Chen Jun, a turbine worker
Chen Jun, a turbine worker
As he has been engaged in nondestructive testing since 1984, Chen Jun involves and witnesses the development and upgrade of the company. During the past decades, he has been earnestly testing the rotor of gas turbines, steam turbines and electric generators, impeller shafts, valve casings, casings, vanes and welded joints of pipelines on the chassis of gas turbines, and found tons of major defects. For example, a defect of over standard was spotted on 2 rotors 160 in the process of research and manufacturing in CFHI (China First Heavy Industries). After careful test and analysis, he thought such defect would pose great threat to the safe operation of the unit, so those 2 rotors were scrapped with the support of leaders. We will often encounter disagreement with suppliers on the testing result in our daily work. In 1996 when he was testing a consignment of 6 generator rotors, he found some defects of over-proof equivalents. He suspected based on his judgment that those defects were fish eyes, which would cause hazardous accidents. He insisted in letting the heavy machinery factory conduct low power test on the remaining steel ingots and confirmed that those defects were fish eyes. Finally, the whole consignment of forged pieces was scrapped, and major accidents were avoided and damages were prevented.
Besides, in the investigation of the “Nanjing 9.18 Case” in 1999, he objected to the conclusion of Southeast University that the dumbbell, a physical evidence, was welded. After comparing the sound velocity for multiple times, he issued a report that the dumbbell was integrally casted, which provided the right direction for investigation and praised by the municipal public security bureau. In addition, he actively devoted himself to serving users. After the defect report on our pump wheel shaft issued by Longyou Power Plant last year, he immediately headed to the site and debated with the inspectors of Zhejiang Electric Power Research Institute on their inspection methods and judgment basis. Finally he denied their report and earned reputations for the company.
When developing the 25MW turbine, the company failed to radiographically inspect the welded joint between the steam cabinet and the casing on the side of the nozzle box, which still remains a challenge in the industry. He actively communicated with the process designer and proposed a process that applies high-temperature and inter-layer magnetic powder and enables radiographic inspection after polishing welded joints thus ensuring the quality of such kind of high temperature and high pressure joints. This process has been since widely applied in the turbine industry. Chen Jun also participated in the drafting of the national standard for the inspection of magnetic powder on turbine blades, and made a contribution to the applicability and advancement of this standard.
In the course of processing the company’s first 135MW unit generator rotor, the rotor carried strong and high-intensity magnetic field in itself. After careful measurement and repeated tests, Chen Jun accurately calculated the size of remanence and eliminated the strong remanence on the rotor by cutting the power at zero magnetic point with high frequency magnetic blast, which ensured the delivery of the unit and received appreciation and positive feedback from Saarschmiede GmbH in Germany.