Method for cooling small-caliber thick-wall steel pipe after rolling

Abstract

The invention belongs to the field of metallurgical industry, and relates to a method for cooling a small-caliber thick-wall steel pipe after rolling. The method comprises the following steps of heating, perforating, injecting nitrogen and borax into a hollow billet, descaling with high-pressure water before continuous rolling, rolling with a continuous rolling pipe mill, removing the pipe, performing induction heating, descaling with high-pressure water before reducing, rolling with a four-roller reducing unit, performing controlled cooling after rolling, spraying water on a cooling bed for cooling, blowing with compressed air on the cooling bed, grouping and arranging, distributing materials, cutting heads and tails, sizing, and collecting and sorting. High-precision rolling of the steel pipe is achieved through a high-pressure water descaling device before reducing and the four-roller or three-roller reducing unit, the product size precision is high, and the head and tail size deviation is small; uniform cooling of the steel pipe is achieved through a cooling bed stepping structure, a cooling mechanism above the cooling bed, a cooling mechanism below the cooling bed and a rotating mechanism, and the cooling efficiency of the steel pipe on the cooling bed is improved; and by controlling structure transformation, an ideal uniform structure is obtained, and finally a product with high uniform structure and high stable mechanical property is obtained.

Description

technical field [0001] The invention belongs to the field of metallurgical industry and relates to a method for cooling small-diameter thick-walled steel pipes after rolling. Background technique [0002] As one of the important products in the steel industry, steel pipes are widely used in transportation, construction, machinery, automobiles, ships, oil pipelines and other fields. The core equipment to realize the steel pipe production process includes piercing machine, pipe rolling mill and sizing and reducing machine. Among them, the sizing and reducing machine is the finishing rolling equipment in the seamless steel pipe production line, which is to expand the range of product specifications and improve the dimensional accuracy of the rolling mill , head and tail dimensional tolerance, an ideal production equipment, however, after the production of the sizing and reducing unit, the steel pipes are air-cooled on the cooling bed, so as to realize the organizational transfo...

AI Technical Summary

Problems solved by technology

[0003] 1. The high-precision sizing and reducing unit only realizes high-precision size control after rolling, and cannot control the cooling method after rolling, and thus cannot control the post-rolling structure;

[0004] 2. During the cooling process of the cooling bed, the air cooling speed is low, and coarse structures are easy to appear;

[0005] 3. The cooling time of the cooling bed is long, and the cooling bed occupies a large area, which increases the investment

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