Factors Affecting the Brightness of Square Tube Surface
Date:2022-05-26View:600Tags:Square Tube, Brightness
When we use the square tube, we sometimes find that the brightness of surface is not enough, which will not only affect the appearance of square tube, but also affect its use effect. So what are factors that affect the surface brightness of square tube?
1. The oil content in the emulsion is too high. The emulsion used in cold rolling mills is composed of water, emulsifier and oil. The emulsion has both a cooling and smoothing effect, and the oil cracks into carbon at high temperatures. If these carbons are not removed in time, they will accumulate on the surface of square tube and form indentations after being flattened by a flat engine. Therefore, the oil content in the emulsion is one of the main factors affecting the quality of square tube.
2. A lot of carbon black is attached to the inner wall of the maintenance cover. Because of the high oil level in the emulsion, carbonization will occur after annealing in a bell furnace. As a result, carbon accumulates on the inner wall of the protective cover, and as the number of annealing furnaces increases, carbon black increases. If it is not cleaned in time, the carbon black will be scattered on other steel coils, and after processing, the carbon will be attached to the surface of square tube.
3. The annealing furnace has insufficient purging capacity and poor recovery function. Since the purging of the maintenance gas break in the annealing furnace is only about 20-25m3/h, the gasified oil pollution during the heating process is often difficult to be blown off, resulting in black bands appearing on the outer ring of steel coil, polluting the outer surface of square tube. In addition, since the normal hydrogen content of this maintenance gas is only 3% to 6%, and most of it is nitrogen, the carbon content cannot be recovered. And because nitrogen is an inert gas, it cannot be combined with the vaporized gas, so it can only be blown out, and the accumulation of carbon cannot be avoided.
4. The furnace table and convection plate are not cleaned. Some carbon black, oil, dust, etc. will also accumulate on the surface of stovetop and convection plate. If the furnace is not cleaned before loading, the carbon black, oil and dust will also be scattered on the steel coil, affecting the appearance quality.
5. The emulsion on the surface of square tube is not cleanly blown off. There is no purging device at the outlet of the cold rolling mill, which is specially designed to purge the residual emulsion and oil stains on the surface of the square tube.
The square tube is a steel tube made of strip steel after processing and rolling. According to its production process, it is divided into seamless square tube and welded square tube. Seamless square tube is formed by extrusion of seamless round tube. 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.
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