The role of hot rolling lubricants

In the initial stage of hot rolling lubrication, there is no special hot-rolling oil, only ordinary mineral oil and animal oil are used as hot-rolling oils, and it is not necessary to select lubricants according to different rolling mills, rolling material and roll material. , as long as it has good oil stability, good wettability and adhesion.

With the advancement of rolling technology and the improvement of the quality of the rolls and rolling elements, the requirements for hot-rolled lubricating oils have begun to be refined and demanded more and more. A variety of special hot-rolled process lubricants with different properties have appeared one after another. For example, QUAKE's NHB–18–H–1 and QUAKERHB–18KT oils are used to finish the front and rear racks respectively. They are selected for the rough rolling, the first few rolling mills, or the Several after rolling; used for high speed rolling, or high lubricity rolling; and also explore the oil concentration, different, the concentration of 2050mm hot oil is 3%, and the concentration of 1580 hot oil is 0.4 %, corresponding to different roll materials, considering whether it is mainly used to prevent hot sticking when rolling general steel or hot sticking when rolling stainless steel, according to different varieties. In the late 1990s, with the introduction of high-speed steel rolls into production, hot-rolled lubricating oils were specially developed for this kind of rolls.

Before the hot rough rolling and hot finishing rolling, several frames are likely to generate black skin due to the scale of iron oxide and form surface defects. Hot rolling occurs easily when rolling stainless steel. After several hot rolling, no iron oxide skin is produced, and the wear is dominant. For different rolling conditions, choose suitable roll materials. For example: when using high-nickel-chromium and high-chromium rolls, the black skin formed by the iron oxide skin can improve the surface defect resistance and wear resistance of the roll, so use black as much as possible skin. Black leather has high hardness and good wear resistance. However, if the black skin is excessively thickened, cracks and flaking will be easily formed, resulting in more serious roll surface defects. The high-speed steel rolls have high high-temperature hardness, which is close to that of the black skin, and has good wear resistance even without black skin. So high-speed steel rolls must control the formation of black skin.

Iron oxide skin has wear resistance, but roll surface defects are easily formed. In the rolling of thin stainless steel, because the iron oxide skin easily falls into the roll gap, resulting in plate surface pitting, therefore, depending on the rolling rolling material, choose the appropriate hot rolling oil.

Hot rolling process lubrication has a significant effect on reducing rolling loads and reducing roll wear. With the increase of product surface quality requirements, hot rolling lubrication has become increasingly important for modern strip rolling.