and conditions
1.4911 is listed in 5 conditions; see the grade overview at 1.4911.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Supply/intermediate condition for rough machining and cold straightening before final quench and temper. | 520 | 780 | 20 | 22 HRC | — |
Quenched and high-tempered, Rm ≈ 800–950 MPa | Highest tempering temperature — pick when maximum toughness and long-term creep stability at 580–600 °C matter more than strength. | 660 | 870 | 18 | 26 HRC | — |
As-forged / hot-rolled | Rough bar, billet or forging supplied before final quench and temper; properties not guaranteed in this state. | 700 | 1,000 | 12 | 34 HRC | 2.9 % IACS |
+QT900DefaultThis page Quenched (≈1040–1070 °C) and tempered, Rm ≈ 900–1050 MPa | Standard commercial delivery condition for turbine bolting, blades and rotor parts — balanced creep strength, toughness and machinability. | 760 | 960 | 16 | 30 HRC | — |
Quenched and low-tempered, Rm ≈ 1000–1200 MPa | Highest-strength condition for highly loaded fasteners and blade roots where service temperature stays below the tempering temperature. | 890 | 1,090 | 13 | 35 HRC | — |
What is 1.4911 +QT900?
1.4911 +QT900 is 1.4911 heat treated to +QT900 — standard commercial delivery condition for turbine bolting, blades and rotor parts — balanced creep strength, toughness and machinability. 1.4911 +QT900 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 216 GPa (31.3 Msi). 1.4911 +QT900 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Advantages
- High strength — 760 MPa (110 ksi), better than 94% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
Limitations
- Needs corrosion protection — 35/100, worse than 97% of stainless steel grades
- Limited ductility — 16%, worse than 88% of stainless steel grades
- Difficult to weld — 32/100, worse than 87% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Low fracture toughness — 85 MPa·√m (77.4 ksi·√in), worse than 77% of stainless steel grades
1.4911 +QT900 properties
Typical room-temperature values for 1.4911 +QT900; 13 are specific to this condition. Other listed values are 1.4911 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4911 +QT900 has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
1.4911 +QT900 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 94% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 216 GPa (31.3 Msi).
Thermal6
1.4911 +QT900 is rated for continuous service to 600°C (1,112 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
1.4911 +QT900 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4911 +QT900 takes about 55 MJ of energy and emits 4.8 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 35%.
Manufacturability8
1.4911 +QT900's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability poor (32/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4911 +QT900
Is 1.4911 easy to machine?
Machine in the annealed or as-quench-and-tempered state with rigid setups, sharp carbide (coated) tools, moderate speed and heavy positive feed to avoid work hardening; grind or hard-turn after final temper.
Can 1.4911 be welded?
Weldable with matching or 9–12Cr filler using 250–350 °C preheat, controlled interpass and mandatory post-weld temper below the base tempering temperature to restore toughness.
Can 1.4911 be formed, bent or molded?
Hot forge at ~1100–850 °C with slow controlled cooling to avoid quench cracks; cold forming is essentially limited to straightening.
What surface finishes work on 1.4911?
Passivate or nitride for wear/oxidation service; steam-oxide, aluminide or thermal-barrier coatings used on turbine components; not anodisable.
1.4911 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 |
|---|---|---|
| Cgrade designation X8 ⇒ ~0.08 % C | 0.05 – 0.12 | 0.08 |
| Si | ≤ 0.5 | 0.3 |
| Mn | ≤ 0.8 | 0.5 |
| Pimpurity | ≤ 0.03 | — |
| Simpurity | ≤ 0.02 | — |
| Cr | 9 – 10.5 | 10 |
| Cosolid-solution / matrix stabiliser | 5 – 7 | 6 |
| Nitoughness, austenite-forming balance | 0.5 – 1.5 | 1 |
| Mocreep strength | 0.4 – 1 | 0.7 |
| VMX carbonitride precipitation | 0.1 – 0.3 | 0.2 |
| Nboptional microalloy | ≤ 0.2 | 0.08 |
| N | 0.02 – 0.07 | 0.04 |
| Fe | balance | — |
1.4911 +QT900 — frequently asked
What is 1.4911 +QT900 used for?
1.4911 +QT900 is typically used for steam turbine blades and rotors, gas turbine components and high-temperature fasteners. In short: cobalt-strengthened 10Cr steel; 760 MPa yield at 600 °C class; forging-grade turbine alloy.
What is the yield strength of 1.4911 +QT900?
1.4911 +QT900 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 94% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4911 +QT900 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Machine in the annealed or as-quench-and-tempered state with rigid setups, sharp carbide (coated) tools, moderate speed and heavy positive feed to avoid work hardening; grind or hard-turn after final temper.
Can 1.4911 +QT900 be welded?
Not readily — weldability is rated poor (32/100). Weldable with matching or 9–12Cr filler using 250–350 °C preheat, controlled interpass and mandatory post-weld temper below the base tempering temperature to restore toughness.
What surface finishes work on 1.4911 +QT900?
Passivate or nitride for wear/oxidation service; steam-oxide, aluminide or thermal-barrier coatings used on turbine components; not anodisable.
Can 1.4911 +QT900 be formed, bent or molded?
Hot forge at ~1100–850 °C with slow controlled cooling to avoid quench cracks; cold forming is essentially limited to straightening.
What is the maximum service temperature of 1.4911 +QT900?
1.4911 +QT900 is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- DIN 17240 — Heat-resisting and creep-resisting steels for bolts and nuts — DIN (1976)
- EN 10269 — Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties — CEN (2013)
- Stahlschlüssel (Key to Steel) — Werkstoff 1.4911 X8CrCoNiMo10-6 — Verlag Stahlschlüssel Wegst (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.