Abstract
The hot extrusion process with porthole dies has been utilized in manufacturing of tubes with hollow or complex semi-hollow metal profiles. Within the porthole die, metal is divided into several strands, which are joined together under high temperature and high pressure conditions in the welding chamber of a die. This joining process occurs as a solid-state bonding and is also known as extrusion welding. In this work, a magnesium alloy (AM30) extrudate has been characterized to better understand the microstructure and integrity of the extrusion welds present in different profile locations. The polarized light microscopy images revealed that there are two types of extrusion welding based on the microstructural characteristics of the weld.