PHASE IDENTIFICATION OF AUSTENITIC STAINLESS STEEL HP50 IN RADIANT ETHYLENE CRACKING TUBE AFTER 4 YEARS OF OPERATION

• Main Author: Fahrell Adlinizar, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68597
• Institution: Institut Teknologi Bandung

Hydrocarbon cracking carried out in the petrochemical industry requires high temperatures in 700-1100oC range and the processing is carried out in radiant ethylene cracking tubes. Cracking tubes are exposed to high temperatures, extreme temperature fluctuations, carburizing, and oxidation. The austenitic stainless steel HP50 was used to examine the effect of high temperatures and extreme processing environments on the microstructure, phase, and hardness. A series of characterizations such as SEM-EDS, XRD, and hardness test (Rockwell B) have been carried out. The results show that due to the oxidation environment, the nucleation of SiO2 and the carbide transformation into Cr2O3 occurs at the sub-surface. Meanwhile, carburization can deposit coke on and within the inner diameter surface and M23C6 -> M7C3 transformation occurs. Due to carburization, inner diameter part has the highest carbide area fraction and hardness (20.07- 39.75%; 76.04-83.64 HRB) while the outer part which experiences decarburization phenomenon has smallest carbide area fraction and hardness (8.86- 9.84%; 70.48-74.24 HRB). Meanwhile, the middle part of three asreceived specimens have similar hardness value with as-cast spesimen (75.4 HRB).