Super Alloy Cobalt 6B (UNS R30016)

Topics Covered

Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties


Super alloys have good creep and oxidation resistance, and can function at very high temperatures and severe mechanical stress. Their strength can be increased by solid-solution hardening, precipitation hardening, and work hardening. They are available in different forms, and comprise a wide range of elements in a variety of combinations so as to achieve the desired result. There are three groups of super alloys, namely cobalt-based, nickel-based, and iron-based alloys. All these alloys can function at temperatures above 540°C (1000°F).

Super alloy cobalt 6B is a cobalt-based chromium- tungsten alloy. It has good wear and cavitation erosion resistance. The following datasheet gives more details about super alloy cobalt 6B.

Chemical Composition

The following table shows the chemical composition of super alloy cobalt 6B.

Elements Content (%)
Cobalt, Co 65
Chromium, Cr 28-32
Tungsten, W 3.50-5.50
Iron, Fe 3
Nickel, Ni 3
Manganese, Mn 2
Molybdenum, Mo 1.50
Carbon, C 0.90-1.40

Physical Properties

The physical properties of super alloy cobalt 6B are given in the following table.

Properties Metric Imperial
Density 8.39 g/cm³ 0.303 lb/in³

Mechanical Properties

The mechanical properties of super alloy cobalt 6B are displayed in the following table.

Properties Metric Imperial
Tensile strength 1000 MPa 145000 psi
Yield strength 621 MPa 90100 psi
Elongation at break 12% 12%
Hardness, Brinell (estimated from Rockwell C) 346 346
Hardness, Knoop (estimated from Rockwell C) 413 413
Hardness, Rockwell A (estimated from Rockwell C) 69.5 69.5
Hardness, Rockwell C 36-40 36-40
Hardness, Vickers (estimated from Rockwell C) 362 362

Thermal Properties

The thermal properties of super alloy cobalt 6B are given in the following table.

Properties Metric Imperial
Thermal conductivity ( @ 0-100°C/32-212°F) 14.8 W/mK 103 BTU in/hr.ft².°F


Super alloy cobalt 6B has the following applications:

  • Chain saw guide bars
  • Furnace fan blades
  • Steam turbine erosion shields
  • High temperature bearings
  • Food processing equipment
  • Centrifuge liners
  • Valve stems
  • Needle valves
  • Nozzles
  • Hot extrusion dies
  • Extruder screws
  • Forming dies
  • Pump plungers
  • Valve parts

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