Stainless Steel 321C11
EN 321C11 · UNS J92710 · ASTM CF8C · JIS SCS21
321C11 is the British Standard cast designation for a stabilized 19Cr-11Ni austenitic stainless steel, equivalent to CF8C / UNS J92710 / SCS21 and to GX5CrNiNb19-11 (1.4552), with niobium (columbium) stabilization to tie up carbon.
Reference datasheet — 321C11 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
321C11 tempers and conditions
321C11 is supplied in 4 conditions, soft to hard. SA 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 |
|---|---|---|---|---|---|---|
SADefault Solution annealed (≈1050–1150 °C, water quenched) per ASTM A351/A743 | Standard supply condition for pressure-containing castings; maximum corrosion resistance and ductility. | 250 | 530 | 39 | 150 HB | — |
Solution annealed then stabilization annealed | Chosen for long-term 500–815 °C service or severe nitric-acid duty, where Nb is fully tied up as NbC before operation. | 255 | 540 | 35 | 155 HB | 2.4 % IACS |
Spheroidize annealed | Only for non-critical, non-corrosive structural castings; interdendritic carbides remain so intergranular corrosion resistance is not guaranteed. | 265 | 500 | 25 | 170 HB | 2.3 % IACS |
Centrifugally cast tube/ring, solution annealed | Pipe, ring and sleeve forms with denser, finer structure and slightly higher strength than static castings. | 275 | 550 | 38 | 160 HB | 2.4 % IACS |
What is 321C11?
321C11 is the British Standard cast designation for a stabilized 19Cr-11Ni austenitic stainless steel, equivalent to CF8C / UNS J92710 / SCS21 and to GX5CrNiNb19-11 (1.4552), with niobium (columbium) stabilization to tie up carbon. Stabilization suppresses intergranular carbide precipitation, so castings can run as-welded and at the highest temperature in this family: 850 °C, with 250 MPa yield, 530 MPa tensile, 39 % elongation and 150 HB (80 HRB). Aqueous corrosion resistance is only that of cast 304 (score 62), so it is a heat-service alloy rather than a chloride-service one. Choose CF8M or CF3M where pitting resistance governs. 321C11 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). 321C11 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 39% and the elastic modulus is 193 GPa (28 Msi).
What is 321C11 used for?
- exhaust/manifold castings
- high-temperature valve bodies
- welded pressure castings
Advantages
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
- High service temperature — 850°C (1,562 °F), better than 80% of stainless steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Hard to polish — 58/100, worse than 85% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
321C11 properties
Typical room-temperature values for 321C11-SA; bars are the position among stainless steel grades.
Physical3
321C11 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
321C11 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 39% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
321C11 is rated for continuous service to 850°C (1,562 °F). It conducts heat at 16.2 W/m·K (9.36 BTU/hr·ft·°F), better than 64% of stainless steel grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
321C11 conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 321C11 takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability7
321C11's machinability is fair (38/100, better than 63% of stainless steel grades); weldability very good (78/100); formability poor (25/100).
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. 321C11 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 321C11
Is 321C11 easy to machine?
Gummy and work-hardening like 347 — use rigid setups, positive-rake carbide, heavy feed with no dwell, 60–100 m/min, flood coolant.
Can 321C11 be welded?
Very good; weld with ER347/E347 or matching Nb filler, low heat input, no preheat and normally no post-weld solution anneal thanks to Nb stabilization.
Can 321C11 be formed, bent or molded?
Sand, investment and centrifugal casting all viable; Nb reduces fluidity so use higher pour temperature and generous risering to avoid interdendritic shrinkage.
321C11 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 |
|---|---|---|
| Ckept low; balance of Nb keyed to actual C | ≤ 0.08 | 0.06 |
| Mn | ≤ 1.5 | 1 |
| Si | ≤ 2 | 1.3 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.04 | 0.02 |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 12 | 10.5 |
| Moresidual only | ≤ 0.5 | 0.2 |
| Nb8×C minimum (Nb+Ta); stabilizing addition | ≤ 1 | 0.7 |
| Fe | balance |
What surface finishes work on 321C11?
Pickle and passivate (HNO₃ or citric) after grinding; not anodizable — electropolish or mechanical polish for hygienic surfaces, casting porosity limits mirror finishes.
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 321C11 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 321C11 cost?
321C11 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.
321C11 — frequently asked
What is 321C11 used for?
321C11 is typically used for exhaust/manifold castings, high-temperature valve bodies and welded pressure castings. In short: highest service temp, 850 °C; stabilized for as-welded use; cast counterpart of 347.
What is the yield strength of 321C11?
321C11 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 321C11 easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Gummy and work-hardening like 347 — use rigid setups, positive-rake carbide, heavy feed with no dwell, 60–100 m/min, flood coolant.
Can 321C11 be welded?
Yes — weldability is rated very good (78/100). Very good; weld with ER347/E347 or matching Nb filler, low heat input, no preheat and normally no post-weld solution anneal thanks to Nb stabilization.
What surface finishes work on 321C11?
Pickle and passivate (HNO₃ or citric) after grinding; not anodizable — electropolish or mechanical polish for hygienic surfaces, casting porosity limits mirror finishes.
Can 321C11 be formed, bent or molded?
Sand, investment and centrifugal casting all viable; Nb reduces fluidity so use higher pour temperature and generous risering to avoid interdendritic shrinkage.
What is the maximum service temperature of 321C11?
321C11 is rated for continuous use to about 850°C (1,562 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 321C11-SA and 321C11 CENT-SA?
SA is the default condition — standard supply condition for pressure-containing castings; maximum corrosion resistance and ductility. CENT-SA: pipe, ring and sleeve forms with denser, finer structure and slightly higher strength than static castings. Yield strength is 250 MPa in SA versus 275 MPa in CENT-SA.
How much does 321C11 cost?
321C11 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 A351/A351M — Castings, Austenitic, for Pressure-Containing Parts (CF8C) — ASTM International (2022)
- ASTM A743/A743M — Castings, Iron-Chromium-Nickel, Corrosion Resistant — ASTM International (2019)
- ASTM A451/A451M — Centrifugally Cast Austenitic Steel Pipe (CPF8C) — ASTM International (2021)
- BS 3100 — Steel castings for general engineering purposes — BSI (1991)
- EN 10213 / EN 10283 — GX5CrNiNb19-11 (1.4552) — CEN (2016)
- JIS G 5121 — Corrosion-resistant steel castings (SCS21) — JSA (2003)
- ASM Specialty Handbook: Stainless Steels — Cast Stainless (ACI) alloys — ASM International (1994)
- ASM Handbook Vol. 1: Properties and Selection: Irons, Steels and High-Performance Alloys — 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.