Stainless Steel 1.4317-QT900
Heat-treated state
EN 1.4317 · UNS J91540 · ASTM A743/A487 Gr. CA6NM
Choose when a higher yield (≥690 MPa) is specified for heavily loaded runners or high-head hydraulic parts, accepting lower toughness margin.
Values for the QT900 condition
Other 1.4317 tempers and conditions
1.4317 is listed in 5 conditions; see the grade overview at 1.4317.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Q&T, double tempered to ≤23 HRC | Specify for wet H2S / sour oilfield valve and pump castings where sulfide stress cracking control caps hardness at 23 HRC. | 585 | 790 | 20 | 22 HRC | 2.9 % IACS |
Stress relieved | Delivery state for weld-repaired or fabricated runner castings: a sub-critical temper (580–610 °C) restores HAZ toughness and relieves welding stress. | 600 | 810 | 18 | 24 HRC | 2.9 % IACS |
QT780Default austenitised ~1000–1050 °C, air/oil quenched, tempered 590–620 °C | The standard commercial delivery condition — best balance of 550 MPa yield, 15 % elongation and high notch toughness for turbine runners, pump and valve castings. | 620 | 830 | 18 | 25 HRC | — |
QT900This page austenitised, quenched, double tempered ~560–600 °C for higher strength | Choose when a higher yield (≥690 MPa) is specified for heavily loaded runners or high-head hydraulic parts, accepting lower toughness margin. | 730 | 930 | 15 | 31 HRC | — |
As fabricated | Foundry raw state only — hard, brittle and not supplied for service; must be austenitised and tempered before use. | 900 | 1,200 | 6 | 43 HRC | 2.8 % IACS |
What is 1.4317-QT900?
1.4317-QT900 is 1.4317 heat treated to QT900 — choose when a higher yield (≥690 MPa) is specified for heavily loaded runners or high-head hydraulic parts, accepting lower toughness margin. 1.4317-QT900 has a yield strength of 730 MPa (106 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi). 1.4317-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). QT780 is the default condition FabDigit quotes; QT900 is available on request or by drawing note.
Advantages
- High strength — 730 MPa (106 ksi), better than 93% of stainless steel grades
- Conducts heat well — 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
Limitations
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Needs corrosion protection — 52/100, worse than 76% of stainless steel grades
1.4317-QT900 properties
Typical room-temperature values for 1.4317-QT900; 12 are specific to this condition. Other listed values are 1.4317 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4317-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
1.4317-QT900 has a yield strength of 730 MPa (106 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4317-QT900 is rated for continuous service to 450°C (842 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4317-QT900 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 76% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4317-QT900 takes about 50 MJ of energy and emits 3.6 kg of CO₂ — less than 80% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
1.4317-QT900's machinability is poor (33/100, worse than 57% of stainless steel grades); weldability good (60/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4317-QT900
Is 1.4317 easy to machine?
Machine in the tempered condition with rigid setups, sharp positive-rake carbide and heavy coolant; gummy chips and work hardening make it roughly 40 % of 1212 speed, so avoid dwelling and use climb-milling where possible.
Can 1.4317 be welded?
Very good for a martensitic grade — use matching 13/4 or 410NiMo consumables (or austenitic 309L/E309 for buttering), preheat 100–160 °C, keep interpass below 300 °C and post-weld temper 580–620 °C to restore HAZ toughness.
Can 1.4317 be formed, bent or molded?
Sand or investment cast only; design generous fillets and directional risering, hot-tear-prone in thick-to-thin transitions, and always austenitise + temper the whole casting rather than cold working.
What surface finishes work on 1.4317?
Passivate or electropolish after grinding to restore the chromium oxide film; takes a good mechanical polish, and hard-chrome or thermal-spray coatings are common on cavitation-exposed turbine surfaces.
1.4317 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 |
|---|---|---|
| Clow C for weldability | ≤ 0.06 | 0.04 |
| Si | ≤ 1 | 0.6 |
| Mn | ≤ 1 | 0.7 |
| PASTM A743 allows 0.04 max | ≤ 0.04 | — |
| SASTM A743 allows 0.03 max | ≤ 0.03 | — |
| CrASTM CA6NM: 11.5–14.0 | 12 – 13.5 | 12.8 |
| NiASTM CA6NM: 3.5–4.5 | 3.5 – 5 | 4.2 |
| MoASTM CA6NM: 0.4–1.0 | ≤ 0.7 | 0.5 |
| Ntypical foundry limit | ≤ 0.05 | — |
| Fe | balance | — |
1.4317-QT900 — frequently asked
What is 1.4317-QT900 used for?
1.4317-QT900 is typically used for hydraulic turbine runners, pump impellers and casings and compressor casings. In short: most weldable cast martensitic; CA6NM turbine standard; tough low-carbon 13Cr-4Ni.
What is the yield strength of 1.4317-QT900?
1.4317-QT900 has a typical yield strength of 730 MPa (106 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 93% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4317-QT900 easy to machine?
Not especially — machinability is rated poor (33/100, worse than 57% of stainless steel grades). Machine in the tempered condition with rigid setups, sharp positive-rake carbide and heavy coolant; gummy chips and work hardening make it roughly 40 % of 1212 speed, so avoid dwelling and use climb-milling where possible.
Can 1.4317-QT900 be welded?
Yes — weldability is rated good (60/100). Very good for a martensitic grade — use matching 13/4 or 410NiMo consumables (or austenitic 309L/E309 for buttering), preheat 100–160 °C, keep interpass below 300 °C and post-weld temper 580–620 °C to restore HAZ toughness.
What surface finishes work on 1.4317-QT900?
Passivate or electropolish after grinding to restore the chromium oxide film; takes a good mechanical polish, and hard-chrome or thermal-spray coatings are common on cavitation-exposed turbine surfaces.
Can 1.4317-QT900 be formed, bent or molded?
Sand or investment cast only; design generous fillets and directional risering, hot-tear-prone in thick-to-thin transitions, and always austenitise + temper the whole casting rather than cold working.
What is the maximum service temperature of 1.4317-QT900?
1.4317-QT900 is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4317-QT780 and 1.4317-F?
QT780 is the default condition — the standard commercial delivery condition — best balance of 550 MPa yield, 15 % elongation and high notch toughness for turbine runners, pump and valve castings. F: foundry raw state only — hard, brittle and not supplied for service; must be austenitised and tempered before use. Yield strength is 620 MPa in QT780 versus 900 MPa in F.
Sources
- EN 10283 — Corrosion resistant steel castings (GX4CrNi13-4 / 1.4317) — CEN (2010)
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant (CA6NM) — ASTM (2021)
- ASTM A487/A487M — Steel Castings Suitable for Pressure Service (CA6NM Class A/B) — ASTM (2020)
- ISO 15156-3 / NACE MR0175 — hardness limits for martensitic stainless steels — ISO/NACE (2020)
- 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)
- GB/T 6967 / GB/T 2100 ZG04Cr13Ni4Mo — SAC (2009)
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.