Probability estimation of weld seam defect formation and calculation of tolerances for narrow gap arc welding parameters

One way to increase productivity is to use narrow gap MIG/MAG welding. However, when using such technology we often face problems of weld seam defect formation: lack of fusion and lack of penetration at edges. Due to this the question of estimating welding parameters possible inaccuracy, random deviation of which might cause such defects, is still relevant. We suggest estimating the probability of defect formation as a ratio of the remainder of the nominal and the threshold values of penetration to its deviation due to the instability of welding parameters, using Laplace’s function. Tolerance on variations of welding parameters may be determined through solving an inverse problem of estimated probability of defect formation. The results obtained comply with the results of experimental studies of the influence of multi pass welding parameters on the formation of separate layers in the narrow gap, and can be used to develop welding technology. 

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