1. Panimula
Nikel 201 (UNS N02201) is a commercially pure nickel alloy that is widely recognized for its exceptional corrosion resistance, excellent thermal stability, and outstanding formability.
Specified under ASTM B162 for plate, Sheet, at hubad, Nikel 201 is essentially a low-carbon variant of Nickel 200.
The reduction in carbon content significantly enhances its resistance to intergranular embrittlement and maintains mechanical integrity at elevated temperatures.
Its combination of purity, ductility, and high corrosion resistance makes it an essential material in chemical processing, mga kapaligiran sa dagat, Mga aplikasyon ng aerospace, and high-temperature industrial operations.
2. What Is ASTM B162 N02201 Nickel Alloy?
ASTM B162 N02201, Karaniwang kilala bilang Nikel 201, is a commercially pure nickel alloy standardized for Plato, Sheet, and strip products.
It is essentially a low-carbon version of Nickel 200, with the carbon content reduced to a maximum of 0.02 wt% to enhance resistance to intergranular kaagnasan at thermal embrittlement during high-temperature service.
Nikel 201 is characterized by:
- High purity nickel content (≥99 wt%), ensuring excellent corrosion resistance in neutral, alkalina, and mildly oxidizing environments.
- Mababang carbon na nilalaman, which prevents the formation of nickel carbides at grain boundaries, maintaining ductility and toughness during prolonged heat exposure.
- Mahusay na kakayahang umangkop, making it suitable for deep drawing, Pag-ikot, and complex fabrication operations.
- Superior thermal stability, allowing continuous operation at elevated temperatures without significant loss of mechanical properties.
3. Chemical Composition of Nickel 201
Nikel 201 (UNS N02201) ay isang commercially pure nickel alloy with carefully controlled impurities and a low carbon content to improve high-temperature performance and corrosion resistance.
The chemical composition is standardized under ASTM B162 to ensure consistent properties for industrial applications.
| Elemento | Tipikal na Nilalaman (wt%) | Mga Tala |
| Nikel (Ni) | ≥ 99.0 | Batayang elemento, ensures corrosion resistance and ductility |
| Carbon (C) | ≤ 0.02 | Low carbon content reduces carbide formation, preventing intergranular corrosion |
| Bakal na Bakal (Fe) | ≤ 0.40 | Residual, minor influence on corrosion resistance |
| Tanso (Cu) | ≤ 0.25 | Impurity level, can slightly improve corrosion resistance in specific environments |
| Mga mangganeso (Mn) | ≤ 0.10 | Minor impurity, minimal effect on mechanical properties |
| Silicon (Si Si) | ≤ 0.10 | Residual element, contributes minimally to oxidation resistance |
| Sulfur (S) | ≤ 0.01 | Controlled to avoid embrittlement and maintain ductility |
| Posporus (P) | ≤ 0.01 | Low phosphorus ensures good toughness and weldability |
Mga Pangunahing Pananaw:
- Nickel Dominance: Higit sa 99 wt% nickel ensures excellent chemical stability in corrosive media.
- Mababang Carbon: The ≤0.02 wt% carbon prevents the precipitation of nickel carbides at grain boundaries during prolonged high-temperature service, which is critical for stress corrosion resistance.
- Controlled Impurities: Elements like iron, tanso, and manganese are kept at minimal levels to balance cost, paglaban sa kaagnasan, at mekanikal na pagganap.
4. Physical Properties of UNS N02201
| Pag-aari | Halaga |
| Densidad ng katawan | 8.89 g/cm³ |
| Melting range | 1435–1446 °C |
| Thermal kondaktibiti | 90 W/m·K |
| Electrical resistivity | 7 μΩ·cm |
| Magnetic permeability | Slightly magnetic below 354 °C (Curie point) |
| Coefficient of thermal expansion | 13.3 μm/m·°C (20-100 ° C) |
5. Mechanical Properties of Nickel 201
Nikel 201 (UNS N02201) exhibits a combination of katamtamang lakas, Mahusay na ductility, at tigas na tigas, making it a versatile material for demanding industrial applications.
| Pag-aari | Tipikal na Halaga | Test Condition / Mga Tala |
| Lakas ng Paghatak (σᵤ) | 480–620 MPa (70–90 ksi) | Annealed condition |
| Yield Lakas (σ₀.₂) | 150–275 MPa (22–40 ksi) | 0.2% Offset |
| Pagpapahaba (A₅₀) | 30–50 % | Measured on 50 mm gauge length |
| Reduction of Area (RA) | 55–65 % | Indicates ductility and toughness |
| Ang katigasan ng ulo (HRB) | 70–100 | Rockwell B scale, annealed condition |
| Lakas ng Paggupit | ~ 310 MPa | Typical value for wrought product |
| Modulus ng Pagkalastiko (E) | 200 GPa | Comparable to structural steels |
| Ratio ng Poisson | 0.31 | Standard for nickel alloys |
Key Mechanical Characteristics:
- Ductility: Nikel 201 can undergo significant plastic deformation before failure, making it suitable for forming, pagbaluktot, and deep-drawing operations.
- Tigas na tigas: Maintains excellent fracture toughness over a wide temperature range, from cryogenic conditions to approximately 600 °C.
- Work Hardening: Can be strengthened through cold working, providing flexibility in design for mechanical components.
- Paglaban sa Pagkapagod: High ductility and low impurity levels contribute to good fatigue performance in cyclic loading environments.
6. Paglaban sa kaagnasan & Temperature Performance
Nikel 201 (UNS N02201) is highly regarded for its pambihirang paglaban sa kaagnasan at thermal katatagan, especially in environments containing neutral and reducing chemicals.
Its performance is superior to many commercial metals due to its high nickel purity (≥ 99.5%) at mababa ang carbon content (< 0.02%), which prevent sensitization and carbide precipitation at elevated temperatures.
Paglaban sa kaagnasan
Nikel 201 demonstrates resistance to a wide range of corrosive agents, making it a material of choice for pagproseso ng kemikal, marine, and high-purity applications.
| Kapaligiran | Corrosion Behavior | Comments |
| Caustic Alkalis (NaOH, KOH) | Napakahusay | Minimal corrosion even at boiling temperatures; used for caustic evaporators and heat exchangers. |
| Neutral & Reducing Salts | Napakahusay | Stable in neutral chloride, sulfate, and nitrate environments. |
| Mga Acid (Hydrochloric, Sulfuric) | Katamtaman hanggang Mabuti | Resistant in dilute concentrations; corrosion increases with higher acidity and temperature. |
| Oxidizing Environments (Nitric acid, Halogens) | Mga Maralita | Not suitable for strong oxidizing acids or halogen gases; Nikel 200/201 are prone to attack. |
| Tubig dagat & Brine | Mabuti na lang | Performs well under stagnant and flowing conditions but not as well as copper-nickel alloys in high-velocity seawater. |
| Organic Compounds (Acetic, Formic acids) | Napakahusay | Stable under most organic acid exposure, making it ideal for process equipment in the chemical industry. |
Mechanism of Resistance:
Nickel 201’s corrosion resistance is derived from the formation of a manipis, adherent oxide film sa ibabaw nito, which passivates the metal and inhibits further attack.
Its low carbon content prevents intergranular kaagnasan, ensuring longevity in thermal cycling or welding environments.
Temperature Performance
Nikel 201 retains mechanical integrity and chemical stability across a wide temperature spectrum, mula sa cryogenic to moderate high-temperature mga kondisyon.
| Saklaw ng Temperatura | Behavior | Mga Karaniwang Aplikasyon |
| −200 °C to 0 °C | Outstanding toughness and ductility | Cryogenic storage vessels, liquid gas handling systems |
| Ambient to 300 °C | Maintains strength and corrosion resistance | Chemical and food processing equipment |
| 300 °C sa 600 °C | Stable against graphitization (unlike Nickel 200) | Mga heat exchanger, furnace components |
| > 600 °C | Gradual reduction in strength; risk of oxidation increases | Limited use, protective coatings recommended |
Key Advantage Over Nickel 200:
Nickel 201’s lower carbon level (< 0.02%) significantly improves its graphitization resistance, enabling safe operation up to 600 °C without embrittlement—whereas Nickel 200 Karaniwan itong limitado sa 315 °C.
7. Gawa-gawa, Pagbuo ng, and Heat Treatment
Nikel 201 (UNS N02201) is highly valued in the fabrication industry for its napakahusay na formability, weldability, at thermal katatagan.
Its low carbon content (< 0.02 %) makes it less susceptible to carbide precipitation during heating, which enhances its workability and resistance to intergranular corrosion during forming and welding.
Fabrication and Machinability
Nikel 201 maaaring maging readily fabricated using conventional methods employed for austenitic stainless steels and other high-nickel alloys.
| Fabrication Process | Mga Katangian | Mga Pinakamahusay na Kasanayan |
| Machining | Produces clean surfaces with moderate tool wear; slightly harder than copper but softer than most steels. | Gamitin ang high-speed steel (HSS) o Mga Tool na may Carbide-Tipped, mababang bilis ng pagputol (15–25 m/min), and generous lubrication. |
| Pagbuo ng | Excellent ductility in both hot and cold conditions; minimal risk of cracking. | Perform cold working at room temperature for precision forming. For heavy forming, gamitin ang hot working between 870–1230 °C. |
| Shearing / Pagsuntok | Easy to cut and punch due to moderate hardness (~70–85 HRB). | Use sharp tools and adequate clearance to prevent edge tearing. |
| Pagbubuo ng mga | Uniform grain structure maintained during hot working. | Heat gradually to 1150–1230 °C, finish forging above 870 °C, Sinundan ng mabilis na paglamig. |
Machinability Index:
Nickel 201’s machinability is rated at 20–25 % of free-cutting steel (AISI 1212), reflecting the need for sharp tools, controlled speeds, and consistent cooling to avoid work hardening.
Forming Characteristics
Nickel 201’s high ductility and moderate strength make it ideal for deep drawing, Pag-ikot, and bending operations.
- Malamig na Pagbuo: The alloy shows minimal spring-back and strain hardening; post-forming annealing restores ductility.
- Mainit na Pagbuo: Effective between 870–1230 °C. Work should not be done below 870 °C to prevent surface cracking.
- Annealing Requirement: After heavy deformation or cold reduction (> 15 %), annealing is recommended to relieve internal stress.
Typical Forming Applications:
- Heat exchanger tubing
- Caustic evaporator trays
- Chemical process vessels
Welding
Nikel 201 mga exhibit mahusay na weldability using most conventional processes:
- Preferred methods: GTAW (TIG), GMAW (MIG), SMAW, and resistance welding.
- Filler metals: Commonly Nikel 201 (ERNi-1) o Nikel 200 filler rods are used.
- Precautions:
-
- Preheating is not required.
- Post-weld heat treatment is opsyonal unless required for dimensional control.
- Avoid excessive heat input to prevent grain growth and oxidation.
Typical weld performance:
Tensile strength of welded joints remains at ≥ 90 % of the base metal, and corrosion resistance is largely unaffected if proper shielding is maintained.
Paggamot ng Heat
Heat treatment of Nickel 201 is primarily used to restore ductility, relieve internal stress, and refine grain structure after fabrication.
| Heat Treatment Type | Saklaw ng Temperatura | Cooling Method | Layunin |
| Annealing | 650-900 ° C | Air or water cooling | Relieves strain from cold work, restores ductility |
| Nakakawala ng stress | 480-650 ° C | Air cooling | Reduces residual stress after machining or welding |
| Solusyon sa Pagsusubo | 760–870 °C | Mabilis na pag-quenching | Ensures uniform microstructure and corrosion resistance |
Caution:
Avoid prolonged exposure above 600 °C in impure atmospheres to prevent surface oxidation and contamination.
8. Mga kalamangan & Limitations of Nickel 201 Nickel haluang metal
Nikel 201 (UNS N02201) ay isang commercially pure wrought nickel designed to offer superior performance in chemically aggressive and high-temperature environments.
Advantages of Nickel 201
Nickel 201’s unique blend of chemical purity, ductility, and metallurgical stability make it one of the most reliable materials for demanding industrial use.
| Kategorya | Advantage | Technical Explanation / Benepisyo |
| Paglaban sa kaagnasan | Excellent resistance to caustic alkalis, neutral salts, and dry gases. | Particularly resistant to sodium hydroxide, potasa hydroxide, and anhydrous ammonia—nickel oxide film formation provides durable passivation. |
| Thermal katatagan | Retains mechanical properties up to ~600 °C. | Unlike Nickel 200, which suffers graphitization above 315 °C, Nickel 201’s reduced carbon (< 0.02 %) prevents carbide precipitation and intergranular embrittlement. |
| Fabrication and Formability | Outstanding cold- and hot-working characteristics. | Can be easily drawn, spun, deep-formed, or forged without cracking; minimal work-hardening compared to stainless steels. |
| Weldability | Excellent weldability with gas tungsten arc (GTAW), gas metal arc (GMAW), and resistance methods. | Weld joints retain up to 90–95 % of base-metal strength and corrosion resistance when proper filler (ERNi-1) is used. |
Mga de koryenteng & Thermal kondaktibiti |
High electrical conductivity (~ 22 % IACS) at thermal kondaktibiti (~61 W/m·K). | Ideal for electrical components, heating elements, and conductive chemical equipment. |
| Mga Katangian ng Magnetic | Non-magnetic in annealed condition. | Suitable for sensitive magnetic and instrumentation environments. |
| Purity and Cleanliness | > 99.6 % Ni content ensures minimal contamination in high-purity processes. | Used in semiconductor, pagkain, and pharmaceutical industries where metallic contamination must be avoided. |
| Resistance to Reducing Environments | Stable in hydrogen and CO₂ atmospheres. | Maintains ductility and mechanical integrity even during exposure to reducing gases. |
Limitations of Nickel 201
Despite its excellent characteristics, Nikel 201 ay not a universal alloy. Its use is limited by mechanical and environmental factors that must be carefully evaluated during material selection.
| Kategorya | Limitasyon | Explanation / Pagbawas |
| Lakas ng Mekanikal | Relatively low yield strength (~60–90 MPa at room temperature). | Not suitable for heavy structural applications; often reinforced with external supports or cladding. |
| Paglaban sa oksihenasyon | Moderate resistance in air above 600 °C. | Prolonged exposure at high temperatures causes surface oxidation and scaling; protective coatings recommended. |
| Gastos | Higher cost than carbon steel or stainless steel. | Justified only in highly corrosive or purity-critical environments. |
Sulfur & Halide Sensitivity |
Susceptible to attack in sulfur-containing or halogen environments (hal., Cl₂, HCl, SO₂). | Avoid use in chlorinated or sulfur-bearing atmospheres; select Nickel Alloy 600 or Alloy 625 sa halip. |
| Work Hardening | Work-hardens during cold forming. | Requires intermediate annealing for extensive deformation. |
| Limited High-Temperature Strength | Loses tensile strength rapidly above 650 °C. | Use Nickel-based superalloys (hal., Inconel 600, Hastelloy C-22) for high-stress or elevated-temperature applications. |
9. Applications of ASTM B162 N02201
Nikel 201 is widely used in industries that demand corrosion resistance and formability:
- Pagproseso ng kemikal: caustic soda evaporators, alkaline tanks
- Marine mga aplikasyon: seawater equipment, offshore components
- Mga heat exchanger & Mga Condenser
- Aerospace: spinning and drawn components
- Mga daluyan ng presyon & Mga boiler requiring low-carbon, Mga materyales na lumalaban sa kaagnasan
10. Comparison to Similar Nickel Alloys
Nikel 201 (UNS N02201) is part of a family of commercially pure nickel alloys that also includes Nikel 200 (UNS N02200) and several mga haluang metal na nakabatay sa nickel tulad ng haluang metal 400 (Monel 400), haluang metal 600 (Inconel 600), at haluang metal 625 (Inconel 625).
Comparative Table – Nickel 201 mga bes. Other Nickel Alloys
| Pag-aari / Tampok | Nikel 200 (UNS N02200) | Nikel 201 (UNS N02201) | Monel 400 (UNS N04400) | Inconel 600 (UNS N06600) | Inconel 625 (UNS N06625) |
| Nominal na komposisyon (wt%) | Ni ≥ 99.5, C ≤ 0.15 | Ni ≥ 99.6, C ≤ 0.02 | Ni ~ 66, Cu ~ 31, Fe ~ 2 | Ni ~ 72, Cr ~ 15.5, Fe ~ 8 | Ni ~ 61, Cr ~ 21.5, Mo ~ 9, Nb + Ta ~ 3.6 |
| Saklaw ng Pagtunaw (°C) | 1435–1446 | 1435–1446 | 1300–1350 | 1354–1413 | 1290–1350 |
| Max Service Temp (°C) | Hanggang sa 315 °C | Hanggang sa 600 °C | Hanggang sa 550 °C | Hanggang sa 1100 °C | Hanggang sa 982 °C (creep-resistant) |
| Densidad ng katawan (g/cm³) | 8.89 | 8.89 | 8.80 | 8.47 | 8.44 |
| Lakas ng Paghatak (MPa, annealed na nga ba) | ~ 370 | ~ 380 | ~ 550 | ~ 655 | ~ 827 |
| Yield Lakas (MPa, 0.2% Offset) | ~ 105 | ~ 100 | ~ 240 | ~ 240 | ~ 414 |
| Pagpapahaba (%) | 45 | 45 | 35 | 40 | 30 |
| Paglaban sa kaagnasan | Excellent in alkalis; moderate in acids | Excellent in alkalis; improved at high T | Excellent in seawater, hydrofluoric acid | Excellent in oxidizing & reducing media | Outstanding in oxidizing, pagbabawas, and chloride environments |
| Weldability / Formability | Napakahusay | Napakahusay | Mabuti na lang | Mabuti na lang | Katamtaman (pagpapatigas ng trabaho) |
| Primary Use Cases | Low-temperature caustic systems, pagproseso ng pagkain | High-temperature caustic service, chemical purity systems | Marine, pump shafts, HF acid service | Mga heat exchanger, furnace tubes, nuclear reactors | Aerospace, chemical process, Tubo ng tubig dagat |
11. Pangwakas na Salita
Nikel 201 (UNS N02201) under ASTM B162 is a high-purity, low-carbon nickel alloy offering excellent corrosion resistance, thermal katatagan, at pagiging formable.
It is especially suited for chemical, marine, aerospace, and high-temperature applications where low carbon is critical to prevent intergranular embrittlement.
While mechanical strength is moderate, its durability, pagiging maaasahan, and fabrication versatility make it a preferred material in demanding industrial environments.
Mga FAQ
What is the difference between ASTM B162 N02201 and N02200?
The primary difference is carbon content: N02201 has a maximum carbon of 0.02% (mga bes. 0.15% for N02201? No—correct: N02200 has 0.15% max C).
N02201’s low C enhances weldability and intergranular corrosion resistance, making it better for welded joints and cryogenics. N02200 is lower cost for non-welded applications.
What is the maximum service temperature for N02201?
N02201 can operate continuously at up to 600°C (1112°F) while retaining >40% pagpapahaba. Above 600°C, tensile strength decreases rapidly, limiting use to intermittent exposure.
Is N02201 weldable?
Yes—N02201 is readily weldable via GTAW (TIG) at GMAW (MIG) using N02201 filler metals (ERNi-1/ENi-1).
Post-weld heat treatment is not required for most applications due to low carbon content.
How does N02201 perform in seawater?
N02201 exhibits excellent seawater corrosion resistance, with a corrosion rate <0.02 mm/year—superior to 304 hindi kinakalawang na asero (0.1 mm / taon). It is ideal for marine cooling systems.
What certifications does N02201 hold for food contact?
N02201 complies with FDA 21 CFR Part 177.2600 (food contact) and EU Regulation (EC) Hindi.
1935/2004, making it safe for food and pharmaceutical processing equipment.
Can N02201 be used in cryogenic applications?
Yes—N02201 retains high ductility (pagpapahaba >40%) at temperatures as low as -253°C (liquid hydrogen boiling point), making it suitable for cryogenic fuel tanks and superconducting systems.
