Outstanding Corrosion Resistance In The As-Welded Condition
HASTELLOY® B-3® alloy is an additional member of the nickel-molybdenum family of alloys with excellent resistance to hydrochloric acid at all concentrations and temperatures. It also withstands sulfuric, acetic, formic and phosphoric acids, and other nonoxidizing media. B-3 alloy has a special chemistry designed to achieve a level of thermal stability greatly superior to that of its predecessors, e.g. HASTELLOY B-2 alloy. B-3 alloy has excellent resistance to pitting corrosion, to stress-corrosion cracking and to knife-line and heat-affected zone attack.
Fabrication
The improved thermal stability of HASTELLOY B-3 alloy minimizes the problems associated with fabrication of B-2 alloy components. This is due to the reduced tendency to precipitate deleterious intermetallic phases in B-3 alloy, thereby, affording it greater ductility than B-2 alloy during and following various thermal cycling conditions.
HASTELLOY B-3 alloy has good overall forming and welding characteristics. It may be forged or otherwise hot-worked, providing that it isheld at 2250°F (1230°C) for a time sufficient to bring the entire piece to
temperature. Since it is a low carbon alloy, the use of lower hot finishing
temperatures may be necessary to achieve grain size control.
B-3 alloy may also be formed by cold working. Although it does work-harden somewhat rapidly, B-3 alloy components can be made using all common cold forming techniques.
Limited tests in boiling 20 percent hydrochloric acid indicate that the uniform corrosion resistance of B-3 alloy is not affected by cold reductions up to 50 percent as compared to that of the alloy in the solution heat-treated condition.
B-3 alloy can be welded by all common welding techniques, although oxyacetylene and submerged arc welding processes are not recommended when the fabricated item is to be used in corrosive service. Special precautions should be taken to avoid excessive heat input.
Heat Treatment
All wrought forms of HASTELLOY B-3 alloy are furnished in the solution heat-treated condition unless otherwise specified. B-3 alloy is solution heat-treated at 1950°F (1065°C) and rapid quenched, except for bright annealed sheet or coil
products which are heat-treated at 2100°F (1150°C) and cooled in hydrogen.
Available in Wrought Form
HASTELLOY B-3 alloy is available in the form of plate, sheet, strip, billet, bar, wire, pipe and tubing.
Applications
HASTELLOY B-3 alloy is suitable for use in all applications previously requiring the use of HASTELLOY B-2 alloy. Like B-2 alloy, B-3 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.
Specifications
HASTELLOY B-3 alloy (UNS N10675) is covered by ASME Section VIII, Division 1. The alloy is covered under ASTM specifications B 333 (plate, sheet, and strip), B 335 (bar), B 366 (welded pipe), B 622 (seamless pipe and tubing), and B 626 (welded tubing). The DIN specification is 17744 No. 2.4600 (all forms), TUV Werkstoffblatt 517 (all forms).
Applicable Patent Coverage
HASTELLOY B-3 alloy is covered under U.S. Patent 6,503,345 B1, in Europe under EP 0 628 088 B1 as well as under a number of patents in other countries around the world.
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