Alloy C-276, UNS N10276, 2.4819 - otherwise hastelloy C-276, CrNiMo16-60-16, NiMo16Cr15Fe6W4 according to ASTM B462 and ISO 9722
Table of content:
| Standard | Grade | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical composition % | |||||||||||||
| Ni: | Mo: | Cr: | Fe: | W: | Co: | Mn: | V: | Si: | P: | S: | C: | Comments: | |
| ASTM, UNS | C-276, Alloy 276, W80276, Hastelloy C-276 | ||||||||||||
| Balance | 15.0-17.0 | 14.5-16.5 | 4.0-7.0 | 3.0-4.5 | <2.5 | <1.0 | <0.35 | <0.08 | <0.03 | <0.03 | <0.01 | <0.01 | |
| ISO | CrNiMo 15-60-16 | ||||||||||||
| Balance | 15.0-17.0 | 14.5-16.5 | 4.0-7.0 | 3.0-4.5 | <2.5 | <1.0 | <0.35 | <0.08 | <0.04 | <0.03 | <0.01 | Ni + Co > 52.0 | |
| ISO | NiMo16Cr15Fe6W4 | ||||||||||||
| Balance | 15.0-17.0 | 14.5-16.5 | 4.0-7.0 | - | <2.5 | <1.0 | <0.35 | <0.08 | <0.04 | <0.03 | <0.01 | <0.01 | |
| DIN | 2.4886, 2.4887, Sg-NiMo16Cr16W, EL-NiMo15Cr15W | ||||||||||||
| >50.0 | 15.0-17.0 | 14.5-16.5 | 4.0-7.0 | 3.0-4.5 | <1.0 | <1.0 | <0.4 | <0.08 | - | <0.015 | <0.02 | Ni: Ni + Co; ET < 0.5 | |
| DIN | 2.4537 | ||||||||||||
| >52.0 | 15.0-18.0 | 14.0-18.0 | <7.0 | 3.0-5.0 | - | <1.0 | - | <1.0 | <0.045 | <0.03 | <0.1 | Cu: <0.5 | |
| GOST | 02Ch15N60M16 | ||||||||||||
| Balance | 15.0-17.0 | 14.5-16.5 | 4.0-7.0 | - | <2.5 | <1.0 | <0.35 | <0.08 | <0.04 | <0.03 | <0.01 | Ni: Ni + Co | |
N10276, Alloy C-276, hastelloy c-276, CrNiMo 16-60-16, NiMo16Cr15Fe6W4 – description
Alloy C-276, known widely as N10276 or Hastelloy C-276 is one of the Nickel-Chronium-Molybdenum alloys, having nickel as the primary element. Like every other alloy in this family, it has exceptional heat and corrosion resistance properties.
History and composition - Alloy C-276 can be seen as an upgrade of Alloy C (N30002) with significantly reduced carbon and silicon content. Alloy C was used in the chemical processing industry for many years, but had to be replaced due to its significant limitations. Alloy C has to be solution treated to remove detrimental weld heat-affected zone (HAZ) precipitates. In oxidizing and chloride-containing environments it could be susceptible to intergranular corrosion, when used in the as-welded condition. Alloy C-276 was made to answer those problems and can be welded without introducing susceptibility to intergranular corrosion. Corrosion behaviour as well as further alterations of this alloy are discussed in further sections of this article.
Applications
Alloy C-276 is used in chemical processing, pollution control, pulp and paper production, industrial and municipal waste treatment, and the recovery of sour natural gas.
Applications include stack liners, ducts, dampers, scrubbers, stack-gas reheaters, fans, fan housings, heat exchangers, reaction vessels, evaporators, and transfer piping.
N10276 - physical and mechanical properties
Room temperature physical properties:
- Density: 8.9 g/cm3
- Linear expansion coefficient: 11.2 *10-6m/(m*K)
- Thermal conductivity: 9.8 W/(m*K)
- Specific heat capacity: 427 J/(kg*K)
- Young's modulus: 205 GPa
- Electrical resistivity: 1.3 μΩ*m
- Superconductor at -73°C (-100°F)
- Shear modulus: 79 GPa
- Melting temperature: 2415-2500 °C
Mechanical properties of N10276 / C-276 (solution annealed):
- Yield strength: > 283 MPa
- Tensile strength Rm: > 690 MPa
- Elongation: > 40 %
- Hardness: 90 HRB
Elastic modulus and temperature (average, in tension)
- In ambient temperature: 205 GPa
- 204°C: 195 GPa
- 316°C: 188 GPa
- 427°C: 182 GPa
- 538°C: 176 GPa
Coefficient of thermal expansion and temperature (linear):
- 24-93°C: 11.2 *10-6m/(m*K)
- 24-205°C: 12.0 *10-6m/(m*K)
- 24-315°C: 12.8 *10-6m/(m*K)
- 24-425°C: 13.2 *10-6m/(m*K)
- 24-540°C: 13.4 *10-6m/(m*K)
- 24-650°C: 14.1 *10-6m/(m*K)
- 24-760°C: 14.9 *10-6m/(m*K)
- 24-870°C: 15.9 *10-6m/(m*K)
- 24-925°C: 16.0 *10-6m/(m*K)
Thermal conductivity and temperature:
- -168°C: 7.2 W/(m*K)
- -73°C: 8.6 W/(m*K)
- -18°C: 9.4 W/(m*K)
- 38°C: 10.2 W/(m*K)
- 93°C: 11.1 W/(m*K)
- 205°C: 13.0 W/(m*K)
- 315°C: 15.0 W/(m*K)
- 425°C: 16.9 W/(m*K)
- 540°C: 19.0 W/(m*K)
- 650°C: 20.9 W/(m*K)
- 760°C: 23.0 W/(m*K)
- 870°C: 24.9 W/(m*K)
- 980°C: 26.7 W/(m*K)
- 1090°C: 28.2 W/(m*K)
Corrosion behaviour
N10276 has exceptional resistance to severe media, including reducing and oxidizing acids, highly oxidizing neutral and acid chlorides, solvents, formic and acetic acids, acetic anhydride, wet chlorine gas, hypochlorites and chlorine solutions.
Average corrosion rates:
- Hydrochloric acid HCl. 2%. boiling: 1.09 mm/rok
- Hydrochloric acid HCl. 3%. 66°C: <0.03 mm/rok
- Hydrochloric acid HCl. 5%. 66°C: 0.13-0.51 mm/rok
- Hydrochloric acid HCl. 10%. 66°C: 0.51 mm/rok
- Hydrochloric acid HCl. 15%. 66°C: 0.7 mm/rok
- Hydrochloric acid HCl. 15%. 93°C: 1.7 mm/rok
- Hydrochloric acid HCl. 15%. 121°C: 6.4 mm/rok
- Sulphuric acid H2SO4. 10%. boiling: 0.51 mm/rok
- Sulphuric acid H2SO4. 80%. 80°C: 0.58 mm/rok
- 10% H2SO4 + 2% HCl. wrzące: 3.51 mm/rok
- Nitric acid HNO3. 10%. wrzący: 0.41 mm/rok
- Phosphoric acid H3PO4. 30%. boiling: <0.13 mm/rok
- Phosphoric acid H3PO4. 85%. boiling: 0.13-0.64 mm/rok
- Acetic acid. 99%. boiling: 0.0076 mm/rok
- Formic acid. 88%. boiling: 0.03 mm/rok
- Ferric chloride. 10%. boiling: 0.05 mm/rok
Pitting - N10276 shows very high resistance to pitting in oxidizing chloride environments. The critical pitting temperature in 6% FeCl
Intergranular corrosion - low carbon and silicon content make C-276 much less susceptible to intergranular corrosion. This means a much slower rate of precipitation in this alloy, compared to those with higher carbon and silicon concentrations. It takes some 30 times longer for Alloy C-276 to develop precipitates, compared to Alloy C.
Hydrogen embrittlement - alloy C-276 resists sulfide stress cracking and stress-corrosion cracking in sour gas environments with hydrogen sulfide, carbon dioxide and chlorides.
Limitations - the corrosion resistance of alloy C-276 is somewhat hampered by the precipitation of an intermetallic compound of tungsten and molybdenum. The alloy is especially susceptible to μ-phase formation when exposed to temperatures ranging from 650 to 1095 °C.
Weldability
Weldability - the alloy belongs to group 43 according to ISO 15608. For brazing, the p-number is equal to 111, according to ASME/AWS.
Selection of welding consumables for Alloy C-276
- Coated electrodes: ENiCrMo3
- Filler metals: ERNiCrMo-4 through -10
A nitrogen blanket is important to strengthen the welds. The corrosion rate of welded alloy C-276 in 70% HF equals:
- Nitrogen blanket: 0.008 mm/year
- Oxygen blanket: 0.94 mm/year
Heat treatment and working
Recommended working and heat treatment parameters for C-276 alloy:
- Solution annealing: 1107-1135 °C
We deliver this steel alloy as:
- Forgings
- Wires
- Bars
- Strips
- Sheets
- Plates
Replacements, equivalents and other designations:
C-276, N10276, AL276, Nickelvac C-276, Unitemp HN, Inconel alloy C-276, 02Ch15N60M16, EP375, CrNiMo15-60-16, NiMo16Cr15, NiMo16Cr15C, 2.4886, SG-NiMo16Cr16W, 2.4887, EL-NiMo15Cr15W, NiMo16CrW, 2.4537, NA48, NiMo16Cr15Fe6W, DNiCrMo-4, DNiCrMo-5, YNiCrMo-4, Alloy C-276, Bohler L276, VRC 279, HGH3113, NS333, NS334, Ch15N55M16V, Nistelle C-276 Deloro, Hastelloy C-276, Phyweld 276, SY 276, W80276,
Variants of C-276 with different chemical composition, properties and applications:
- N06455 / Alloy C-4 - improved thermal stability.
- N06022 / Alloy C-22 - better resistance to chloride-induced localized corrosion and sulfide stress cracking.
- N06059 / Alloy 59 - better resistance to corrosion
- C06200 / Alloy C-2000 - improved corrosion resistance in sulfuric acid and reducing media