Magnetic Method for Rapid Detection of Carburization Degree of Fe-Cr-Ni Series High-Temperature Heat-Resistant Alloy

In view of the carburization of Fe-Cr-Ni high-temperature heat-resistant alloys in the ethylene cracking furnace and the hydrogen conversion furnace, this paper implemented the GMRI-I carburizing detector to test the degree of carburization of 25Cr35NiNb+ microalloy inlet pipe and 35Cr45NiNb+ microalloy outlet pipe of the ethylene cracking furnace after service as well as the reinforced joint made of Incoloy 800H from the hydrogen-making reformer. In conjunction with the results of the low-power acid corrosion test, a rapid detection method for the degree of carburization was proposed. Based on the experimental results of the carburizing detector and the laboratory test data, the carburization degree test curve of the above three alloys based on the magnetic field strength has been established. The detection accuracy was circa. 5% and the error was ±10%, which is convenient for guiding the use and replacement of Fe-Cr-Ni high-temperature heat-resistant alloy materials for ethylene cracking furnace and hydrogen conversion furnace, thereby ensuring the safe and stable operation of the device.

Application of Ultrasonic Guided Wave in LMPH Tube of Ethylene Cracking Furnace

LMPH (Radiation heat exchange tube), the key section of ethylene cracking furnace, has various failure behaviors (e.g., carbonation, vulcanization, oxidation, and deformation) because of its rigorous working conditions and complicated structure [1]. In this paper, the ultrasonic guided wave is applicable to inspect the interior and surface of the LMPH tube. The results demonstrate that large components in the similar structure of the heat exchange bent tube bundle can be inspected effectively, efficiently, conveniently, compared with the traditional inspection method. One inspection example of an ethylene cracking furnace tube bundle is forwarded. The paper also provides an engineering application/case and valuable crafting process for the detection of similar structures by the ultrasonic guided wave method.