How to reduce the scale on the surface of a500 square tube?

During the hot rolling process of a500 square tube, if it encounters scale problems, it will affect the surface quality, and it will also affect the subsequent cold rolling process. In order to solve this problem, we can take the following four measures:

1. Lubricated rolling

During finishing rolling, the rolls are lubricated and rolled to improve the lubrication effect of the roll surface. This can effectively prevent the formation of scale and roll sticking, prevent damage to the roll surface, and improve roll utilization and surface quality.

2. Fully remove phosphorus

Adjust the height and assembly angle of the rectangular tube dephosphorization nozzle to maintain the best effect. Check the condition of the nozzle to prevent excessive wear, clogging and falling off. Check the nozzle seat for leakage and reduce the pipeline pressure, check the filter regularly and replace it in time if any abnormality is found. Strengthen the maintenance of water quality, regularly clean up debris and add new water.

3. Rolling temperature

When the temperature is high, the high-temperature slab will quickly generate secondary oxide scale, and the oxide scale is in a molten state at high temperature and is difficult to remove. Especially the head and tail of the slab are more prone to oxidation due to the higher temperature of the radiant heat from the furnace wall. Therefore, in order to ensure the effective phosphorus removal of the rectangular tube, on the one hand, the temperature of the finish rolling and starting rolling at the head of the intermediate billet should be controlled as much as possible, and on the other hand, the parameters of the delay head and tail should be reasonably controlled in operation. At the same time, control the tapping speed, prevent over-planned rolling, and reasonably control the number of rolling meters. It can also reduce the online time of the intermediate billet and prevent the thickening of the oxide layer from causing difficulties. At the same time, it can avoid the oxidation film peeling off of the work roll due to overload work, and the plowing phenomenon, which will cause the oxidation problem during the finishing rolling.

4. Heating method

According to environmental changes and actual production conditions, adjust the heating method, it is best to divide summer heating and winter heating. In terms of square rectangular tube slabs, the temperature of the soaking section is considered according to the width of the slab, and some clear regulations can be made on the heating time according to the actual situation.

A500 square tube is a steel tube rolled from strip steel after process treatment. Generally, the strip steel is unpacked, flattened, crimped, welded to form a round pipe (usually a welded pipe, or a seamless pipe), and then rolled into a square pipe from the round pipe and then cut to the required length. It is widely used in machinery manufacturing, construction industry, metallurgical industry, agricultural vehicles, agricultural greenhouses, automobile industry, railway, highway guardrail, container skeleton, furniture, decoration and steel structure fields, etc.

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