Bolts (nuts) widely used in industrial production, in the open air high temperature or corrosive environment, some of them have thread loss due to being smashed and touched, which makes it very difficult to remove nuts. In the past, the nuts were often cut off by electric (gas) welding. However, under some special working conditions, it is sometimes strictly forbidden to use fire (electric) welding operations, such as replacing nuts and bolts in pulverized coal silos, oil pipelines, high-pressure and high-temperature pipelines, etc. in power plants. The patented hydraulic nut cutter developed by scientific researchers of our company can solve the difficult problems of bolt and nut disassembly and replacement simply, quickly, safely and efficiently without using electricity or fire or damaging the bolt thread.