CORRELAÇÃO ENTRE MICROESTRUTURA E PROPRIEDADES MECÂNICAS EM METAL DE SOLDA COM DIFERENTESTEORES DE MN, SUBMETIDO A TRATAMENTOS TÉRMICOS / MICROSTRUCTURE AND MECHANICAL PROPERTIES CORRELATIONS FOR HEATTREATED STEEL WELD METALS WITH DIFFERENT MN CONTENT

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Traditionally, both Cr-Mo class steels and the weld metals produced in joining such materials have been considered to be susceptible to the phenomenon of temper embrittlement. The current study evaluates 2,25%Cr-1,0%Mo type weld metals with varying Mn levels (0,4%- 1,1%), produced using coated electrodes with an SMAW process. The welded joints were subjected to three types of heat treatment; either stress relief annealing, or step cooling or stress relief annealing and step cooling. Charpy-V impact testing results indicated a gain in toughness and tensile strength for materials with Mn levels in the 0,9% to 1.1% range, and that the step cooling alone did not cause any appreciable changes in toughness for any of the Mn levels studied. Furthermore, scanning electron microscopy revealed that the bainitic microstructure of the materials studied was relatively little affected by the applied heat treatments. The values obtained for the traditional embrittlement indexes, X -Factor, PE-Factor and J-Factor were observed to be inconsistent and incompatible with the actual quantified impact behaviour of the weld metals investigated. This would suggest that a reevaluation of these traditional embrittlement indexes should be considered. The temper embrittlement susceptibility of steels of this type as they are currently manufactured may, in this way, come to be considered much lower than would otherwise be the case, even after post weld heat treatments.

ASSUNTO(S)

eletrodo revestido tratamento pos-soldagem tratamento de step-cooling step-cooling. weld metal multipass weld metal de solda post weld heat treatment

ACESSO AO ARTIGO

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