Alloy B2 / UNS N10665

Description

Alloy B2 (UNS N10665 / W.Nr. 2.4617) is a solid solution strengthened, nickel-molybdenum alloy, typically used in extreme reducing conditions. B2 has significantly lower carbon, silicon and iron compared to its’ predecessor, Alloy B (UNS N10001), making the alloy less susceptible to decreased corrosion resistance in the weld zone, in the as-welded condition. Controlling other alloying elements such as iron and chromium solved other issues concerning fabricability. Stringent chemistry control along with years of development has resulted in the alloy used today, both in Alloy

B2 and Alloy B-3®. Today, Alloy B2 with restricted chemistry can be used in the welded condition and is less susceptible to SCC under many conditions. As always, care must taken in selecting the right alloy for the desired application.

Alloy B2 should not be used at temperatures between 1000°F and 1600°F as the alloy forms secondary phases that could decrease the ductility of the material.

Resistance to Corrosion

The high molybdenum content in Alloy B2 gives the alloy excellent resistance to hydrochloric acid over a wide range of concentrations and temperatures. Alloy B2 also shows good resistance to hydrogen chloride, sulfuric acid and phosphoric acids and has excellent resistant to pitting and stress corrosion cracking in the heat–affected zone. Uniform corrosion rates in various environments is very similar compared to the other Ni-Mo alloys such as B-3®. The presence of any oxidizing media, even in trace amounts, will significantly increase corrosion. Alloy B2 should not be used in oxidizing media, as these alloys show little to no resistance in such environments.

Fabrication and Heat Treatment

Welding Alloy B2 can be performed by TIG, MIG as well as coated electrode. Dissimilar metal welding Alloy B2 to Alloy B-3® is possible using AWS ERNiMo-10 for GTAW and GMAW operations and ENiMo-10 for SMAW welding. The work piece should be thoroughly cleaned with acetone or other suitable cleaners to insure that all contaminants and markings are removed. Grinding prior to welding can be performed with a clean alumina-wheel that has not been previously used on any iron-based materials. There is no need for pre or post heat treatment processes unless the work piece has been formed by any means.

A full solution anneal before welding is required on pieces that have been formed. Cold-formed pieces must be shot-peened before annealing.

Hot working should be performed in a temperature range between 1700°F to 2250°F with heavy deformation performed toward the upper end of the range. Re-heating of the work piece may be necessary. A full solution anneal should be performed on all hot-worked pieces and any cold-worked pieces with more than 15% deformation followed by a water quench.

Solution annealing of Alloy B2 is performed at 1950°F for 10 minutes at temperature followed by a water quench. Subject material should be charged into a hot furnace and monitored closely for accurate time at temperature. Contact thermocouples are preferred.

Specifications

N10665, ASTM B619, ASME SB619, ANNEALED, B/SB619 CLASS I OR II, X-RAY PER ASME SECTION VIII DIVISION 1 UW-51, MERCURY FREE, EN 10204-3.1, ASTM B366, ASME SB366, WPHB2-S, ASME B16.11, ASTM B335, ASME SB335, ASME B16.3, MSS SP-83, ASTM B564/ASME SB564, COLD DRAWN, HOT FINISHED, ASTM B333, ASME SB333, SHEET IS COLD ROLLED, HOT ROLLED, ENIMO-7, AWS A-5.11, ASME SFA-5.11

Data Sheet

Chemical Composition:

Element Nickel Molybdenum Iron Chromium Carbon Silicon
Avg. Nominal % Balance 28.0 2.0 Max 1.0 Max 0.01 Max 0.10 Max

Standard Products

Alloy B2 Plate

Alloy B2 Fittings

Alloy B2 Tube

Alloy B2 Pipe

Alloy B2 Bar

Alloy B2 Sheet

Alloy B2 Fasteners

Alloy B2 Flanges

Alloy B2 Welding Product

Alloy B2 Coil

Alloy B2 Plate Shapes

Alloy B2 Custom Profiles

Alloy B2 Forgings

Alloy B2 Machined Parts

Alloy B2 Welded Components