Computational Dynamics of Anti-Corrosion Performance of Laser Alloyed Metallic Materials

Laser surface alloying (LSA) is a material processing technique that utilizes the high power density available from defocused laser beam to melt both reinforcement powders and a part of the underlying substrate. Because melting occurs solitary at the surface, large temperature gradients exist across the boundary between the underlying solid substrate and the melted surface region, which results in rapid self-quenching and resolidifications. Reinforcement powders are deposited in the molten pool of the substrate to produce corrosion-resistant coatings. These processes influence the structure and properties of the alloyed region. A 3D mathematical model is developed to obtain insights on the behavior of laser melted pools subjected to various process parameters. It is expected that the melt pool flow, thermal and solidification characteristics will have a profound effect on the microstructure of the solidified region

TIG Welding Methods of Repairing Steel Components with Stainless Steel Coatings

Structural steel components tend to wear when exposed to corrosive and cyclic loading environments. These components can be repaired by welding on failure. This study studied the weld parameters and weld quality (porosity, depth of penetration, and coating thickness), hardness, corrosion, and wear resistance during repair welding. Mild steel samples were weld coated by varying alternating (AC) and direct (DC) currents: 40 A, 50 A, 55 A, 60 A, 65 A, and 70 A. The base material used was AISI 1045 steel, and Castolin 6825 was used as the welding electrode. The results showed that three wear mechanisms were dominant: abrasion, adhesion, and delamination. The porosity in the coated samples increased with increasing currents for both AC and DC. The welding current and current type influenced the coating thickness and penetration depth. When dipped in warm NaCl solution, the corrosion mechanism experienced by both sets of coated samples was pitting corrosion. In both cases (alternating and direct currents), the hardness values increased towards the coating surface from the substrate