KPMBOLT super nuts adopt 100% full inspection, suitable for thermal power boilers, feed pumps and high-pressure flanges, resistant to high temperature and creep, maintaining stable preload and preventing flange leakage.

Thermal power generation remains the mainstay of China’s energy supply. Core equipment such as boilers, high-pressure feed pumps, main steam pipelines and high-temperature flanges operate continuously under extreme conditions of high temperature, high pressure and thermal alternating load. Frequent unit start-up and shutdown cause thermal expansion and contraction. Ordinary standard nuts are prone to preload attenuation, thread creep, loosening and flange sealing leakage under long-term thermal stress. Once leakage occurs, it leads to heat loss, reduced unit efficiency, and even high-temperature medium ejection and unplanned shutdown, bringing huge pressure onSafety operation and maintenance cost.

Traditional ordinary nuts and spring washers have poor temperature resistance and are prone to failure under long – term high temperature. They require annual shutdown inspection and re – tightening, incurring high labor costs and significant power loss. As a result, they can no longer meet the requirements for the long – term maintenance – free and safe operation of large thermal power units.

With decades of heavy – duty fastening technology accumulation, the KPMBOLT super nut adopts a multi – jackbolt mechanical pre – tightening structure. Different from the traditional friction anti – loosening principle, it implements strict full – process quality control from material smelting, forging heat treatment, precision machining to non – destructive testing. Customized for the high – temperature and high – pressure working conditions of thermal power equipment, it has become the preferred long – term fastening solution for thermal power boilers, feed pumps, and high – pressure flanges.

The KPMBOLT super nut consists of three core components: the nut body, jackbolts, and hard alloy thrust washers. Each component adheres to independent manufacturing inspection standards and a traceability system. The nut body is made of high – quality alloy structural steel. The raw material certificate is checked, and the spectral composition is re – inspected. After overall quenching and tempering, the hardness is stably controlled at HRC 30–36, with full piece – by – piece hardness inspection. Ultrasonic UT non – destructive inspection is adopted to eliminate internal… I hidden defects and ensure structural stability at high temperature.

The high – strength jackbolts are made of ultra – high strength alloy steel. Their heat – treatment hardness reaches up to HRC 48–54, and the yield strength is over 1500 MPa. Every piece undergoes a hardness test, and every batch completes a mechanical property test. 100% magnetic particle MT inspection avoids surface micro – cracks and the risks of fatigue fracture. The matched thrust washer is precisely processed after quenching and tempering, with a hardness of HRC 40–44. It has uniform pressure bearing, effectively dispersing the flange contact stress and protecting the sealing surface.

Adopting the pure axial preload principle, no shear stress or additional bending moment is generated during installation. The preload is evenly and accurately distributed, avoiding local stress concentration and fundamentally eliminating loosening and leakage caused by high – temperature creep.

It is widely used in boiler cylinder flanges, high – temperature flue flanges, feed pump end covers, main steam pipeline flanges, heat exchangers, and pressure vessel connections. The complete specifications from M30 to M120 can directly replace the original nuts without equipment modification. Installation only requires a standard torque wrench, which is suitable for the narrow space of the boiler room and high – altitude pipeline construction.

• After operation, the KPMBOLT super nut is high – temperature resistant and creep resistant, maintaining stable locking without annual re – tightening. Field data shows that flange leakage failure is reduced by moreOver 95%, greatly cutting maintenance labor, spare parts cost and shutdown loss. Complete test reports, material certificates and NDT reports.
• As the thermal power industry upgrades, KPMBOLT super nut provides a safe, reliable, and economical fastening solution for thermal power plants.
• References:
• Thermal power industry upgrades and energy saving, intelligent operation, and long – cycle stable operation.
• KPMBOLT MPP inspection plan.

Research on high – temperature fastening technology for thermal power equipment.