Production method of hot-bending elbow

Abstract

The invention discloses a production method of a hot-bending elbow. The method comprises the following steps that, during the smelting process section, the grade of B-type non-metallic inclusions in steel of the hot-bending elbow is controlled to be smaller than or equal to 1.0; during the hot rolling process section, the water cooling final temperature of the hot-bending elbow after steel plate rolling is controlled to be 470 DEG C-520 DEG C; during the hot rolling process section, the steel plate stacking cooling temperature of the hot-bending elbow is controlled to be 400 DEG C-480 DEG C, and the stacking cooling time is more than or equal to 24 hours; during the tube-making process section, the cooling speed of a weld joint after the hot-bending elbow is welded is less than or equal to0. 6 DEG C per second; and during tube-making process section, the expanding rate of the hot-bending elbow is controlled to be 0.72%-0.78%. According to the method, the inclusions and internal stressin the weld joint area are effectively reduced, the problems that the the weld joint of the hot-bending elbow is cracked or is checked to be below standard in the high-temperature heating bending forming process and the heat treatment technological process are solved, and the safety and reliability of the hot-bending elbow in the oil-gas transportation service process are improved.

Description

technical field [0001] The present application relates to the technical field of production and manufacture of oil and gas transportation pipelines, in particular to a production method of hot-simmered bent pipes. Background technique [0002] In the field of oil and gas transportation, the pipelines used usually include hot-simmered elbows and conventional straight pipes. Hot-simmered elbows are mainly used for turning connections of pipelines in special terrains. strict. The manufacturing process of hot-simmered bent pipe is complicated. In the process of making steel pipes from steel plates, high-temperature simmered bending forming and tempering heat treatment are required. The conventional straight pipe will not crack in the weld area during the pipe making process. It can be seen that the weld seam of the hot-simmered elbow is the weakest link of the entire oil and gas pipeline, and there is an urgent need for a production method of the hot-simmered elbow, which can ...

AI Technical Summary

Problems solved by technology

[0003] The invention provides a production method of hot-simmered bent pipes to solve or partially solve the technical problem that weld seam cracking defects often occur when hot-simmered bent pipes are bent and formed at high temperature

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