Induction Shrink Fitting
Induction heating equipment is commonly used for induction shrink fitting, which can be performed quickly and with great precision when using a properly designed system. Induction shrink fitting uses electromagnetic induction heating technology to pre-heat metal components between 150 °C (302 °F) and 300 °C (572 °F) to cause them to expand and allow the insertion or removal of another component. Usually, the lower temperature range is used on non-magnetic or paramagnetic metals such as aluminum and titanium while higher temperatures are used on magnetic metals such as low/medium carbon steels. The process avoids changing mechanical properties of the metals while allowing components to be worked.
Above is an induction heating shrink fitting system for shrink fitting bushings into aerospace components for both industrial and military applications. The system is designed for individually heating six (6) locations in the housing. The power supply, coaxial cable for remote heating, three (3) inductors, infrared temperature sensor with closed loop feedback for automatic power control, chilled water cooling system and mounted to a fabricated rugged heavy duty aluminum stand for portability and protection of the sensitive components.
Above are the induction heating components for shrink fitting a truck rear differential housing and axle tube housings together. The system consists of two power supplies, chilled water cooling recirculating unit, two (2) water cooled multi-turn inductors, two (2) remote control panels and two (2) infrared monitoring and closed loop power control units. The heating is accomplished with the use of two (2) ID heating inductors that will be cast into a ceramic casing before being inserted at each side of the differential housing for heating the opening before automatically inserting the axle housings to complete the assembly.
Shown above is an induction heating system designed for shrink fitting titanium bushing inserts into a titanium alloy component for aerospace applications. The induction heating power supply, 18 foot coaxial cable, inductor, shrink fitting fixture and chilled water recirculating system is mounted to a heavy duty aluminum fabricated stand with caster for portability. The unit can be used for manual or robotic positioning for heating and automatic insertion of bushing assembly. Infrared temperature sensing and closed loop feedback for automatic power control is used to assure consistent and precise assembly. System can also be used in reverse for removing bushings for planned maintenance service and repair operations.
Electroheat Technologies induction heating systems are being used to shrink fit fuel channel nuclear cooling rod tube assemblies for use in critical water cooling during steam generation from nuclear reactor operations. Assemblies are over 7 in in diameter and over 8 feet long, weighing 800lbs and require special robotic handling equipment to position and transfer cooling ring onto OD of ½ wall high nickel alloy machined tube.