In the manufacturing and repair industry there is often the need to join components via an interference fit.

An increasingly popular method is to shrink one of the components using the cold properties of liquid nitrogen at -196oC.

Parts ranging from large axles to small bushes are immersed either partially or totally until the item has shrunk sufficiently to to be inserted into the other component. The time taken to achieve this shrinkage is relatively short and the combined items return to normal temperature over a similar time scale.

For this technique to work properly there must be a specific interference fit between the parts being secure.

• It is quick, clean and safe
• There is no distortion or scoring - reduced scrapping
• Minimum metallurgical changes e.g. hardness of the metal
• Low capital outlay
• Can be carried out on the smaller component
• Can be carried out on sections of a component

Liquid nitrogen shrink fitting is one of the safest assembly methods. Liquid Nitrogen is inert and non toxic, so there is little risk of explosion or contamination.

See our product information section for more details on the properties of liquid nitrogen.

When handling liquid nitrogen BOC Cryospeed recommend that you follow suitable safety precautions:

• Avoid contact with the skin as intense cold can produce cold burns. See our cryogenics safety section for more information.
• Avoid use in enclosed spaces. See our risks of oxygen deficiency safety section for more information.
• All operators should wear personal protective clothing such as cryogenic gloves and goggles. BOC Cryospeed can supply all your cryogenic equipment requirements.