Nov 14 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Applications
Introduction
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 |
Applications
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