Super Alloy INCONEL 693 (UNS N06693)

Topics Covered

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

Introduction

Super alloys also known as high performance alloys are used in environments with very high temperature where deformation resistance and high surface stability are very important. These alloys have good oxidation and creep resistance.

INCONEL alloy 693 provides resistance to high temperature corrosion mechanisms. The alloy also has excellent resistance to metal dusting in chemical and petrochemical processing environments. The alloy's high chromium content provides it excellent resistance to oxidation and sulfidation. It possesses excellent mechanical properties.

The following section explains in detail about super alloy INCONEL 693.

Chemical Composition

The chemical composition of INCONEL 693 is outlined in the following table.

Element Content (%)
Nickel. Ni 53.34 - 67.5
Chromium, Cr 27 - 31
Iron, Fe 2.5 - 6
Aluminum, Al 2.5-4
Titanium, Ti ≤ 1
Manganese, Mn ≤ 1
Niobium, Nb 0.50 - 2.5
Copper, Cu ≤ 0.50
Silicon, Si ≤ 0.50
Carbon, C ≤ 0.15
Sulfur, S ≤ 0.010

Physical Properties

The physical properties of INCONEL 693 are tabulated below.

Properties Metric Imperial
Density 7.77 g/cm3 0.281 lb/in3
Melting point 1317 - 1367 °C 2403 - 2493 °F

Mechanical Properties

The following table shows mechanical properties of INCONEL 740.

Properties Metric Imperial
Tensile strength (hot-rolled and annealed plate) 882.6 MPa 128000 psi
Yield strength 489.5 MPa 71000 psi
Elastic modulus 137 GPa 19900 ksi
Elongation at break 42% 42%

Hardness, Rockwell C

Thermal Properties

The thermal properties of INCONEL 740 are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@100°C/212°F) 13.04 µm/m°C 7.244 µin/in°F
Thermal conductivity (@23°C/73.4°F) 9.10 W/m-K 63.2 BTU in/hr.ft².°F

Fabrication and Heat Treatment

INCONEL 693 is easy to fabricate by using the traditional methods. The forming and machining characteristics are similar to those of INCONEL 600 or 690.

Welding

Weldability of INCONEL 693 is good especially for matching and dissimilar joints. It is recommended that this process be performed in the annealed condition. The two commonly used welding processes are gas tungsten arc-welding and gas metal-arc welding. The ideal filler metal is INCONEL Filler Metal 53MD, which is a near-matching composition welding product.

Annealing

Annealing of INCONEL 693 is performed by heating to 1010° to 1066°C (1850°-1950°F), holding for a time corresponding with section thickness, which is followed by rapid cooling in air or water quenching.

Applications

INCONEL 740 is chiefly used in the following application areas:

  • Petrochemical for syntheses gas production
  • Water to energy and biomass incinerators
  • Thermal processing
  • Burner nozzles
  • High-temperature fuel cell reformers

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