The Study of Welding Repair Parameters of Tube 35Cr-45Ni-Nb Alloy of the Ethylene Heating Furnace

Abstract

The aim of this research is to study the effects of welding repair parameters on weld joint of tube 35Cr-45Ni-Nb alloy by using the Gas Tungsten Arc Welding (GTAW) process of two different base metals. One was a new tube material and other was a used tube treated with carburized condition. The 35Cr-45Ni filler metal was sellected for welding repair experiments. The SEM-EDS analysis was used to observe a segregation of atom in the used tube specimen. The non-destructive examination (NDE) tests were done to check the imperfected area of weldment and heat affect zone (HAZ). Data from this research can be used as the guideline suggestion for the welding procedure specificcation (WPS) and the procedure qualification record (PQR) for the welding repair in the peroid of maintenace.

Evaluation of creep rupture behaviour for weld joint and base metal of the Cr35Ni45Nb alloy

“…As the weldability of the ethylene pyrolysis furnace tubes is deteriorated due to microstructure deterioration [18,19], carburisation and oxidation [20] in the service process, many researchers have studied welding repair parameters of ethylene cracking furnace tubes after a long-term service [21][22][23]. As the weak part of the ethylene pyrolysis furnace tube, the microstructure and mechanical properties of the Cr35Ni45Nb alloy weld joint after service are rarely reported.…”

Effect of Carburizing on Microstructure and Weldability of 35Cr-45Ni-Nb Alloys in the Ethylene Heating Furnace

“…Saavedra et al [2] suggested that there are several factors causing the coke formation such as operating loads, temperature, time, heat flow and the partial pressure of the hydrocarbon. In our previous work [3], the 35Cr-45Ni-Nb tube can be magnetized by the carburization process. The microstructure in the carburized tube shows a large amount of areas with fractions of precipitated complex carbides of (Cr,Mn) 23 C 6 and SiC.…”