X80 steel made pipe fittings and manufacture technique thereof

Abstract

The invention relates to a pipeline made of X80 steel and a method for manufacturing the same. The chemical compositions are that: 0.06 to 0.1 percent of C, 0.1 to 0.3 percent of Si, 1.4 to 2.0 percent of Mn, less than or equal to 0.015 percent of P, 0.01 percent of S, 0 to 0.45 percent of Cr, 0 to 0.3 percent of Mo, 0 to 0.3 percent of Cu, 0 to 0.5 percent of Ni, 0.05 to 0.15 percent of Nb, 0 to 0.06 percent of Ti, 0 to 0.06 percent of V, Ceq controlled between 0.36 and 0.44 percent, Pcm controlled between 0.17 and 0.23 percent. The pipeline manufactured with the controlled rolled steel plate of the compositions by means of controlling the forming temperature, hardening heat, drawing temperature, cooling velocity, etc. has low-temperature impact toughness more than 90 J, completely meets the technical requirement on the X80 pipelines and is suitable to be used as X80 steel pipelines for oil and gas pipelines.

Description

technical field [0001] The invention belongs to the field of iron and steel, and in particular relates to an X80 steel, a manufactured pipe fitting and a manufacturing process thereof. Background technique [0002] Pipeline transportation of oil and gas has the advantages of safety, reliability, economy, energy saving, and high efficiency compared with other means of transportation. Therefore, with the continuous development of the world's oil industry, the construction of oil and gas pipelines around the world is developing rapidly, and its requirements for pipe performance are also increasing. higher. [0003] At present, large-scale pipe fittings generally adopt the production process of quenching and tempering after hot-pressing with molds on a press. This process is mainly used to manufacture low-strength pipe fittings, and there are less production and research on pipe fittings above X70 and X80 steel, especially thick-walled pipe fittings. [0004] Domestically, X80...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the disadvantages of common X80 steel in the manufacturing process of pipe fittings due to repeated heating and cooling, which can lead to reduced performance of pipe fittings and cannot meet the requirements, and provide a kind of X80 steel, its application, and the manufacturing process of the pipe fittings , the strength of the pipe fittings is greater than 555Mpa, and the low-temperature impact toughness is greater than 90J, which can fully meet the technical requirements of X80 pipe fittings. It is an X80 steel grade pipe fitting suitable for oil and natural gas pipelines.