Fixed diameter reducing machine for eliminating inner squares of steel pipe

Abstract

The invention belongs to the technical field of a hot milling seamless steel pipe, and particularly relates to a fixed diameter reducing machine for eliminating inner squares of a steel pipe. The fixed diameter reducing machine comprises a total assembling machine frame, a shaft, a bearing, a milling roller machine frame and milling rollers, wherein the milling rollers are arranged on the milling roller machine frame. The fixed diameter reducing machine is characterized in that the center line of each milling roller of the fixed diameter reducing machine forms an included angle alpha with a connecting line of a hole groove bottom center and a hole center of the milling roller, and in addition, the milling rollers are all in clockwise or anticlockwise direction arrangement. Each milling roller axial line of the original steel pipe fixed diameter reducing machine rotates an angle alpha by using the connecting line of the hole groove bottom center and the hole center of the corresponding milling roller as the axis, so that the steel pipe rotates in the milling process, the thickening sections of each machine frame are staggered, the lamination effect of the thickening sections of the machine frame in the same region is avoided, and the inner square phenomenon of the steel pipe is eliminated. The fixed diameter reducing machine has the advantages that the operation is simple and reliable, the wall thickness precision of the steel pipe can be greatly improved, and particularly, the inner square problem of thick wall pipes can be solved.

Description

technical field [0001] The invention belongs to the technical field of hot-rolled seamless steel pipes, in particular to a sizing and reducing machine for eliminating the inner side of the steel pipe. Background technique [0002] The steel pipe sizing, reducing and tension reducing process is a continuous rolling process with a hollow body without a mandrel. There are many forms of steel pipe sizing and reducing machines. According to the number of rolls, they can be divided into two-roll, three-roll and four-roll types. The roll axes are all in the same plane perpendicular to the rolling line for continuous rolling. During the rolling process of the sizing and reducing unit, if the pipe has a large diameter reduction and thick-walled pipe, the inner wall of the steel pipe will form inner squares or inner hexagonal inner polygonal defects, which reduces the wall thickness accuracy of the steel pipe. Take the three-roll sizing and reducing machine as an example, such as fi...

AI Technical Summary

Problems solved by technology

For thin-walled pipes, the additional influence of additional axial stress on the change of wall thickness is small, and the phenomenon of "inner hexagonal" is not obvious, but for thick-walled pipes, the additional influence of additional axial stress on the change of wall thickness is greater, and the phenomenon of "inner hexagonal" is not obvious. "The phenomenon is more obvious, resulting in the wall thickness accuracy can not meet the standard requirements

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