AISI904L

904L is a Molybdenum and Copper Alloyed Cr-Ni austenitic stainless steel with low Carbon content.

Its specific characteristics are:

 Austenitic micro structure.

 High resistance to:

 Pitting and crevice corrosion.

 Stress corrosion and corrosion fatigue.

 Uniform corrosion.

 Good ductility and weldability.

INSPECTION STANDARDS

Europe

EN 10217-7 Welded SS tubes for pressure purposes

EN 10296-2 Welded SS tubes for general purposes.

USA

ASTM A 249 Welded Austenitic SS Heat Exchanger Tubes

ASTM A 269 Welded and seamless Austenitic SS Tubing

ASTM A 312 Welded and seamless Austenitic SS Pipes

ASTM A 358 EF Welded Austenitic Pipe with filler metal

ASTM B 673 Welded Pipe

ASTM B 674 Welded Tube

CHEMICAL COMPOSITION, %

Grade                    Cmax            Cr                   Ni                 Mo             Cu             PRENmin

904L                    0.020        19.5-20.5       24.0-26.0       4.0-4.5       1.2-2.0       35.0

EN 1.4539            0.020        19.0-21.0        24.0-26.0        4.0-5.0        1.2-2.0        35.0

UNS N08904       0.020        19.0-23.0         23.0-28.0       4.0-5.0        1.0-2.0        35.0

Cold forming

Excellent cold forming properties. The same properties as for other standard

austenitic stainless steels.

Hot forming

904L is slightly harder at higher temperatures than austenitic standard

grades. Forming at temperatures in the range 1000-1200 C does not require

any post heat treatment, if the operation is followed by a reasonable

fast cooling, (>600C/min).

Heat treatment

1120-1180 C followed by rapid cooling to at least 700 C. At

temperatures between 900-800 C, intermetallic phases that impair the

properties will form within a few minutes.

APPLICATIONS

 Chloride containing environments

 Heat exchanger tubes

 Pipe systems within

 Chemical and Petrochemical

 Hydrometallurgy