Field Metallographic Examination Method of Pearlitic Ferrite Heat Resistant Steel Thin-walled Pipe for Utility Boiler

For the general main steam pipeline of utility boiler, the pipe wall is thick and the diameter is large, so the field metallographic examination is easy to operate. However, for the thin-walled pipe, especially for the high-temperature and high-pressure heating surface, the wall thickness is generally 3.0-4.0 mm, and the outer diameter is generally 30-50 mm, so it is very difficult to prepare sample for field metallographic examination. If the pipe is cut for sampling, it is not only difficult to recover, but also affects the performance of the equipment. Therefore, based on the field metallographic examination, a metallographic examination method for high-temperature heating surface (pearlitic ferrite heat resistant steel thin-walled) pipe of utility boilers was studied. The results show that the microstructure morphology is clear and the analysis result is accurate and reliable by using the portable metallographic microscope and the sample preparation method. This method not only optimized the examination process, but also shortened the examination time and improved the economic benefits of the enterprise. At the same time, it avoided the damage of cutting pipe, and solved the problem of difficult welding recovery of thin-walled pipe.