タイトルまたは説明

Grade ***5 Duplex (UNS S****5/S****3)

Duplex ***5 is the most widely used duplex (ferritic/austenitic) stainless steel grade. It finds applications due to both excellent corrosion resistance and high strength.

The standard S****3 composition has over the years been refined by many steel suppliers, and the resulting restricted composition range was endorsed as UNS S****5 in ***6. S****5 gives better guaranteed corrosion resistance, but much of the S****3 currently produced also complies with S****5.

***5 is not generally suitable for use at temperatures above **0°C as it suffers from precipitation of brittle micro-constituents, nor below **0°C because of its ductile-to-brittle-transition.

Chemical Composition, %

Applications of Duplex ***5

• Chemical process vessels, piping and heat exchangers
• Pulp mill digesters, bleach washers, chip pre-steaming vessels
• Food processing equipment
• Oil field piping and heat exchangers
• Flue gas desulfurization equipment

Corronsion Resistance

Excellent general corrosion resistance; superior to Grade **6 in most environments. Excellent resistance to localised corrosion including intergranular, pitting and crevice corrosion; the CPT of ***5 is generally at least *5°C. The grade is also resistant to chloride stress corrosion cracking (SCC) at temperatures of up to about **0°C. Grade ***5 will often perform well in environments which cause premature failure of austenitic grades. It has better resistance to sea water than grade **6.

Heat Resistance

Although ***5 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 **0°C. If embrittled this can only be rectified by a full solution annealing treatment. Duplex stainless steels are almost never used above **0°C.

Size range

O.D.: ****0mm, length **6 meter