| High strength galvanized steel wire is skeleton reinforced materials in line of long span and distance transmission for electric power. High carbon steel wire rod is drawn with large strain in the production process, affected by temperature and time in the process of lead bath skim and hot dip galvanizing. It leads to changes about the strength, toughness and plasticity of steel wire. In this paper, the microstructure and properties of high strength galvanized steel wire in the process of drawing and its absorbent and hot galvanizing are studied. Through the observation of microstructure, mechanical properties during processing and the establishment of the work hardening model of steel wire tension deformation, the influences of drawing deformation, lead bath and hot galvanizing temperature and time on the microstructure and properties of steel wire are obtained. The temperature field model of steel wire interior in the process of galvanizing are established. Prediction with cold drawn wire from the surface to the internal core temperature distribution prediction during zinc plating process are achievedWhen steel wire is Online lead bath skim at 400?C and 450?C, a fibrous tissue with a characteristic of long recovery is inside. With the increase of the skim temperature, the resistivity decreases and resistivity of the steel with a large amount of cold deformation decreases slowly. With the skim temperature increases from 400?C to 500?C,the tensile strength of steel wire drawing deformation decreases from 50 to 100 MPa, the extension rate improves and the torsional performance slightly decreases. The mechanical properties of steel wire changes unobviously during the skim experimental time of 9-18 s. Tensile strain hardening model is established based on the hardening model of tensile deformation of Hollomon model before and after the cold drawing wire lead degreasing bath. The tensile property prediction of hard-drawn steel wire before and after skim archives. The work hardening exponent of the steel wire decreases with the increase of the strain after skim. The work hardening exponent is higher than that of non-absorbent steel wire under the same strain.Through the observation of the microstructure of the galvanized layer, according to spectrum analysis, and based on the phase diagram of zinc-iron, The evolution law of the microstructure of the zinc coating under certain technological process is studied. Cold-drawing SWRS-87 AM wires(RA=1.61) after 400?C×9s skim,galvanized layer body of Delta, zeta ETA and Zn Fe compound solution is formed on the surface. The thickness d of Fe-Zn alloy layer increases according to the law of index.The electrical resistivity of cold drawn wire with different deformation( RA) decreases with the prolonging of the galvanizing time in zinc plating process. The resistivity of cold drawn steel wire increases with the amount of cold drawing deformation at the same galvanizing time. With the extension of galvanizing time, the tensile strength of steel wire slightly decreases, and the change of extension rate is not large, but the torsion performance of the characterization of toughness significantly decreases.In the end, the manufacturing process of high strength and high toug hness steel wire finally determines. That is to cold drawing deformation on 6.5mm steel wire of supply state(RA=1.6-2.1) + 400?C?9s nonfat + 450?C?(5-11s) hot galvanizing. The weather resistant steel wire with high strength and high toughness is obtained, supporting the manufacture of the transmission line framework. |
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