Method for welding cold-expansion tube production line draw rod

Abstract

The invention provides a method for welding a pull rod for a production line of cold expansion pipes, which comprises the following steps: preparing before welding; preparing a short joint end of the pull rod; preparing of a long joint end of the pull rod; welding; detecting after the welding, namely, carrying out ultrasonic and dye penetration inspection for the welded joint after the pull rod is welded. The method has the advantages that by adopting an unconventional method to weld and repair the pull rod for the production line of the cold expansion pipes, the method solves the technical problems of integral preheating of the pull rod, heat treating after the welding and welding at low temperature, avoids multiple technical defects, shortens repair time, and reduces loss of oil fields. The pull rod is a key component of production line equipment for the cold expansion pipes in the oil fields, and directly influences production operation after the pull rod is damaged, then the downtime loss is 320, 000 Yuan per hour, and if spare parts are bought abroad, several months are needed. The method generates certain social benefit and larger economic benefit, and provides scientific repair method for guiding production practice for projects in the same field.

Description

technical field [0001] The invention relates to a welding process, in particular to a method for welding tie rods of a cold-expanded pipe production line. Background technique [0002] In the oilfield cold expansion production line, the tie rod is the key component of the cold expansion equipment, and the damage of the tie rod directly affects the production. The traditional welding process for repairing tie rods is: (1), groove bevel before welding, solid welding of butt joints, local preheating; (2) selection of welding materials, butt welding, and temperature control between layers; (3) welding After local heat treatment, non-destructive testing. [0003] For the welding of such large tie rods, the traditional welding process method is prone to the following disadvantages due to the lack of welding production technology: [0004] 1. The groove form of the tie rod before welding is V-shaped or U-shaped. The V-groove fracture requires a lot of filler metal in the weld se...

AI Technical Summary

Problems solved by technology

The interlayer temperature control of the weld is related to the cooling rate during welding of materials with hardening tendency and overheating tendency. If the interlayer temperature control is not good, it is easy to cause uneven cooling temperature and cooling speed and cause cracks in the weld

[0006] 3. After the tie rod is welded, the overall heat treatment cannot be carried out, because limited by the volume of the tie rod, only partial flame heat treatment can be used

This non-uniform flame heat treatment does not achieve the desired results and can lead to cracks in the welded joint