Effect of Modified Water‐Bath Method on Microstructure and Mechanical Properties of Wire Arc Additive Manufactured Low‐Carbon Low‐Alloy Steel.

Of late, wire arc additive manufacturing (WAAM) is extensively used in the aerospace and automotive fields to produce large complex metallic components. The water‐bath method is applied for active cooling to address the heat accumulation problem in WAAM. Herein, the modified water‐bath method with a changing level is used to realize different phase transformations, and the microstructure and mechanical properties of the sample are investigated. Heat accumulation in the sample is eliminated using the modified water‐bath method. Furthermore, the microstructure of the fabricated sample shows a mixture of polygonal ferrite (PF), upper bainite (UB), and lath bainite (LB). Layer bands are formed in the entire sample, except in the final layer, and equiaxed ferrite (EF) and an increased fraction of PF appear in these zones. The microhardness and tensile property are enhanced due to the fine LB. The considerable difference in the microhardness between LB and PF causes an obvious wave of hardness, and the tensile property along the horizontal direction is better than the vertical. This study is expected to help broaden the application of the water bath in the microstructure control. [ABSTRACT FROM AUTHOR]