Stainless Steel 1.4423
EN 1.4423
1.4423 (X1CrNiMoCu12-7-3) is a higher-alloyed soft martensitic stainless — 12Cr-7Ni-3Mo with copper and carbon below 0.02 % — used where 1.4422 lacks corrosion resistance.
Reference datasheet — 1.4423 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +QT900 condition
1.4423 tempers and conditions
1.4423 is supplied in 7 conditions, soft to hard. +QT900 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Quenched and tempered to Rm 700–850 MPa | High-tempering condition for maximum toughness and sour-service hardness limits (<22 HRC targets where required). | 560 | 760 | 20 | 21 HRC | — |
Annealed | Pick for heavy machining, deep drilling or cold straightening before a final quench-and-temper cycle. | 600 | 800 | 20 | 25 HRC | 2.3 % IACS |
Quenched and tempered to Rm 800–950 MPa | Balanced strength/toughness condition for valve stems and medium-duty pump shafts. | 680 | 870 | 18 | 27 HRC | 2.3 % IACS |
As-welded deposit | Reference condition for fabrication checks; a post-weld temper is normally required to restore toughness and sour-service hardness. | 700 | 900 | 13 | 35 HRC | 2.3 % IACS |
+QT900Default Quenched and tempered to Rm 900–1050 MPa | Standard stocked condition for pump shafts and impellers needing high strength with good corrosion resistance. | 780 | 950 | 16 | 31 HRC | — |
Cold drawn | Choose for close-tolerance shaft blanks where h9/h7 dimensional accuracy and surface finish are needed without further turning. | 820 | 980 | 14 | 32 HRC | 2.3 % IACS |
Quenched and low-temperature tempered / Cu-aged, Rm ≥ 1000 MPa | Highest-strength condition, using copper precipitation on low tempering; choose for highly loaded shafts in non-sour service. | 900 | 1,080 | 14 | 36 HRC | — |
What is 1.4423?
1.4423 (X1CrNiMoCu12-7-3) is a higher-alloyed soft martensitic stainless — 12Cr-7Ni-3Mo with copper and carbon below 0.02 % — used where 1.4422 lacks corrosion resistance. Supplied as bar, forgings and castings in annealed and quenched-and-tempered conditions (+QT700 to +QT1000), it is chosen for pump and valve parts handling aggressive media. Default values are 780 MPa yield, 950 MPa tensile, 16 % elongation and 300 HB (31 HRC), with service to about 300 °C. Machinability is limited at 38/100, and duplex 1.4462 is the usual alternative when higher pitting resistance is required. 1.4423 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). 1.4423 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 95% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi).
What is 1.4423 used for?
- Chemical process pumps
- Valve trim
- Marine pump impellers
Advantages
- High strength — 780 MPa (113 ksi), better than 95% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- Limited ductility — 16%, worse than 88% of stainless steel grades
1.4423 properties
Typical room-temperature values for 1.4423-+QT900; bars are the position among stainless steel grades.
Physical3
1.4423 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
1.4423 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 95% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4423 is rated for continuous service to 300°C (572 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4423 conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4423 takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
1.4423's machinability is fair (38/100, better than 63% of stainless steel grades); weldability very good (72/100); formability poor (32/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 1.4423 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.4423
Is 1.4423 easy to machine?
Machines like a 30 HRC low-carbon martensitic stainless: gummy and work-hardening, so use rigid setups, sharp coated carbide, positive rake, 60–110 m/min turning speeds and generous high-pressure coolant.
Can 1.4423 be welded?
Very good for a martensitic grade thanks to <0.02 % C — TIG/MIG with matching or 22-9-3/625-type filler, low heat input, preheat 100–150 °C on heavy sections and a post-weld temper below the base-metal tempering temperature.
Can 1.4423 be formed, bent or molded?
Hot forge 1150–900 °C then air-cool and re-austenitize/temper; cold forming is limited to mild straightening and thread rolling in the softened condition.
1.4423 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 |
|---|---|---|
| Cultra-low carbon, ensures soft/tough martensite | ≤ 0.02 | 0.01 |
| Si | ≤ 0.7 | 0.35 |
| Mn | ≤ 2 | 0.7 |
| P | ≤ 0.03 | |
| Slow S for toughness and pitting resistance | ≤ 0.01 | |
| Cr | 11 – 12.5 | 12 |
| Ni | 6 – 7.5 | 7 |
| Mo | 2.5 – 3.5 | 3 |
| Cuapproximate; provides age-hardening response | 1 – 2 | 1.5 |
| N | ≤ 0.02 | |
| Fe | balance |
What surface finishes work on 1.4423?
Polishes to a fine finish and passivates well in nitric or citric acid; avoid chloride-bearing pickles at high temperature, and keep final hardness ≤ 32 HRC where sour-service or plating-related hydrogen embrittlement is a concern.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 1.4423 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- X1CrNiMoCu12-7-3
How much does 1.4423 cost?
1.4423 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
1.4423 — frequently asked
What is 1.4423 used for?
1.4423 is typically used for chemical process pumps, valve trim and marine pump impellers. In short: most corrosion-resistant soft martensitic; upgrade from 1.4422; carbon below 0.02 %.
What is the yield strength of 1.4423?
1.4423 has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 95% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.4423 easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Machines like a 30 HRC low-carbon martensitic stainless: gummy and work-hardening, so use rigid setups, sharp coated carbide, positive rake, 60–110 m/min turning speeds and generous high-pressure coolant.
Can 1.4423 be welded?
Yes — weldability is rated very good (72/100). Very good for a martensitic grade thanks to <0.02 % C — TIG/MIG with matching or 22-9-3/625-type filler, low heat input, preheat 100–150 °C on heavy sections and a post-weld temper below the base-metal tempering temperature.
What surface finishes work on 1.4423?
Polishes to a fine finish and passivates well in nitric or citric acid; avoid chloride-bearing pickles at high temperature, and keep final hardness ≤ 32 HRC where sour-service or plating-related hydrogen embrittlement is a concern.
Can 1.4423 be formed, bent or molded?
Hot forge 1150–900 °C then air-cool and re-austenitize/temper; cold forming is limited to mild straightening and thread rolling in the softened condition.
What is the maximum service temperature of 1.4423?
1.4423 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.
What is the difference between 1.4423 +QT900 and 1.4423-AW?
+QT900 is the default condition — standard stocked condition for pump shafts and impellers needing high strength with good corrosion resistance. AW: reference condition for fabrication checks; a post-weld temper is normally required to restore toughness and sour-service hardness. Yield strength is 780 MPa in +QT900 versus 700 MPa in AW.
How much does 1.4423 cost?
1.4423 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- EN 10088-3 Stainless steels — Technical delivery conditions for semi-finished products, bars, rods, wire — CEN (2014)
- EN 10088-1 Stainless steels — List of stainless steels (physical property data) — CEN (2014)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ANSI/NACE MR0175 / ISO 15156-3 — Materials for use in H2S-containing environments — NACE/ISO (2015)
- Supermartensitic stainless pump-shaft bar datasheets (12Cr-Ni-Mo-Cu class) — European long-product mills (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.