Nickel 201 is the low-carbon version of commercially pure (99.0% minimum) wrought nickel, developed specifically for service at elevated temperatures where the standard grade would embrittle. This datasheet presents the material within the trade-name designation system.
It is essentially identical to Nickel 200 but with the maximum carbon content reduced to 0.02% (versus 0.15%). This low carbon level gives virtual immunity to intergranular embrittlement from grain-boundary graphite precipitation above about 315 °C (600 °F), so the grade is preferred over Nickel 200 for all sustained service above this temperature. The reduced carbon also lowers the base hardness and work-hardening rate and raises ductility, making the material particularly well suited to spinning and severe cold forming.
It retains the outstanding resistance of pure nickel to caustic alkalies (up to and including the molten state), good resistance in acid, alkaline and neutral salt solutions, and excellent resistance to chloride-ion stress-corrosion cracking. It is ferromagnetic with high thermal and electrical conductivity. In dry chlorine and hydrogen chloride it may be used to about 550 °C. Typical applications include caustic evaporators, food-processing equipment, chemical shipping drums, electronic and electroplating components, combustion boats, rocket-motor cases and magnetostrictive devices. The presence of chlorates should be kept to a minimum, as they accelerate attack.
Values per Special Metals official datasheet, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.89 | g/cm³ |
| Melting range | 1435–1446 | °C |
| Young's modulus (20 °C) | 204 | GPa |
| Specific heat capacity (20 °C) | 456 | J/kg·K |
| Thermal conductivity (20 °C) | 79.3 | W/m·K |
| Electrical resistivity (20 °C) | 0.085 | µΩ·m |
| Coefficient of thermal expansion (20–100 °C) | 13.3 | µm/m·°C |
| Curie temperature | ~360 | °C |
| Magnetic response | Ferromagnetic | — |
| Recommended service temperature | >315 (preferred over Nickel 200) | °C |
Limiting composition per ASTM B160 (UNS N02201).
| Element | Symbol | Min % | Max % | Role / Note |
|---|---|---|---|---|
| Nickel (+ Cobalt) | Ni | 99.0 | — | Commercially pure base; corrosion + conductivity |
| Carbon | C | — | 0.02 | Low carbon — prevents graphitisation above 315 °C (key vs Nickel 200) |
| Manganese | Mn | — | 0.35 | Deoxidiser |
| Iron | Fe | — | 0.40 | Residual |
| Sulphur | S | — | 0.01 | Residual impurity |
| Silicon | Si | — | 0.35 | Deoxidiser |
| Copper | Cu | — | 0.25 | Residual |
Note: this is the low-carbon variant of commercially pure nickel; the only specification difference from Nickel 200 is the maximum carbon level (0.02% vs 0.15%).
Typical room-temperature properties, annealed condition.
| Property | Value | Source |
|---|---|---|
| Ultimate tensile strength | 345–540 MPa | Annealed (lower than Nickel 200) |
| 0.2% proof strength (yield) | 80–180 MPa | Annealed |
| Elongation at break | 40–50 % | Annealed |
| Hardness | ~35–55 HRB | Annealed (lower base hardness than Nickel 200) |
The lower carbon content reduces base hardness and work-hardening rate and increases ductility, making the grade especially suitable for spinning and deep drawing. Values are typical; confirm against the mill test certificate for each delivery.
| Environment | Performance | Notes |
|---|---|---|
| Caustic soda (NaOH, incl. molten) | Outstanding | Resists up to and including the molten state |
| Alkaline solutions | Excellent | High nickel content |
| Neutral / reducing salt solutions | Very Good | Non-oxidising salts |
| Dry chlorine / hydrogen chloride | Very Good | Usable to ~550 °C |
| Intergranular attack (>315 °C) | Outstanding | Virtually immune (low carbon) — key advantage |
| Chloride stress-corrosion cracking | Outstanding | High nickel content |
| Mineral acids | Variable | Better de-aerated; depends on conc./temp. |
| Oxidising salts / oxidising acids | Poor | Severe attack — avoid; keep chlorates to a minimum |
Low-carbon commercially pure nickel; strengthened only by cold work (not age-hardenable). Heat treatment is for annealing / stress relief.
Anneal Temperature: 704–871 °C (1300–1600 °F), time depending on section and prior cold work Purpose: softening and recrystallisation after cold work.
Key advantage: because of the low carbon content (0.02% max), Nickel 201 is virtually immune to grain-boundary graphitisation and intergranular embrittlement above ~315 °C, and is therefore the grade of choice for sustained elevated-temperature service where Nickel 200 would degrade.
Readily joined by welding, brazing and soldering — easily welded and processed. The low carbon content is beneficial for elevated-temperature welded service.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG · GMAW / MIG | Excellent | AWS A5.14 ERNi-1 (matching nickel filler) |
| SMAW / stick | Good | AWS A5.11 ENi-1 |
| Brazing / soldering | Suitable | Appropriate brazing alloys |
Clean joints thoroughly before welding; avoid sulphur-bearing marking materials and lubricants, which embrittle nickel at temperature.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Condition | Lower base hardness than Nickel 200; machine cold-drawn or stress-relieved |
| Work hardening | Lower work-hardening rate than Nickel 200 |
| Coolant | Flood coolant recommended |
Forming Processes
| Process | Notes |
|---|---|
| Hot working | 649–1232 °C; heavy forming above 871 °C |
| Cold forming | Excellent — low hardness/work-hardening rate ideal for spinning and deep drawing |
| Annealing | 704–871 °C after heavy cold work |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Chemical processing | Caustic evaporators (esp. >315 °C), reactors, piping, shipping drums | Caustic + elevated-temperature service |
| Food processing | Equipment for foods, fatty acids, fruit juices | Corrosion resistance + non-contamination |
| Electrical / electronics | Electronic components, electroplating hardware, magnetostrictive devices | High conductivity; ferromagnetic |
| Aerospace | Rocket-motor cases, missile components | Strength + corrosion resistance |
| Chlor-alkali | Combustion boats, plater bars, dry-halogen handling (to 550 °C) | Caustic + dry-halogen resistance |
| Hydrocarbon chlorination | HCl production, chlorination of benzene/methane/ethane | Reducing-environment resistance |
| Product Form | ASTM Standard | ASME Code |
|---|---|---|
| Rod and bar | ASTM B160 | ASME SB-160 |
| Plate, sheet and strip | ASTM B162 | ASME SB-162 |
| Seamless pipe and tube | ASTM B161 / B163 / B829 | ASME SB-161 / SB-163 |
| Welded pipe / tube | ASTM B725 / B730 | ASME SB-725 / SB-730 |
| Forgings | ASTM B564 | ASME SB-564 |
| Wire | ASTM B160-related | — |
| Welding consumables | AWS A5.14 ERNi-1 · AWS A5.11 ENi-1 | — |
Low-carbon commercially pure wrought nickel. UNS N02201; SAE AMS 5553; ASME Boiler Code Sections III, VIII, IX.
| Grade | Ni % | Key Element | Type | Best Used For |
|---|---|---|---|---|
| Nickel 201 | ≥99.0 | C ≤0.02 | Low-carbon | Caustic/alkali ABOVE 315°C (no graphitisation) |
| Nickel 200 | ≥99.0 | C ≤0.15 | Standard | Caustic/alkali to 315°C; conductivity |
| Monel 400 | 63–70 | Cu 28–34 | Ni-Cu | Seawater, HF, reducing acids |
| Inconel 600 | ≥72 | Cr 14–17 | Ni-Cr-Fe | High-temperature oxidation to 1095°C |
| Nickel 205 | ≥99.0 | C ≤0.15, Mg/Ti | Electronic | Electronic/electrical (controlled Mg/Ti) |




