Affiliation:
1. College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China
2. National Key Laboratory for Remanufacturing, Army Academy of Armored Forces, Beijing 100072, China
Abstract
Arc welded 316 stainless steel coatings with flux-cored wires are very promising for marine service environments due to their low cost, high efficiency, and satisfactory performance, while they suffers from Cr dilution during the preparation process. Herein, based on the consideration of increasing the Cr content and ensuring the same value of the Cr/Ni equivalence ratio (Creq/Nieq), 316-modified flux-cored wires, 316F (19Cr-12Ni-3Mo) and 316G (22Cr-14Ni-3Mo), were designed under the guidance of a Schaeffler diagram for the improvement of the electrochemical and mechanical properties of 316 stainless steel coatings. The designed flux-cored wires were welded into a three-layer cladding by the tungsten inert gas welding (TIG) process, and the microstructure, corrosion resistance, and mechanical properties of the claddings were investigated. The results showed that 316F and 316G consist of γ-Fe (austenite) and a small portion of δ-Fe (ferrite) as the Creq/Nieq is approximately 1.5. However, due to the higher value of the equivalent Cr content (ECC), 316G has an additional intermetallic phase (σ), which precipitates as a strengthening phase at grain boundaries, significantly increasing the tensile and yield strength of 316G but reducing its plasticity. In addition, the corrosion current density (icorr) and pitting potential (Eb) for 316G are 0.20447 μA·cm−2 and 0.634 V, respectively, while the values for 316F are 0.32117 μA·cm−2 and 0.603 V, respectively, indicating that 316G has better anti-corrosion performance.
Funder
National Natural Science Foundation of China
Science and Technology Innovation Program of Hunan Province
Natural Science Foundation of Hunan Province
Scientific Research Foundation of Hunan Provincial Education Department