Table of Contents
Understanding Flange Material Grades
Understanding flange material grades helps you make more reasonable choices, ensuring the system’s safety, reliability, and cost-effectiveness, while avoiding various issues caused by material mismatches. The correct material selection is key to the successful and efficient operation of a piping system.
If the flange material is improperly selected, it may result in frequent maintenance, leaks, or replacements. Especially in harsh environments, flanges made from unsuitable materials may not withstand the expected operating conditions, leading to system failure. Understanding the applicability of flange materials can effectively avoid such situations.
The ASTM standards provide various material types and grades for flanges, helping engineers select the appropriate materials based on the specific needs of the project. For example, certain piping systems may have high requirements for corrosion resistance, so selecting materials with high corrosion resistance (such as 304 or 316 stainless steel) becomes very important. For general low-temperature or room-temperature applications, carbon steel flanges (such as ASTM A105) might be a more economical choice. By understanding these material descriptions, designers can ensure that the chosen flange material strikes the best balance in terms of cost, performance, and application.
Carbon Steel Flanges
- High Strength: Carbon steel flanges have high tensile strength and pressure resistance, making them suitable for high-pressure environments.
- Economical: They are relatively low-cost and widely used in common water pipelines and low to moderate corrosion environments.
- Good Machinability: Carbon steel is easy to weld, process, and form.
- Poor Corrosion Resistance: In humid, acidic, or seawater environments, carbon steel flanges are prone to rust or corrosion and may require coatings or corrosion treatment to enhance corrosion resistance.
- Wide Application: Used in common industrial pipelines such as oil, natural gas, and water treatment.
Common Carbon Steel Flange Materials
| Material Name | Chemical Composition/Characteristics | Applicable Environment | Application Area |
| ASTM A105 | Common carbon steel, suitable for normal temperature and medium temperature environments. | -29°C to 425°C, suitable for normal temperature and medium pressure conditions | Oil, gas, chemical, and power industries, general pipeline systems. |
| ASTM A350 LF2 | Low-temperature carbon steel with lower carbon content for improved low-temperature toughness. | Low-temperature environments (e.g., -45°C to -196°C) | Low-temperature liquid transport (e.g., LNG, LPG). |
| ASTM A106 Gr. B | Primarily used for seamless carbon steel pipes, commonly used in pipelines that endure higher pressures. | Medium-low temperature, high-pressure environments | Oil, gas, chemical pipelines, especially for seamless pipe connections. |
| ASTM A181 | Forged carbon steel with good toughness and machinability. | Normal and low-temperature environments | Commonly used in pipe fittings for liquid and gas pipelines. |
| ASTM A694 F42/F52/F60/F65 | High-strength carbon steel, suitable for high-pressure and extreme pressure conditions. | High-pressure, high-strength environments | High-pressure pipeline connections in the oil and gas industry. |
| ASTM A516 Gr. 60/Gr. 70 | Carbon steel for boilers and pressure vessels, suitable for medium temperature and pressure conditions. | Medium temperature and pressure environments | Boilers, pressure vessels, and pipelines in oil, chemical, and power industries. |
| ASTM A105N | A105 material annealed to improve weldability and plasticity. | Normal and medium temperature environments | Oil, gas, power, etc., especially where high weldability is required. |
| ASTM A350 LF3 | Low-temperature carbon steel with more alloying elements for better low-temperature performance. | Extremely low-temperature environments (e.g., LNG transport) | Extremely low-temperature pipeline systems, such as LNG transport. |
Corresponding Carbon Steel Pipe and Fitting Materials
| Flange Material (ASTM Standard) | Corresponding Steel Pipe Material (ASTM Standard) | Corresponding Pipe Fitting Material (ASTM Standard) |
| ASTM A105 | ASTM A106 Gr. B, ASTM A53 Gr. B | ASTM A234 WPB (carbon steel fittings), ASTM A420 WPL6 (low-temperature fittings) |
| ASTM A350 LF2 | ASTM A350 LF2, ASTM A420 WPL6 | ASTM A234 WPB (carbon steel fittings), ASTM A420 WPL6 (low-temperature fittings) |
| ASTM A106 Gr. B | ASTM A106 Gr. B | ASTM A234 WPB (carbon steel fittings) |
| ASTM A181 | ASTM A105, ASTM A106 Gr. B, ASTM A53 Gr. B | ASTM A234 WPB (carbon steel fittings) |
| ASTM A694 F42/F52/F60/F65 | ASTM A106 Gr. B, ASTM A333 Gr. 6 (low-temperature) | ASTM A234 WPB, ASTM A420 WPL6 (low-temperature fittings), ASTM A860 WPHY (high-strength fittings) |
| ASTM A516 Gr. 60/Gr. 70 | ASTM A106 Gr. B, ASTM A53 Gr. B | ASTM A234 WPB (carbon steel fittings), ASTM A420 WPL6 (low-temperature fittings) |
| ASTM A105N | ASTM A106 Gr. B, ASTM A53 Gr. B | ASTM A234 WPB (carbon steel fittings) |
| ASTM A350 LF3 | ASTM A350 LF3, ASTM A333 Gr. 6 (low-temperature) | ASTM A234 WPB (carbon steel fittings), ASTM A420 WPL6 (low-temperature fittings) |
Stainless Steel Flanges
- Excellent Corrosion Resistance: Stainless steel flanges resist various corrosive media, including water, steam, air, saltwater, etc.
- High Strength and Toughness: They have high tensile strength, making them suitable for high-temperature and high-pressure applications.
- Good High-Temperature Performance: Stainless steel flanges can be used at high temperatures, suitable for high-temperature gas and steam pipelines.
- Good Hygiene Properties: Widely used in food, pharmaceutical, and other industries that require cleanliness and hygiene.
- Good Weldability and Formability: They can be processed in various ways and are suitable for welding complex structures.
Common Stainless Steel Flange Materials
| Flange Material Name | Chemical Composition/Characteristics | Applicable Environment | Application Area |
| ASTM A182 F304 | Contains 18% chromium and 8% nickel, providing good corrosion resistance and formability. | Typically used for temperatures up to 870°C. | Food processing, chemical, oil, gas, and other industries. |
| ASTM A182 F304L | A low-carbon version of 304, with better weldability and reduced risk of intergranular corrosion. | Suitable for temperatures up to 870°C. | Suitable for piping systems with frequent welded joints, especially in food and pharmaceutical industries. |
| ASTM A182 F316 | Contains 16% chromium, 10% nickel, and 2-3% molybdenum, enhancing resistance to chloride corrosion. | High-temperature, seawater, and chloride environments (up to 870°C). | Marine, chemical, pharmaceutical, food processing industries, and environments with high corrosion requirements. |
| ASTM A182 F316L | A low-carbon version of F316, with better weldability and excellent intergranular corrosion resistance. | High-temperature, seawater, and chloride environments (up to 870°C). | Food, pharmaceutical, and marine applications. |
| ASTM A182 F321 | Contains titanium to prevent intergranular corrosion in welded conditions. | High-temperature environments (up to 870°C), especially where welding conditions are challenging. | High-temperature chemical equipment, aerospace, oil, and gas industries. |
| ASTM A182 F347 | Contains tantalum and molybdenum, offering excellent resistance to intergranular corrosion. | High-temperature environments (up to 870°C). | Chemical, oil, and gas industries with high corrosion resistance requirements. |
| ASTM A182 F904L | High chromium, nickel, and molybdenum content, providing superior corrosion resistance, especially in strong acidic environments. | Acidic, seawater, and high-temperature environments (up to 870°C). | Chemical, power industries, and applications in acidic environments. |
Corresponding Stainless Steel Pipe and Fitting Materials
| Flange Material | Corresponding Pipe Material | Corresponding Fitting Material |
| ASTM A182 F304 | ASTM A312 TP304 (Austenitic Stainless Steel) | ASTM A403 WP304 (Austenitic Stainless Steel) |
| ASTM A182 F304L | ASTM A312 TP304L (Austenitic Stainless Steel) | ASTM A403 WP304L (Austenitic Stainless Steel) |
| ASTM A182 F316 | ASTM A312 TP316 (Austenitic Stainless Steel) | ASTM A403 WP316 (Austenitic Stainless Steel) |
| ASTM A182 F316L | ASTM A312 TP316L (Austenitic Stainless Steel) | ASTM A403 WP316L (Austenitic Stainless Steel) |
| ASTM A182 F304H | ASTM A312 TP304H (Austenitic Stainless Steel) | ASTM A403 WP304H (Austenitic Stainless Steel) |
| ASTM A182 F316H | ASTM A312 TP316H (Austenitic Stainless Steel) | ASTM A403 WP316H (Austenitic Stainless Steel) |
| ASTM A182 F347 | ASTM A312 TP347 (Austenitic Stainless Steel) | ASTM A403 WP347 (Austenitic Stainless Steel) |
| ASTM A182 F347H | ASTM A312 TP347H (Austenitic Stainless Steel) | ASTM A403 WP347H (Austenitic Stainless Steel) |
| ASTM A182 F321 | ASTM A312 TP321 (Austenitic Stainless Steel) | ASTM A403 WP321 (Austenitic Stainless Steel) |
| ASTM A182 F904L | ASTM A312 TP904L (Austenitic Stainless Steel) | ASTM A403 WP904L (Austenitic Stainless Steel) |
Duplex Stainless Steel Flanges
- Higher Strength and Corrosion Resistance: Duplex stainless steel flanges have better corrosion resistance than austenitic and ferritic stainless steel, especially in chloride and pitting environments.
- Excellent Stress Corrosion Cracking Resistance: Performs excellently in high-stress environments, resistant to chloride stress corrosion cracking.
- Higher Wear Resistance: Duplex stainless steel has better wear resistance and impact resistance than regular stainless steel.
- Suitable for Extreme Environments: Suitable for industries requiring high-temperature, corrosion resistance, and high mechanical performance, such as oil, natural gas, and marine industries.
- Good Oxidation Resistance: Has good oxidation resistance in medium to high-temperature environments.
Common Duplex Stainless Steel Flange Materials
| Flange Material Name | Chemical Composition/Characteristics | Applicable Environment | Application Area |
| ASTM A182 F51 (Duplex) | Contains chromium (22%), nickel (5-6%), and molybdenum (3%) duplex steel, offering strong corrosion resistance and high strength for harsh environments. | Highly corrosive and high-temperature environments (up to 300°C). | Oil, natural gas, marine engineering, and chemical industries. |
| ASTM A182 F53 (Super Duplex) | Contains chromium (25%), nickel (7%), and molybdenum (4%), providing superior corrosion resistance and strength compared to regular duplex steel. | Highly corrosive and high-temperature environments (up to 300°C). | Chemical, oil, natural gas, and marine engineering applications in corrosive environments. |
Corresponding Duplex Stainless Steel Pipe and Fitting Materials
| Flange Material Name | Corresponding Pipe Material | Corresponding Fitting Material |
| ASTM A182 F51 (Duplex) | ASTM A790 S31803 (Duplex Stainless Steel) | ASTM A815 WP-S31803 (Duplex Stainless Steel) |
| ASTM A182 F53 (Super Duplex) | ASTM A790 S32750 (Super Duplex) | ASTM A815 WP-S32750 (Super Duplex) |
Alloy Steel Flanges
- High Strength and High-Temperature Performance: Alloy steel flanges typically contain elements like chromium and molybdenum, which provide high strength and excellent high-temperature performance.
- Good Corrosion Resistance: Alloy steel flanges resist corrosion from acids, alkalis, salts, and other chemical media, making them widely used in petrochemical, metallurgy, and other industries.
- Suitable for High Pressure and High-Temperature Environments: Due to their strength and toughness, they are suitable for harsh environments requiring high pressure or high temperature.
- Excellent Weldability: Alloy steel flanges are easy to weld and maintain their strength and structural integrity after welding.
- Wide Application: Used extensively in the chemical, petroleum, natural gas, and heat exchanger industries.
Common Alloy Steel Flange Materials
| Flange Material Name | Chemical Composition/Characteristics | Applicable Environment | Application Area |
| ASTM A182 F5 | Contains chromium (5%) and molybdenum (0.5%), offering good high-temperature performance for high-temperature applications. | High-temperature environments (up to 540°C). | Oil, chemical, and power industries; used in high-temperature gas or steam pipelines. |
| ASTM A182 F9 | Contains chromium (9%) and molybdenum (1%), enhancing high-temperature, oxidation, and corrosion resistance. | High-temperature and high-pressure environments (up to 650°C). | Power generation, chemical equipment, oil pipelines, etc. |
| ASTM A182 F11 | Contains chromium (1.25%) and molybdenum (0.5%), improving strength and durability in high-temperature and corrosive environments. | High-temperature and high-pressure environments (up to 600°C). | Oil, natural gas, chemical, and power industries’ high-temperature pipelines. |
| ASTM A182 F22 | Contains chromium (2.25%) and molybdenum (1%), offering strong resistance to high temperature and corrosion. | High-temperature and high-pressure environments (up to 650°C). | Oil, natural gas, chemical, and power industries’ high-temperature pipelines. |
| ASTM A182 F91 | Contains chromium (9%) and molybdenum (1%), offering excellent high-temperature and oxidation resistance. | High-temperature and high-pressure environments (up to 760°C). | Oil, natural gas, and power industries’ high-temperature, high-pressure applications. |
| ASTM A336 F1 | Contains chromium (1%) and molybdenum (0.5%), suitable for medium temperature and pressure environments. | Medium to high-temperature environments (up to 540°C). | Oil, natural gas, and chemical equipment; suitable for medium-temperature pipelines. |
| ASTM A336 F5a | Contains chromium (5%) and molybdenum (0.5%), offering better oxidation resistance compared to F5. | High-temperature environments (up to 540°C). | High-temperature gas or steam pipelines in oil and natural gas industries. |
Corresponding Alloy Steel Pipe and Fitting Materials
| Flange Material Name | Corresponding Pipe Material | Corresponding Fitting Material |
| ASTM A182 F5 | ASTM A335 P5 | ASTM A234 WP5 |
| ASTM A182 F9 | ASTM A335 P9 | ASTM A234 WP9 |
| ASTM A182 F11 | ASTM A335 P11 | ASTM A234 WP11 |
| ASTM A182 F22 | ASTM A335 P22 | ASTM A234 WP22 |
| ASTM A182 F91 | ASTM A335 P91 | ASTM A234 WP91 |
| ASTM A336 F1 | ASTM A335 P1 | ASTM A234 WP1 |
| ASTM A336 F5a | ASTM A335 P5a | ASTM A234 WP5a |
Nickel Alloy Flanges
- Excellent Corrosion Resistance: Nickel alloy flanges perform excellently in extreme environments, especially in corrosive media such as seawater, sulfuric acid, chlorides, and fluorides.
- Good High-Temperature Performance: Nickel alloy flanges maintain high strength and toughness in high-temperature environments, making them suitable for high-temperature, high-pressure applications.
- Strong Oxidation and Carburization Resistance: Suitable for severe high-temperature oxidation, carburization, and other corrosive environments.
- Fatigue and Stress Corrosion Cracking Resistance: Nickel alloy flanges can withstand high-stress conditions and are not prone to stress corrosion cracking.
- Wide Application: Used in marine, aerospace, chemical, petrochemical, and other high-performance applications, especially in harsh environments.
Common Nickel Alloy Steel Flange Materials
| Flange Material Name | Chemical Composition/Characteristics | Applicable Environment | Application Area |
| Ni200 (Nickel 200) | Chemical Composition: >99% Nickel. Characteristics: High purity, excellent corrosion resistance in reducing environments, good mechanical properties at both room and elevated temperatures. | Environment: Reducing environments, caustic alkalis, acids like hydrochloric acid (non-oxidizing). | Application Area: Chemical processing, electronics, food processing, and electrical industries. |
| Ni201 (Nickel 201) | Chemical Composition: >99% Nickel with low carbon content. Characteristics: Similar to Ni200, but with enhanced resistance to embrittlement and oxidation at high temperatures. | Environment: Higher temperatures, steam, and corrosive liquids, especially in sulfuric acid. | Application Area: High-temperature applications, chemical reactors, and food processing. |
| Monel 400 | Chemical Composition: Approx. 63% Nickel, 29% Copper, small amounts of iron, manganese, and silicon. Characteristics: Excellent resistance to seawater, acids, and alkalis, good strength at elevated temperatures. | Environment: Seawater, sulfuric acid, hydrochloric acid, alkalis, and other harsh chemicals. | Application Area: Marine engineering, chemical processing, heat exchangers, valves, and pumps. |
| Hastelloy C276 | Chemical Composition: Ni 57%, Mo 15-17%, Cr 14-16%, Fe 4-7%, W 3-4%, Co < 3%. Characteristics: Excellent resistance to corrosion, pitting, and stress corrosion cracking in highly aggressive environments. | Environment: Chemical environments, particularly in sulfuric, hydrochloric, and phosphoric acids, and seawater. | Application Area: Chemical processing, pollution control, aerospace, and marine environments. |
| Hastelloy C22 | Chemical Composition: Ni 56%, Cr 22%, Mo 13%, Fe 3%, Co < 3%. Characteristics: Superior resistance to pitting, crevice corrosion, and stress-corrosion cracking. Better than Hastelloy C276 in some environments. | Environment: Aggressive chemical environments including acids and chlorides, chlorine gas, and oxidizing conditions. | Application Area: Chemical processing, aerospace, flue gas desulfurization, and marine applications. |
| Incoloy 800 | Chemical Composition: Ni 30-35%, Cr 19-23%, Fe balance, small amounts of Al, Ti, and others. Characteristics: Excellent resistance to oxidation and carburization at elevated temperatures, good mechanical properties. | Environment: High temperatures (up to 1100°C), oxidation, carburization, and in sulfur-containing environments. | Application Area: Heat exchangers, furnaces, reactors, power plants, and thermal processing. |
| Incoloy 825 | Chemical Composition: Ni 38-46%, Fe 22-30%, Cr 19-23%, Mo 2.5-3.5%, Cu 1.5-3%, Ti, Al. Characteristics: Excellent resistance to sulfuric acid, seawater, and reducing acids, good mechanical properties at elevated temperatures. | Environment: Sulfuric acid, seawater, phosphoric acid, and harsh chemical environments. | Application Area: Chemical processing, marine, and oil and gas industries. |
| Inconel 600 | Chemical Composition: Ni 72%, Cr 14-17%, Fe 6-10%, small amounts of Al, Ti, and others. Characteristics: High resistance to oxidation and carburization, excellent strength at elevated temperatures. | Environment: High-temperature environments, oxidative environments, steam, and nitric acid. | Application Area: Aerospace, chemical processing, nuclear, and heat exchangers. |
| Inconel 625 | Chemical Composition: Ni 58%, Cr 21%, Mo 9%, Nb 3.5%, Ti 0.4%, Fe 5%. Characteristics: Exceptional resistance to oxidation, corrosion, and fatigue at high temperatures, excellent weldability. | Environment: High-temperature environments, seawater, acidic solutions, and in high-stress environments. | Application Area: Aerospace, chemical processing, marine, power plants, and petrochemical industries. |
| Inconel 718 | Chemical Composition: Ni 50-55%, Cr 17-21%, Fe 18-23%, Mo 2.8-3.3%, Ti 0.7-1.2%, Al 0.2-0.8%. Characteristics: Excellent mechanical properties at high temperatures, good oxidation and corrosion resistance, especially in gas turbines. | Environment: High-temperature and high-stress environments, including in the presence of sulfur and chlorine. | Application Area: Aerospace, gas turbines, nuclear, and other high-performance mechanical systems. |
| CuNi 90/10 | Chemical Composition: 90% Copper, 10% Nickel. Characteristics: Good resistance to seawater corrosion, high strength, and good weldability. | Environment: Seawater, brine, mild acids, and alkaline environments. | Application Area: Marine engineering, shipbuilding, desalination plants, and heat exchangers. |
| CuNi 70/30 | Chemical Composition: 70% Copper, 30% Nickel. Characteristics: Superior strength and corrosion resistance compared to CuNi 90/10, especially in seawater and brine environments. | Environment: Seawater, brine, mild acid, and alkaline solutions. | Application Area: Marine engineering, shipbuilding, desalination, and chemical processing industries. |
Corresponding Nickel Alloy Steel Pipe and Fitting Materials
| Flange Material | Corresponding Pipe Material | Corresponding Fitting Material |
| Ni200 (Nickel 200) | ASTM B161 Ni200 (Nickel 200) | ASTM B366 WP Ni200 (Nickel 200) |
| Ni201 (Nickel 201) | ASTM B161 Ni201 (Nickel 201) | ASTM B366 WP Ni201 (Nickel 201) |
| Monel 400 | ASTM B164 Monel 400 (Nickel-Copper Alloy) | ASTM B366 WP Monel 400 (Nickel-Copper Alloy) |
| Hastelloy C276 | ASTM B622 Hastelloy C276 (Nickel-Molybdenum-Chromium Alloy) | ASTM B366 WP Hastelloy C276 (Nickel-Molybdenum-Chromium Alloy) |
| Hastelloy C22 | ASTM B574 Hastelloy C22 (Nickel-Chromium-Molybdenum Alloy) | ASTM B366 WP Hastelloy C22 (Nickel-Chromium-Molybdenum Alloy) |
| Incoloy 800 | ASTM B407 Incoloy 800 (Nickel-Chromium-Iron Alloy) | ASTM B366 WP Incoloy 800 (Nickel-Chromium-Iron Alloy) |
| Incoloy 825 | ASTM B423 Incoloy 825 (Nickel-Iron-Chromium-Molybdenum Alloy) | ASTM B366 WP Incoloy 825 (Nickel-Iron-Chromium-Molybdenum Alloy) |
| Inconel 600 | ASTM B167 Inconel 600 (Nickel-Chromium Alloy) | ASTM B366 WP Inconel 600 (Nickel-Chromium Alloy) |
| Inconel 625 | ASTM B443 Inconel 625 (Nickel-Chromium-Molybdenum Alloy) | ASTM B366 WP Inconel 625 (Nickel-Chromium-Molybdenum Alloy) |
| Inconel 718 | ASTM B705 Inconel 718 (Nickel-Chromium Alloy) | ASTM B366 WP Inconel 718 (Nickel-Chromium Alloy) |
| CuNi 90/10 | ASTM B171 CuNi 90/10 (Copper-Nickel Alloy) | ASTM B366 WP CuNi 90/10 (Copper-Nickel Alloy) |
| CuNi 70/30 | ASTM B171 CuNi 70/30 (Copper-Nickel Alloy) | ASTM B366 WP CuNi 70/30 (Copper-Nickel Alloy) |
More resources：
Materials for Flanges and Flanged Fittings in ASME B16.5
