Stainless Steel 1.4313 +QT900
Heat-treated state
EN 1.4313 · UNS S41500 · GB 0Cr13Ni4Mo
+QT900 = quenched and tempered, Rm 900–1100 MPa
Highest-strength single-temper condition for highly loaded shafts and bolting where toughness and sour-service hardness limits are not the controlling factor.
Values for the +QT900 condition
Other 1.4313 tempers and conditions
1.4313 is listed in 5 conditions; see the grade overview at 1.4313.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for machining of blanks, cold straightening or forming before final quench-and-temper; hardness capped for shop workability. | 550 | 750 | 18 | 24 HRC | — |
Quenched and tempered, Rm 650–850 MPa | Highest-toughness / lowest-hardness Q&T condition — choose for sour service (≤23 HRC per NACE MR0175) and heavy welded fabrications. | 580 | 740 | 20 | 21 HRC | — |
Quenched and tempered, Rm 700–900 MPa | Intermediate forging/casing condition (EN 10250-4 style) when a little more strength than QT650 is needed with near-identical toughness. | 620 | 790 | 19 | 23 HRC | — |
+QT780Default Quenched and tempered, Rm 780–980 MPa | Workhorse stock condition for hydro-turbine runners, pump shafts and valve parts — best balance of strength, toughness and weld repairability. | 700 | 870 | 18 | 26 HRC | — |
+QT900This page Quenched and tempered, Rm 900–1100 MPa | Highest-strength single-temper condition for highly loaded shafts and bolting where toughness and sour-service hardness limits are not the controlling factor. | 850 | 990 | 15 | 32 HRC | — |
What is 1.4313 +QT900?
1.4313 +QT900 is 1.4313 heat treated to +QT900 — highest-strength single-temper condition for highly loaded shafts and bolting where toughness and sour-service hardness limits are not the controlling factor. 1.4313 +QT900 has a yield strength of 850 MPa (123 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi). 1.4313 +QT900 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,440°C (2,624 °F). +QT780 is the default condition FabDigit quotes; +QT900 is available on request or by drawing note.
Advantages
- High strength — 850 MPa (123 ksi), better than 97% 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
Limitations
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Needs corrosion protection — 45/100, worse than 85% of stainless steel grades
- Limited service temperature — 350°C (662 °F), worse than 84% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
1.4313 +QT900 properties
Typical room-temperature values for 1.4313 +QT900; 19 are specific to this condition. Other listed values are 1.4313 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4313 +QT900 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,440°C (2,624 °F).
Mechanical16
1.4313 +QT900 has a yield strength of 850 MPa (123 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4313 +QT900 is rated for continuous service to 350°C (662 °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
1.4313 +QT900 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 85% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4313 +QT900 takes about 53 MJ of energy and emits 4.8 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
1.4313 +QT900's machinability is poor (27/100, worse than 83% of stainless steel grades); weldability good (62/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4313 +QT900
Is 1.4313 easy to machine?
Machines like a tough 30-HRC alloy steel: rigid setups, sharp positive-rake coated carbide, ~60–110 m/min turning, heavy feeds and flood coolant to avoid work-hardened glazing and built-up edge.
Can 1.4313 be welded?
Very good for a martensitic grade — GTAW/GMAW/SMAW with 410NiMo (E410NiMo) filler, preheat/interpass ~100–160 °C for heavy sections and PWHT temper at 580–620 °C (double temper for optimum toughness); keep hydrogen low.
Can 1.4313 be formed, bent or molded?
Hot work at 1150–900 °C followed by slow cool and soft anneal; cold forming is limited to gentle bends in the +A condition — final shape is normally machined after quench and temper.
What surface finishes work on 1.4313?
Passivate (ASTM A967 nitric or citric) after machining; takes a good mechanical or electropolished finish, and is commonly hard-chrome plated or HVOF-coated on wear surfaces — avoid cathodic overprotection/plating hydrogen without bake-out.
1.4313 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 carbon gives soft martensite and weldability | ≤ 0.05 | 0.03 |
| Si | ≤ 0.7 | 0.4 |
| Mn | ≤ 1.5 | 0.8 |
| P | ≤ 0.04 | — |
| S0.030 max for some product forms | ≤ 0.02 | — |
| Cr | 12 – 14 | 13 |
| Ni | 3.5 – 4.5 | 4 |
| Mo | 0.3 – 0.7 | 0.5 |
| N | ≤ 0.02 | — |
| Fe | balance | — |
1.4313 +QT900 — frequently asked
What is 1.4313 +QT900 used for?
1.4313 +QT900 is typically used for hydro-turbine runners, pump impellers/shafts, valve bodies and offshore equipment. In short: best-welding martensitic stainless; wrought equivalent of CA6NM; high toughness at 26 HRC.
What is the yield strength of 1.4313 +QT900?
1.4313 +QT900 has a typical yield strength of 850 MPa (123 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 97% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4313 +QT900 easy to machine?
Not especially — machinability is rated poor (27/100, worse than 83% of stainless steel grades). Machines like a tough 30-HRC alloy steel: rigid setups, sharp positive-rake coated carbide, ~60–110 m/min turning, heavy feeds and flood coolant to avoid work-hardened glazing and built-up edge.
Can 1.4313 +QT900 be welded?
Yes — weldability is rated good (62/100). Very good for a martensitic grade — GTAW/GMAW/SMAW with 410NiMo (E410NiMo) filler, preheat/interpass ~100–160 °C for heavy sections and PWHT temper at 580–620 °C (double temper for optimum toughness); keep hydrogen low.
What surface finishes work on 1.4313 +QT900?
Passivate (ASTM A967 nitric or citric) after machining; takes a good mechanical or electropolished finish, and is commonly hard-chrome plated or HVOF-coated on wear surfaces — avoid cathodic overprotection/plating hydrogen without bake-out.
Can 1.4313 +QT900 be formed, bent or molded?
Hot work at 1150–900 °C followed by slow cool and soft anneal; cold forming is limited to gentle bends in the +A condition — final shape is normally machined after quench and temper.
What is the maximum service temperature of 1.4313 +QT900?
1.4313 +QT900 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10088-3 Stainless steels — semi-finished products, bars, rods, sections — CEN (2014)
- EN 10088-1 Stainless steels — List of stainless steels (physical properties) — CEN (2014)
- ASTM A240 / A182 (UNS S41500) — ASTM International (2023)
- EN 10250-4 Open die steel forgings — stainless steels — CEN (2000)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Soft martensitic 13Cr-4Ni stainless bar/forging datasheets (Sandvik, Böhler, Outokumpu) — various producers (2023)
- NACE MR0175 / ISO 15156-3 (13Cr-4Ni hardness limits) — NACE/ISO (2020)
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.