Experimental modeling of the behavior of welded joints with discontinuities under critical loads

The diagnostic inspection of structures during their service lifetime often reveals discontinuity defects of the weld metal (pores, solid non-metallic inclusions) that are larger than standard defects allowed. Technical conditions of these structures can be evaluated on the basis of the actual strength of a welded joint containing such defects. This paper presents the results of experimental studies of destruction of steel samples, including welded samples with simulated defects. The experiments showed that the weld metal is 15 percent as strong as the base metal. The strength of the welded joint decreases if the internal defect makes up more than 30 percent of the welded part thickness. At the same time, according to normative documents, this value should not exceed 20 percent. Thus, defects in objects being exploited can be estimated by their critical size at which the strength of the structure reduces. The results of modeling will be useful when monitoring the growth of defects in structures in service.

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