Reinforcing thermal treatment technology for pipe end of petroleum steel pipe in quenching and tempering condition

Abstract

The invention discloses a reinforcing thermal treatment technology for the pipe end of a petroleum steel pipe in a quenching and tempering condition. The technology comprises the following steps of: S1, performing the first-stage quenching and tempering treatment on the whole pipe; and S2, performing secondary tempering treatment on the middle part of the pipe body of the steel pipe obtained by the step S1. The secondary tempering treatment on the middle part of the pipe body of the steel pipe aims at reducing the strength of the middle part of the steel pipe and realizing the strength performance of a final product. The technology disclosed by the invention can realize strength mismatching between the pipe body and the pipe end of a petroleum steel pipe in a quenching and tempering condition, so that no obvious transition area exists between the pipe body and the pipe end of the steel pipe. According to the reinforcing thermal treatment technology for the pipe end of a petroleum steel pipe in a quenching and tempering condition, disclosed by the invention, the strength of the treated petroleum steel pipe is distributed in a mismatching manner, the weak point of easy deformation and even breakage caused by stress concentration of a threaded structure at the pipe end of an existing product can be eliminated, and the service safety of the steel pipe can be improved.

Description

technical field [0001] The invention relates to the technical field of metal engineering materials, in particular to a quenched and tempered oil steel pipe end strengthening heat treatment process for steel pipes used in petroleum industry exploration and development. Background technique [0002] Steel pipes used in the petroleum industry mainly include drill pipes, oil pipes and casings. According to the current industrial standard, the drill pipe and some small-diameter tubing and casing have pipe end thickening and heat treatment processes, which can realize the misalignment of the load. For most oil pipes and casings, the pipe body and pipe end have a uniform outer diameter and wall thickness. After the pipe end is threaded and connected with a coupling, it is supplied to oilfield users as an end product. The final heat treatment of these oil and casing pipes is an overall quenching and tempering treatment. The pipe body and pipe end have the same strength. Since the s...

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Problems solved by technology

The final heat treatment of these oil and casing pipes is an overall quenching and tempering treatment. The pipe body and pipe end have the same strength. Since the strength of the coupling is higher than that of the pipe body and pipe end, and the stress concentration effect of the threaded connection part of the pipe end, the pipe end It is easy to be deformed, even broken, tripped and other failures, which will bring significant economic losses to oil field production

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