Stainless Steel Alloy 611
UNS S30601
Alloy 611 (UNS S30601) is a molybdenum-modified 310-type high-temperature austenitic stainless with improved resistance to sulfidizing and carburizing atmospheres compared with standard 310.
Reference datasheet — Alloy 611 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
Alloy 611 tempers and conditions
Alloy 611 is supplied in 4 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed and pickled (plate, sheet, tube, pipe) | Standard supply condition for all corrosion service — maximum ductility and a fully solutionized, film-forming surface. | 330 | 650 | 45 | 190 HB | — |
As-welded deposit | Condition of welded pipe/tube seams and site welds; expect slightly lower ductility and use over-alloyed or matching high-Si filler plus post-weld pickling for full acid resistance. | 350 | 640 | 30 | 200 HB | 1.8 % IACS |
Cold drawn | Bar/wire form for fasteners, spray nozzles and machined acid-plant fittings; anneal after heavy drawing if full corrosion performance is required. | 560 | 800 | 25 | 24 HRC | 1.8 % IACS |
1/4 Hard | Use only where extra stiffness/strength is needed and the part will not see high-stress acid service (SCC and film-forming behaviour favour the annealed state). | 600 | 860 | 20 | 25 HRC | 1.8 % IACS |
Supply forms, finishes and certifications
Ways Alloy 611 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
2B | Cold rolled, annealed, pickled and lightly skin-passed sheet | Surface finish |
What is Alloy 611?
Alloy 611 (UNS S30601) is a molybdenum-modified 310-type high-temperature austenitic stainless with improved resistance to sulfidizing and carburizing atmospheres compared with standard 310. Annealed material provides about 330 MPa yield, 650 MPa tensile, 45 % elongation and 190 HB (90 HRB), and is supplied as annealed and 2B sheet, cold-worked 1/4H and cold-drawn bar and as-welded tube. It is a tough, abrasive alloy to cut (machinability score 30) with only moderate weldability (score 60) and formability (score 68), so allow reduced speeds, generous bend radii and post-weld pickling; standard 310S is the lower-cost alternative where sulfidation is not the controlling mechanism. Alloy 611 has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,350°C (2,462 °F). Alloy 611 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 57% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 190 GPa (27.6 Msi).
What is Alloy 611 used for?
- High-temperature furnace components
- Petrochemical process tubing
- Furnace retorts in sulfidising atmospheres
- Radiant tubes
- Carburizing furnace fixtures
- Reformer and heater hardware
- Heat-treat baskets and trays
Advantages
- 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
- Poor heat conductor — 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 93% of stainless steel grades
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
Alloy 611 properties
Typical room-temperature values for Alloy 611-Annealed; bars are the position among stainless steel grades.
Physical3
Alloy 611 has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,350°C (2,462 °F).
Mechanical13
Alloy 611 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 57% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal5
Alloy 611 is rated for continuous service to 800°C (1,472 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), worse than 93% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical2
Alloy 611 has an electrical resistivity of 9.5×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of Alloy 611 takes about 62 MJ of energy and emits 6 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
Alloy 611's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (60/100); 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. Alloy 611 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Alloy 611
Is Alloy 611 easy to machine?
Treat as a tough, abrasive austenitic: rigid setups, sharp coated carbide, positive rake, 20–35 % lower speed than 304, heavy flood coolant, avoid dwell to prevent work hardening.
Can Alloy 611 be welded?
GTAW/GMAW/SAW with matching high-Si or over-alloyed austenitic filler, low heat input, no preheat, interpass below ~150 °C; keep dilution low and pickle/passivate the weld zone before acid service.
Can Alloy 611 be formed, bent or molded?
Cold forms like a high-work-hardening austenitic — allow generous bend radii, extra springback and intermediate annealing (1050–1120 °C, rapid cool) for severe drawing; hot work 900–1150 °C.
Alloy 611 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 to avoid sensitization | ≤ 0.02 | 0.01 |
| Sikey element for the sulfuric-acid passive film | 5 – 5.6 | 5.3 |
| Mn | 0.4 – 1 | 0.6 |
| P | ≤ 0.03 | |
| S | ≤ 0.01 | |
| Cr | 17 – 18 | 17.5 |
| Nihigh Ni stabilizes austenite against the ferritizing effect of Si | 17 – 18 | 17.5 |
| Moresidual only — limits chloride pitting resistance | ≤ 0.2 | 0.1 |
| Cu | ≤ 0.35 | |
| Fe | balance |
What surface finishes work on Alloy 611?
Pickle in nitric/HF or nitric-based passivating bath to remove the silica-rich scale after welding or annealing; mechanical polishing works well, no anodizing or plating normally used.
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 Alloy 611 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30601
How much does Alloy 611 cost?
Alloy 611 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.
Alloy 611 — frequently asked
What is Alloy 611 used for?
Alloy 611 is typically used for high-temperature furnace components, petrochemical process tubing, furnace retorts in sulfidising atmospheres, radiant tubes, carburizing furnace fixtures and reformer and heater hardware. In short: sulfidation-resistant 310 variant; molybdenum-modified heat-resistant grade; tougher to machine than 304.
What is the yield strength of Alloy 611?
Alloy 611 has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 57% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is Alloy 611 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Treat as a tough, abrasive austenitic: rigid setups, sharp coated carbide, positive rake, 20–35 % lower speed than 304, heavy flood coolant, avoid dwell to prevent work hardening.
Can Alloy 611 be welded?
Yes — weldability is rated good (60/100). GTAW/GMAW/SAW with matching high-Si or over-alloyed austenitic filler, low heat input, no preheat, interpass below ~150 °C; keep dilution low and pickle/passivate the weld zone before acid service.
What surface finishes work on Alloy 611?
Pickle in nitric/HF or nitric-based passivating bath to remove the silica-rich scale after welding or annealing; mechanical polishing works well, no anodizing or plating normally used.
Can Alloy 611 be formed, bent or molded?
Cold forms like a high-work-hardening austenitic — allow generous bend radii, extra springback and intermediate annealing (1050–1120 °C, rapid cool) for severe drawing; hot work 900–1150 °C.
What is the maximum service temperature of Alloy 611?
Alloy 611 is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Alloy 611 Annealed and Alloy 611-CD?
Annealed is the default condition — standard supply condition for all corrosion service — maximum ductility and a fully solutionized, film-forming surface. CD: bar/wire form for fasteners, spray nozzles and machined acid-plant fittings; anneal after heavy drawing if full corrosion performance is required. Yield strength is 330 MPa in Annealed versus 560 MPa in CD.
How much does Alloy 611 cost?
Alloy 611 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 A249/A269 — Welded and Seamless Austenitic Stainless Steel Tubing — ASTM International (2022)
- SAE/ASTM DS-56 (Metals & Alloys in the Unified Numbering System) — UNS S30601 — SAE International / ASTM (2017)
- High-silicon austenitic stainless steel for concentrated sulfuric acid (S30601 grade datasheet) — Sandvik Materials Technology / Alleima (2022)
- ASM Handbook Vol.13B — Corrosion: Materials (sulfuric acid service) — ASM International (2005)
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.