Research Status and Development Tendency of Salt Bath Heat Treatment of Sorbite Wire Rod

The crucial point for obtaining high-strength wire is controlling the microstructure, and the refinement of the interlamellar spacing between 80 and 150 nm gives sorbite excellent tensile strength and plastic deformation ability. To realize sorbitization, the fastest possible cooling rate should be used to avoid austenite being transformed into coarse pearlite. In this article, the main production processes, advantages, and disadvantages of wire rods for bridges are discussed, and the relationship between microstructure and mechanical characteristics of wire rods is argued. On this basis, the research works of simulation and experiments for heat treatment of wire rods in a salt bath, together with the convection and boiling heat exchange mechanism of wire rods in a salt bath, are discussed and provided. The salt bath quenching course is capable of cooling the wire rapidly from the austenitizing temperature to the sorbite temperature region and also dissipates the latent heat, thus reducing the reheating temperature of the wires. It can realize precise control over the microstructure and characteristics of wire and has advantages in improving the wire strength, hardness, wear, and corrosion resistance. The process parameters are highly adjustable, with strong adaptability and flexibility. To obtain ultra-high-strength sorbite steel wire, the key technical problems to be solved include selecting the suitable coolant, controlling the internal microstructure, and precisely controlling the cooling effect.