A COMPARISON OF AS-WELDED AND SIMULATED HEAT AFFECTED ZONE (HAZ) MICROSTRUCTURES

The high-strength steel grade S690QL and a filler welding wire Mn3Ni1CrMo were the materials chosen for welding a V-shaped butt weld. In order to prevent the weld's cold cracking, a multi-pass welding technique was applied. A metallographic investigation revealed microstructure variations in different areas of the weld's heat-affected zone. A reverse-engineering approach was used to test a dilatometer's capabilities to simulate different HAZ microstructures. Hollow steel-cylinder specimens were subjected to several weld thermal cycles in order to generate similar microstructures as in the real weld's HAZ. The microstructures of the as-welded and simulated heat-affected zone specimens were investigated. Good agreement was found between the dilatometer-simulated HAZ microstructures and those in a real HAZ weld.