The iron oxide scale on the surface of the high-strength and heavy-duty automobile girder steel is broken and peeled off during the process of leveling and straightening,which causes the iron oxide scale to be pressed into the surface and forms pits with different sizes during the subsequent straightening process.The corresponding relationship between the process factors such as finish rolling inlet temperature,rolling speed,cooling rate and coiling temperature and the thickness of iron oxide scale was studied.The results show that the thickness of the iron oxide scale increases slowly with the increase of the inlet temperature when the inlet temperature of finishing rolling is below 1040 ℃,and the thickness of iron oxide scale increases sharply with the increase of the inlet temperature when the inlet temperature is above 1040 ℃;with the increases of the rolling speed,the scale of iron oxide formed on the surface of the strip becomes thinner;larger cooling rate can inhibit the growth and thickening of iron oxide scale;at 560-630 ℃,the higher the coil temperature,the thicker the iron oxide skin.By optimizing the heating system,increasing the rolling speed,optimizing the laminar cooling rate and coiling temperature,the pitting defects on the surface of girder steel can be effectively controlled.
维普
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