Özet:

In this study, the method AISI 420 TIG welding of martensitic stainless steels in the protected environment of Ar gas and 75 amps and with a weld speed of 45cm/min was carried out. For this purpose, specimens of Ø 50mm diameter and thickness of 2, 3.5, 5 and 6 mm was sliced. Weld bead was formed along the specimen for about 50mm long and following the welding, specimens were immersed into a different cooling fluids to cool to room temperature. Microhardness measurement was carried out mainly from the base metal towards the weld seam. Microstructural characteristics were investigated by optical microscope, scanning electron microscopy (SEM). As a result, the martensitic transformation of the austenitic structure has been influenced by the high cooling rate. This type of stainless steel must not be cooled below a critical cooling rate and it is necessary to take the appropriate measures.

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