Cold Expansion is a tried and tested fatigue enhancement technology from the Aerospace Industry.
Aircraft and other metal structures are made up of a number of assemblies that are riveted or bolted together. Attaching holes are a necessary part of the design. However, these holes concentrate stresses and under cyclic tensile loads are primary sources of fatigue cracks, which start from microscopic defects in the material. Over a period of time these cracks can result in fatigue failure of the structure.
Torrent Trackside are the sole UK supplier for the proven Split Sleeve Cold Expansion system that prevents these cracks from becoming serious problems.
The RailTec System was developed for the rail industry and is based on FTI's Split Sleeve Cold Expansion System. The flexibility of the system enables it to be easily applied to all main line or branch line track as part of routine maintenance. Rail with small fatigue cracks can be reworked and safely returned to service. Additionally, the system can be used during the manufacture of rails, frogs, and switches.
The cold expansion process increases the life of a bolt hole by producing a zone of residual compressive stresses around the hole. This is achieved by drawing an oversized, tapered mandrel through an internally pre-lubricated split sleeve in the hole. When the mandrel passes through the hole, the combined major diameter of the mandrel and thickness of the sleeve enlarge the hole, yielding the material directly around the hole and creating the protective zone of residual stress. This zone protects the hole from the stresses applied to the rail end and significantly decreases the probability of fatigue cracks. The cold expansion process, when applied to typical rail stock, increases the life of the bolt hole by at least 3:1.
Some of the benefits include: - Improves the fatigue life of the hole by at least 3:1
- Arrests the growth or small cracks
- Cost-effective alternative to new track
- Reduces maintenance and inspection costs
- Increases the overall structural integrity and safety of the line
The RailTec SystemRailTec system tooling is both flexible and durable. To facilitate track maintenance, the FT-600 PowerPak incorporates a gasoline powered engine to drive the hydraulic pump. An electric powered version, the FT-700, is available for workshop environments or where electric power is preferable.
The RailTec tooling system includes:- Mandrel
- Jaws
- Split Sleeves
- Combination Gage
- Mandrel Gage
- Nosecap
- Puller
- Power Par
The RailTec System was developed for the rail industry and is based on FTI's Split Sleeve Cold Expansion System. The flexibility of the system enables it to be easily applied to all main line or branch line track as part of routine maintenance. Rail with small fatigue cracks can be reworked and safely returned to service. Additionally, the system can be used during the manufacture of rails, frogs, and switches.
The cold expansion process increases the life of a bolt hole by producing a zone of residual compressive stresses around the hole. This is achieved by drawing an oversized, tapered mandrel through an internally pre-lubricated split sleeve in the hole. When the mandrel passes through the hole, the combined major diameter of the mandrel and thickness of the sleeve enlarge the hole, yielding the material directly around the hole and creating the protective zone of residual stress. This zone protects the hole from the stresses applied to the rail end and significantly decreases the probability of fatigue cracks. The cold expansion process, when applied to typical rail stock, increases the life of the bolt hole by at least 3:1.
Some of the benefits include: - Improves the fatigue life of the hole by at least 3:1
- Arrests the growth or small cracks
- Cost-effective alternative to new track
- Reduces maintenance and inspection costs
- Increases the overall structural integrity and safety of the line
The RailTec Process
Step 1. Measure the diameter of the hole using the Mandrel Selection Gage
Step 2. Slide the internally pre-lubricated split sleeve over the selected mandrel
Step 3. Insert and seat the mandrel/sleeve assembly into the hole ensuring that the tang end of the mandrel is on the outside of the rail
Step 4. Place the nosecap of the puller unit down onto the tang end of the mandrel. Make sure the nosecap is flush against the rail
Step 5. Activate the puller unit to pull the mandrel through the sleeve and cold expand the hole
Step 6. Remove the used sleeve from the hole and discard