Pipeline steel magnetic characteristics detection method

Abstract

The invention provides a pipeline steel magnetic characteristics detection method. The pipeline steel magnetic characteristics detection method comprises the following steps: step I: designing a sample: selecting multiple groups of pipeline steel cylindrical bar test pieces of different production batches, cutting each group of pipeline steel cylindrical bar test pieces into five pieces, wherein the five test pieces are respectively used for five test conditions, i.e. microscopic structure electron microscopic scanning, magnetic hysteresis curve determination, magnetic parameter determination,magnetic flux-tensile stress test, and magnetic flux-pressure stress; step II: observing a microscopic structure: performing the microscopic structure microscopic metallographical mapping analysis for the test piece under a 200-times magnification times by using a Leica DMI3000M / DFC450 inverted metallurgic microscope; step III: drawing a magnetization curve: loading a magnetic field at a speed of100 Oe / s at the normal temperature, obtaining a correspondence between a magnetic field intensity and magnetic moment, and inversely calculating a B-H relationship curve, i.e. the magnetization curve; and step IV: physically interpreting magnetic hysteresis parameters by using a Jiles Atherton model, correcting the magnetic hysteresis parameters according to test measured data, solving a differential equation of the magnetization intensity for a change rate of the magnetic field by adopting Matlab software auto-program, and establishing a magnetics constitutive model of the pipeline steel.

Description

technical field [0001] The invention belongs to the technical field of pipeline magnetic force detection, and in particular relates to a detection method for pipeline steel magnetic force characteristics. Background technique [0002] Natural gas pipelines are affected by complex factors such as load, material properties, medium corrosion, and environment during construction and operation. During the service period, the pipeline wall has been damaged to varying degrees, causing the actual stress state to be inconsistent with the design, or even reach or exceed the design limit. value, leading to major engineering safety accidents. Relevant studies at home and abroad have shown that natural gas pipeline detection technology is mainly aimed at corrosion pits, defects, remaining wall thickness and leakage, and is developing in the direction of multi-data detection. At present, magnetic flux leakage detection technology and equipment The field of natural gas pipeline detection in ...

AI Technical Summary

Problems solved by technology

Natural gas pipeline steel is a typical ferromagnetic material. Scholars at home and abroad have made many achievements in the field of magnetic detection technology for pipeline defects and stress detection of ferromagnetic materials, but there is no research on the magnetic effects and applications of common pipeline steels.

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