Factors Affecting the Surface Brightness of 304 Stainless Tubing

When we use 304 stainless tubing, we sometimes find that the brightness of the surface is not enough, which will not only affect the appearance of 304 stainless tubing, but also affect its use effect.

Ⅰ. About 304 stainless tubing

304 stainless steel is a common material in stainless steel, with a density of 7.93 g/cm³, also known as 18/8 stainless steel in the industry. High temperature resistance of 800 ℃, has the characteristics of good processing performance and high toughness, 304 stainless tubing is widely used in industry and furniture decoration industry and food and medical industry. 304 is a general-purpose stainless steel that is widely used to make equipment and parts that require good overall performance.

Ⅱ. Factors affecting the surface brightness of 304 stainless tubing

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 the 304 stainless steel tube and strip, and will 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 304 stainless tubings.

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 maintenance hood, and as the number of annealing passes increases, the carbon black increases. If it is not cleaned in time, under certain conditions, the carbon black will be scattered on other steel coils. After processing, the carbon will be attached to the surface of the 304 stainless tubing strip.

3. The annealing furnace has a lack of purging, and the recovery function is poor. Because the purging sensitivity of the maintenance gas in the annealing furnace is only about 20 to 25 m3 (norm)/h, so, in the heating and middle. The vaporized oil is often difficult to blow off. As a result, the outer ring of the steel coil still has a black band. Contaminates the appearance of 304 stainless tubing. In addition, because the normal hydrogen content of this maintenance gas is only 3% to 6%, most of which is nitrogen, so the carbon content cannot be recovered. Because nitrogen is an inert gas, it is impossible to merge with the vaporized gas, so it can only be blown out to avoid the accumulation of carbon.

4. The furnace table and convection plate are not cleaned. Some carbon black, oil, dust, etc. will also accumulate on the surface of the furnace table and convection plate. If it is not cleaned up in time before installing the furnace, the carbon black, oil and dust will also be scattered on the steel coil, affecting the appearance quality.

5. The emulsion on the 304 stainless tubing is not clean after blowing off. The outlet of the tandem cold rolling mill is equipped with a purging device to blow off the residual emulsion and oil stains on the surface of the 304 stainless tubing.