Ferrite impeder cores are used for concentration of magnetic flux in high frequency, RF, induction welding of steel tubes and pipes. In this application ferrite core experiences temperature upto 150°C and the core properties must be optimized for this environment. Properties which influences the efficiency and the speed of the process are :
- A high permeability (p) material to ensure high degree of magnetic flux concentration.
- A high Saturation flux density Bs, at the working temperature, which determines, the maximum field in which the ferrite core can usually perform.
- A high curie temperature at which the material ceased to concentrate magnetic flux, due to loss of ferrimagnetic properties.
For these applications, special ferrite materials are offered - They are having following excellent physical properties.
(a) High Curie temperature and a low temperature dependence of the initial permeability and of magnetic flux density in the working temperature range.
(b) A high saturation flux density in the working temperature range upto150 °C.
(c) Low losses with increase of temperature.
(d) A relative high amplitude permeability.
(e) A high stability of the initial permeability vs. frequency upto 1 MHz.
Following four types of Impeder Core are produced and supplied :
1. Solid Plain Core - P
2. Solid Fluted Core - F
3. Hollow Plain Core - PH
4. Hollow Fluted Core - FH
The overall straightness of Impeder Core is excellent and is controlled by passing it through a 200 mm long gauge with an inner diameter equal to, nominal outer diameter of the Core plus 1.0 mm.
All types of Impeder Core are supplied in a nominal length, equal to 200 + 5mm.
Primitive Compasses, Diamond or Cubic Boron Nitride, Impeder Coolant Systems, High Frequency Welding of Tubes and Pipes etc.