Bolt Electric Heating Rod
0 The bolt electric heating rod is an electric heating device specially used for the installation and removal of large bolts in steam turbines and other pressure-containing vessels. Below is a comprehensive introduction for you:
Working Principle
The bolt heating rod is inserted into the center hole of the bolt and heated by electricity. It uses current passing through a high-resistance electric heating alloy wire to generate heat, causing the bolt to expand and elongate. After expansion, the nut can be easily tightened or removed. After cooling, the bolt contracts, achieving precise preload control. The entire process requires no open flame and is safe and reliable.
Main Technical Parameters
According to industry standard ZBK54019-88, the core parameters of the bolt heating rod are as follows:
Rated voltage: 220V±20V / DC 100V / low voltage 50V
Surface power density: 811W/cm²
Power deviation: ±5%
Working temperature: 400℃
Diameter specifications: 10mm30mm
Length range: 100mm4500mm
Insulation resistance: ≥50MΩ
Withstand voltage: 1500V/1min without breakdown
Cumulative service life: no less than 50 hours
Applicable bolt center hole diameter: 22.6±0.2mm (other specifications can be customized) Structure and Materials
Heating element: 0Cr27A17Mo2 high-resistance electric heating alloy wire
Protective sleeve: 1Cr18Ni9Ti heat-resistant stainless steel tube
Insulation material: high-purity magnesium oxide powder (must be dried before use)
Structure type: divided into hard tube type, flexible tube type, and semi-flexible type, and must be used with a DC adjustable control cabinet
Instructions for Use
Preparation: Confirm that the power is off, and insert the heating rod into the center hole of the bolt to be heated
Energize and heat: Connect the power supply, and set the heating time according to the bolt specifications (usually 1020 minutes each time)
Removal/tightening: After the bolt expands, quickly perform the nut operation
Removal: After power off, remove the heating rod and wait for the bolt to cool naturally
During heating, ensure uniform heating, and local overheating is strictly prohibited; the heating position is the screw section, and direct heating of the thread and nut parts should be avoided.
Core Advantages
Efficient and fast: Heating is completed in a short time, greatly shortening installation and removal time
Safe and reliable: No open flame, no flammable materials, equipped with automatic power-off protection
Precise temperature control: Heating temperature can be precisely controlled to avoid overheating damage to bolts
Wide application: Suitable for large bolt operations in electric power, chemical, petroleum, heavy machinery, and other industries
🛒 Selection Points
Match bolt specifications: Ensure that the fit clearance between the heating rod diameter and the bolt center hole is reasonable (total clearance 0.81.3mm)
Power density: Standard selection is 811W/cm²
Explosion-proof requirements: Explosion-proof products should be selected for flammable and explosive places such as petrochemical sites
Intelligent temperature control: For temperature-sensitive high-alloy steel bolts, models equipped with PID temperature control modules are recommended
Usage scenarios: For high-altitude or confined spaces, lightweight portable models can be selected
