How to solve the oxide problem of square tube?

1. Lubricating rolling. In the rolling process, the roll is lubricated to improve the surface lubrication effect of the roll. In this way, it can effectively prevent the occurrence of oxide skin and sticky roll, prevent the damage to the roll surface, improve the utilization rate of the roll and the surface quality of the square tube.

2. Phosphorus removal. Adjust the height and mounting Angle of the square tube dephosphorization nozzle to maintain the best practical results. Check the condition of the nozzle to avoid excessive wear, clogging and loosening. Check the nozzle seat for leakage and shorten the pipeline pressure, check the filter device regularly, and replace it immediately if any abnormality is found. Strengthen water quality protection, remove debris regularly, and add new water.

3. Rolling temperature. The high temperature raw material of the tube blank will quickly form oxide, and will appear in a molten state at high temperature, which is difficult to remove. In particular, the head and tail of the slab are more prone to oxidation because of the strong radiant heat temperature of the furnace wall. Therefore, in order to ensure effective dephosphorization of the square tube, the first stage should control the rolling temperature of the middle billet head as much as possible, in addition, the head and tail parameters should be reasonably controlled during operation. At the same time, to control the steel rate, must not exceed the expected rolling amount, and reasonably control the rolling count. It can also shorten the length of the intermediate billet and prevent the inconvenience caused by the thickening of the oxide layer. At the same time, the oxidation film loosening, furrow problems and oxidation problems in rolling process caused by work roll overload are avoided.

4. Heating method. According to the change of environment and actual production conditions, the heating mode is adjusted. In general, it is recommended to distinguish between summer heating and winter heating. For rectangular tubesheet, the temperature of the holding section is considered according to the width of the slab, and the heating time is specified clearly according to the actual situation.