Close-up of induction heating coil applied to turbine bolts
Induction Heating
Bolt Expansion System
An induction-based system for fast, safe and precise expansion of bolts used in turbines and heavy-duty assemblies.
Manufactured byENRX
Up to 50%Faster than flame
10 mFlexible cables
TwinTwo bolts at once
Overview
Bolt expansion for turbines
Induction heating is a fast, controlled and highly efficient method for expanding bolts in steam and gas turbines. A specially designed induction coil is inserted directly into the bolt, generating localized heat that expands the bolt by a precise predetermined amount, enabling easy removal of the nut without damaging the threads.
Because the heating process is extremely rapid, heat does not migrate to the thread area, preventing thread damage and eliminating the risk of rods melting inside the bolt—an issue often seen with resistance or flame heating. Operators can pre-set key parameters such as temperature, ramp-up time and dwell time, ensuring repeatable and consistent bolt expansion quality.
the Minac 25/40 Twin, which features two independent handheld transformers powered by one compact converter. This enables a single operator to heat two bolts simultaneously, effectively doubling productivity.
Applications
Where bolt expansion is used
Induction heating used for expanding large industrial bolts during assembly and maintenance
Induction heating coil applied to bolts during turbine maintenance
Bolt expansion in steam and gas turbines
Bolt loosening in heavy industrial equipment
Maintenance tasks requiring controlled, localized heating
Power plants and turbine overhaul environments
Petrochemical and processing facilities
Features
Coils, control and mobility
- Rapid, precisely controlled bolt expansion
- Prevents thread damage due to localized heating
- Eliminates rod-melting issues common in flame/resistance heating
- Pre-programmable temperature, ramp-up and dwell settings
- Quick-release, specially shaped coils for different bolt geometries
- Angle adapters for fast coil insertion
- Mobile Minac systems with up to 10 m flexible cables
- Minac Twin version allows simultaneous two-bolt heating
- Compact and hoist-friendly design for scaffolding and elevated work
Benefits
Faster, safer turbine maintenance
Up to 50% faster than flame or resistance heating
Safer operation with no open flames or overheated rods
Higher maintenance efficiency and reduced downtime
Improved bolt integrity and consistent repeatability
Increased productivity with Twin systems
Suitable for tight maintenance windows in turbines
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