Steel 28NiCrMoV8-5 +QT900
Heat-treated state
EN 28NiCrMoV8-5
+QT900 = quenched and tempered, 900–1050 MPa class
Higher-strength temper for medium-section shafts, discs and highly loaded couplings.
Values for the +QT900 condition
Other 28NiCrMoV8-5 tempers and conditions
28NiCrMoV8-5 is listed in 8 conditions; see the grade overview at 28NiCrMoV8-5.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Supply condition for rough machining of forgings before final quench and temper. | 420 | 640 | 22 | 200 HB | — |
Normalized | Grain-refining intermediate treatment after forging; rarely a final delivery condition. | 560 | 850 | 15 | 25 HRC | 7.5 % IACS |
Normalized and tempered | Used for very large sections where full through-quenching is not achievable. | 560 | 780 | 17 | 22 HRC | 7.6 % IACS |
Quenched and tempered, 700–850 MPa class | Lower-strength temper for very thick rotor bodies and best toughness / lowest FATT. | 620 | 780 | 19 | 22 HRC | — |
+QT800Default Quenched and tempered, 800–950 MPa class | Standard delivered condition for turbine/generator rotors and heavy shafts: balanced strength and toughness. | 720 | 880 | 16 | 27 HRC | — |
+QT + gas nitrided | Pick when journals or sealing surfaces need wear and fretting resistance without loss of core toughness (V content gives good nitriding response). | 720 | 880 | 15 | 60 HRC | 7.5 % IACS |
+QT900This page Quenched and tempered, 900–1050 MPa class | Higher-strength temper for medium-section shafts, discs and highly loaded couplings. | 830 | 980 | 14 | 31 HRC | — |
Quenched and tempered, 1000–1150 MPa class | Maximum-strength temper for small-diameter bars and highly stressed fasteners/blades roots; toughness margin is reduced. | 930 | 1,080 | 12 | 35 HRC | — |
What is 28NiCrMoV8-5 +QT900?
28NiCrMoV8-5 +QT900 is 28NiCrMoV8-5 heat treated to +QT900 — higher-strength temper for medium-section shafts, discs and highly loaded couplings. 28NiCrMoV8-5 +QT900 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). 28NiCrMoV8-5 +QT900 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F). +QT800 is the default condition FabDigit quotes; +QT900 is available on request or by drawing note.
Advantages
- High strength — 830 MPa (120 ksi), better than 87% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 38/100, worse than 80% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
28NiCrMoV8-5 +QT900 properties
Typical room-temperature values for 28NiCrMoV8-5 +QT900; 13 are specific to this condition. Other listed values are 28NiCrMoV8-5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
28NiCrMoV8-5 +QT900 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
28NiCrMoV8-5 +QT900 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
28NiCrMoV8-5 +QT900 is rated for continuous service to 380°C (716 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
28NiCrMoV8-5 +QT900 conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 28NiCrMoV8-5 +QT900 takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
28NiCrMoV8-5 +QT900's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (30/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 28NiCrMoV8-5 +QT900
Is 28NiCrMoV8-5 easy to machine?
Rough machine in the annealed condition; in Q&T (250–300 HB) use rigid setups, coated carbide, 60–110 m/min turning with generous coolant, and stress-relieve before finish grinding.
Can 28NiCrMoV8-5 be welded?
Poor weldability (CE > 0.9) — restrict to repair welds with low-hydrogen consumables, 250–350 °C preheat/interpass and 580–620 °C PWHT below the tempering temperature.
Can 28NiCrMoV8-5 be formed, bent or molded?
Hot forge 1100–1200 °C with slow controlled cooling to avoid flakes; cold forming is not practical, and hydrogen-removal / de-gassing treatments are mandatory for heavy forgings.
What surface finishes work on 28NiCrMoV8-5?
Grind and polish journals to fine finish; protect by phosphating, oil, painting or metal spray — the alloy has no inherent corrosion resistance and does not anodize.
28NiCrMoV8-5 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 | 0.24 – 0.32 | 0.28 |
| Sioften ≤0.10 for low-Si rotor practice | ≤ 0.35 | 0.2 |
| Mn | 0.2 – 0.6 | 0.35 |
| Prestricted to limit temper embrittlement | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0 |
| Cr | 1.1 – 1.5 | 1.3 |
| Ni | 1.8 – 2.2 | 2 |
| Mo | 0.35 – 0.6 | 0.45 |
| V | 0.05 – 0.15 | 0.1 |
| Curesidual | ≤ 0.2 | 0.08 |
| Alresidual, grain refining | ≤ 0.02 | 0.01 |
| Sn+As+Sbtramp elements limited for embrittlement (J-factor / X-factor) | ≤ 0.03 | 0.02 |
| Fe | balance | — |
28NiCrMoV8-5 +QT900 — frequently asked
What is 28NiCrMoV8-5 +QT900 used for?
28NiCrMoV8-5 +QT900 is typically used for turbine rotors, turbine shafts and large power-plant forgings. In short: heavy-section rotor forging steel; uniform properties through thickness; repair welding only.
What is the yield strength of 28NiCrMoV8-5 +QT900?
28NiCrMoV8-5 +QT900 has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 28NiCrMoV8-5 +QT900 easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Rough machine in the annealed condition; in Q&T (250–300 HB) use rigid setups, coated carbide, 60–110 m/min turning with generous coolant, and stress-relieve before finish grinding.
Can 28NiCrMoV8-5 +QT900 be welded?
Not readily — weldability is rated poor (30/100). Poor weldability (CE > 0.9) — restrict to repair welds with low-hydrogen consumables, 250–350 °C preheat/interpass and 580–620 °C PWHT below the tempering temperature.
What surface finishes work on 28NiCrMoV8-5 +QT900?
Grind and polish journals to fine finish; protect by phosphating, oil, painting or metal spray — the alloy has no inherent corrosion resistance and does not anodize.
Can 28NiCrMoV8-5 +QT900 be formed, bent or molded?
Hot forge 1100–1200 °C with slow controlled cooling to avoid flakes; cold forming is not practical, and hydrogen-removal / de-gassing treatments are mandatory for heavy forgings.
What is the maximum service temperature of 28NiCrMoV8-5 +QT900?
28NiCrMoV8-5 +QT900 is rated for continuous use to about 380°C (716 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10250-3 Open die steel forgings for general engineering purposes — Alloy special steels — CEN (2000)
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- DIN 17240 / EN 10269 Heat resisting steels for bolting and rotor applications — DIN / CEN (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture (NiCrMoV rotor steels) — ASM International (1996)
- Heavy rotor and shaft forging steel datasheets (Saarschmiede / Böhler / voestalpine class) — producers (2022)
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.