Stainless Steel S44626
UNS S44626 · ASTM XM-33
S44626 (XM-33) is a low-interstitial 18Cr-2Mo ferritic stainless steel stabilized with titanium, supplied as welded and seamless annealed tube, strip and bar.
Reference datasheet — S44626 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
S44626 tempers and conditions
S44626 is supplied in 2 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault bright/mill annealed (ASTM A268 / A176 TP XM-33) | Standard supply condition for tube, sheet and bar; maximum corrosion resistance and ductility. | 380 | 520 | 27 | 170 HB | — |
Cold worked / cold drawn (not annealed) | Higher strength and better machining finish for bar and small-diameter tube; ductility and corrosion margin reduced. | 550 | 620 | 12 | 16 HRC | 2.9 % IACS |
Supply forms, finishes and certifications
Ways S44626 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Seamless Annealed | Seamless tube, annealed and pickled | Supply form |
Welded Tube Annealed | Welded and annealed tube | Supply form |
What is S44626?
S44626 (XM-33) is a low-interstitial 18Cr-2Mo ferritic stainless steel stabilized with titanium, supplied as welded and seamless annealed tube, strip and bar. It is chosen for better resistance to chloride pitting and stress-corrosion cracking than Type 444 in mildly aggressive waters, with 380 MPa yield, 520 MPa tensile and 27 % elongation annealed at 170 HB. Service is capped near 300 °C and heavy sections are notch-sensitive, so use is mainly thin-wall tubing; welding needs clean argon shielding to limit HAZ embrittlement. Type 444 is the usual lower-cost alternative. S44626 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,425°C (2,597 °F). S44626 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
What is S44626 used for?
- feedwater heaters
- condenser tubing
- process heat exchangers
Advantages
- Easy to machine — 55/100, better than 94% of stainless steel grades
- Low embodied carbon — 3.3 kg CO₂/kg, better than 93% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Good corrosion resistance — 75/100, better than 79% of stainless steel grades
- Conducts heat well — 20.9 W/m·K (12.1 BTU/hr·ft·°F), better than 75% of stainless steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
S44626 properties
Typical room-temperature values for S44626-Annealed; bars are the position among stainless steel grades.
Physical3
S44626 has a density of 7.65 g/cm³ (0.276 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
S44626 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S44626 is rated for continuous service to 300°C (572 °F). It conducts heat at 20.9 W/m·K (12.1 BTU/hr·ft·°F), better than 75% of stainless steel grades. Thermal expansion is 9.9 µm/m·K (5.5 µin/in·°F).
Electrical3
S44626 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 79% of stainless steel grades.
Sustainability4
Producing a kilogram of S44626 takes about 45 MJ of energy and emits 3.3 kg of CO₂ — less than 91% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
S44626's machinability is good (55/100, better than 94% of stainless steel grades); weldability good (60/100); formability good (65/100).
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. S44626 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S44626
Is S44626 easy to machine?
Machines like a medium-hard ferritic stainless — gummy chips, use sharp positive-rake carbide, rigid setup, generous coolant and lower speeds than 430; roughly 55 % of 1212.
Can S44626 be welded?
GTAW/plasma with matched or Ni-base filler under high-purity argon backing; keep heat input and interpass low to limit HAZ grain growth, no preheat, avoid pick-up of C/N/O.
Can S44626 be formed, bent or molded?
Good cold formability as thin strip and tube (bending, expanding, U-bending); allow more springback than austenitics and avoid heavy sections due to notch sensitivity.
S44626 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 interstitial | ≤ 0.06 | 0.02 |
| Mn | ≤ 0.75 | 0.3 |
| Si | ≤ 0.75 | 0.4 |
| P | ≤ 0.04 | |
| S | ≤ 0.02 | |
| Cr | 25 – 27 | 26 |
| Mo | 0.75 – 1.5 | 1 |
| Ni | ≤ 0.5 | 0.2 |
| Cu | ≤ 0.2 | |
| N | ≤ 0.04 | 0.02 |
| Timin 7×(C+N) | 0.2 – 1 | 0.35 |
| Fe | balance |
What surface finishes work on S44626?
Pickle and passivate (HNO3/HF) or electropolish after welding for full corrosion performance; not anodizable, takes a good mechanical or bright-annealed finish.
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 S44626 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- XM-33
How much does S44626 cost?
S44626 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S44626 — frequently asked
What is S44626 used for?
S44626 is typically used for feedwater heaters, condenser tubing and process heat exchangers. In short: low-interstitial 18Cr-2Mo ferritic; outperforms Type 444 in waters; thin-wall tube grade.
What is the yield strength of S44626?
S44626 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 52% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is S44626 easy to machine?
Reasonably — machinability is rated good (55/100, better than 94% of stainless steel grades). Machines like a medium-hard ferritic stainless — gummy chips, use sharp positive-rake carbide, rigid setup, generous coolant and lower speeds than 430; roughly 55 % of 1212.
Can S44626 be welded?
Yes — weldability is rated good (60/100). GTAW/plasma with matched or Ni-base filler under high-purity argon backing; keep heat input and interpass low to limit HAZ grain growth, no preheat, avoid pick-up of C/N/O.
What surface finishes work on S44626?
Pickle and passivate (HNO3/HF) or electropolish after welding for full corrosion performance; not anodizable, takes a good mechanical or bright-annealed finish.
Can S44626 be formed, bent or molded?
Good cold formability as thin strip and tube (bending, expanding, U-bending); allow more springback than austenitics and avoid heavy sections due to notch sensitivity.
What is the maximum service temperature of S44626?
S44626 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does S44626 cost?
S44626 is a premium-cost stainless steel ($$$), cheaper than about 51% 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 A268/A268M — Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing — ASTM (2023)
- ASTM A176 — Stainless and Heat-Resisting Chromium Steel Plate, Sheet, and Strip — ASTM (2022)
- ASTM A959 / SAE J1086 — UNS designations for stainless steels — ASTM/SAE (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)
- Superferritic 26Cr-1Mo stainless tubing data — specialty stainless tube producers (2022)
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.