Angular distortion of fillet welded T joint using low transformation temperature welding wire

Abstract

A newly developed low transformation temperature welding wire, of which the transformation start temperature is lower than that of conventional welding wires, was applied to fabrication of fillet welded T joints. The welding angular distortion and the temperature profile of the weld metal were continuously measured during the welding process. The angular distortion of the fabricated T joint was reduced when the weld metal reached the martensitic transformation start temperature. The residual angular distortion was less with the low transformation temperature welding wire than that with the conventional welding wires. The welding distortion of T joints was calculated by a numerical simulation with consideration of the effect of phase transformation under weld thermal cycles. The welding distortion was reproduced with high accuracy in the numerical simulation. Results of the numerical simulation also determined that there was a direct correspondence between the transformation expansion of the weld metal and the angular distortion.

Phase transformations contributing to the properties of modern steels

“…• C. This has led to welding consumables which not only have been demonstrated to reduce residual stress and distortion, but also to consequently enhance the fatigue life by impressive amounts [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. This is an excellent example of how phase transformation theory has contributed to the alloy design for an essentially practical purpose.…”

“…The stress may therefore favour the formation of certain crystallographic variants of the martensite over others whose deformations do not comply with the applied stress. [5] In recent years, this phenomenon of transformation plasticity has been exploited for one of the most pernicious problems in welding technology, that of the residual stresses [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. The aim is to design welding alloys which compensate for the effects of thermal contraction and stress whilst maintaining the overall mechanical performance [66,67].…”

Análise da Influência da Espessura de Aba, Espessura de Alma e Energia de Soldagem sobre as Distorções Angulares em Juntas em Ângulo de Filete

“…Mikami et al (2009) utilizaram como metal de adição um arame de baixa de temperatura de transformação, observando menores distorções angulares quando comparado ao convencional por efeito volumétrico durante a solidificação. Sadat et al (2012) comprovaram, via modelo numérico, o efeito do pré-aquecimento de uma junta de filete na distorção final da mesma, para diferentes valores de diâmetro de eletrodo e níveis de energia.…”

Prediction and Exploitation of Transformation Texture

“…The key therefore is to design welding alloys in which the transformation becomes exhausted only when ambient temperature is reached. This is a large and exciting subject and the reader is referred to an extensive literature which includes major reviews [24,25,26,27,23,28,29,30,31,32,33,34,35,36,37,38]. Fig.…”