The Influence of the Welding Process on the Ultrasonic Inspection of 9%Ni Steel Pipe Circumferential Welded Joints

Abstract

This work aims to compare the ultrasonic inspection of 9%Ni steel joints welded with the Gas Metal Arc Welding (GMAW) process and Shielded Metal Arc Welding (SMAW) process. These are the two most widely used processes used to weld pipes for CO2 injection units for floating production storage and offloading (FPSO) in the Brazilian oil and gas industry. The SMAW equipment is simple and portable, which is convenient for the FPSO; however, the GMAW process has the advantage of welding with high productivity. In this study we performed a numerical simulation using the software CIVA, 11th version, to analyze the behavior of ultrasonic longitudinal wave beams through GMAW and SMAW dissimilar weld joints. Ultrasonic tests were performed on calibration blocks drawn from both welded joints to evaluate the simulation results. The results are discussed with regard to the microstructure of the weld metal via electron backscatter diffraction (EBSD) analyses. The SMAW process presented better inspection performance than the GMAW process in terms of attenuation and dispersion effects. Although the SMAW had a better outcome, for both processes the configuration of 16 active elements and a scanning angle of 48° resulted in an optimized inspection of the entire joint.

Assessment of the Structural State of Dissimilar Welded Joints by the Acoustic Emission Method

“…The use of ultrasonic testing for dissimilar welded joints of reactor equipment is noted in several works [7,8].Essentially, testing is carried out using special equipment and techniques that take into account the design features of each welded joint [9,10]. However, the coarse-grained structure leads to a high attenuation of ultrasonic vibrations in the austenitic steels, and the complex structure of a dissimilar welded joint displays a high level of interference [11]. Even though ultrasonic testing provides a fairly reliable detection of cracks, pores, cavities and lack of penetration, its sensitivity is not enough to detect structural defects, such as carbide and decarburized interlayers.…”

Effect of Temperature on Microstructure and Mechanical Properties of Fe-9Ni-2Cu Steel during the Tempering Process

“…The development of the global new energy industry, the adjustment of the domestic energy structure, and the increase of environmental protection pressure have led to a sharp increase in the demand for natural gas, so it is necessary to increase the quality of vehicles for natural gas. 9Ni steel with high strength and high low-temperature toughness has attracted a great deal of attention over the past few years [ 1 , 2 , 3 , 4 , 5 , 6 ].…”