Research On The Spalling And Pickling Time Of Oxide Scales Under Different Descaling Parameters

Steel acid pickling is an important technique to remove the surface oxide scales of hot rolled strip. The descaling and tension leveler is a vital part of pickling line and the purpose of descaling is to crack oxide scales and makes it spalled partly which can speed up the pickling rate and improve the shape of strip.The screw down amount and tension are the two primary parameters of descaling process. Reasonable combination of them is vital to enhance pickling rate, control surface quality and reduce the wear of the descaling roller. In order to explore and test the performance of oxide scales under different descaling parameters and stress states, the hot rolled strip was descaled by the self designed descaling and tension leveler. The oxide scales after descaling were analyzed by ABAQUS finite element software, SEM, EDS, metalloscope and pickling experiments. The pickling time of hot rolled strip was determined by the first zero potential differential value method.The results showed that oxide scales mainly spall in a delamination way under tensile state and mainly entirely spall under compressive state.The compressive stress has a more obvious effect than tensile stress on the complete spalling rate and the pickling time under the same screw down amount.The tensile stress has a stronger effect than compressive stress to decrease binding force and pickling time under the same or similar complete spalling rate. Given the descaling characteristics under the tensile and compressive stress, it is more beneficial to improve the pickling rate by increasing appropriatescrew down amountbefore the elongation rate reachs the saturation value.