A method for detecting magnetic properties of pipeline steel

Abstract

The invention provides a method for detecting the magnetic properties of pipeline steel. Step 1: Design samples: select multiple groups of pipeline steel round bar samples of different production batches, cut each group into five pieces, and use them for microstructure electron microscope scanning and magnetic hysteresis respectively. Curve measurement, magnetization parameter determination, magnetic flux-tensile stress test, magnetic flux-compressive stress test and other five test conditions; Step 2: Microstructure observation: use Leica DMI3000M / DFC450 inverted metallographic microscope to test the sample at 200 Under the condition of multiple times, the microstructure and micrometallography analysis were carried out; Step 3: Magnetization curve drawing: at room temperature, a magnetic field was applied at a rate of 100Oe / s to obtain the corresponding relationship between the magnetic field strength and the magnetic moment, and then calculate B‑ The H relationship curve is the magnetization curve; Step 4: Use the Jiles Atherton model to physically explain the hysteresis parameters, and correct it in combination with the experimental data, and use the Matlab software to solve the differential equation of the magnetization intensity versus the magnetic field change rate, and establish a pipeline Magnetic constitutive model of 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.

Images