Effect of Heat Inputs on the Microstructures and Properties of 316L Stainless Steel Parts Manufactured by Wire and Arc Additive Manufacturing Processing

The application of complex structure additive manufacturing parts is becoming increasingly widespread, but there is relatively little research, especially in wire and arc additive manufacturing (WAAM). The heat dissipation performance of complex components is different from the simple structural parts. Reasonable optimization can improve the performance and service life of parts. This article selected the partition plate structure mainly used in shell and tube heat exchangers as the main research object. At present, most research mainly focuses on the influence of individual parameters such as current, velocity, or gas flow rate, and there is little research on the comprehensive effects of heat input. Meanwhile, heat input is one of the important factors affecting the quality, microstructure, and mechanical properties of formed parts. Therefore, this paper used heat input as the main research object. And, Q235 steel was used as the substrate for the WAAM parts of 316L wire. As the heat input increased in the range of 2.41-3.59 kJ/cm, the grain was coarsened, and the hardness decreased slightly. The tensile strength and the corrosion resistance declined. The fabricated tube wall exhibited large height and thickness values with a heat input of 3.59 kJ/cm. The specimen with a heat input of 2.41 kJ/cm had a maximum tensile strength of 490 MPa and a minimum elongation after a break of 43.33%. When the heat input was set to 3.59 kJ/cm, the specimen had the worst corrosion resistance, and the self-corrosion current was the highest, 3.853 × 10⁻⁵ A·cm⁻².