MICROSTRUCTURE CHANGE FOR MULTI-PASS WELDING BETWEEN AUSTENITIC STAINLESS
STEEL AND CARBON STEEL
T. Nhung Le1,2, M. Khanh Pham2 , A. Tuan Hoang3,4, T.N. Mai Bui1 , D. Nam Nguyen1
1Vietnam Maritime University, Vietnam
2Hanoi University of Science and Technology
3Ho Chi Minh city University of Transport
4The Central Transport College VI, Vietnam
*Corresponding Author Email: [email protected]
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The purpose of this study was to discuss the change in microstructures and hardness values in fusion zone (FZ) and heat-affected zone (HAZ) of austenitic stainless steel and carbon steel welds. By comparison, the morphology of δ – Ferrite which formed in the fusion zone of single-pass and multi-pass welding was analyzed. The columnar dendritic shape can be seen as features extending from the fusion line of a weld pass toward the subsequent passes. Furthermore, the δ-Ferrite morphology changed from fine cellular to columnar dendrite or equiaxed dendrite. The recrystallization phenomenon was only observed in the HAZ carbon steel side of multi-pass welding. This zone was divided into HAZ-1 (grain-refining region) and HAZ-2 (partial grain-refining region). The hardness values in each zone were measured with the highest value was on fusion boundary of carbon steel side. Transverse tensile was carried out.