Stainless Steel CT15C
UNS N08151
CT15C (N08151, ASTM A351/A743) is a high-nickel Cr-Mo-Cu cast alloy comparable to wrought Alloy 825 (N08825), used for its balanced resistance to both reducing and oxidizing acids.
Reference datasheet — CT15C 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
CT15C tempers and conditions
CT15C is supplied in 3 conditions, soft to hard. SA 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 |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for pressure-containing castings to ASTM A351/A743; best ductility and corrosion resistance. | 240 | 490 | 30 | 170 HB | 1.7 % IACS |
Spheroidize annealed | Used for non-pressure, high-temperature furnace hardware where interdendritic carbides are acceptable and creep life matters more than room-temperature ductility. | 255 | 470 | 18 | 180 HB | 1.7 % IACS |
Centrifugally cast, solution annealed | Choose for tubes, sleeves and rings where the denser, more directional centrifugal structure gives higher strength and better soundness than static castings. | 260 | 525 | 28 | 175 HB | 1.7 % IACS |
What is CT15C?
CT15C (N08151, ASTM A351/A743) is a high-nickel Cr-Mo-Cu cast alloy comparable to wrought Alloy 825 (N08825), used for its balanced resistance to both reducing and oxidizing acids. It is supplied as solution-annealed, as-cast or centrifugally cast pump and valve components, with 240 MPa yield, 490 MPa tensile, 30 % elongation and 170 HB, and a maximum service temperature of 1000 °C. Machinability is low (score 30) and the corrosion score of 70 is below the high-Mo super-austenitics, so CN3MN is the better choice for severe chloride or sulfuric acid duty. CT15C has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,340°C (2,444 °F). CT15C has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 193 GPa (28 Msi).
What is CT15C used for?
- chemical process pumps
- valves for mixed-acid service
- pollution control equipment
Advantages
- High service temperature — 1,000°C (1,832 °F), better than 88% of stainless steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- Poor heat conductor — 12.5 W/m·K (7.22 BTU/hr·ft·°F), worse than 90% of stainless steel grades
- Hard to polish — 55/100, worse than 89% of stainless steel grades
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
CT15C properties
Typical room-temperature values for CT15C-SA; bars are the position among stainless steel grades.
Physical3
CT15C has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,340°C (2,444 °F).
Mechanical16
CT15C has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CT15C is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 12.5 W/m·K (7.22 BTU/hr·ft·°F), worse than 90% of stainless steel grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
CT15C conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of CT15C takes about 85 MJ of energy and emits 6 kg of CO₂ — more than 92% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
CT15C's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability good (60/100); formability poor (20/100).
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. CT15C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CT15C
Is CT15C easy to machine?
Machine with rigid setups, sharp carbide or ceramic tooling, slow speeds and heavy positive feeds to cut under the work-hardened skin; flood coolant essential.
Can CT15C be welded?
GTAW/SMAW with Ni-base (ERNiCr-3 / ENiCrFe-type) or matching Nb-bearing filler, low heat input, no preheat needed; solution anneal after major repair welds on pressure castings.
Can CT15C be formed, bent or molded?
Supplied as static or centrifugal castings; feed heavy sections generously and control Si/Nb to avoid interdendritic shrinkage — cold forming is not applicable.
CT15C 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 |
|---|---|---|
| C | 0.05 – 0.15 | 0.1 |
| Mn | 0.15 – 1.5 | 0.8 |
| Si | 0.5 – 1.5 | 1 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Cr | 19 – 21 | 20 |
| Ni | 31 – 34 | 32.5 |
| Nbcolumbium, carbide stabilizer | 0.5 – 1.5 | 1 |
| Fe | balance |
What surface finishes work on CT15C?
Sand/shot blast and pickle-passivate to restore the chromium oxide film; can be ground and polished, though the cast dendritic structure 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 CT15C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N08151
- Similar grades
- N08825
How much does CT15C cost?
CT15C 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.
CT15C — frequently asked
What is CT15C used for?
CT15C is typically used for chemical process pumps, valves for mixed-acid service and pollution control equipment. In short: cast Alloy 825 equivalent; mixed acid resistance; service to 1000 °C.
What is the yield strength of CT15C?
CT15C has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 96% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CT15C easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Machine with rigid setups, sharp carbide or ceramic tooling, slow speeds and heavy positive feeds to cut under the work-hardened skin; flood coolant essential.
Can CT15C be welded?
Yes — weldability is rated good (60/100). GTAW/SMAW with Ni-base (ERNiCr-3 / ENiCrFe-type) or matching Nb-bearing filler, low heat input, no preheat needed; solution anneal after major repair welds on pressure castings.
What surface finishes work on CT15C?
Sand/shot blast and pickle-passivate to restore the chromium oxide film; can be ground and polished, though the cast dendritic structure limits mirror finishes.
Can CT15C be formed, bent or molded?
Supplied as static or centrifugal castings; feed heavy sections generously and control Si/Nb to avoid interdendritic shrinkage — cold forming is not applicable.
What is the maximum service temperature of CT15C?
CT15C is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CT15C-SA and CT15C CC-SA?
SA is the default condition — standard supply condition for pressure-containing castings to ASTM A351/A743; best ductility and corrosion resistance. CC-SA: choose for tubes, sleeves and rings where the denser, more directional centrifugal structure gives higher strength and better soundness than static castings. Yield strength is 240 MPa in SA versus 260 MPa in CC-SA.
How much does CT15C cost?
CT15C 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 A351/A351M — Castings, Austenitic, for Pressure-Containing Parts — ASTM International (2018)
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant — ASTM International (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (heat- and corrosion-resistant castings) — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- UNS N08151 alloy designation data — SAE/ASTM Unified Numbering System (2019)
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.