What is the appropriate clearance between the bolt center hole and the heating rod? A total clearance of 0.8~1.3mm is a common fit range; too large will reduce heat transfer efficiency, while too small will make installation and removal difficult. The following outlines key points from a selection perspective.
The heating rod diameter should match the bolt center hole, with a recommended total clearance of 0.8~1.3mm. The power density is generally 8~11W/cm², which can be adjusted according to bolt specifications and heating time requirements. The applicable standard is ZBK54019-88 "Electric Heaters for Steam Turbine Bolts".
For temperature-sensitive high-alloy steel bolts, models with a PID temperature control module are recommended. Explosion-proof products should be selected for flammable and explosive locations such as petrochemical sites. The equipment has an automatic power-off protection function and no open flame.
It can be used with the DJ22-54 DC adjustable bolt heating control cabinet, with an adjustable DC output voltage of 0~220V and support for up to 12 load circuits. It is suitable for large bolt disassembly and assembly operations in industries such as power, chemical, petroleum, and heavy machinery.
For high-altitude or confined spaces, lightweight portable models can be selected. The heating rod should avoid mechanical damage and be kept dry during storage.
