ALLOY20 (Carpenter 20Cb3)


AALLOY20 is a low carbon, Nb stabilised austentic Ni-Fe-Cr alloy with alloying additions of Cu & Mo.。

  • • excellent resistance to sulphuric and phosphoric acids
  • • good resistance to intergranular corrosion
  • • very good resistance to chloride-ion induced stress-corrosion cracking
  • • good resistance to pitting and crevice corrosion
  • • good mechanical properties at both ambient and elevated temperatures, up to approximately 500 °C (930 °F).

Stock Form and Sizes

※ ◆1000㎜ ◎2000㎜ ▲3000㎜ ■3500㎜ ●4000㎜ ★2500㎜~3990㎜

Round BarsSpecification:ASTM B473 ASME SB473 NACE MR0175(ISO 15156)
size 1〜13
size 16〜50
size 55〜135
size 140〜300
Hex barsSpecification:ASTM B473
Nuts and washersSpecification:Nuts JIS B1181 Class1 washers,JIS B1256 Normal Series Grade.A

※Please enquire about grades and sizes not in stock.

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Sourceable Ex-Stock Material for other Forms from Distributors World-Wide

EquivalentRound BarsPlatePipe/TubeWelding Rod & Wire
MinMax MinMax
Carpenter 20Cb34.76~279.41.6~50.8

*○: Various sizes available in stock. △: Only limited sizes available in stock. ☆: Please contact us for more details.
*We can supply materials and products that comply with various standards including ASTM, ASME, AMS, and NACE standards. Please contact us for more details.

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Corrosion resistance

ALLOY20has excellent corrosion resistance to sulphuric, phosphoric and organic acids and to aqueous solutions of their salts. Resistance to nitric acid is also good. Due to the controlled chemical composition, the alloy also has excellent resistance to such forms of corrosion as intergranular corrosion and stress corrosion. The molybdenum content ensures good resistance to pitting and crevice corrosion. Optimum corrosion resistance can only be obtained if the material is in the correct metallurgical condition and clean.


ALLOY20 is used in a wide variety of applications up to temperatures of approximately 500°C (930°F).

Typical applications are:
  • • equipment for the manufacture of sulphuric acid and for processes based on sulphuric acid
  • • extraction columns in the production of amines and the processing of pharmaceuticals
  • • production of plastics and synthetic fibres
  • • equipment for food processing to protect against contamination

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Chemical composition

min36.519.0bal. 1.0  

※The values in the table are for reference only and do not guarantee minimum or maximum values. For further information, please contact us.

Mechanical properties(Round Bar)

 ConditionYield Strength(Mpa)Tensile Strength(Mpa)Elongation(%)Hardness(HB)
ASTM Min ValueSoft Annealed24155130 
Typical Values at RTSoft Annealed27461750184

Above standard values and typical values of Round Bar.
Please contact us with any questions about reference or value of plate and pipe.
※The values in the table are for reference only and do not guarantee minimum or maximum values. For further information, please contact us.

International Standard Comparison Chart

 MaterialRound BarsPlatePipe/Tube
ASMESB473SB463 SB464/SB468

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Stock list



Inquiry/Request for information

TEL 81-6-6586-5626
FAX 81-6-6586-5858

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