Finishing rolling method and device of oblique axial rolling cored steel

Abstract

The invention discloses a finishing rolling method and device of oblique axial rolling cored steel. Cross piercing rolling, cored (rod) oblique rolling tube rolling, secondary (rod) core-free oblique rolling tube sizing rolling are performed by adopting existing cross piercing process to obtain a heat pipe blank. When the heat pipe blank is in finishing rolling, the heat pipe blank is continuously rolled by the way of arranging two rolling groups on a Y-type roller. Each roll group consists of three rollers. The roller of one rolling group and the roller of the other rolling group are matched in installation in a reversing manner at 180 degrees. The rolling central lines are maintained consistent. According to the invention, the heat pipe blank is rolled in all directions, and the coefficients of elongation of the two rolling groups in the rolling process are different, so that the heat pipe blank is subjected to a certain micro tension, thus, effectively improving the surface quality of inner holes of cored steel products. The method and device have the advantages of good product quality, easy operation, simple structure of device, less investment, low manufacturing cost, adaptability to large-scale production and the like.

Description

technical field [0001] The invention relates to a final rolling method and device for oblique longitudinal rolling of hollow steel, belonging to the technical field of metal pressure processing. Background technique [0002] The process of oblique longitudinal rolling hollow steel is also called hot piercing and hot drawing process and hot piercing and hot rolling process. This method is a hollow steel production process independently developed and developed by our country in the world. It uses the basic technology of manufacturing seamless steel pipes to produce hollow steel, and hollow steel is essentially a round or hexagonal seamless steel pipe with ultra-thick walls, so the basic technology of manufacturing seamless steel pipes is used to manufacture hollow steel It is more reasonable. The production of hollow steel by this process has the best geometric size and cross-section shape, one-fired material, fixed-length production, high final synthetic material rate, flexi...

AI Technical Summary

Problems solved by technology

[0003] 1. The oblique longitudinal rolling hollow steel production process has been born and developed for less than 30 years. Although many problems in the process, equipment and product quality have been overcome through efforts, due to the characteristics of the oblique rolling process, the inner and outer surfaces of the steel pipe after perforation and diameter reduction are helical. Traces (wrinkles in the inner hole) must exist, and the surface quality of the circular hollow steel cannot be truly guaranteed. Although the hexagonal hollow steel is formed by hot drawing or hot longitudinal rolling, its six edges cannot be processed, and its helical The traces are preserved, and the edge transition arc cannot be tangent to the hexagonal plane, so the shape of the hollow steel still cannot reach a more ideal level, and it also affects the quality of the hollow steel to a certain extent.

[0004] 2. In the existing oblique longitudinal rolling hollow steel production process, core rolling is used for primary reduction, which greatly improves the inner surface quality of the product. At present, core rolling cannot be performed for secondary reduction, and new slight defects will still occur.

However, the hollow steel formed by hot longitudinal rolling will reduce the product quality due to the wall-increasing effect.

However, hot drawing needs to increase the rolling head process. As a passive longitudinal rolling method, drawing is slow, employs many people, has high labor intensity, and low yield and production efficiency, so it has obvious weaknesses.

[0005] 3. The hot longitudinal rolling forming of the existing inclined longitudinal rolling hollow steel production process currently adopts six-roll active rolling equipment and technology. Although the work efficiency is high, no rolling head is used, and almost no human operation is required, the biggest problem is Longitudinal rolling wall increase brings the increase of cross-rolling defects in the inner hole, which cannot be solved in the final rolling stage, thus greatly affecting the quality of hollow steel

[0006] To sum up, due to the existing oblique longitudinal rolling hollow steel production process in the final rolling process, there are many problems such as slow final rolling speed, many procedures, many operators, high labor intensity, low yield, low productivity, and irregular shape. , local cross-rolling defects cannot be eliminated, inner hole quality defects and outer surface quality defects cannot be eliminated caused by hot-piercing and hot-rolling process, so the final rolling method in the existing oblique longitudinal rolling hollow steel production process is still not ideal

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