Eventos Anais de eventos
CONEM 2018
X Congresso Nacional de Engenharia Mecânica
Analysis of the variation of heat input in welded joints of API 5L-X70 Steel with pulsed Nd: YAG laser weld
Submission Author:
Willian Valicelli Sanitá , SP
Co-Authors:
Willian Valicelli Sanitá, Vicente Afonso Ventrella, Juno Gallego
Presenter: Vicente Afonso Ventrella
doi://10.26678/ABCM.CONEM2018.CON18-1270
Abstract
At present our society is extremely dependent on metals. In transport, household appliances, tools and especially buildings in general. In this way the study of the metal, as well as the study of the manufacturing process, that is, of the stages in which these metals will undergo transformation. We carried out a study of laser welding provided "bead on plate" in micro-alloyed steel ARBL API 5L Gr. X70 in the form of plates with 1,0 x 20 x 120 mm (H x W x D). 12 welds was performed in argonic gas flow of 15 l/min, beam diameter 0,2 mm, angle of 90°, repetition rate of 9, 8, 7, 6 and 5 Hz, welding speed of 1 mm/s, gas depths focus equal to 0,58 mm below the surface of the workpiece and the pulse energy (Ep) set at 10,0 J. The time width (Lt) set at 10 ms. The heat input was varied at 90, 80, 70, 60 and 50 J/mm. The results were analyzed based on the relationship between power, weld bead geometry and microstructure. For the development of the solder metals, 5% Nital reagent was used. The measurements of the geometry (width and depth) of the weld beads were made through images obtained in a digital camera under a common optical microscope. The largest values of depth width were found at higher values of power and temporal width. The microstructures of the samples presented formations of acicular ferrite, allotriomorphic ferrite and possible high martensite contents in the case of samples with the lowest thermal input (60 and 50 J / mm). It is concluded that the laser welding of the established parameters maintained excellent results, both in the regularity of the welding seams and in good surface quality. For these cases the relationship was found that in higher thermal input rates the concentration of martensite decreases which may possibly reduce the hardness coefficient, whereas at lower contribution rates the concentration of martensite increases.
Keywords
welding, LASER, Nd: YAG, Micro-alloyed steels, Heat Input
