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HAYNES® Alloys

30451For Hot-Dip Galvanizing Process Hardware

Molten zinc is one of industry’s most aggressive high-temperature environments. In hot-dip galvanizing processes, chains, hooks, baskets, racks, trays, T/C protection tubes, and all sorts of other immersed components can simply dissolve away before your eyes! But you can minimize dissolution and bath contamination problems with HAYNES® 556® alloy. The 556 alloy combines resistance to molten zinc with excellent high-temperature strength, so you can design your components to weigh less and last longer

Product Description

HAYNES 556 alloy is an iron-nickel-chromium-cobalt alloy that combines effective resistance to sulfidizing, carburizing, and chlorine-bearing environments at high temperatures with good oxidation resistance, fabricability, and excellent high-temperature strength. It has also been found to resist corrosion by molten chloride salts and molten zinc.

30452

HAYNES 556 alloy is highly useful for service at elevated temperatures in moderately to severely corrosive environments. Applications include tubing and structural members in waste heat recuperators, super heaters, and internals in municipal and chemical waste incinerators; power plant burner buckets, air nozzles and fluidized bed combustor heat exchangers and internals; high speed furnace fans, galvanizing bath hardware and brazing fixtures; and high-temperature rotary calciners and kilns. There are also additional uses in the chemical/petrochemical process and pulp and paper industries.

Corrosion of Alloys Exposed in 850°C (454°C) Zinc for 50 Hours
Alloy Base Metal Loss*
556® Iron 1.6
25 Cobalt 2.3
188 Cobalt 2.5
446 Iron 9.3
800H Iron 11.0
304 Iron 14.1
625 Nickel >24.0
X Nickel >24.0

Nominal Composition

Iron: Balance
Nickel: 20
Cobalt: 18
Chromium: 22
Molybdenum: 3
Tungsten: 2.5
Tantalum: 0.6
Nitrogen: 0.2
Silicon: 0.4
Manganese: 1
Aluminum: 0.2
Carbon: 0.1
Lanthanum: 0.02
Zirconium: 0.02

Typical Tensile Properties, Plate

Test Temperature 0.2% Yield Strength Ultimate Tensile Strength Elongation
°F °C ksi MPa ksi MPa %
RT RT 55 375 116 805 51
1000 540 31 210 90 625 60
1200 650 31 210 83 575 57
1400 760 29 200 69 470 53
1600 870 28 190 49 340 69
1800 980 19 130 31 210 84
2000 1095 9 60 16 110 95

Typical Rupture Properties, Plate

Test Temperature Typical Rupture Properties: Stress Required to Produce Rupture in Hours Shown
100 h 1,000 h 10,000 h
°F °C ksi MPa ksi MPa ksi MPa
1400 760 25.0 172 17.5 121 11.9 82
1500 815 17.0 117 11.8 81 7.8 53
1600 870 11.5 79 7.5 52 4.9 34
1700 915 7.6 52 4.8 33 3.0 21
1800 980 4.8 33 3.0 21 1.9 13

Typical Room Temperature Physical Properties

Physical Property British Units Metric Units
Density 0.297 lb/in3 8.23 g/cm3
Electrical Resistivity 37.5 µohm-in 95.2 µohm-cm
Modulus of Elasticity 29.7 x 106 psi 206 GPA
Thermal Conductivity 77 Btu-in/ft2-h-°F 11.1 W/m-°C
Specific Heat 0.111 Btu/lb-°F 464 J/Kg-°C

Environmental Resistance

Oxidation in Air - Excellent at 2000°F (1095°C)

Sulfidation - Second only to Co-base alloys

Molten Chloride Salts - Equal to alloy X

Chlorination - Very good to 1650°F (900°C)

Carburization - Equal to alloy 800H

Molten Zinc - Best Available

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