904L

┃Material

904L, UNS N08904, W.Nr. 1.4539

┃ Overview

904L is a non-stabilised low carbon high alloy austenitic stainless steel, which designed for moderate to high corrosion resistance in a wide range of process environments. The addition of copper to this grade gives it greatly improved resistance to strong reducing acids, particularly sulphuric acid. The combination of high nickel and molybdenum content, assure good chloride stress corrosion cracking resistance, including pitting, crevice corrosion and stress corrosion cracking. Even down to cryogenic temperatures, the austenitic structure also gives 904L stainless steel excellent toughness, easily welded and processed by standard shop fabrication practices.

┃ Chemical Composition (%)

┃ Mechanical Property

┃ Application

Oil and Gas: Offshore platforms, subsea equipment, and pipelines

Chemical Processing: Reactors, tanks, heat exchangers, and piping systems

Pharmaceutical Industry: Tanks, vessels, and process piping systems

Desalination Plants: Heat exchangers, evaporators, and brine heaters

Power Generation: Flue gas desulfurization (FGD) systems, cooling water systems, and boilers

Food Processing: Storage tanks, mixing vessels, and piping systems

Marine Applications: Seawater piping, heat exchangers, and offshore structures

┃Corrosion Resistance

904L was originally developed for its resistance to sulphuric acid, its offers exceptionally good resistance to uniform corrosion due to the high content of alloying elements, and also has a very high resistance to a wide range of environments such as warm sea water and other high chloride. In most environments, 904L material has a corrosion performance intermediate between the standard austenitic grade 316L and the very highly alloyed 6% molybdenum and similar "super austenitic" grades, which has proven to be a good alternative to most conventional stainless steels. Its important to note that 904L should be solution treated after cold work to maximum stress corrosion cracking resistance in critical environments.

┃Machining

904L material is a high purity, low sulphur grade, can be machined using standard techniques, but the machinability is not as well as other grades optimised for machinability. The cold work hardening rate of 904L makes it less machinable than 410 and 304 stainless steels.

┃Welding

904L can be welded using a common welding process, the most appropriate weldingmethods are manual arc welding and tungsten-argon arc welding. When welding, a filler metal of the same composition as the base metal is suggested, such as 20 25 CuL covered electrode and 20 25 CuL wire, for the best corrosion properties in welds. Care needs to be taken as this grade solidifies fully austenitic, so is susceptible  hot cracking, particularly in constrained weldments. No pre-heat should be used and in most cases post weld heat treatment is also not required.

┃ Product Forms 

Ø Bar & Rod

Ø Plate & Sheet

Ø Coil & Strip

Ø Pipe & Tube

Ø Fitting: Flange, Tee, Elbow, Reducer etc.

Ø Forging: Ring, Shaft, Circle, Block etc.

┃ Note

Ronsco is a supplier with more than 27 years of experience in the stainless steel and nickel alloy field, we always adheres to the business phiosophy of "customer-centered", tries its best to meet the requirements of customers and pursues win-win cooperation with customers. Are you looking for metal products one-stop supplier! Contact Us Now! Email: service@ronsteel.com