scholarly journals Evaluation of the quality of the shielded metal arc welding process using speckle interferometry

Author(s):  
Felipe Maia Prado ◽  
Daniel José Toffoli ◽  
Sidney Leal Da Silva

Speckle, which is a branch of optics that studies the interference pattern caused by the incidence of coherent light in a material’s surface, has some optical techniques and methods that can be successfully applied to determine properties of materials. In this work we used the method called THSP, Time History Speckle Pattern, in samples made of AISI 1020 carbon steel that were submitted to the shielded metal arc welding (SMAW) process, with the objective of identifying (qualitatively) the level of irregularity on its welded surface, by comparing these samples with a default sample, made with the same material. The technique of spekle by reflection was used for data collection. The results showed quantitative diferences between the default welded sample and the other samples, and there are good perspectives that speckle can be applied to determine the quality of the welding process, since the results showed more accuracy than visual inspection.  

Joining of materials is the need of modern industries and stuctures. Shielded metal arc welding process is one of the most popular and commonly used method of joining materials. The weld reinforcement height should be optimum for mechanical properties of the weld. If the reinforcement height is less or negative, it is not recommended considering strength of weld as surface area will be reduced and if the reinforcement height is more, it will produce stress concentration which is not recommended. In the present work the investigation of the effect of three different types of electrodes at three different welding currents in shielded metal arc welding process utilizing Low Carbon Steel plate of API 5L Grade X 52, was done for reinforcement height. The three different electrodes as E 6013, E 7016 and E 7018 and the varying currents as 90 A, 100 A and 110 A. Total 18 pieces were used to obtain 9 welds which were used to analyze the effect of current and the electrode on reinforcement height. The dimensions of the work pieces were taken as 75 mm x 50 mm x 5 mm. The values of reinforcement height in each weld were written in a table and respective diagrams were drawn to make clear the effect of welding current on reinforcement height for the three different electrodes.


2019 ◽  
Vol 269 ◽  
pp. 01012 ◽  
Author(s):  
Neville Cornish ◽  
Rahim. Kurji ◽  
Anthony Roccisano ◽  
Reza Ghomashchi

Quenched and Tempered (Q&T) steels welded structures that have numerous applications, particularly in the defence industry. However these steels are particularly prone to Hydrogen Assisted Cold Cracking (HACC) and require a highly-skilled welder to fabricate defect-free structures. This is due to the selection of the manual metal arc welding process of shielded metal arc welding (SMAW). The introduction of Modified Pulsed arc mode of depositions; a variation to Pulsed Arc deposition, has advanced deposition rates and can be employed by welders with a greater variation in skill. In this body of work, full strength butt welds are fabricated on 20mm, sections of Q&T AS/NZS 3597 Grade 700 steel under a high level of restraint using Modified Pulse Gas Metal Welding (GMAW-P) and conventional Shielded Metal Arc Welding (SMAW). The study investigates the economic feasibly of the two modes of deposition and the propensity for cracking when welded under high restraint. The study concluded that modified GMAW-P achieved reduction of 63% in the ‘Arc-On' time and an 88% reduction in the total normalised fabrication time. However, due to the increased propensity to lack of fusion type defects, strict controls must be employed in optimising the welding procedure to mediate for such defects if GMAW-P is to provide a techno-economically beneficial alternative to conventional SMAW when welding Q&T steels.


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