ASTM B729 UNS N08020 Alloy 20 Seamless Pipe
Product Introduction
ASTM B729 UNS N08020 Alloy 20 seamless pipe is a nickel-iron-chromium alloy pipe designed for severe corrosion environments in chemical processing and industrial applications. With controlled additions of nickel, chromium, molybdenum, and copper, Alloy 20 provides excellent resistance to sulfuric acid, phosphoric acid, chloride-containing media, and other aggressive chemicals.
Manufactured according to ASTM B729 / ASME SB729 specifications, UNS N08020 seamless pipes are supplied with uniform dimensions, smooth internal surfaces, and reliable mechanical properties for pressure-containing equipment and corrosive process piping systems.
Due to its superior corrosion resistance compared with conventional stainless steels, Alloy 20 seamless pipe is widely selected for chemical reactors, pressure vessels, acid transfer systems, heat exchangers, and pollution control equipment.
Product Specifications
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Item
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Description
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Product Name
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Alloy 20 Seamless Pipe
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Material Grade
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UNS N08020
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Alloy Type
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Nickel-Iron-Chromium Alloy
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Standard
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ASTM B729 / ASME SB729
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Manufacturing Process
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Seamless Cold Drawn / Cold Finished
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Outer Diameter
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6 mm - 610 mm
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Wall Thickness
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0.5 mm - 40 mm
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Length
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Random Length / Fixed Length / Customized
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Surface Finish
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Annealed & Pickled / Bright Annealed
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End Type
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Plain End / Beveled End
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Heat Treatment
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Solution Annealing
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Inspection
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PMI, Hydrostatic Test, Eddy Current Test, UT
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Certification
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EN10204 3.1 Material Certificate
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Chemical Composition
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Element
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Content
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Nickel (Ni)
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32.0 - 38.0%
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Chromium (Cr)
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19.0 - 21.0%
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Molybdenum (Mo)
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2.0 - 3.0%
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Copper (Cu)
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3.0 - 4.0%
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Carbon (C)
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≤0.07%
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Iron (Fe)
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Balance
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Mechanical Properties
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Property
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Value
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Tensile Strength
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≥620 MPa
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Yield Strength
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≥300 MPa
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Elongation
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≥30%
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Key Performance Features
Excellent Resistance to Sulfuric Acid Corrosion
Alloy 20 was originally developed for sulfuric acid service. The combination of nickel, chromium, copper, and molybdenum provides strong resistance against sulfuric acid corrosion across a wide range of concentrations and temperatures.
Superior Resistance to Pitting and Crevice Corrosion
The addition of molybdenum improves resistance to localized corrosion caused by chloride ions, making UNS N08020 suitable for chemical environments containing acidic and saline media.
Suitable for High-Corrosion Process Systems
Compared with standard stainless steel grades such as 304 and 316L, Alloy 20 offers improved corrosion resistance in aggressive chemical applications where stainless steels may experience accelerated corrosion.
Reliable Seamless Pipe Performance
The seamless manufacturing process provides consistent wall thickness, smooth internal surfaces, and excellent pressure resistance for process piping and equipment applications.
Typical Equipment Applications
Chemical Processing Equipment
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Chemical Reactors
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Pressure Vessels
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Mixing Tanks
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Process Piping Systems
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Acid Circulation Lines
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Chemical Storage Systems
Sulfuric Acid & Phosphoric Acid Plants
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Acid Transfer Pipelines
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Acid Coolers
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Acid Concentration Units
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Evaporators
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Heat Recovery Systems
Fertilizer Manufacturing Equipment
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Phosphate Fertilizer Equipment
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Sulfuric Acid Production Units
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Acid Slurry Pipelines
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Process Circulation Systems
Pollution Control Systems
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Flue Gas Desulfurization (FGD) Equipment
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Wet Scrubbers
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Waste Acid Treatment Systems
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Chemical Neutralization Units
Petrochemical Equipment
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Corrosion Resistant Process Piping
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Chemical Injection Systems
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Refinery Acid Service Equipment
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Process Separation Units
Heat Transfer Equipment
Available Product Forms
YUHONG supplies UNS N08020 Alloy 20 products including:
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Seamless Pipe
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Seamless Tube
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Heat Exchanger Tube
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U Bend Tube
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Precision Tube
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Instrument Tube
Quality Inspection
Each ASTM B729 UNS N08020 seamless pipe is inspected according to project requirements, including:
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Chemical Composition Analysis
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Mechanical Property Testing
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Positive Material Identification (PMI)
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Hydrostatic Testing
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Eddy Current Testing
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Ultrasonic Testing
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Dimensional Inspection
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Surface Examination
Packaging & Delivery
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Pipes are packed with protective caps to prevent end damage.
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Each bundle is marked with material grade, size, heat number, and standard.
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Suitable packaging methods are available for sea transportation and international projects.
FAQ
What is ASTM B729 UNS N08020 Alloy 20 pipe?
ASTM B729 UNS N08020 is a nickel-iron-chromium alloy seamless pipe designed for highly corrosive environments, especially sulfuric acid and chemical processing applications.
Is Alloy 20 stainless steel or nickel alloy?
Alloy 20 is generally classified as a nickel-iron-chromium corrosion-resistant alloy. Although it contains chromium and iron, it is mainly used as a high-performance corrosion-resistant alloy rather than conventional stainless steel.
What industries use Alloy 20 seamless pipe?
Alloy 20 seamless pipes are commonly used in chemical processing, fertilizer production, petrochemical plants, pharmaceutical equipment, pollution control systems, and acid handling applications.
What is the difference between Alloy 20 and 316L stainless steel?
Alloy 20 provides improved resistance to sulfuric acid, chloride stress corrosion cracking, and aggressive chemical environments compared with 316L stainless steel, making it suitable for more demanding corrosion applications.
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