Large-diameter thick-wall seamless cylinder and manufacturing method thereof

Abstract

The invention discloses a large-diameter thick-wall seamless cylinder and a manufacturing method thereof. The method comprises the steps that a target steel ingot is obtained; the target steel ingot is forged and formed, and a forged blank is obtained; primary heat treatment including normalizing and annealing is conducted on the forged blank, then the blank obtained through primary heat treatment is machined, and a seamless cylinder blank is obtained; and secondary heat treatment including quenching and tempering is conducted on the seamless cylinder blank, and therefore the target seamless cylinder is obtained. According to the method, the seamless cylinder is manufactured through the processes of integral forging, two-time heat treatment and the like, so that the strength and low-temperature impact toughness of the seamless cylinder are guaranteed, and then the use performance of a metal product manufactured through the seamless cylinder in the low-temperature environment is guaranteed.

Description

technical field [0001] The invention relates to the technical field of metal product forming, in particular to a large-diameter thick-walled seamless cylinder and a manufacturing method thereof. Background technique [0002] Cylinders are key upstream products for the manufacture of pressure piping components, pressure vessels and other metal products. [0003] Existing large-diameter, thick-walled cylinders are mainly made by steel plate coil welding. The welding seam is the weak part of the cylinder body and is the key link in the quality control of the cylinder. [0004] In the process of using a cylinder to manufacture downstream metal products, it is usually necessary to perform heat treatment processes such as high temperature heating, quenching, and tempering on the cylinder. The complex thermoforming process is easy to change the structure of the weld, which may reduce its strength and toughness and affect the overall performance. And some metal products are used ...

AI Technical Summary

Problems solved by technology

The complex thermoforming process is easy to change the structure of the weld, which may lead to a decrease in its strength and toughness and affect the overall performance

Moreover, some metal products are used in harsh environments and have higher requirements for overall performance.

Taking my country-Russia East Line Natural Gas Pipeline (Northern Section) as an example, the extreme temperature in the area where the pipeline passes is lower than -45°C. This environment requires the metal products on the pipeline to have extremely high low-temperature impact toughness, but currently steel coil welding is used The impact toughness of the cylinder prepared by the method is insufficient under low temperature conditions, and it is difficult to meet the performance requirements

At the same time, as the structural size of metal products increases, the diameter and thick wall of the cylinder also increase accordingly, resulting in an increase in manufacturing difficulty.

Therefore, the existing cylinder manufacturing method can no longer meet the actual needs

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