How to Reduce the Oxide Scale on Rectangular Tube Surface?

During the hot rolling process of rectangular tube, if the problem of oxide scale is encountered, the surface quality will be affected, and the subsequent cold rolling process will also be affected. To solve this problem, we can take the following four measures:

1. Lubrication rolling

In the finishing rolling, the rolls are rolled with lubrication to improve the lubrication effect of the roll surface. This can effectively prevent the formation of iron oxide scale and sticking to the roll, and can also prevent the damage of the roll surface, improve the utilization rate of the roll and the surface quality of the rectangular tube.

2. Sufficient phosphorus removal

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

3. Rolling temperature

When the temperature is high, the high temperature slab will rapidly generate secondary iron oxide scale, and the iron oxide scale is in a molten state and difficult to remove at high temperature. Especially the head and tail of the slab are more prone to oxidation due to the higher radiant heat temperature of the furnace wall. Therefore, in order to ensure the effective dephosphorization of the rectangular tube, on the one hand, the finishing rolling and rolling temperature of 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 rolling beyond the plan, and reasonably control the number of rolling meters. It can also reduce the online time of the intermediate blank and prevent the difficulty caused by the thickening of the oxide layer. At the same time, it avoids the oxide film falling off due to the overloaded work of the work roll, and the phenomenon of furrowing, which causes the oxidation problem during the finishing rolling.

4. Heating method

Adjust the heating method according to environmental changes and actual production conditions. It is best to divide heating in summer and heating in winter. In the aspect of rectangular tube slab, the temperature of soaking section is considered according to the width of the slab, and the heating time can also be specified according to the actual situation.

The rectangular tube is a steel tube made of strip steel through process treatment. Generally, the strip is unpacked, flattened, coiled, welded to form a round tube, and then rolled into a square tube from the round tube and then cut to the required length. Widely used in machinery manufacturing, construction, metallurgical industry, agricultural vehicles, agricultural greenhouses, automobile industry, railways, highway guardrails, container skeletons, furniture, decoration and steel structure fields.