Duplex Stainless Erw Steel Pipe

Duplex Stainless Erw Steel Pipe

DUPLEX CORROSION RESISTANCE

Excellent general corrosion resistance; superior to Grade 316 in most environments. Excellent resistance to localized corrosion including intergranular, pitting and crevice corrosion; the CPT of 2205 is generally at least 35ºC. The grade is also resistant to chloride stress corrosion cracking (SCC) at temperatures of up to about 150ºC. Duplex Stainless Erw Steel Pipe Grade 2205 will often perform well in environments which cause premature failure of austenitic grades. It has better resistance to sea water then Grade 316.

DUPLEX HEAT RESISTANCE

Although 2205 has good high temperature oxidation resistance, this grade – like other duplex stainless steels – suffers from embrittlement if held for even short times at temperatures above 300ºC. If embrittled, this can only be rectified by a full solution annealing treatment. Duplex stainless steels are almost never used above 300ºC.

DUPLEX HEAT TREATMENT

Solution treatment (annealing) – heat to 1020ºC-1100ºC and cool rapidly. This grade cannot be hardened by thermal treatment, but does work harden.

Duplex Stainless Erw Steel Pipe are becoming more common. They are being offered by all the major stainless steel mills for a number of reasons:

• Higher strength leading to weight saving

• Greater corrosion resistance particularly stress corrosion cracking

• Better price stability 

• Lower price


There is a conference on the subject of duplex every 2-3 years where dozens of highly technical papers are presented. There is a lot of marketing activity surrounding these grades. New grades are being announced frequently. 

Yet, even with all this interest, the best estimates for global market share for duplex are between 1 and 3%. The purpose of this article is to provide a straightforward guide to this steel type. The advantages and disadvantages will be described.