Download

Alloy 25-6Mo

Alloy 25-6Mo, Alloy 926, UNS N08925, UNS N08926, W.Nr. 1.4529

Alloy 25-6Mo is a super austenitic stainless steel containing 6% molybdenum and enhanced by an addition of nitrogen. The nickel and chromium contents of this alloy make it resistant to a wide range of corrosive environments. The alloy is especially resistant to non-oxidizing acids such as sulfuric and phosphoric. The high molybdenum content and nitrogen provide resistance to pitting and crevice corrosion, while copper enhances resistance to sulfuric acid.

Alloy 25-6Mo offers excellent corrosion resistance in a wide variety of aggressive, aqueous environments. It replaces the conventional, austenitic stainless steels (AISI 316 and 317), where their capabilities are pushed to their performance limits. The alloy, therefore, falls into a "super austenitic stainless steel" category. It can also represent a cost-effective alternative to the higher nickel alloys in some marine and chemical processing environments.

One of the outstanding attributes of Alloy 25-6Mo is its resistance to environments containing chlorides or other halides. This alloy is especially suited to handle high-chloride environments such as brackish water, sea water, caustic chlorides and pulp mill bleach systems.

◎ It has high resistance to point corrosion and crevice corrosion in halide medium and acid medium containing H2S

◎ It can effectively resist chloride ion stress corrosion cracking in practical application

◎ It has excellent corrosion resistance to all kinds of corrosion in the usual REDOX environment

◎ The mechanical properties were greatly improved than Cronifer 1925LC-alloy 904L.

◎ The metallurgical stability was improved than those alloys with 18% nickel content.

Applications of Alloy 25-6MO include chemical and food processing, pulp and paper bleaching plants, marine and offshore platform equipment, salt plant evaporators, air pollution control systems, and condenser tubing, service water piping, polished rods in corrosive wells, and feedwater heaters for the power industry.

It has good corrosion resistance and stability in oxidizing and reducing media, with mechanical properties slightly better than 904L. It can be used in the manufacturing of pressure vessels from -196°C to 400°C.

Alloy 25-6Mo in the solution annealed condition as per ASTM B677

Alloy 25-6Mo is an austenitic stainless steel with similar chemical composition to alloy 904L. The nitrogen content is increased to about 0.2% and the molybdenum content is about 6.5%. The increase of nitrogen and molybdenum content significantly improved the resistance to pitting corrosion and crevice corrosion in the halide medium. This test was conducted in the severe pitting corrosion temperature range in the standard ferric chloride solution.

At the same time, nickel and nitrogen not only ensure the metallographic stability, but also reduce the tendency of intercrystalline phase precipitation in the process of hot processing or welding than the alloy with low content of nickel and nitrogen.

Excellent local corrosion resistance and 25% nickel content make the alloy especially outstanding corrosion resistance in chloride medium.

In addition, only when the material is in the correct metallurgical state and clean conditions can have the best corrosion resistance.

(1) Hot formed, annealed, descaled

(2) Cold worked and bright annealed

(3) Cold worked, bright annealed, polished (MP, EP, CP etc.)

Chemical composition

Tension

Hardness

Flaring

Flange

Flattening

Micro structure

Hydrostatic

NDT

Intergranular Corrosion

Surface condition

Shape and dimension

Positive Material Identification