Shrink Fitting

Induction shrink-fitting is used for inserting a concentric metal component into another concentric metal component. The metal component, which will house the other component, is heated to expand the hole in the component. After the expansion the other metal component is inserted into it. Once cooled, the components cannot be separated without significant force, or by reheating and reversing the process.

The induction shrink fitting process requires little or no pressure for assembly and is preferred in mechanical assembly of delicate parts where it is detrimental to apply mechanical pressure.

The main advantages of thermal shrink fitting are the reduction of stresses and residual deformations. It is also a quick and effortless process with minimal risk of mechanical damage to the component.

Typically, a lower temperature range is used on metals such as aluminum and higher temperatures are used on metals such as low/medium carbon steels. The low temperature avoids degrading of mechanical properties

Metals typically expand in response to heating and contract on cooling; this dimensional response to temperature change is expressed as a coefficient of thermal expansion.

Advantages/Benefits

• The induction heater heats only the part, not the atmosphere around it, making the process energy efficient and fast with process consistency and repeatability.
• The induction heating process produces a highly uniform and consistent heat.
• This often allows less heat to be used for a given process. Easy reversibility of the process for removal.