Hastelloy Alloy C-22 emerges as the most advanced evolution in nickel-chromium-molybdenum-tungsten superalloy technology, offering superior resistance to localized corrosion and stress corrosion cracking in the most challenging industrial environments. We at MWalloys have witnessed this exceptional material revolutionize applications in nuclear waste processing, desalination systems, and advanced chemical manufacturing where traditional superalloys reach their performance limits. With its optimized composition featuring 22% chromium, 13% molybdenum, and 3% tungsten within a nickel matrix, C-22 delivers unprecedented resistance to pitting, crevice corrosion, and general attack in chloride-rich environments at elevated temperatures. The alloy's exceptional thermal stability and fabrication versatility make it the material of choice for critical infrastructure projects including high-level radioactive waste storage, seawater desalination plants, and pharmaceutical manufacturing facilities where material failure carries catastrophic consequences for both safety and economics.
What is Hastelloy Alloy C-22?
Hastelloy Alloy C-22 represents the latest advancement in nickel-based superalloy technology, specifically engineered to address the limitations of earlier corrosion-resistant alloys in highly aggressive environments. We classify this material as a versatile, solid-solution strengthened superalloy that combines exceptional corrosion resistance with superior mechanical properties across extreme temperature ranges.
The alloy's development arose from the nuclear industry's stringent requirements for materials capable of withstanding highly radioactive, high-temperature environments while maintaining structural integrity over decades of service. Traditional materials, including earlier Hastelloy grades, showed limitations in these extreme conditions, necessitating the development of C-22's advanced composition.
C-22's metallurgical structure features a stable austenitic matrix that remains consistent across temperature variations from cryogenic conditions to 1000°C. This microstructural stability prevents the formation of detrimental secondary phases that could compromise either mechanical properties or corrosion resistance during extended service periods.
The alloy's low carbon content, combined with careful control of impurity elements, minimizes the potential for sensitization during welding and high-temperature exposure. This design philosophy ensures that C-22 maintains uniform corrosion resistance throughout complex fabricated structures, including heat-affected zones where other materials might develop vulnerabilities.
What is The Chemical Composition Of Hastelloy Alloy C-22?
The chemical composition of Hastelloy Alloy C-22 represents a carefully optimized balance of elements designed to maximize corrosion resistance while maintaining excellent mechanical properties and fabricability. Understanding these elemental contributions provides insight into the alloy's exceptional performance characteristics.
| Element | Gewichtsprozent (%) | Primäre Funktion |
|---|---|---|
| Nickel (Ni) | 50.0 - 59.0 | Base metal matrix providing stability |
| Chrom (Cr) | 20.0 - 22.5 | Passivation and oxidation resistance |
| Molybdän (Mo) | 12.5 - 14.5 | Pitting and crevice corrosion resistance |
| Wolfram (W) | 2.5 - 3.5 | Enhanced localized corrosion resistance |
| Eisen (Fe) | 2.0 - 6.0 | Structural stability and cost optimization |
| Kobalt (Co) | 2,5 max | Steigerung der Stärke |
| Kohlenstoff (C) | 0,015 max | Minimized to prevent carbide precipitation |
| Mangan (Mn) | 0,50 max | Deoxidation and processing aid |
| Silizium (Si) | 0,08 max | Deoxidizer, controlled for stability |
| Phosphor (P) | 0,02 max | Controlled to prevent embrittlement |
| Schwefel (S) | 0,02 max | Minimiert für verbesserte Duktilität |
| Vanadium (V) | 0,35 max | Grain structure refinement |
The synergistic interaction between chromium, molybdenum, and tungsten provides C-22 with exceptional resistance to localized attack forms, including pitting and crevice corrosion in chloride environments. We emphasize that the higher chromium content compared to C-276 enhances passivation characteristics, while the molybdenum-tungsten combination provides superior performance in reducing conditions.
The extremely low carbon and sulfur contents distinguish C-22 from conventional stainless steels and even earlier superalloys, preventing the formation of inclusions and precipitates that could serve as initiation sites for corrosion attack. This compositional purity ensures consistent performance throughout the material's service life.
What are Hastelloy Alloy C-22 Mechanical Properties?
The mechanical properties of Hastelloy Alloy C-22 demonstrate outstanding performance characteristics across an extensive temperature range, enabling reliable operation from cryogenic applications to high-temperature service conditions. These properties reflect the alloy's sophisticated metallurgical design and processing optimization.
| Eigentum | Raumtemperatur | 538°C | 700°C | Test Standard |
|---|---|---|---|---|
| Zugfestigkeit (MPa) | 760-930 | 520-680 | 380-520 | ASTM E8 |
| Streckgrenze (MPa) | 350-450 | 280-360 | 200-280 | ASTM E8 |
| Dehnung (%) | 45-65 | 40-55 | 35-50 | ASTM E8 |
| Verkleinerung der Fläche (%) | 70-85 | 65-80 | 60-75 | ASTM E8 |
| Härte (HRB) | 90-100 | - | - | ASTM E18 |
| Aufprallenergie (J) | 350-450 | 300-400 | 250-350 | ASTM E23 |
| Elastizitätsmodul (GPa) | 207 | 182 | 165 | ASTM E111 |
| Fatigue Strength (MPa) | 380-420 | 320-380 | 280-340 | ASTM D7791 |
These mechanical properties highlight C-22's excellent balance of strength and ductility, essential for both fabrication operations and service performance. We observe that the alloy maintains exceptional impact toughness even at elevated temperatures, preventing catastrophic brittle failures under dynamic loading conditions.
The high elongation and reduction of area values indicate superior formability compared to many other superalloys, enabling complex component fabrication through conventional metalworking processes. This characteristic proves particularly valuable for nuclear waste containers and chemical processing equipment requiring intricate geometries.
What is the Specification of Hastelloy Alloy C-22?
Hastelloy Alloy C-22 specifications encompass comprehensive international standards that govern material composition, properties, and quality requirements across various product forms and applications. These specifications ensure consistent performance and reliability in critical service environments.
| Spezifikation Kategorie | Einzelheiten | Standard-Referenz |
|---|---|---|
| ASTM-Bezeichnung | B575, B619, B622, B626, B564 | Mehrere Produktformen |
| UNS-Nummer | N06022 | Einheitliches Nummerierungssystem |
| AMS-Spezifikationen | 5850, 5887G | Aerospace and nuclear applications |
| ASME-Code-Fall | N-06022 | Nuclear pressure vessel construction |
| AWS-Klassifizierung | ERNiCrMo-10 | Schweißzusatzwerkstoffe |
| Produkt Formulare | Plate, sheet, bar, pipe, tube, wire, forgings | Verschiedene ASTM-Normen |
| Dickenbereich | 0.4mm - 400mm | Produktform abhängig |
| Wärmebehandlung | Lösungsgeglüht | 1120-1175°C |
| Zustand der Oberfläche | Geglüht, gebeizt, blankgeglüht | ASTM A480 |
| Abmessungstoleranz | ±0.05mm to ±6.0mm | Abhängig von Größe und Anwendung |
| Chemische Analyse | Gemäß ASTM B575 | Heat and product analysis |
| Mechanische Prüfung | Room and elevated temperature | ASTM E8, E21, E23 |
| Corrosion Qualification | Multiple test methods | ASTM G28, G48, G61 |
The comprehensive specification framework ensures that C-22 meets the most stringent quality requirements for nuclear, chemical, and marine applications. We maintain rigorous adherence to these standards throughout our manufacturing processes, ensuring material traceability and performance consistency.
International harmonization of specifications facilitates global procurement while maintaining performance standards across different suppliers and manufacturing locations. The unified numbering system provides clear identification for engineering specifications and quality control procedures.
What Does Hastelloy Alloy C-22 Stand For?
Hastelloy Alloy C-22 derives its designation from the established Hastelloy naming convention, where "C" indicates membership in the chromium-rich family of Hastelloy alloys, and "22" represents the specific compositional variant optimized for advanced corrosion resistance applications.
The Hastelloy trademark, now owned by Haynes International, encompasses a comprehensive family of nickel-based superalloys developed for extreme service conditions. The systematic numbering approach helps engineers and procurement specialists identify specific alloy compositions and their performance characteristics.
We recognize that the "C-22" designation has become synonymous with premium performance in nuclear waste processing and advanced chemical applications. The "22" identifier reflects both the approximate chromium content and the alloy's position in the evolutionary development of advanced corrosion-resistant materials.
This standardized designation system facilitates accurate material identification throughout the global supply chain, ensuring proper material selection, specification compliance, and quality assurance for critical applications where material performance directly impacts safety and operational success.
What is the Density of Hastelloy Alloy C-22?
The density of Hastelloy Alloy C-22 measures 8.69 g/cm³ at room temperature, positioning it slightly lighter than C-276 but heavier than conventional stainless steels. This density value plays a crucial role in structural calculations, weight optimization, and thermal analysis for engineering applications.
Temperature variations influence C-22's density through thermal expansion effects, with the density decreasing to approximately 8.55 g/cm³ at 538°C and 8.45 g/cm³ at 700°C. We incorporate these temperature-dependent properties into thermal stress analyses and high-temperature structural designs.
The moderate density of C-22 reflects its balanced composition, providing an optimal relationship between material properties and weight considerations. This characteristic proves particularly important for nuclear waste containers where both corrosion resistance and structural integrity are essential while minimizing overall system weight.
Compared to titanium alloys with densities around 4.5 g/cm³, C-22 is significantly heavier but offers vastly superior corrosion resistance and high-temperature stability. The density-performance relationship makes C-22 the preferred choice when environmental resistance takes precedence over weight considerations.
What is the Difference Between Hastelloy Alloy C-22, G-30 and C-276?
The differences between Hastelloy Alloys C-22, G-30, and C-276 reflect distinct compositional strategies optimized for specific performance requirements and application environments. Understanding these variations enables engineers to select the most appropriate material for their service conditions.
Hastelloy Alloy C-22 features higher chromium content (22%) compared to C-276 (15.5%), providing enhanced passivation characteristics and superior resistance to oxidizing environments. The molybdenum content (13.5%) is slightly lower than C-276 but combined with tungsten (3%) to optimize crevice corrosion resistance.
Hastelloy G-30 incorporates the highest chromium content (30%) with moderate molybdenum (5.5%) and tungsten (2.5%), specifically designed for mixed acid environments and applications involving both oxidizing and reducing conditions. This composition provides excellent performance in nitric acid and other strongly oxidizing media.
Hastelloy C-276 contains the highest molybdenum content (16%) with moderate chromium (15.5%), optimizing it for reducing acid environments and applications involving hydrochloric acid and sulfuric acid. The lower chromium content limits its performance in highly oxidizing conditions compared to C-22.
Performance characteristics vary significantly between these alloys. C-22 excels in nuclear waste processing and seawater applications, G-30 performs optimally in mixed acid chemical processing, while C-276 provides superior resistance in reducing acid environments. We recommend specific corrosion testing for critical applications.
What is a Hastelloy Alloy C-22 Used For?
Hastelloy Alloy C-22 finds primary application in nuclear waste processing facilities where long-term containment of highly radioactive materials requires exceptional corrosion resistance and structural integrity. The alloy's performance in these extreme environments makes it indispensable for high-level radioactive waste storage containers and processing equipment.
Desalination and seawater processing systems utilize C-22 for critical components including heat exchanger tubing, evaporator sections, and brine handling equipment. The alloy's superior resistance to chloride-induced localized corrosion enables reliable operation in concentrated seawater environments where other materials suffer rapid degradation.
Chemical processing industries employ C-22 for reactor vessels, distillation equipment, and piping systems handling highly corrosive chemicals at elevated temperatures. We observe exceptional performance in applications involving chlorinated organic compounds, wet chlorine environments, and mixed acid processing systems.
Pharmaceutical and biotechnology manufacturing facilities use C-22 for sterile processing equipment, fermentation vessels, and purification systems where product purity requirements demand materials with exceptional cleanliness and corrosion resistance. The alloy's surface characteristics support stringent contamination control standards.
Geothermal energy systems incorporate C-22 for heat exchanger components, wellhead equipment, and piping systems where high-temperature geothermal brines create extremely corrosive conditions. The alloy's performance enables economic utilization of geothermal resources with high mineral content.
What is Hastelloy Alloy C-22 Classification?
Hastelloy Alloy C-22 is classified as a nickel-chromium-molybdenum-tungsten superalloy according to international metallurgical classification systems. The Unified Numbering System designates it as UNS N06022, providing universal identification across global markets and standards organizations.
According to ASTM classification frameworks, C-22 belongs to the category of nickel-chromium-molybdenum alloys with enhanced localized corrosion resistance. Multiple ASTM specifications address various product forms, with B575 covering plate and sheet, B619 addressing welded pipe, and B622 specifying seamless pipe and tube products.
European standards classify C-22 under EN 2.4602, ensuring material consistency and performance equivalency between American and European supply sources. This classification harmonization facilitates international procurement while maintaining identical technical requirements.
Nuclear industry classifications recognize C-22 under various reactor pressure vessel codes and nuclear waste processing standards. We utilize these specialized classifications for applications requiring enhanced safety factors and extended service life predictions in radioactive environments.
What is Equivalent to Hastelloy C-22 Material?
Hastelloy C-22 equivalents exist from various international suppliers, though direct substitution requires comprehensive evaluation of composition, processing, and performance characteristics. Understanding equivalent materials helps ensure supply security and competitive sourcing for large projects.
International equivalents include Alloy 22 from various suppliers, Nicrofer 6022 hMo from VDM Metals, and Cronifer 1925 hMo LC from ThyssenKrupp. These materials share similar composition ranges but may differ in processing methods, quality control procedures, and certification standards.
European designations such as NiCr22Mo13W3 (EN 2.4602) and German standard 2.4602 provide equivalent specifications for European markets. Japanese equivalent JIS NW0022 ensures consistency in Asian manufacturing and supply chain operations.
Chinese equivalent materials include NS3308 and similar compositions produced by domestic manufacturers. We emphasize that while these materials may share similar nominal compositions, qualification testing is essential to verify equivalent performance in specific applications, particularly for nuclear and critical chemical processing uses.
Is Hastelloy Considered Stainless Steel?
Hastelloy alloys, including C-22, are not classified as stainless steels despite sharing some similar characteristics such as corrosion resistance and austenitic structure. The fundamental differences in composition, properties, and applications distinguish these material categories.
Stainless steels typically contain 10.5-30% chromium with iron as the base element, while Hastelloy C-22 uses nickel as the primary constituent (50-59%) with chromium (20-22.5%) and significant molybdenum content. This compositional difference results in vastly different performance characteristics and cost structures.
Corrosion resistance mechanisms differ significantly between stainless steels and Hastelloy alloys. While stainless steels rely primarily on chromium oxide film formation, C-22's resistance stems from the synergistic effects of chromium, molybdenum, and tungsten in a nickel matrix, providing superior performance in aggressive environments.
We classify Hastelloy C-22 as a nickel-based superalloy, representing a distinct category of high-performance materials designed for extreme service conditions where conventional stainless steels would fail. The performance capabilities and cost levels reflect this fundamental material category difference.
Weltmarktpreise 2025 im Vergleich
The global market for Hastelloy Alloy C-22 reflects its specialized nature and limited supplier base, with pricing influenced by raw material costs, processing complexity, and application-specific quality requirements. Regional variations depend on local demand, supply chain logistics, and competitive dynamics.
| Region | Preisspanne (USD/kg) | Markt-Faktoren | Status der Versorgung |
|---|---|---|---|
| Nord-Amerika | $65-85 | Nuclear industry demand, domestic production | Gute Verfügbarkeit |
| Europa | $68-88 | Environmental regulations, nuclear applications | Stabile Versorgung |
| Asien-Pazifik | $62-78 | Manufacturing growth, cost competition | Ausgezeichnet |
| Naher Osten | $70-90 | Desalination projects, import logistics | Mäßig |
| Südamerika | $72-92 | Limited suppliers, infrastructure projects | Variabel |
| Afrika | $75-95 | Import dependencies, mining applications | Begrenzt |
Price fluctuations primarily result from raw material cost variations, particularly nickel, chromium, and molybdenum, which represent substantial portions of the total material value. We recommend long-term supply agreements for major projects to minimize price volatility and ensure material availability.
The specialized processing requirements and stringent quality control standards contribute to premium pricing compared to conventional corrosion-resistant alloys. However, the superior performance and extended service life typically justify the investment in critical applications where material failure carries severe consequences.
Can Hastelloy Alloy C-22 be Welded?
Hastelloy Alloy C-22 demonstrates excellent weldability using conventional fusion welding processes, making it suitable for complex fabrication and field installation operations. The alloy's metallurgical characteristics facilitate high-quality welding without requiring extensive preheating or complex post-weld treatments.
Gas tungsten arc welding (GTAW) represents the preferred welding method for C-22, providing precise heat input control and producing welds with exceptional corrosion resistance and mechanical properties. We recommend using matching composition filler metals (ERNiCrMo-10) to maintain chemical compatibility and optimal performance.
Preheating requirements for C-22 are minimal, typically involving only surface cleaning and moisture removal. The alloy's stable austenitic structure and low carbon content prevent the formation of brittle phases that could compromise weld integrity or require thermal post-treatments.
Post-weld heat treatment is generally unnecessary for C-22 weldments, though solution annealing may be specified for nuclear applications or maximum corrosion resistance requirements. The alloy's solid-solution strengthening mechanism prevents precipitation effects that could complicate thermal processing.
Welding procedure considerations include maintaining appropriate heat input levels to preserve corrosion resistance, using high-purity shielding gases (typically argon or argon-hydrogen mixtures), and implementing strict cleanliness protocols to prevent contamination that could affect performance in critical applications.
Advantages of Hastelloy Alloy C-22
The advantages of Hastelloy Alloy C-22 stem from its advanced metallurgical design and exceptional performance characteristics in the most demanding industrial environments. These benefits make it the material of choice for applications where conventional alloys cannot provide adequate service life or reliability.
Superior localized corrosion resistance represents the primary advantage, with exceptional performance against pitting, crevice corrosion, and stress corrosion cracking in chloride-rich environments. The alloy maintains this resistance across temperature ranges where other materials show significant degradation.
Outstanding thermal stability prevents metallurgical changes during extended high-temperature exposure, ensuring consistent properties throughout the service life. This stability proves crucial for nuclear waste processing applications requiring centuries of reliable containment performance.
Excellent fabricability despite high performance characteristics enables complex component manufacturing using standard metalworking techniques. We observe that C-22 can be formed, machined, and welded without extraordinary procedures, facilitating cost-effective production of intricate geometries.
Broad environmental resistance covers both oxidizing and reducing conditions, mixed acids, and chlorinated compounds, providing versatility for multi-purpose facilities. This characteristic reduces material inventory requirements and simplifies specifications for complex processing systems.
Manufacturing Process of Hastelloy Alloy C-22
The manufacturing process of Hastelloy Alloy C-22 begins with vacuum induction melting (VIM) utilizing high-purity raw materials to achieve precise chemical composition control and eliminate impurities that could compromise performance. This primary melting process ensures homogeneous distribution of alloying elements and maintains the ultra-low carbon and sulfur levels essential for optimal corrosion resistance.
Secondary refining through vacuum arc remelting (VAR) further enhances metallurgical quality by eliminating macro-segregation and reducing inclusion content. We carefully control cooling rates during solidification to prevent the formation of undesirable phases and optimize the ingot structure for subsequent processing.
Hot working operations including forging, rolling, or extrusion are performed within carefully controlled temperature ranges to develop optimal grain structure and mechanical properties. The working temperature typically ranges from 1000-1200°C, depending on specific product requirements and dimensional specifications.
Solution heat treatment follows hot working, performed at temperatures between 1120-1175°C to dissolve any precipitates and establish the desired single-phase austenitic microstructure. Rapid cooling, typically by water quenching, preserves this structure and maximizes corrosion resistance characteristics.
Cold finishing operations, when required, are performed after solution treatment to achieve precise dimensional tolerances and surface specifications. The degree of cold work is carefully controlled to prevent excessive work hardening while achieving required mechanical properties.
Quality assurance throughout manufacturing includes comprehensive chemical analysis using advanced spectroscopic techniques, mechanical property verification, corrosion resistance testing using standardized methods, and complete dimensional inspection. Each processing step undergoes rigorous monitoring to ensure specification compliance and maintain full material traceability for critical applications.
French Nuclear Facility Procurement Case Study
A major nuclear research facility in Cadarache, France, successfully implemented Hastelloy Alloy C-22 components for their advanced nuclear waste vitrification project, demonstrating the material's exceptional performance in high-radiation, high-temperature environments. This project showcased C-22's capabilities in one of the most demanding nuclear processing applications.
The facility required materials capable of withstanding intense gamma radiation, temperatures up to 800°C, and highly corrosive molten glass environments during the vitrification of high-level radioactive waste. Previous materials experienced accelerated corrosion and premature failure, compromising both safety and operational efficiency.
MWalloys supplied 32 tons of C-22 in various configurations including melter components, off-gas system piping, condensate handling equipment, and structural supports. The procurement process involved extensive material qualification testing, including radiation exposure studies and high-temperature corrosion evaluation in simulated service environments.
Installation required specialized procedures developed in cooperation with French nuclear regulatory authorities, including comprehensive welding qualification programs and non-destructive testing protocols. Local fabrication teams received intensive training on C-22 processing techniques and quality control requirements.
Performance monitoring over 48 months revealed outstanding results, with C-22 components showing minimal degradation despite exposure to extreme radiation levels and corrosive conditions. Corrosion rates decreased by over 85% compared to previous materials, and equipment availability improved significantly.
The success led to facility-wide adoption of C-22 for all critical radioactive waste processing applications, including planned expansion projects. The installation now serves as a reference facility for European nuclear waste processing operations considering material upgrades.
Economic benefits exceeded €6.2 million over four years when considering reduced maintenance, improved operational efficiency, and enhanced safety performance. The project established C-22 as the preferred material for advanced nuclear waste processing throughout the European nuclear industry.
Häufig gestellte Fragen
Q1: What makes C-22 superior to C-276 for nuclear applications?
C-22 offers enhanced resistance to localized corrosion, particularly pitting and crevice corrosion, due to its higher chromium content and optimized molybdenum-tungsten balance. This provides superior long-term performance in chloride-containing environments typical of nuclear waste processing. We recommend C-22 for applications requiring centuries of reliable containment performance.
Q2: Can C-22 withstand direct contact with molten salts at high temperatures?
C-22 demonstrates excellent performance in molten salt environments up to 700°C, particularly in chloride and fluoride salt systems. The alloy's resistance to hot corrosion and thermal cycling makes it suitable for advanced reactor concepts and energy storage applications. Specific salt composition evaluation is recommended for optimization.
Q3: What surface preparation is required for C-22 in critical applications?
Critical applications typically require electropolished surfaces with Ra values below 0.4 μm to optimize corrosion resistance and facilitate decontamination. Standard preparation includes solution annealing, pickling in mixed nitric-hydrofluoric acid, and final electropolishing. We provide detailed surface preparation specifications for specific applications.
Q4: How does C-22 perform in hydrogen-containing environments?
C-22 exhibits excellent resistance to hydrogen embrittlement and maintains mechanical properties in hydrogen-rich environments at moderate temperatures and pressures. The alloy is suitable for hydrogen processing applications and reformer service. High-pressure hydrogen applications require specific evaluation and testing.
Q5: What non-destructive testing methods are most effective for C-22 components?
Liquid penetrant testing, ultrasonic inspection, and radiographic examination are all effective for C-22. Eddy current testing works well for tubing applications. The alloy's austenitic structure requires adjusted magnetic particle testing procedures. We recommend helium leak testing for nuclear containment applications.
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