Causes of Wrinkles on the Surface of HP235 Steel

There are three reasons for the surface wrinkle of HP235 steel plate:

1.There are obvious banded structures in HP235 steel. Due to uneven cooling, the cooling rate on the surface of HP235 steel is uneven, resulting in the appearance of pearlite bands in the structure of HP235 steel plate. The part with a slower cooling rate has sufficient time for the accumulation of manganese in HP235 steel, when the pearlite band (band structure) is more significant, the performance of each part of HP235 steel plate surface will be uneven, which will affect the drawing performance of HP235 steel plate and cause the surface to wrinkle.

2. The thickness of HP235 steel plate is uneven. When HP235 steel plate is drawn into a steel cylinder, the pressure on the four sides of HP235 steel plate is the same. When the thickness deviation of HP235 steel plate is large, the pressure on the thicker side is greater, and it is not easy to slide during the drawing process, while the thinner side is relatively less stressed, and liquid steel flows easily during the drawing process. The uneven deformation on both sides leads to uneven liquid steel flows on both sides, resulting in wrinkles on the surface of HP235 steel plate.

3. The thickness of HP235 steel plate is relatively uniform, but the compressive stress around the drawing machine is different, resulting in different pressures on HP235 steel plate during the drawing process. So the metal flow is uneven, and wrinkles appear on the surface during deep drawing .

Through the analysis of the above reasons, it is known that the uniformity of the cooling rate of HP235 steel plate should be improved during hot rolling, at the same time, on the basis of ensuring performance, the cooling rate is appropriately increased, and reduce the band structure in HP235 steel. The thickness deviation of HP235 steel plate should be reduced by stabilizing the hot rolling process parameters.