Microstructures of laser welded steels

Abstract

Nd:YAG laser welding was carried out on austenitic stainless steel(316LN) and duplex stainless steel(2205). The structures were examined using optical and colour etching metallography. This showed optically that the austenitic steel solidified as totally austenitic structure, but the TEM work confirmed the presence of ferrite. In the case of the duplex stainless steel, the solidification structure was almost 100% ferrite. However, the properties required were met. Dissimilar Nd:YAG laser welding was performed on a duplex stainless steel to carbon steel joint and on an austenitic stainless steel to carbon steel joint. This revealed the presence of preferential flow in the weld metal and areas of excessive hardness. The results of this study were that filler wire was required to counteract the high hardness effects. An evaluation has also taken place of CO2 laser welds of D and DH 36 steel. Mechanical properties of the DH 36 steel have been found to be acceptable, and the structure of the D grade material has been examined using TEM, Pearlite and bainite have been identified as being present.Nd:YAG laser welding was carried out on austenitic stainless steel(316LN) and duplex stainless steel(2205). The structures were examined using optical and colour etching metallography. This showed optically that the austenitic steel solidified as totally austenitic structure, but the TEM work confirmed the presence of ferrite. In the case of the duplex stainless steel, the solidification structure was almost 100% ferrite. However, the properties required were met. Dissimilar Nd:YAG laser welding was performed on a duplex stainless steel to carbon steel joint and on an austenitic stainless steel to carbon steel joint. This revealed the presence of preferential flow in the weld metal and areas of excessive hardness. The results of this study were that filler wire was required to counteract the high hardness effects. An evaluation has also taken place of CO2 laser welds of D and DH 36 steel. Mechanical prope...