Alloy - 20

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Alloy - 20

Alloy 20, also known as Carpenter 20, is a highly corrosion-resistant austenitic stainless steel alloy designed primarily for use in sulfuric acid environments. It offers excellent resistance to chloride stress corrosion cracking, pitting, and crevice corrosion. With its combination of nickel, chromium, molybdenum, and copper, Alloy 20 provides outstanding performance in chemical processing, petrochemical, pharmaceutical, and marine applications while maintaining good mechanical properties and ease of fabrication.

Monel Products and their Grades

Product Grades
Refractory Anchors ASTM B473 UNS N08020, ASTM B462 UNS N08020, ASTM B729 UNS N08020, ASTM B464 UNS N08020
Pipes B729
Tubes B729
Pipe Fitting B366
Forged Fitting B564
Flanges B564

Chemical Composition of Alloy 20

Grade Ni (%) Cr (%) Mo (%) Cu (%) Nb+Ta (%) C (%) Si (%) Mn (%) P (%) S (%) Fe (%)
Alloy 20 32.0 – 38.0 19.0 – 21.0 2.0 – 3.0 3.0 – 4.0 8xC min – 1.0 max 0.07 max 1.0 max 2.0 max 0.045 max 0.035 max Balance

Mechanical Properties of Alloy 20

Grade Tensile Strength (MPa) Yield Strength 0.2% Proof (MPa) Elongation (%) Hardness (Brinell)
Alloy 20 551 241 30 217 HB

Applications of Alloy 20

Alloy 20, also known as Carpenter 20, is a nickel-iron-chromium austenitic alloy designed for superior corrosion resistance, particularly against sulfuric acid. It offers excellent resistance to pitting, crevice corrosion, and chloride stress-corrosion cracking, making it a preferred material in chemical, pharmaceutical, and food processing industries.

Chemical Processing

Used in storage tanks, piping, and process equipment handling sulfuric, phosphoric, and nitric acids.

Pharmaceutical Industry

Ideal for equipment requiring high corrosion resistance and sanitary processing standards.

Food Processing

Used in food production equipment exposed to acidic and chlorinated cleaning solutions.

Petrochemical Industry

Applied in heat exchangers, reactor vessels, and piping systems handling aggressive hydrocarbons.

Pollution Control

Used in flue gas scrubbers, waste treatment, and environmental control equipment.

Marine Applications

Suitable for seawater service where resistance to chloride-induced corrosion is required.