Hangbo Alloy Group
Shanghai · Est. 2012
UNS N02201 / W.Nr. 2.4068 — Low-carbon commercially pure nickel with superior caustic resistance and high-temperature stability, eliminating graphitization risk above 315°C.
Nickel 201 (UNS N02201 / W.Nr. 2.4068) is the low-carbon version of Nickel 200, with carbon content strictly controlled to 0.02% maximum. This reduction in carbon eliminates the risk of graphitization — the precipitation of carbon as graphite particles at temperatures above 315°C (600°F) — which can cause embrittlement and loss of integrity in standard-purity nickel. As a result, Nickel 201 is the preferred choice for high-temperature caustic soda (NaOH) production, food processing equipment, and any application where the material will be exposed to elevated temperatures in corrosive media.
The alloy consists of at least 99.0% nickel, with careful control of impurities such as iron, manganese, silicon, copper, and carbon. This high purity gives Nickel 201 exceptional resistance to a wide range of corrosive environments, particularly concentrated caustic alkalis at all concentrations and temperatures. It also offers excellent mechanical properties at both cryogenic and elevated temperatures, good thermal and electrical conductivity, and outstanding magnetostrictive properties that make it valuable in electronic and instrumentation applications.
Nickel 201 is produced by induction melting followed by refining to achieve the high purity required. It is typically supplied in the annealed condition, which optimizes ductility and formability. The alloy can be readily formed by cold working operations including bending, drawing, and pressing. Welding is performed using gas tungsten arc welding (GTAW) with matching filler metal ERNi-1, and the low carbon content minimizes the risk of carbide precipitation in the heat-affected zone.
At Hangbo Alloy Group, Nickel 201 is supplied in plate, sheet, strip, round bar, forging stock, and seamless tubing forms, all with full mill test reports and third-party inspection available. We serve customers in chemical processing, food manufacturing, electronics, and energy industries with reliable quality and competitive lead times.
Nickel 201 is specified with very high minimum nickel content and tightly controlled carbon to prevent graphitization. The chemistry is essentially the same as Nickel 200 except for the carbon limit, which is reduced from 0.15% maximum to 0.02% maximum.
| Element | Min % | Max % |
|---|---|---|
| Nickel (Ni) | 99.0 | — |
| Carbon (C) | — | 0.02 |
| Manganese (Mn) | — | 0.35 |
| Iron (Fe) | — | 0.40 |
| Sulfur (S) | — | 0.01 |
| Silicon (Si) | — | 0.35 |
| Copper (Cu) | — | 0.25 |
Nickel 201 retains the outstanding physical properties of pure nickel: high thermal conductivity, excellent electrical conductivity, and good ductility from cryogenic temperatures up to moderately elevated temperatures. Its coefficient of thermal expansion is significantly lower than that of ferritic or austenitic stainless steels, making it advantageous in applications with thermal cycling.
| Property | Value | Unit |
|---|---|---|
| Density | 8.89 | g/cm³ |
| Melting Range | 1435 – 1446 | °C |
| Specific Heat (21°C) | 456 | J/kg·K |
| Thermal Conductivity (21°C) | 70 | W/m·K |
| Electrical Resistivity (21°C) | 0.085 | μΩ·m |
| Modulus of Elasticity (21°C) | 207 | GPa |
| Mean CTE (21–93°C) | 13.3 | μm/m·°C |
| Curie Temperature | 360 | °C |
Nickel 201 is typically supplied in the annealed condition per ASTM B160. The annealed temper provides the best combination of ductility, formability, and corrosion resistance. Cold working significantly increases strength and hardness but reduces ductility, which can be restored by annealing at 700–900°C depending on Section thickness and desired grain size.
| Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| Annealed (Plate/Sheet) | 380 – 520 | 110 – 340 | 40 – 55 |
| Annealed (Bar) | 345 – 655 | 110 – 345 | 40 – 50 |
| 1/4 Hard | 400 – 550 | 275 – 415 | 25 – 40 |
| 1/2 Hard | 480 – 620 | 415 – 550 | 15 – 30 |
| Full Hard | 620 – 860 | 550 – 790 | 5 – 15 |
The defining advantage of Nickel 201 over Nickel 200 is its resistance to graphitization at elevated temperatures. In standard-purity nickel (0.10–0.15% C), carbon can precipitate as graphite particles when the material is held above approximately 315°C (600°F) for extended periods. These graphite particles create weak interfaces that can lead to intergranular cracking under stress.
By limiting carbon to 0.02% maximum, Nickel 201 suppresses graphite formation and maintains its ductility and strength even after long-term exposure to temperatures up to approximately 1230°C (2250°F) in intermittent service, or up to 600°C (1110°F) in continuous service. This makes Nickel 201 the correct choice for:
At elevated temperatures, Nickel 201 retains useful strength up to approximately 600°C in continuous service. Above this temperature, oxidation becomes the limiting factor, although the alloy forms a protective nickel oxide scale that provides reasonable protection in air up to approximately 980°C for intermittent exposure.
Nickel 201 offers the same excellent corrosion resistance as Nickel 200, with the added advantage of high-temperature stability. Its corrosion performance is governed by the formation of a stable, adherent surface oxide film that protects the underlying metal in many oxidizing and reducing environments.
Nickel 201 is specified wherever high-purity nickel is required in a corrosive environment at elevated temperature, particularly where caustic alkalis are present.
Hangbo Alloy Group supplies Nickel 201 in a full range of product forms with material test reports and third-party inspection available on request.
| Standard | Description |
|---|---|
| ASTM B160 | Rod and Bar |
| ASTM B161 | Seamless Pipe and Tube |
| ASTM B162 | Plate, Sheet, and Strip |
| ASTM B163 | Seamless Condenser and Heat Exchanger Tubes |
| ASME SB-160 / SB-163 | Boiler and Pressure Vessel Code |
| AWS A5.14 | Welding Wire (ERNi-1) |
| DIN 17740 | Ni 99.2 (W.Nr. 2.4068) |
The primary selection criterion between Nickel 200 and Nickel 201 is service temperature. For service below approximately 315°C (600°F), Nickel 200 is typically adequate and more economical. For service above 315°C, or where the material will be heated into that range during fabrication or operation, Nickel 201 is mandatory to avoid graphitization. For cryogenic service (down to −250°C), either grade may be used, with Nickel 201 offering slightly better toughness retention after high-temperature exposure.
Hangbo Alloy Group maintains mill-direct supply of Nickel 201 plates, sheets, bars, tubes, and welding wire. Our technical team can assist with material selection, formability guidance, welding procedure review, and export documentation. We support chemical processing, food manufacturing, electronics, and energy industry customers with short lead times and reliable quality.
For quotations, material certifications, or technical consultation, contact our sales team or call +86-136-1165-6360. We typically respond within 10 minutes.
Request a quotation for Nickel 201 plates, bars, tubes, or welding wire. Low carbon purity for high-temperature caustic service.