Cold shrink fitting
Precision shrink fitting on large components
Cold shrink fitting is a process that allows two complementary shaped components to be joined, creating a sort of “interlocking weld” without the use of heat or mechanical deformation.
The technique uses liquid nitrogen at -196°C, which causes slight contraction of one component, allowing it to be perfectly inserted into the other. Once the piece returns to room temperature, the bond becomes extremely strong and stable.
This method has become highly important in the construction of transmissions and gearboxes, proving particularly effective for the coupling of shafts and gears, as well as for any application requiring a precise and durable connection.
Applications of Cryogenic Shrink Fitting
Cold shrink fitting can be used for both single-piece and mass production, always ensuring maximum precision and reliability. Some typical examples include:
- Valve seats and guides, automatically shrink-fitted into cylinder heads
- Gearboxes and other mechanical components requiring stable and durable assemblies
- Shafts and gears of cable car reducers
- Wheels of port cranes
- Shafts of 30-ton rolling mills
Thanks to the precision of cold shrink fitting, it is possible to achieve extremely strong assemblies without altering the geometry or structure of the materials.
Advantages of Cryogenic Shrink Fitting
Cold shrink fitting offers numerous advantages, especially when it is necessary to assemble shafts, collars, or similar components with gears or large housings, or when interference fits must provide high strength. The main benefits are:
- Higher joint strength compared to a simple press fit
- Material structure and component geometry remain unchanged, avoiding unwanted deformations
- Simple and fast assembly, allowing shrink fitting to be performed directly on site
- Low investment costs, making the process accessible even for small productions or one-off interventions
Cryogenic shrink fitting thus proves to be a reliable, effective, and versatile solution for anyone needing precise, durable assemblies without compromising material quality.
Custom Shrink Fitting
We have a dedicated department for cryogenic and thermal shrink fitting, capable of handling a wide range of temperatures and sizes. We perform cold shrink fittings using liquid nitrogen at -196 °C and dry ice at -78.5 °C, as well as gas nitrogen shrink fittings from 0 °C to -150 °C. We also offer hot shrink fittings up to +450 °C and mixed cold/hot processes, with specific positive or negative temperatures, according to customer requirements.
We handle components up to 3,000 kg and valve spheres up to 40”. For large-scale operations, the department is equipped with:
- Liquid nitrogen tank: Ø 1,750 × H 2,800 mm
- Cryogenic gas nitrogen box: 4,300 × 2,100 × H 1,800 mm
- Heating oven: 1,500 × 4,000 × H 2,000 mm
We also perform sub-zero heat treatments, ideal for:
- Transformation of residual austenite into martensite
- Crack detection
- Shrink fitting operations requiring superior dimensional stability
