Effects of ambient temperature and humidity on the controlled cooling of hot-rolled wire rod of steel

• We model the effect of moist air on the cooling process of hot-rolled wire rod.
• The cooling performance of different weather conditions is analyzed and verified.
• High temperature and low humidity decrease the cooling performance of steel.
• Low temperature and high humidity increase the cooling performance of steel.
• The same cooling performance can be achieved via the control of blower.

The effects on the controlled cooling of hot-rolled wire rod of steel at different ambient temperature and humidity have been investigated. The results indicate that the convective heat-transfer coefficients and heat flux increase as humidity increase and temperature decrease. And it results in the increase of cooling rate and the decrease of phase transformation temperature of steel. According to the empirical relationship between the isothermal transformation temperature and experimental results of ultimate tensile strength with steel of SWRH82B and diameter of 12.5 mm, the maximum ultimate tensile strength (UTS) is 1206 MPa at −15 °C and humidity level of 100%, and the minimum UTS is 1139 MPa at 55 °C and humidity level of 0%. The predicted results agree well with the inspection results of industrial trials. And then, some references of the optimal outputs of blower have been provided for stabilizing product quality.