Super Alloy INCONEL 22 (UNS N06022)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Applications

Introduction

Super alloys are high performance alloys that are known for their excellent resistance to creep at elevated temperatures, superior mechanical strength, good surface stability, and good corrosion and oxidation resistance.

Super Alloy INCONEL 22 is a fully austenitic advanced corrosion-resistant alloy. Apart from providing good resistance to general corrosion, stress corrosion cracking, crevice corrosion, pitting, and intergranular attack, this alloy has the ability to resist aqueous corrosion and attack at high temperatures.

The following section explains in detail about super alloy INCONEL 22.

Chemical Composition

The chemical composition of INCONEL 22 is outlined in the following table.

Element Content (%)
Nickel. Ni 50.01 - 63
Chromium, Cr 20 - 22.5
Molybdenum, Mo 12.5 - 14.5
Iron, Fe 2-6
Tungsten, W 2.5 - 3.5
Cobalt, Co ≤ 2.5
Manganese, Mn ≤ 0.50
Vanadium, V ≤ 0.35
Silicon, Si ≤ 0.080
Phosphorous, P ≤ 0.020
Sulfur, S ≤ 0.020
Carbon, C ≤ 0.015

Physical Properties

The physical properties of INCONEL 22 are tabulated below.

Properties Metric Imperial
Density 8.61 g/cm3 0.311 lb/in3
Melting point 1351 - 1387 °C 2464 - 2529 °F

Mechanical Properties

The following table shows mechanical properties of INCONEL 22.

Properties Metric Imperial
Tensile strength 772 MPa 112000 psi
Yield strength 365 MPa 52900 psi
Elongation at break 54% 54%
Elastic modulus 209 GPa 30300 ksi
Hardness, Rockwell B 89 89

Thermal Properties

The thermal properties of INCONEL 22 are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@193°C/379°F) 12.42 µm/m°C 6.900 µin/in°F
Thermal conductivity (@23°C/73.4°F) 7.3995 W/mK 51.353 BTU in/hr.ft².°F

Fabrication and Heat Treatment

INCONEL 22 can be readily fabricated using the conventional processes applied for nickel alloys. The high ductility of this alloy allows easy cold forming. Work hardening of this alloy might require intermediate annealing. Welding processes that can be used are gas tungsten-arc, gas metal-arc, and shielded metal-arc processes.

Applications

INCONEL 22 is used in following application areas:

  • In the marine sector
  • In waste disposal industries
  • In pulp and paper processing
  • In chemical/petrochemical processing
  • In pollution control (flue gas desulfurization)
  • For protection of waterwalls, boiler tubes, and other components in coal-fired electric power generation boilers.

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