Stainless Steel 1.4150-QT900
Heat-treated state
EN 1.4150
Choose when maximum toughness and thermal stability above 600 °C matter more than hardness.
Values for the QT900 condition
Other 1.4150 tempers and conditions
1.4150 is listed in 5 conditions; see the grade overview at 1.4150.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Delivery condition for machining, forging blanks and cold sawing before hardening. | 550 | 850 | 18 | 260 HB | — |
QT900This page hardened and high-temperature tempered (Rm ≈ 900–1100 MPa) | Choose when maximum toughness and thermal stability above 600 °C matter more than hardness. | 780 | 1,000 | 15 | 31 HRC | — |
QT1100Default hardened and tempered (Rm ≈ 1100–1300 MPa, ≈ 35–43 HRC) | Standard supply/service condition for engine intake valves, stems and high-strength heat-resistant parts. | 950 | 1,200 | 12 | 39 HRC | — |
+QT + nitrided | Pick for valve stems and shafts needing 900–1100 HV surface wear resistance on a tough tempered core. | 950 | 1,200 | 10 | 39 HRC | 2.3 % IACS |
hardened and low tempered (≈ 45–50 HRC) | Use where wear resistance and seat hardness dominate and service temperature stays below ~450 °C. | 1,250 | 1,500 | 7 | 47 HRC | — |
What is 1.4150-QT900?
1.4150-QT900 is 1.4150 heat treated to QT900 — choose when maximum toughness and thermal stability above 600 °C matter more than hardness. 1.4150-QT900 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 95% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 215 GPa (31.2 Msi). 1.4150-QT900 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F). QT1100 is the default condition FabDigit quotes; QT900 is available on request or by drawing note.
Advantages
- High strength — 780 MPa (113 ksi), better than 95% of stainless steel grades
- Conducts heat well — 22 W/m·K (12.7 BTU/hr·ft·°F), better than 77% of stainless steel grades
Limitations
- Low fracture toughness — 30 MPa·√m (27.3 ksi·√in), worse than 99% of stainless steel grades
- Difficult to weld — 20/100, worse than 95% of stainless steel grades
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
1.4150-QT900 properties
Typical room-temperature values for 1.4150-QT900; 13 are specific to this condition. Other listed values are 1.4150 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4150-QT900 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
1.4150-QT900 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 95% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
1.4150-QT900 is rated for continuous service to 700°C (1,292 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), better than 77% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4150-QT900 conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4150-QT900 takes about 53 MJ of energy and emits 5.2 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 35%.
Manufacturability7
1.4150-QT900's machinability is fair (35/100, better than 51% of stainless steel grades); weldability poor (20/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4150-QT900
Is 1.4150 easy to machine?
Machine in the annealed state with sharp carbide tools, rigid setups and generous coolant; above ~40 HRC switch to CBN/ceramic finish turning or grinding.
Can 1.4150 be welded?
Poor weldability — preheat 250–350 °C, use matching or austenitic filler, and temper immediately after welding to avoid cold cracking.
Can 1.4150 be formed, bent or molded?
Hot forge/upset between about 1100 °C and 900 °C followed by slow cooling and soft annealing; cold forming is essentially limited to straightening.
What surface finishes work on 1.4150?
Passivate after hardening for best corrosion behaviour; stems are commonly nitrided or hard-chrome plated, and the fine carbide structure polishes to a good mirror finish.
1.4150 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 |
|---|---|---|
| Cdesignation-derived (X53) | 0.48 – 0.58 | 0.53 |
| Siraises scaling resistance and tempering stability | 1.7 – 2.3 | 2 |
| Mn | ≤ 0.8 | 0.4 |
| Pimpurity limit | ≤ 0.04 | — |
| Simpurity limit | ≤ 0.03 | — |
| Cr | 15 – 17 | 16 |
| Mohot strength / temper resistance | 0.8 – 1.3 | 1 |
| Vfine carbonitride strengthening | 0.2 – 0.5 | 0.35 |
| N | 0.05 – 0.15 | 0.1 |
| Niresidual | ≤ 0.6 | — |
| Fe | balance | — |
1.4150-QT900 — frequently asked
What is 1.4150-QT900 used for?
1.4150-QT900 is typically used for exhaust valves, high-temperature valve components, high-strength fasteners and pump internals. In short: high-strength valve steel; 650 °C martensitic stainless; nitrided stem applications.
What is the yield strength of 1.4150-QT900?
1.4150-QT900 has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 95% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4150-QT900 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine in the annealed state with sharp carbide tools, rigid setups and generous coolant; above ~40 HRC switch to CBN/ceramic finish turning or grinding.
Can 1.4150-QT900 be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — preheat 250–350 °C, use matching or austenitic filler, and temper immediately after welding to avoid cold cracking.
What surface finishes work on 1.4150-QT900?
Passivate after hardening for best corrosion behaviour; stems are commonly nitrided or hard-chrome plated, and the fine carbide structure polishes to a good mirror finish.
Can 1.4150-QT900 be formed, bent or molded?
Hot forge/upset between about 1100 °C and 900 °C followed by slow cooling and soft annealing; cold forming is essentially limited to straightening.
What is the maximum service temperature of 1.4150-QT900?
1.4150-QT900 is rated for continuous use to about 700°C (1,292 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4150-QT1100 and 1.4150-A?
QT1100 is the default condition — standard supply/service condition for engine intake valves, stems and high-strength heat-resistant parts. A: delivery condition for machining, forging blanks and cold sawing before hardening. Yield strength is 950 MPa in QT1100 versus 550 MPa in A.
Sources
- EN 10088-1 Stainless steels — List of stainless steels — CEN (2014)
- EN 10090 Steels and nickel alloys for valves for internal combustion engines — CEN (1998)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Stahlschlüssel (Key to Steel) — Verlag Stahlschlüssel Wegst (2019)
- Valve steel bar datasheets (martensitic Cr-Si-Mo-V grades) — Böhler / Sandvik (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.