Sales Bulletin - Duplex 2205 Alloy

May 06, 2008

Background:

Duplex 2205 is a relatively newer grade of stainless steel alloy that offers a multitude of advantages over 316 & 316L alloys. The "duplex" term refers to the dual-grain structure nature of this alloy - it is 45% ferritic and 55% austenitic. The "2205" refers to the 22% chromium/5% nickel constituents present in the alloy. The wide array of advantages that the duplex alloy provides over 316 & 316L alloys have enabled it to rapidly gain acceptance in a number industries including marine, oil & gas, petrochem, pulp & paper, wastewater, and desalination. These advantages include:

• Lower coefficient of thermal expansion
• Higher thermal conductivity
• Resistance to chloride stress-cracking
• Superior resistance to pitting & crevice corrosion
• Superior erosion fatigue properties
• High yield strength; ~ twice that of austenitic stainless steels
• Low cost

Ampco Pumps' Duplex Alloy Offerings:

Beginning in the 2008 Q1, Ampco Pumps will begin to offer duplex 2205 as a standard alloy option in its "R", "K", "Z", and "E" Series pumps. Key points/advantages for this new offering will include:

• Superior corrosion resistance
• Superior resistance to the effects of cavitation
• Enhanced resistance to particle contamination
• Longer life for individual pump components

Additional key points:

Duplex 2205 is 45% ferritic - as such, it will be far more magnetic than any 304 or 316 alloy that you will encounter.

The term "Super Duplex" refers to duplex alloys such as UR52N+ that incorporate copper into their chemistry. The addition of copper provides dramatically improved corrosion resistance to hot chlorides and strong reducing acids, such as H2SO4. The duplex 2205 alloy used by Ampco may contain a small amount of copper, but can not be referred to as a "Super" Duplex.

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