Austenitic
Duplex Steel
Nickel Alloy
Cobalt Alloy

Alloy B-2 UNS N10665

Summary

A corrosion-resistant solid-solution nickel-molybdenum alloy, Alloy B-2 exhibits excellent corrosion resistance in aggressive reducing media such as hydrochloric acid in a wide range of temperatures and concentrations, as well as in medium-concentrated sulphuric acid even with limited chloride contamination. Can also be used in acetic and phosphoric acids, and to a wide range of organic acids. The alloy has good resistance to chloride-induced stress corrosion cracking (SCC).

Standard
Product Forms

Pipe, tube, sheet, plate, round bar ，flanes, valve, and forging.

Limiting Chemical Composition, %

Physical
Constants

Typical
Mechanical
Properties

Microstructure

Alloy B-2 has a face-centered-cubic structure. The alloy's controlled chemistry with minimum iron and chromium content reduces the risk of embrittlement occurring during fabrication, as this retards precipitation of Ni4Mo phase in the temperature range 700-800 ℃.

Characters

1. Controled chemistry with a minimum iron and chrlmium content to retard the formation of ordered β-phase Ni4Mo ;
2. Significant corrosion resistance to reducing environment;
3. Excellent resistance to medium-concentrated sulphuric acid and a number of non-oxidizing acids;
4. Good resistance to chloride-induced stress-corrosion cracking (SCC);
5. Good resistance to a wide range of organic acids.

Corrosion Resistance

The extremely low carbon and silicon content of Hastelloy B-2 reduces precipitation of carbides and other phases in the heat-affected zone of welds and ensures adequate corrosion resistance even in the welded condition. Hastelloy B-2 exhibits excellent corrosion resistance in aggressive reducing media such as hydrochloric acid in a wide range of temperatures and concentrations, as well as in medium-concentrated sulphuric acid even with limited chloride contamination. It can also be used in acetic and phosphoric acids. Optimum corrosion resistance can be obtained only if the material is in the correct metallurgical condition and exhibits a clean structure.

Applications

Alloy B-2 is used in a wide range of applications in the chemical process industry, especially for processes involving sulphuric, hydrochloric, phosphoric and acetic acid. B-2 is not recommended for use in the presence of ferric or cupric salts as these salts may cause rapid corrosion failure. Ferric or cupric salts may develop when hydrochloric acid comes in contact with iron or copper.