Hastelloy alloy B3 is another member of the nickel-molybdenum family of alloys with thermal stability better than that of Hastelloy B-2. Hastelloy B 3 has excellent resistance to pitting, corrosion, and cracking due to stress corrosion. It has extra-ordinary resistance to hydrochloric acid at every concentration and range of temperatures.
|ALLOY B-3||NO||NAME||NiMo29Cr||B 333, B 622, B 619, B 366|
The main function of the Hastelloy B 3 alloy is to remain intact under high-stress, high-temperature applications; the primary advantage of Hastelloy B 3 is its resistance to hydrochloric acid at every temperature and concentration. This alloy possesses resistance to other vigorously corrosive agents too.
Alloy B3, like most nickel alloys, has excellent resistance to corrosion. Alloy B3 is particularly beneficial in chemical processes with highly corrosive acids at temperatures that would normally create rapid and catastrophic corrosion.
Hastelloy B 3 can also withstand sulfuric, acetic, formic, and phosphoric acids, along with other non-oxidizing media. It has extremely well structural stability as compared to previous B-type alloys, which is useful in eliminating concerns during welding, fabrication, and service.
Fabrication and Heat Treatment
Hastelloy B-3 alloy throughout cold-working techniques is also an ideal option while forming components. Alloy B3 material hardens instantly while cold-working, which leads to more stages of cold-working and annealing. Cold working can further reduce alloy B3’s resistance to stress corrosion cracking.
|Grade||Density (g/cm3)||Elastic Modulus (GPa)||Coeff of Thermal Expansion (μm/m/°C)||Thermal Conductivity (W/m.K)||Electrical Resistivity (Ωμ.m)||Elastic Modulus (GPa)||Specific Heat (J/Kg.K)||Melting Range|
|Alloy B-3||7.69||220||0-100°C||0-100°C||1.37||216||at 100°C||1370-1418|
Where B-2 alloy embrittles very quickly while heat treating, Hastelloy B 3 normally takes several hours to brittle. Alloy B3 material has a strong resistance to pitting stress-corrosion cracking, as well as knife-line and heat-affected zone attack.
Alloy B 3 can be forged or even hot-worked, considering it is held at 2250°F for a sufficient amount of time to bring the entire material piece to the desired temperature. Since it is a low carbon alloy, it may be necessary to use the lower hot finishing temperatures to achieve grain size control. It may also be formed by cold working.
Hastelloy B 3 possesses overall good forming and welding characteristics. A low carbon content allows Hastelloy B 3 to be used in the as-welded state. All regular welding techniques may be used with alloy B3, however, oxyacetylene and submerged arc welding techniques are not suggested when the fabricated item is to be utilized in corrosive working environments.
Applications of Hastelloy B 3
Hastelloy B 3 is popularly used in the production and processing of various concentrated acids. Alloy B3 is also used to produce mechanical components and vacuum furnaces.
Hastelloy B 3 also has various applications in chemical processing. These applications include making plants for ethylbenzene, phenol, and acetic anhydride manufacturing. The pressure vessels utilized while chloroprene production, nuclear reactors, chemical reactors and distillation equipment are created with Hastelloy B3 alloy.
NOTE: Hastelloy B3 is a registered trademark of Haynes International Inc.