Development of methodology for measurements of residual stresses in welded joint based on displacement of points in a coordinated table

Abstract

Residual stresses in a welded joint of ASTM A131 grade AH32 steel was measured either by the X-ray diffraction or by displacements of referenced points measured on a coordinate measuring machine before and after heat treatment. For all tests, the welding was performed with Shielded Metal Arc Welding, vertical-up position, by a certified welder. After welding, some specimens were subjected to marking, made through small holes evenly spaced and mapped on a coordinate measuring machine. After labeling, the samples were subjected to heat treatment at temperatures nearby recrystallization. After heat treatment, the samples were subjected to new measurements by coordinate measuring machine to evaluate the displacements of the points produced by the recrystallization. In parallel, residual stress measurements were made by XRD for validation of this new methodology. The results obtained either by X-ray or by coordinate measuring machine showed a good correlation between the two measurement methodologies employed.

Measurement of Residual Stresses in Welded Joints by DCP Method

“…Recently, residual stresses of a welded joint of ASTM AH-32 naval steel were measured by Siqueira Filho et al 7 using this same methodology (still under development). The results obtained by these authors 7 have already shown to be very close to the results obtained by X-ray diffraction (XRD), a technique already well-estabilished and widely used.…”

“…In addition, each pass the welding direction was alternated, since, according to previous studies by the research group 7,8,9 , the alternation or maintenance of the welding direction influence the results of the residual stresses significantly. Small variations in the welding parameters were produced to modify the heat input.…”

“…Measurement of the residual stresses present in a component, i.e. its magnitude, orientation and distribution, makes it possible to determine the performance of the material under different static or dynamic loading conditions 1,2,7 . This knowledge is always advantageous and primordial for the optimization of projects, weight and cost reduction 4 .…”

Influência da geometria do pino da ferramenta de soldagem nas propriedades mecânicas e tensões residuais de juntas soldadas de ligas de alumínio 5052-O pelo processo FSW

“…Por fim, a fim de determinar a magnitude das tensões residuais nas juntas soldadas, empregou-se uma variação da técnica semi-destrutiva do furo cego, conforme desenvolvido por Siqueira Filho et al 24 . O método consiste em utilizar uma máquina de medição de coordenadas e determinar a variação das coordenadas pré-determinadas para o centro de um furo após a realização deste.…”

Welded Joints' Heat Affected Zone's Extension Prediction by Switching Welding Parameters

“…The method that was adopted to measure residual stresses was the DCP 6 , which consists in of measuring the extension of previously mapped displacement points. For so, five holes with 2 mm depth were drilled with a 2 mm diameter ( Figure 4) and their centers were mapped in X, Y.…”