Analysis on warping of steel plate under controlled cooling

A numerical analysis of the warping of steel plates during controlled cooling has been conducted by beam model with one-dimensional stress and thermo-elastic-plastic material. In order to prove the validity of this analysis, experiments were conducted using a newly designed experimental device and SM490, nickel, and 304 stainless steels. The continuous changes in temperature and warping were measured in water cooling. The validity of this analysis was quantitatively proved by comparison with the experimental results. It is expected that this calculation technique will be applied to the control of warping of steel plates and shape steels in the controlled cooling process. From the results of this analysis, it was found that the main factors of warping were phase transformation, yield stress and thermal conductivity. In the case of low-temperature-transformation, both warping behavior during cooling and residual warp are large, because of large expansion in phase transformation and high yield stress at low temperature. A higher yield stress leads to large warping. A higher thermal conductivity leads to a high, steep temperature slope in thickness, which causes a higher thermal stress and larger warping.