Stainless Steel 1.4525 +QT1
Heat-treated state · default condition
EN 1.4525
+QT1 = solution treated ~1020–1070 °C, quenched and precipitation aged…
Default condition for pump casings, impellers and valve bodies where toughness, weld repairability and SCC resistance matter more than peak strength.
Values for the +QT1 condition
Other 1.4525 tempers and conditions
1.4525 is listed in 3 conditions; see the grade overview at 1.4525.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+QT1DefaultThis page Solution treated ~1020–1070 °C, quenched and precipitation aged… | Default condition for pump casings, impellers and valve bodies where toughness, weld repairability and SCC resistance matter more than peak strength. | 620 | 870 | 20 | 26 HRC | — |
Solution annealed | Interim condition supplied when the fabricator will machine, weld-repair and then age the casting to the final QT class. | 750 | 1,000 | 12 | 34 HRC | 2.1 % IACS |
Solution treated ~1020–1070 °C, quenched and precipitation aged… | Choose when higher yield strength, wear resistance and cavitation resistance are required (impellers, wear rings, high-pressure valve trim) and service is not aggressively chloride-bearing. | 900 | 1,050 | 14 | 35 HRC | — |
What is 1.4525 +QT1?
1.4525 +QT1 is 1.4525 heat treated to +QT1 — default condition for pump casings, impellers and valve bodies where toughness, weld repairability and SCC resistance matter more than peak strength. 1.4525 +QT1 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 197 GPa (28.6 Msi). 1.4525 +QT1 has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- High strength — 620 MPa (89.9 ksi), better than 88% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Limited formability — 20/100, worse than 86% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
1.4525 +QT1 properties
Typical room-temperature values for 1.4525 +QT1; 18 are specific to this condition. Other listed values are 1.4525 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4525 +QT1 has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
1.4525 +QT1 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 197 GPa (28.6 Msi).
Thermal6
1.4525 +QT1 is rated for continuous service to 300°C (572 °F). It conducts heat at 17.5 W/m·K (10.1 BTU/hr·ft·°F), better than 72% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
1.4525 +QT1 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4525 +QT1 takes about 53 MJ of energy and emits 4.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
1.4525 +QT1's machinability is fair (45/100, better than 84% of stainless steel grades); weldability good (65/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4525 +QT1
Is 1.4525 easy to machine?
Machine in the overaged +QT1 (or solution-treated) state with rigid setups, sharp carbide tooling, positive rake and generous coolant; work-hardening and gummy chips make low speed/high feed preferable, and finish-machining after final ageing should allow ~0.1 % dimensional change.
Can 1.4525 be welded?
Readily weld-repaired with matching 630/17-4 filler (AWS ER630) using low heat input; preheat 100–150 °C for heavy sections and always re-solution + re-age (or at minimum re-age) after welding to restore properties.
Can 1.4525 be formed, bent or molded?
Cast to shape only — sand or investment casting with adequate feeding; the alloy is not cold-formed, and hot straightening must be followed by full solution treatment and ageing.
What surface finishes work on 1.4525?
Passivate per ASTM A967 (nitric or citric) after machining; polishes well to bright finishes, accepts hard chrome or nitriding for wear surfaces, and must not be anodized.
1.4525 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 |
|---|---|---|
| CGX5 designation | ≤ 0.07 | 0.05 |
| Si | ≤ 0.8 | 0.5 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 15 – 17 | 16 |
| Ni | 3 – 5 | 4 |
| Cuprecipitation-hardening element (ε-Cu) | 3 – 4 | 3.5 |
| Nbstabiliser; some specs require Nb ≥ 5×C | 0.15 – 0.45 | 0.28 |
| Mooptional / residual | ≤ 0.8 | 0.3 |
| Fe | balance | — |
1.4525 +QT1 — frequently asked
What is 1.4525 +QT1 used for?
1.4525 +QT1 is typically used for high-strength pump components, valve stems and trim and shafts requiring aging treatment. In short: precipitation-hardening cast stainless; highest strength CA-family casting; copper-bearing 16Cr-4Ni.
What is the yield strength of 1.4525 +QT1?
1.4525 +QT1 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 870 MPa (126 ksi) — stronger than 88% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4525 +QT1 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Machine in the overaged +QT1 (or solution-treated) state with rigid setups, sharp carbide tooling, positive rake and generous coolant; work-hardening and gummy chips make low speed/high feed preferable, and finish-machining after final ageing should allow ~0.1 % dimensional change.
Can 1.4525 +QT1 be welded?
Yes — weldability is rated good (65/100). Readily weld-repaired with matching 630/17-4 filler (AWS ER630) using low heat input; preheat 100–150 °C for heavy sections and always re-solution + re-age (or at minimum re-age) after welding to restore properties.
What surface finishes work on 1.4525 +QT1?
Passivate per ASTM A967 (nitric or citric) after machining; polishes well to bright finishes, accepts hard chrome or nitriding for wear surfaces, and must not be anodized.
Can 1.4525 +QT1 be formed, bent or molded?
Cast to shape only — sand or investment casting with adequate feeding; the alloy is not cold-formed, and hot straightening must be followed by full solution treatment and ageing.
What is the maximum service temperature of 1.4525 +QT1?
1.4525 +QT1 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10283 — Corrosion resistant steel castings (GX5CrNiCu16-4, 1.4525) — CEN (2010)
- EN 10213 — Steel castings for pressure purposes — CEN (2016)
- ASTM A747/A747M — Steel Castings, Stainless, Precipitation Hardening (CB7Cu-1) — ASTM (2021)
- 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)
- Steel Founders' Society of America — Cast stainless steel property data — SFSA (2019)
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.