Alloy C276 Pipe Bursting Pressure Tables

Introduction to Alloy C276 Pipes

Alloy C276, also known as Hastelloy C276, UNS N10276, or W.Nr. 2.4819, is a nickel-molybdenum-chromium superalloy renowned for its exceptional corrosion resistance and high strength in extreme environments. Widely used in chemical processing, нефти и газа, и морское применение, it resists pitting, щелевая коррозия, and stress-corrosion cracking (SCC) in aggressive media like chlorides and acids. Alloy C276 pipes, available in seamless (ASTM B622) и сваренный (ASTM B626) forms, are critical for high-pressure systems where reliability is paramount. Bursting pressure tables, Рассчитано с использованием формулы Барлоу, provide theoretical internal pressures that pipes can withstand before failure, guiding engineers in selecting appropriate pipe schedules for specific applications.

The alloy’s versatility stems from its balanced composition and robust mechanical properties, making it suitable for pipes in sizes ranging from 1/8 дюйм к 30 дюймов в диаметре. Bursting pressure data, sourced from reputable suppliers like Corrosion Materials and NeoNickel, indicate pressures as high as 35,175 PSI for small-diameter, thick-walled pipes (например, 1/8 дюйм, Schedule 80S). This article details Alloy C276’s chemical composition, Механические свойства, Устойчивость к коррозии, производственные процессы, Приложения, and bursting pressure tables, with comparisons to Inconel 625, Сплав 20, ASTM A671 CC60, and API 5L PSL2 BNS. A comprehensive table summarizes bursting pressures and key parameters, ensuring a valuable resource for engineers.

 

Химический состав и анализ материала

Alloy C276’s chemical composition is optimized for corrosion resistance and strength. It contains nickel (Баланс, ~55–57%), Молибден (15.0–17.0%), хром (14.5–16.5%), Железо (4.0–7.0%), вольфрам (3.0–4.5%), кобальт (≤2.5%), марганец (≤1.0%), УГЛЕРОД (≤0,01%), кремний (≤0,08%), фосфор (≤0.04%), серы (≤0.03%), and vanadium (≤0,35%). The high molybdenum content enhances resistance to pitting and crevice corrosion in chloride environments, while chromium provides oxidation resistance. Low carbon and silicon minimize carbide precipitation during welding, обеспечение целостности сварки. Tungsten adds strength and corrosion resistance in reducing acids.

По сравнению с Inconel 625 (58% min nickel, 8–10% molybdenum), Alloy C276 has higher molybdenum, offering superior resistance to localized corrosion but slightly lower strength. Сплав 20 (32–38% nickel, 2–3% molybdenum, 3–4% copper) excels in sulfuric acid but is less effective in chlorides. ASTM A671 CC60 (0.04–0.27% carbon, 0.85–1.20% manganese) and API 5L PSL2 BNS (≤0.12% carbon) are carbon steels with minimal alloying, полагаясь на покрытия для защиты от коррозии. Alloy C276’s austenitic structure ensures ductility and toughness, supporting its use in high-pressure pipes. The composition’s low impurity levels and stabilization make it ideal for welded pipes, as seen in bursting pressure tables, where weld integrity is critical for high-pressure performance.

 

Механические свойства

Alloy C276 pipes exhibit excellent mechanical properties, supporting their use in high-pressure applications. В отожженном состоянии, Бесшовные трубы (ASTM B622) have a minimum tensile strength of 690 MPA (100 Ksi), Урожайность 283 MPA (41 Ksi), и удлинение 40%. Сварные трубы (ASTM B626) have similar properties, with tensile strength ≥690 MPa and yield ≥283 MPa, though cold-working can increase strength (например, До 1000 MPa tensile for cold-hardened pipes). Hardness is typically 185–230 Brinell. These properties are maintained up to 450°F (232° C), with good performance at higher temperatures for short-term exposure.

По сравнению с Inconel 625 (Растяжение 827 MPA, Уступать 414 MPA), Alloy C276 has slightly lower strength but better corrosion resistance in reducing environments. Сплав 20 (Растяжение 551 MPA, Уступать 241 MPA) is weaker but optimized for acid resistance. ASTM A671 CC60 (tensile 415–550 MPa, Уступать 220 MPA) and API 5L PSL2 BNS (tensile 415–760 MPa, Уступать 245 MPA) are significantly weaker, designed for low-temperature or sour service pipelines. Bursting pressure tables reflect Alloy C276’s high strength, with Schedule 80S pipes (например, 1/8 дюйм, 0.095-inch wall) achieving up to 35,175 пси. The alloy’s toughness and ductility ensure reliability under dynamic loads, critical for chemical and oil/gas applications.

 

Коррозионные характеристики

Alloy C276 is renowned for its exceptional corrosion resistance, particularly in aggressive environments like chlorides, серная кислота, and sour gas. Its pitting resistance equivalent number (ДРЕВЕСИНА) is approximately 69, indicating outstanding resistance to pitting and crevice corrosion. The alloy is immune to chloride SCC and performs well in oxidizing and reducing acids, with corrosion rates as low as 0.1–0.2 mm/year in boiling sulfuric acid. В кислом обслуживании, it meets NACE MR0175 requirements, resisting sulfide stress cracking (SSC) in H2S environments, making it ideal for oil and gas wells.

По сравнению с Inconel 625 (PREN ~52), Alloy C276 offers superior resistance to localized corrosion due to higher molybdenum. Сплав 20 (PREN ~34) excels in sulfuric acid but is less effective in chlorides. ASTM A671 CC60 and API 5L PSL2 BNS, both carbon steels, require coatings for corrosion protection, unlike Alloy C276’s inherent resistance. The alloy’s performance in high-pressure pipes, as shown in bursting pressure tables, is enhanced by its corrosion resistance, ensuring long-term integrity in chemical processing and marine applications. Например, a 1-inch Schedule 40S pipe withstands 15,175 PSI without corrosion-related weakening, supporting its use in harsh environments.

 

Производство и обработка

Alloy C276 pipes are manufactured using vacuum induction melting or electric arc furnaces, followed by hot or cold working to produce seamless (ASTM B622) или сварено (ASTM B626) ТРУБЫ. Seamless pipes are extruded or drawn, with annealing at 1040–1150°C (1900–2100 ° F.) to restore ductility. Welded pipes are formed from strip or plate, welded via GTAW or GMAW with matching filler metals (например, Ernichrmo-4), and annealed to minimize weld stresses. Machining requires rigid setups and carbide tools due to work-hardening, with cutting speeds of 10–20 m/min.

По сравнению с Inconel 625, Alloy C276’s processing is similar but benefits from lower carbon for better weldability. Сплав 20 is easier to fabricate due to lower nickel, while ASTM A671 CC60 and API 5L PSL2 BNS use simpler EFW processes for carbon steel. Неразрушающий контроль (Ультразвуковой, radiographic) ensures weld качество, critical for high bursting pressures (например, 26,250 PSI for 1/2-inch Schedule 80S). The manufacturing process supports a range of pipe sizes (1/8–30 inches) и графики (5S, 10S, 40S, 80S), as reflected in bursting pressure tables, ensuring reliability in high-pressure systems.

 

Приложения

Alloy C276 pipes are used in demanding applications requiring high corrosion resistance and pressure capacity. В химической обработке, they handle acids and chlorides in reactors, Теплообменники, and piping systems. Oil and gas applications include downhole tubing and sour gas pipelines, leveraging NACE compliance. Marine environments use C276 for seawater piping, while pollution control employs it in flue-gas desulfurization systems. Bursting pressure tables guide their use, with 1/4-inch Schedule 40S pipes supporting 24,450 пси, ideal for high-pressure chemical lines.

По сравнению с Inconel 625, used in aerospace and severe marine settings, C276 is preferred for sour service and acid resistance. Сплав 20 targets sulfuric acid applications, while ASTM A671 CC60 is for low-temperature pipelines and API 5L PSL2 BNS for sour gas transport. Alloy C276’s high bursting pressures and corrosion resistance make it ideal for critical infrastructure, reducing maintenance in harsh environments like offshore platforms and chemical plants. Its versatility across pipe sizes and schedules ensures broad applicability.

Bursting Pressure Tables

Bursting pressure tables for Alloy C276 pipes, Рассчитано с использованием формулы Барлоу (P = 2ST/D, where P is pressure, S is allowable stress, T is wall thickness, D is outer diameter), provide theoretical internal pressures for seamless and welded pipes. Data from Corrosion Materials and NeoNickel for seamless pipes (ASTM B622) across Schedules 5S, 10S, 40S, and 80S are summarized below. Сварные трубы (ASTM B626) have similar pressures, with slight variations due to weld factors.

Номинальный Размер Трубы (дюймов)	Nominal OD (дюймов)	Расписание	Толщина стенки (дюймов)	Burst Pressure (пси)
1/8	0.405	5S / 10S / 40S / 80S	0.049 / 0.068 / 0.095 / –	18,150 / 25,175 / 35,175 / –
1/4	0.540	5S / 10S / 40S / 80S	0.065 / 0.088 / 0.119 / –	18,050 / 24,450 / 33,050 / –
3/8	0.675	5S / 10S / 40S / 80S	0.065 / 0.091 / 0.126 / –	14,450 / 20,225 / 28,000 / –
1/2	0.840	5S / 10S / 40S / 80S	0.065 / 0.083 / 0.109 / 0.147	11,600 / 14,825 / 19,475 / 26,250
3/4	1.050	5S / 10S / 40S / 80S	0.065 / 0.083 / 0.113 / 0.154	9,275 / 11,850 / 16,150 / 22,000
1	1.315	5S / 10S / 40S / 80S	0.065 / 0.109 / 0.133 / 0.179	7,425 / 12,450 / 15,175 / 20,425
1 1/4	1.660	5S / 10S / 40S / 80S	0.065 / 0.109 / 0.140 / 0.191	5,875 / 9,850 / 12,650 / 17,250
1 1/2	1.900	5S / 10S / 40S / 80S	0.065 / 0.109 / 0.145 / 0.200	5,125 / 8,600 / 11,450 / 15,800
2	2.375	5S / 10S / 40S / 80S	0.065 / 0.109 / 0.154 / 0.218	4,100 / 6,875 / 9,750 / 13,775
2 1/2	2.875	5S / 10S / 40S / 80S	0.083 / 0.120 / 0.203 / 0.276	4,325 / 6,250 / 10,600 / 14,400
3	3.500	5S / 10S / 40S / –	0.083 / 0.120 / 0.216 / –	3,550 / 5,150 / 9,250 / –
4	4.500	5S / 10S / 40S / –	0.083 / 0.120 / 0.237 / –	2,750 / 4,000 / 7,900 / –
6	6.625	5S / 10S / 40S / –	0.109 / 0.134 / 0.280 / –	2,475 / 3,050 / 6,350 / –
8	8.625	5S / 10S / 40S / –	0.109 / 0.148 / 0.322 / –	1,900 / 2,575 / 5,600 / –

Заметки: Pressures are theoretical, based on Barlow’s Formula, and for reference only. Actual performance may vary due to material variations, температура, and corrosion effects. Consult ASME Boiler and Pressure Vessel Code for design.

 

размерные допуски

Dimensional tolerances for Alloy C276 pipes ensure compatibility in high-pressure systems. Бесшовные трубы (ASTM B622) and welded pipes (ASTM B626) варьируется от 1/8 Кому 30 inches in outer diameter (OD), with tolerances of ±0.5% for OD and ±10% for wall thickness (например, ±0.0095 inches for 0.095-inch wall). Lengths are typically up to 6 метры, with straightness ≤0.2% of length. Weld seam height for welded pipes is ≤3.2 mm, и конец заканчивается (например, beveled per ASME B16.25) ensure proper connections.

По сравнению с Inconel 625 (ASTM B444: ± 0,25 мм для небольших диаметров), Alloy C276 has similar tolerances but is optimized for larger pipes. Сплав 20 (ASTM B729/B464: ±0.5% OD) matches C276’s tolerances, while ASTM A671 CC60 (±0.5% OD) and API 5L PSL2 BNS (± 0,75%) are looser due to larger pipeline sizes. These tolerances support high bursting pressures, ensuring reliable installation in chemical and oil/gas systems where precision is critical.

 

Comparison with Other Alloys and Pipes

Alloy C276 pipes are compared to Inconel 625, Сплав 20, ASTM A671 CC60, and API 5L PSL2 BNS. ИНКОНЕЛЬ 625 (Растяжение 827 MPA, PREN ~52) offers high strength but slightly lower pitting resistance than C276 (PREN ~69). Сплав 20 (Растяжение 551 MPA, PREN ~34) is suited for sulfuric acid but less effective in chlorides. ASTM A671 CC60 (tensile 415–550 MPa) and API 5L PSL2 BNS (tensile 415–760 MPa) are carbon steels for low-temperature and sour service pipelines, соответственно, with lower strength and no inherent corrosion resistance. Alloy C276’s high bursting pressures (например, 35,175 PSI for 1/8-inch Schedule 80S) and corrosion resistance make it ideal for extreme conditions, unlike carbon steels requiring coatings.

Проблемы и ограничения

Alloy C276 pipes face challenges in cost and fabrication. Their high nickel and molybdenum content makes them more expensive than ASTM A671 CC60 or API 5L PSL2 BNS, limiting use to critical applications. Machining is difficult due to work-hardening, requiring low cutting speeds and rigid setups. Welded pipes must avoid contamination to maintain corrosion resistance, и высокие температуры (>450° F) can reduce ductility. Bursting pressure tables assume ideal conditions, but actual pressures may be lower due to corrosion or defects. По сравнению с Inconel 625, C276 is less versatile in ultra-high temperatures, and Alloy 20 is limited in chloride environments. These challenges are mitigated through precise manufacturing and application-specific design, ensuring reliability in high-pressure systems.

Будущие тенденции и инновации

The future of Alloy C276 pipes involves advancements in manufacturing and applications. Additive manufacturing is being explored for custom fittings, reducing waste. Передовые методы сварки, like laser welding, improve seam качество, supporting high bursting pressures. Nanotechnology-based coatings enhance corrosion resistance in extreme environments, extending pipe life in sour gas and chemical applications. The alloy’s use in renewable energy, such as geothermal and offshore wind, is growing due to its durability. Compared to Inconel 625’s aerospace focus, C276 targets chemical and oil/gas innovations. ASTM A671 and API 5L pipes are seeing coating advancements, but C276’s inherent properties position it for high-value applications. Digital monitoring for corrosion and pressure will further enhance reliability, ensuring Alloy C276 remains a premier choice for high-pressure, corrosive systems.

Заключение

Alloy C276 (UNS N10276) pipes are critical for high-pressure, агрессивные среды, offering exceptional strength and corrosion resistance. Bursting pressure tables, based on Barlow’s Formula, show pressures up to 35,175 PSI for small-diameter, thick-walled pipes, guiding their use in chemical, oil/gas, и морское применение. The alloy’s nickel-molybdenum-chromium composition ensures resistance to pitting, SCC, and acids, outperforming Inconel 625 in localized corrosion and Alloy 20 in chlorides. Compared to ASTM A671 CC60 and API 5L PSL2 BNS, C276 offers superior performance but at higher cost. The provided table summarizes bursting pressures and key parameters, aiding engineers in design. Future innovations in manufacturing and coatings will enhance Alloy C276’s role in critical infrastructure, ensuring reliability in extreme conditions.