Nov 15 2012
Topics Covered
Introduction
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Forging
Cold Working
Annealing
Applications
Introduction
Niobium is a soft and light weight metal, and is sometimes also referred to as columbium. It forms a bluish cast when it is exposed to air for a long period of time. Alloys used in aerospace, electronics, and medical industries are produced by adding niobium to nickel or iron. It has high malleability, corrosion resistance and ductility. It is not naturally found in a free state. The chemical and physical properties of niobium are very similar to that of tantalum.
The following datasheet gives more details about niobium.
Physical Properties
The physical properties of niobium are highlighted in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
8.57 g/cm³ |
0.310 lb/in³ |
|
Melting point |
2415°C |
4380°F |
Mechanical Properties
The mechanical properties of niobium are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
275 - 585 MPa |
39900 - 84800 psi |
|
Yield strength (@ strain 0.200%) |
207 MPa |
30000 psi |
|
Modulus of elasticity |
103 GPa |
14900 ksi |
|
Elongation at break |
5-30% |
5-30% |
|
Hardness, Vickers |
80 - 120 |
80 - 120 |
Thermal Properties
The thermal properties of niobium are displayed in the following table.
|
Thermal Properties |
Metric |
Imperial |
|
Thermal conductivity |
52.3 W/mK |
363 BTU in/hr. ft².°F |
Other Designations
Other designations that are equivalent to niobium are:
-
ASTM B391
-
ASTM B392
-
ASTM B393
-
ASTM B394
Fabrication and Heat Treatment
Machinability
Niobium can be machined using high speed tooling with good lubrication. It can be modified similar to lead or soft copper. It has high gall tendency.
Forming
Niobium can be easily formed, stamped and spun due to its low work hardening rate.
Welding
Niobium can be welded using TIG welding method with small modifications. Inert gas is used for covering a weld pool on back and a face of the weld area.
Forging
At room temperature, niobium is cold forged from ingot.
Cold Working
Niobium has good cold working characteristics.
Annealing
Niobium is annealed by heating at 1200°C (2192°F) in vacuum or inert gas. It can be stress relieved at 800°C (1472°F).
Applications
Niobium finds applications in the following areas:
-
Nuclear power industry
-
Jet engine components
-
Optics
-
Electronics
-
Advanced air frame systems
-
Numismatics
-
Jewellery