Stainless Steel S44800
UNS S44800
S44800 (AL 29-4-2) is the highest-purity commercial 29Cr-4Mo super-ferritic stainless steel, with 2% Ni added for toughness and interstitial carbon, nitrogen and oxygen held very low instead of Ti/Nb stabilization.
Reference datasheet — S44800 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 Annealed condition
S44800 tempers and conditions
S44800 is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-welded (autogenous GTAW, no post-weld anneal) | Reference condition for fabricated joints: strength is retained but HAZ grain coarsening lowers toughness. | 470 | 610 | 15 | 17 HRC | 2.3 % IACS |
AnnealedDefault mill annealed, pickled (plate/sheet/strip) | Standard stocked condition for all forming, welding and corrosion service; best ductility and toughness. | 480 | 620 | 25 | 210 HB | — |
Cold worked (as-rolled / temper rolled strip, not annealed) | Special order only — higher strength springy strip, at the cost of ductility and notch toughness. | 700 | 800 | 6 | 28 HRC | 2.2 % IACS |
Supply forms, finishes and certifications
Ways S44800 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Annealed Strip | Annealed thin strip/sheet | Supply form |
Welded Tube Annealed | Welded tube, bright annealed | Supply form |
What is S44800?
S44800 (AL 29-4-2) is the highest-purity commercial 29Cr-4Mo super-ferritic stainless steel, with 2% Ni added for toughness and interstitial carbon, nitrogen and oxygen held very low instead of Ti/Nb stabilization. It offers the family's best combination of chloride corrosion resistance (score 88) and fabricability, and is available as annealed sheet and strip, welded tube, and cold-worked product. Annealed strength is 480 MPa yield and 620 MPa tensile at 25% elongation, 210 HB (96 HRB), with a 300 °C service ceiling and moderate formability (score 55). Welding demands very clean, high-purity-gas practice; S44735 is the easier grade to weld in a general shop. S44800 has a density of 7.67 g/cm³ (0.277 lb/in³), lighter than 95% of stainless steel grades. It melts at 1,420°C (2,588 °F). S44800 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
What is S44800 used for?
- seawater heat exchangers
- chemical process equipment
- high-chloride service piping
Advantages
- Good corrosion resistance — 88/100, better than 97% of stainless steel grades
- High strength — 480 MPa (69.6 ksi), better than 75% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
S44800 properties
Typical room-temperature values for S44800-Annealed; bars are the position among stainless steel grades.
Physical3
S44800 has a density of 7.67 g/cm³ (0.277 lb/in³), lighter than 95% of stainless steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
S44800 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 75% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S44800 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 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
S44800 conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of S44800 takes about 70 MJ of energy and emits 5.2 kg of CO₂ — more than 81% of stainless steel grades. Typical recycled content is 30%.
Manufacturability7
S44800's machinability is fair (35/100, better than 51% of stainless steel grades); weldability good (55/100); formability good (55/100).
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. S44800 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S44800
Is S44800 easy to machine?
Machines like a tough ferritic stainless (~40% of 1212): rigid setups, sharp positive-rake carbide, heavy feeds and flood coolant to avoid work-hardened glazing and built-up edge.
Can S44800 be welded?
Weld autogenously by GTAW/PAW with very high-purity argon (trailing and backing gas), low heat input and scrupulous cleanliness; carbon, nitrogen or oxygen pickup embrittles the weld — avoid austenitic fillers where matching corrosion resistance is required, and never preheat above ~150 °C.
Can S44800 be formed, bent or molded?
Cold forms well for a super-ferritic in thin gauge (roll forming, tube making, moderate draws); use generous bend radii, expect higher springback than 304 and warm form ~150–250 °C for severe bends in heavier sections.
S44800 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 |
|---|---|---|
| CC+N ≤ 0.025% | ≤ 0.01 | 0.01 |
| NC+N ≤ 0.025% | ≤ 0.02 | 0.01 |
| Cr | 28 – 30 | 29 |
| Mo | 3.5 – 4.2 | 4 |
| Niadded for toughness | 2 – 2.5 | 2.2 |
| Mn | ≤ 0.3 | 0.2 |
| Si | ≤ 0.2 | 0.15 |
| P | ≤ 0.03 | |
| S | ≤ 0.02 | |
| Cu | ≤ 0.15 | |
| Fe | balance |
What surface finishes work on S44800?
Pickle and passivate after hot work or welding to restore the Cr-Mo oxide film; electropolishing or mechanical polishing gives excellent seawater-service surfaces — 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 S44800 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- AL 29-4-2
- Also called
- 29-4-2
How much does S44800 cost?
S44800 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.
S44800 — frequently asked
What is S44800 used for?
S44800 is typically used for seawater heat exchangers, chemical process equipment and high-chloride service piping. In short: purest super-ferritic grade; highest chloride resistance, ferritic; toughest 29Cr-4Mo variant.
What is the yield strength of S44800?
S44800 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 75% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is S44800 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machines like a tough ferritic stainless (~40% of 1212): rigid setups, sharp positive-rake carbide, heavy feeds and flood coolant to avoid work-hardened glazing and built-up edge.
Can S44800 be welded?
Yes — weldability is rated good (55/100). Weld autogenously by GTAW/PAW with very high-purity argon (trailing and backing gas), low heat input and scrupulous cleanliness; carbon, nitrogen or oxygen pickup embrittles the weld — avoid austenitic fillers where matching corrosion resistance is required, and never preheat above ~150 °C.
What surface finishes work on S44800?
Pickle and passivate after hot work or welding to restore the Cr-Mo oxide film; electropolishing or mechanical polishing gives excellent seawater-service surfaces — no anodizing.
Can S44800 be formed, bent or molded?
Cold forms well for a super-ferritic in thin gauge (roll forming, tube making, moderate draws); use generous bend radii, expect higher springback than 304 and warm form ~150–250 °C for severe bends in heavier sections.
What is the maximum service temperature of S44800?
S44800 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.
How much does S44800 cost?
S44800 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
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip — ASTM International (2023)
- ASTM A268/A268M — Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing — ASTM International (2022)
- AL 29-4-2 Alloy (UNS S44800) Technical Data Sheet — ATI / Allegheny Ludlum (2014)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (superferritic stainless steels) — ASM International (1990)
- Outokumpu Corrosion Handbook / Stainless Steel Handbook — Outokumpu (2020)
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.