Stainless Steel 1.4439
EN 1.4439
1.4439 (X2CrNiMoN17-13-5, S31726/317LMN) is a nitrogen-strengthened, low-carbon austenitic stainless with about 5 % molybdenum for high pitting resistance in chloride and acid service.
Reference datasheet — 1.4439 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 SA condition
1.4439 tempers and conditions
1.4439 is supplied in 5 conditions, soft to hard. SA is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for plate, bar, tube and fittings — maximum corrosion resistance and ductility. | 320 | 640 | 45 | 190 HB | — |
As-welded deposit | For weldment design checks; use over-alloyed filler (ER317LMN, 625 or 2209) and expect slightly lower ductility. | 380 | 620 | 30 | 200 HB | 2 % IACS |
Cold drawn | Bar and shafting where higher strength and tighter tolerance than annealed are needed. | 480 | 720 | 30 | 20 HRC | 2 % IACS |
1/4 Hard | Springy strip or lightly stiffened panels where moderate strength gain is wanted. | 560 | 820 | 20 | 25 HRC | 2 % IACS |
1/2 Hard | Rarely stocked; used for high-strength clamps, springs and wire in aggressive chloride media. | 780 | 970 | 12 | 31 HRC | 2 % IACS |
Supply forms, finishes and certifications
Ways 1.4439 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
TUBE-AT | Annealed tube | Supply form |
1D | Hot rolled, solution annealed and pickled plate | Surface finish |
2B | Cold rolled, annealed, pickled and skin-passed sheet | Surface finish |
What is 1.4439?
1.4439 (X2CrNiMoN17-13-5, S31726/317LMN) is a nitrogen-strengthened, low-carbon austenitic stainless with about 5 % molybdenum for high pitting resistance in chloride and acid service. It is selected for seawater and chemical duty in plate, solution-annealed tube, cold-drawn bar and cold-worked strip, with annealed properties of 320 MPa yield, 640 MPa tensile, 45 % elongation and 190 HB. Machinability is low (score 32) and formability is moderate (68), so it costs more and works harder than 316L; move to 1.4434/316LN if the extra molybdenum is not needed, or to a 6 % Mo grade if it is not enough. 1.4439 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,370°C (2,498 °F). 1.4439 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
What is 1.4439 used for?
- seawater desalination
- chemical tanks
- offshore equipment
- pulp & paper
Advantages
- Tough — resists crack growth — 220 MPa·√m (200.2 ksi·√in), better than 97% of stainless steel grades
- Good corrosion resistance — 80/100, better than 88% of stainless steel grades
- Readily welded — 80/100, better than 80% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
- Forms and bends easily — 68/100, better than 75% of stainless steel grades
Limitations
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
1.4439 properties
Typical room-temperature values for 1.4439-SA; bars are the position among stainless steel grades.
Physical3
1.4439 has a density of 8 g/cm³ (0.289 lb/in³), heavier than 92% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
1.4439 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4439 is rated for continuous service to 450°C (842 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
1.4439 conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 88% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4439 takes about 62 MJ of energy and emits 5.5 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
1.4439's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability very good (80/100); formability good (68/100).
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. 1.4439 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.4439
Is 1.4439 easy to machine?
Tough and gummy with high work hardening — use rigid setups, positive-rake coated carbide, 25–60 m/min, heavy feed and flood coolant; never dwell or let the tool rub.
Can 1.4439 be welded?
Readily welded by GTAW/GMAW/SMAW with no preheat or PWHT; use over-alloyed filler (ER/E317LMN, ERNiCrMo-3 or 2209), low heat input and back-purge to keep weld-metal PREN and avoid hot cracking.
Can 1.4439 be formed, bent or molded?
Cold forms and deep draws well but needs ~50 % more press force and springback allowance than 304; hot work 1150–900 °C followed by full solution anneal and water quench.
1.4439 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, avoids sensitization | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.5 |
| P | ≤ 0.05 | |
| SASTM A240 S31726 allows 0.030 max | ≤ 0.02 | |
| CrS31726: 17.0–20.0 | 16.5 – 18.5 | 17.5 |
| NiS31726: 13.5–17.5 | 12.5 – 14.5 | 13.5 |
| Mopitting resistance | 4 – 5 | 4.5 |
| Nsolid-solution strengthening; S31726: 0.10–0.20 | 0.12 – 0.22 | 0.17 |
| Fe | balance |
What surface finishes work on 1.4439?
Pickle (HNO₃/HF) and passivate after welding or grinding to restore the passive film; electropolishing or mechanical polishing to Ra <0.5 µm for pharma/chemical service — no anodizing.
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 1.4439 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- X2CrNiMoN17-13-5
- Similar grades
- S31726317LMN
How much does 1.4439 cost?
1.4439 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.
1.4439 — frequently asked
What is 1.4439 used for?
1.4439 is typically used for seawater desalination, chemical tanks, offshore equipment and pulp & paper. In short: high-PREN austenitic; stronger than 316L; chloride pitting resistant.
What is the yield strength of 1.4439?
1.4439 has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4439 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Tough and gummy with high work hardening — use rigid setups, positive-rake coated carbide, 25–60 m/min, heavy feed and flood coolant; never dwell or let the tool rub.
Can 1.4439 be welded?
Yes — weldability is rated very good (80/100). Readily welded by GTAW/GMAW/SMAW with no preheat or PWHT; use over-alloyed filler (ER/E317LMN, ERNiCrMo-3 or 2209), low heat input and back-purge to keep weld-metal PREN and avoid hot cracking.
What surface finishes work on 1.4439?
Pickle (HNO₃/HF) and passivate after welding or grinding to restore the passive film; electropolishing or mechanical polishing to Ra <0.5 µm for pharma/chemical service — no anodizing.
Can 1.4439 be formed, bent or molded?
Cold forms and deep draws well but needs ~50 % more press force and springback allowance than 304; hot work 1150–900 °C followed by full solution anneal and water quench.
What is the maximum service temperature of 1.4439?
1.4439 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 1.4439-SA and 1.4439-CD?
SA is the default condition — standard supply condition for plate, bar, tube and fittings — maximum corrosion resistance and ductility. CD: bar and shafting where higher strength and tighter tolerance than annealed are needed. Yield strength is 320 MPa in SA versus 480 MPa in CD.
How much does 1.4439 cost?
1.4439 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 10088-1/-2/-3 Stainless steels — X2CrNiMoN17-13-5 (1.4439) — CEN (2014)
- ASTM A240/A240M — Cr and Cr-Ni stainless plate, sheet and strip (UNS S31726) — ASTM (2022)
- ASTM A312 / A213 — welded and seamless austenitic stainless pipe and tube — ASTM (2022)
- Outokumpu 4439 / 317LMN datasheet — Outokumpu (2023)
- ASM Handbook Vol.1 — Properties of Stainless Steels — ASM International (1990)
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.