Zong Hao,Liu Lu,He Jiafeng,et al.Effect of Spray Combined Cooling Control on Microstructure and Properties of ϕ12.0 mm Hard Wire steel[J].Special Steel,
Zong Hao,Liu Lu,He Jiafeng,et al.Effect of Spray Combined Cooling Control on Microstructure and Properties of ϕ12.0 mm Hard Wire steel[J].Special Steel,DOI:.
Effect of Spray Combined Cooling Control on Microstructure and Properties of 12.0 mm Hard Wire steel
The effects of different controlled cooling processes on the cooling curve, microstructure morphology, mechanical properties, and surface quality of high-speed wire rods were investigated by means of tensile, hardness, metallographic, and other testing methods. Results showed that when spray cooling was adopted, the strength was improved by increasing the cooling rate to refine the pearlite lamellar spacing; When combined with air cooling on the basis of spray cooling, the conditioning effect of air cooling was utilized to suppress the temperature rise after cooling, resulting in a more complete and uniform sorbite cluster; further increasing the spray pressure allowed phase transformation to occur at lower temperatures, promoting significant refinement of cementite and simultaneous improvement in strength and ductility; when using excessively high pressure spraying, the cooling rate was too fast, resulting in the formation of hard and brittle martensite, leading to significant performance fluctuations and brittle fracture. Compared with traditional Stelmor air cooling, the temperature difference between the overlap point and the center point was reduced from 60 ℃ to 10 ℃, the variation of tensile strength was reduced from 60 MPa to 30 MPa, reduction of area was reduced from 10% to 5%, and the sorbite content was increased from an average of 80% to 95%. In summary, the optimal process is spray cooling with a roller table speed of 0.50 m/s, 10 insulation covers, 4 fans turned on, and a nozzle pressure of 3.5 MPa. This process has been verified by customers to be effective and provides a reliable path for process improvement in similar products.