Abstract The present study is aimed to examine the structure of a welded joint of low-carbon structural steel A 516–55 formed by melting under laser irradiation and by subsequent melt solidification. The main disadvantage of the weld structure in this steel is the formation of plate- and needle-like Widmanstatten ferrite in the conditions of ultra-fast heating and cooling which adversely affects the strength properties of the welded joints. It is shown that the application of ultrasonic vibrations during welding changes the melt solidification conditions and positively affects the dispersion of dendrites and growing Widmanstatten ferrite crystals.

中文翻译：

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超声波辅助激光焊接形成的低碳结构钢焊缝组织

摘要 本研究旨在研究低碳结构钢 A 516-55 焊接接头的组织结构，该焊接接头是在激光照射下熔化并随后通过熔融凝固形成的。这种钢焊接结构的主要缺点是在超快速加热和冷却条件下形成板状和针状 Widmanstatten 铁素体，这对焊接接头的强度性能产生不利影响。结果表明，在焊接过程中施加超声波振动会改变熔体凝固条件，并对枝晶的分散和 Widmanstatten 铁素体晶体的生长产生积极影响。