engleski

Influence of welded Joint Structure on Fatigue Strength of the Impact Loaded Weld Fillet Joint between Radial Carrier and Rapping Device Drive Shaft

Cleaning heat exchanger surfaces of the steam boiler from layers of ash ensures higher heat energy efficiency of the smoke. With harp type heat exchangers for cleaning it is possible to apply mechanical rapping devices which are used in a waste incinerator steam boiler in Riverside. That device is composed of rapping device drive shaft with welded radial carriers. The fracture of the welded joint between radial carrier and rapping device drive shaft occurred during active work of a waste incinerator steam boiler in Riverside. Welded joint between radial carrier and drive shaft was made as double fillet weld. This welded joint is loaded with impact load which causes material fatigue due to the repetitive behaviour. This paper presents results of welded joint laboratory research. Hardness measuring and metallographic testing established current states of welded joints on a rapping device drive shaft. Conducted research enabled evaluation of the results procured through mathematical model, which was established during earlier research. Procured results proved the appliance of fillet weld joint loaded with impact load to be a bad choice. It has been confirmed that earlier suggested analytical calculation model is applicable with designing of a rapping device.

impact loading; fatigue; mechanical rapping device; double fillet weld; weld joint strength; metallographic testing; weld joint hardness; micro cracks in welded joint

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