Abstract
This paper presents a study of acoustic emission (AE) during the deformation of dissimilar welded joints of austenitic steel to pearlitic steel. One of the specific problems in these welded joints is the presence of decarburized and carbide diffusion interlayers, which intensively increase in width during long-term high-temperature operation. The presence of wide interlayers negatively affects the mechanical properties of welded joints. Moreover, welded defects are difficult to diagnose in welded joints containing interlayers: due to the high structural heterogeneity, interlayers create structural noises that can hinder the detection of defects such as cracks, pores, or a lack of penetration. The AE method may become a complex decision for diagnosing dissimilar welded joints due to applicability to the testing of heterogenic materials with a complex microstructure. Specimens cut from dissimilar welded joints of austenitic steel to pearlitic steel were tested by tension to rupture, with parallel AE data registration. According to the research results, the characteristic features of the AE were revealed for specimens containing defects in the form of lack of penetration as well as for specimens with diffusion interlayers. The results obtained show that the AE method can be used to test both typical welding defects and diffusion interlayers in welded joints of steels of different structural classes.
Highlights
Dissimilar welded joints of austenitic to pearlitic steel are widely used in the manufacturing of elements for power equipment and pipelines at thermal power plants and nuclear power plants, in steam and gas turbines, and in pipelines at chemical and petrochemical plants
The nature of acoustic emission (AE) data recorded during loading of the 12Kh18N10T steel specimens is consistent with the tension diagram
The maximum AE hits rate is observed at the moment of reaching the yield point of the material, and in the stage of strain hardening, the AE hits rate decreases monotonically
Summary
Dissimilar welded joints of austenitic to pearlitic steel are widely used in the manufacturing of elements for power equipment and pipelines at thermal power plants and nuclear power plants, in steam and gas turbines, and in pipelines at chemical and petrochemical plants. The use of such structures allows one to reduce significantly the cost of products, reduce their weight and sizes, and increase the reliability and durability of critical equipment. For such welded joints having an austenitic structure in the weld seam, interlayers are formed on
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