A182 F51 Duplex Stainless Steel

Designations: A182 F51 · UNS S31803 · cast equivalent CD3MN (ASTM A890 / A995 Grade 4A)A182 F51 is 22% chromium duplex stainless steel of the 2205 type. Its mixed austenite–ferrite structure gives roughly twice the yield strength of 316 and better resistance to chloride stress corrosion cracking. ASTM A182 covers forgings; the cast equivalent is CD3MN (ASTM A890 or A995 Grade 4A), used for pump casings, valve bodies and impellers in oil and gas, water and chemical service. Kormax casts CD3MN to order for customers in the United States and Canada.

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Chemical Composition

A182 F51 Duplex Stainless Steel — chemical composition, % by weight
Element	Symbol	Range / limit %
Carbon	C	0.030 max
Manganese	Mn	2.00 max
Silicon	Si	1.00 max
Phosphorus	P	0.030 max
Sulfur	S	0.020 max
Chromium	Cr	21.0–23.0
Nickel	Ni	4.5–6.5
Molybdenum	Mo	2.5–3.5
Nitrogen	N	0.08–0.20
Iron	Fe	Balance

Mechanical Properties

A182 F51 Duplex Stainless Steel — mechanical properties
Property	Metric	Imperial
Tensile Strength, min	620 MPa	90 ksi
Yield Strength, min	450 MPa	65 ksi
Elongation, min	25%	25%
Hardness (Brinell), max	293 HB	293 HB

Values to ASTM A182 F51 (UNS S31803). The cast equivalent CD3MN to ASTM A995 Grade 4A specifies 620 MPa (90 ksi) tensile, 415 MPa (60 ksi) yield and 25% elongation minimum.

Comparable and Related Specifications

The standards and grades below may have similar composition, properties or applications, but they should not be treated as direct equivalents without review. Chemistry, heat treatment, toughness requirements and testing provisions can differ between standards.