In on-site operation and maintenance, if the power density of a bolt electric heating rod is set too high, the local surface temperature of the rod body can easily exceed the allowable range of the bolt material, potentially causing changes in metallographic structure; if set too low, the heating rate is slow, and a typical working condition requiring heating to 450°C within 30 minutes may not be met. In addition, when the heating rod is energized at rated voltage in air for 2-3 minutes, there must be no overheating phenomenon, the insulation resistance must not be less than 0.5MΩ, and the leakage current must not exceed 0.5mA per kilowatt. These parameters are directly related to the safety and efficiency of disassembly and assembly operations.
The ZDR-450 type bolt electric heating rod is designed in accordance with the ZBK54019-88 industry standard, and balances power density and material matching to address the above problems. The rod body uses a stainless steel sheath, with the internal heating wire and magnesium oxide powder densely filled, ensuring no overheating when energized at rated working voltage for 2-3 minutes, cold insulation resistance not less than 0.5MΩ, and leakage current not greater than 0.5mA per kilowatt. The 450 in the model indicates the applicable bolt specification range; specific power and length can be selected according to bolt size, making it convenient to select on site by referring to the parameter table.
This heating rod is mainly used for heating and disassembly/assembly of bolts in equipment such as steam turbines and large compressors. During operation, ensure that the heating rod is inserted fully into the center hole of the bolt, connect the rated voltage, and control the heating time according to process requirements. Before use, check the insulation resistance; if it is below 0.5MΩ, drying treatment is required. During heating, avoid striking or bending the rod body to prevent damage to the internal structure.
