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Journal ArticleDOI

Influences of shielded metal arc welded cruciform joint dimensions on toe crack failures of pressure vessel grade steels

TL;DR: In this paper, a mathematical model has been developed to predict the fatigue life of SMAW cruciform joints failing from toe region by using Response Surface Method (RSM) Analysis of Variance (ANOVA) technique.
About: This article is published in Engineering Failure Analysis.The article was published on 2000-06-01. It has received 7 citations till now. The article focuses on the topics: Shielded metal arc welding.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the influence of welding speed and laser power on weld quality of 16mm thick Ti−−6Al−−4V sheets autogenously laser beam welded in butt configuration using a Nd-YAG laser was studied The joint quality was characterized in terms of weld morphology, microstructure and mechanical properties.

174 citations

Journal ArticleDOI
TL;DR: In this article, numerical simulations of transversely stressed butt joints were performed, and the relationship between undercut geometry and fatigue strength of weldments was studied by means of a fracture mechanics approach, recommending for the acceptance of weld undercuts and comparison with current standard tolerances were discussed.

23 citations

Journal ArticleDOI
TL;DR: In this article, fracture mechanics-based IBESS approach is applied to the determination of FAT classes of butt welds with crack initiation along the weld toe, and the effect of the geometrical parameters toe radius, flank angle, reinforcement and secondary notches such as roughness or undercuts are discussed both individually and in combination.
Abstract: The fracture mechanics-based IBESS approach is applied to the determination of FAT classes of butt welds with crack initiation along the weld toe. The aim is an investigation of the effect of the geometrical parameters toe radius, flank angle, reinforcement and secondary notches such as roughness or undercuts. The influence of these parameters is discussed both individually and in combination; however, excluding statistical distributions of them and the material data. The results, when compared with conventional FAT classes for butt welds, are encouraging with respect to a potential contribution of IBESS to the discussion of more advanced quality criteria for welds. To that purpose, demands for further research are proposed.

15 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristic fatigue life prediction of A 356.2 T6 aluminum alloy has been statistically analyzed by log normal distribution, and the experimental results are presented in the form of R-S-N curves, which are helpful for designers.
Abstract: In the present investigation the characteristic fatigue life prediction of A 356.2 T6 aluminum alloy has been statistically analyzed by log normal distribution. Fatigue tests were conducted on aluminum alloy specimen on rotary bending fatigue testing machine at six different stress levels. A step wise procedure is outlined to determine the number of specimen required at predetermined stress amplitudes. Details of generation of S-N curve for A 356.2 T6 aluminum alloy using a regression analysis is delineated. ANOVA is performed in order to check the significance of regression equation. The adequate sample size required for evaluating the average fatigue life of A 356.2 T6 with an acceptable error at 50 % probability and 90 % confidence level using log normal distribution is established from this study. The experimental results are presented in the form of R-S-N curves, which are helpful for designers.

11 citations

Journal ArticleDOI
TL;DR: In this paper, post-weld heat treatment (PWHT) is required for stress relieving both the weld metal and heat-affected zone in A517 Quenched and Tempered (QT) steels.
Abstract: Sometimes post-weld heat treatment (PWHT) is required for stress relieving both the weld metal and heat-affected zone in A517 Quenched and Tempered (QT) steels. This process unavoidably results in further tempering which adversely affects the mechanical properties of the welded joints. Investigations on A517 QT steel are presented in as-welded condition and after PWHT at 560 and 630 °C. Microstructural variation upon applying PWHT and its influence on impact absorbed energy, fatigue behavior, tensile and hardness properties of the material in as-welded condition and after PWHT are studied. The decrease in hardness is very remarkable after PWHT at 630 °C. Increasing heat treatment temperature from 560 to 630 °C results in reduction of YS and UTS. Void coalescence and coarsening of carbides after PWHT makes the fracture easier and results in reduction of absorbed impact energy. Elimination of acicular ferrite after PWHT at 630 °C increases crack growth rate, and fatigue endurance limit is reduced.

9 citations

References
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433 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used fracture mechanics techniques to estimate the stress intensity factor for cracks with low a/2c values and the effect of the weld stress concentration factor was incorporated in the solution.
Abstract: In most of the lower fatigue strength welded joints failure occurs by the propagation of a semi-elliptical surface crack which initiates at the weld toe. In order to analyse the progress of these cracks using fracture mechanics techniques, the solution for the stress intensity factor, K, is required. Fatigue cracks in most welded joints adopt shapes which give low a/2c values (up to approximately 0.3) while solutions in the literature are more applicable to a/2c values close to 0.5. Therefore, results in the literature were used to estimate the stress intensity factor for cracks with low a/2c values. Furthermore, the effect of the weld stress concentration factor was incorporated in the solution. The accuracy of the resulting solution was confirmed by using it to determine ΔK values of weld toe cracks for which crack propagation data were available. The results agreed with the expected da/dN vs. ΔK scatterband obtained from centre-notched specimens.

174 citations

Journal ArticleDOI
TL;DR: In this article, the correction function of the stress intensity factor Yu has been split into a function for the general configuration Y, and a function Mk, which covers the local stress concentration field of the weld.

119 citations