The Department of Materials Engineering at the University of Technology awarded a master’s degree to the student Sara Mohamed Kamel, Department of Materials Engineering/ University of Technology, for his thesis  titled  (Studying Microstructure and Mechanical Properties of Alloy Steel Weld Joint of Boiler Tubes Power Plant)

The discussion was held on the discussions hall / building B / Department of Materials Engineering / University of Technology on Sunday  (09/10/2022). The discussion committee was formed of the teaching staff listed:

As well as the scientific evaluation of the thesis by a Asst. professor. Hussein Ibrahim Khalaf/ Basra University/ College of Engineering/ Mechanical Engineering Department, and Asst. Prof. Naseer Hamed Farhoud/ University of Technology/ Department of Electromechanical Engineering, and linguistically by Asst.  Prof. Khaled Khudair Abbas/ University of Technology/ Department of Materials Engineering.

After the discussion committee made their remarks and observations on the thesis, which were divided between explanation, correction and the student’s defense of her message and the discussion ended, the committee decided to evaluate the thesis, and decided to grant the student a master’s degree with a Pass grade

Abstract

The thesis aimed to study the mechanical properties and microstructure of welded tubes (similar and dissimilar welding).(T22-T22),(T91-T91),(T91-T22)  by using different filler metals (ER90S-B3,ER90S-B9,ERNiCr-3) used in steam boilers in electric power plants. The welding process (GTAW) was carried out for the pipes, taking into account the heat treatment before welding and after welding and the (purging process for root pass only) by argon gas. Also, six tests were conducted to examine the microstructure, mechanical properties and effectiveness of the weld, which include: radiography, optical microscopy, electron microscopy (SEM), energy dispersive spectroscopy (EDS), hardness test (HV), tensile test at high temperature ( 550) degrees Celsius to simulate the real conditions of the pipes inside the boiler. The results of the work in the similar welding (T22-T22) showed that when using the filler metal (ER90S-B3), the highest tensile strength (419 MPa) was obtained with elongation (20%) compared to the other sample when using filler metal (ERNiCr-3), tensile strength (379 MPa) with elongation (21%) was obtained. The highest hardness value (230 HV) was obtained in (HAZ of T22) in dissimilar welding when using filler metal (ER90S-B3) compared to other samples when using filler metal (ERNiCr-3) was obtained (205 HV), and when using filler metal (ER90S-B9) was (206 HV). Also, the tensile test showed that the fracture site of the samples it varies with the filler metals used. The efficiency of the welded samples was also extracted, and the efficiency was (100%) for all welds with similar and dissimilar welding.