Why do we need to blow borax in the production process of seamless steel pipe? What is the process and purpose? The limit mandrel continuous rolling mill has one more process than the floating and semi-floating mill. Oxidizer, whose technological purpose is to remove iron oxide scale on the inner surface and prevent secondary oxidation. Antioxidants in molten state at high temperature can play a good lubricating effect. There are strict requirements for the composition, particle size, chemical stability, physical stability, blowing quantity, blowing pressure and time of the antioxidant, mainly to solve the problem of the large extension of the pipe rolling mill, the mandrel and the rolling during rolling. The relative movement between the parts is large, the working conditions of the mandrel bar are worse, the mandrel bar is more prone to wear and scratches, and the rolling jam accident is likely to occur when the lubrication condition is not good or the de-piping machine cannot remove the waste pipe from the mandrel bar at the end of rolling. successfully extracted.
At the beginning of the mandrel rolling mill with limited movement, there is no air reducer, and a tube blank of one specification is used to correspond to a pass. This is mainly because the relative movement ratio of the mandrel and the inner surface of the rolled piece during rolling is Larger, the working conditions of the mandrel are worse, and the mandrel is more prone to wear and scratches. Restriction mandrel technology does not allow the longitudinal movement of the capillary before entering the rolling mill. The secondary oxidation of the inner surface of the capillary must be effectively prevented to ensure the quality of the seamless steel pipe, so it is impossible to arrange an air reducer between the piercer and the rolling mill like a floating mandrel. If the tandem arrangement of semi-floating mandrels is used, the rolling rhythm will become slower due to the increase in the length of the mandrels (due to the backward movement of the mandrels at the end of rolling), which will affect the production capacity of the unit, which is also uneconomical. In the past ten years, the restraining mandrel unit has also been continuously absorbing the advantages of other units. One overhead reducer (two-roll, three-roll, and four-roll forms are available) is arranged in series on the inlet side of the tube rolling mill, in order to eliminate the inner diameter of the capillary tube. The gap between the surface and the mandrel and the head and tail diameter deviation of the outer diameter of the capillary make the rolling more stable, thereby improving the service life of the roll and ensuring the geometric accuracy of the seamless steel pipe and the quality of the inner and outer surfaces.