High-strength steel wire magnetic flux leakage detection method considering corrosion-fatigue coupling effect

Abstract

The invention discloses a high-strength steel wire magnetic flux leakage detection method considering a corrosion-fatigue coupling effect. The high-strength steel wire magnetic flux leakage detection method comprises the following steps: S1, manufacturing a simple cable; s2, high-strength steel wires with different corrosion degrees are manufactured, and the cable body corrosion condition in the cable operation state is simulated; s3, carrying out fatigue loading on the cable body, and simulating the action state of vehicle load on the bridge and alternating stress such as wind, rain and shock; s4, performing pre-fatigue-corrosion-fatigue and pre-corrosion-fatigue-corrosion interaction working conditions on the simple cable by adopting the interaction effect of fatigue and corrosion working conditions, and simulating the combined action state of cable body corrosion and alternating stress in a real state; s5, the processed cable is placed in a magnetic flux leakage detection platform for magnetic signal data collection, three-dimensional magnetic flux leakage signal detection is carried out through an axial route and a circumferential route, and cable damage is analyzed and judged through magnetic flux leakage signals. And a new thought and a new solution can be provided for bridge health detection.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic flux leakage detection, and in particular to a magnetic flux leakage detection method for high-strength steel wire considering corrosion-fatigue coupling effect. Background Art

[0002] At present, the main methods for non-destructive testing of internal defects of bridge cables are: magnetic acoustic emission detection method, ultrasonic detection method and magnetic leakage detection method. Among them, magnetic acoustic emission detection method refers to the conversion of mechanical energy into electrical energy and then emitting signals through acoustic emission sensors in the environment of alternating magnetic field of ferromagnetic materials, which is used as the basis for measurement. Although this method has great potential, the signal it generates is affected by many factors and in a complex way, so there is a lot of controversy in the signal generation mechanism and it is difficult to be widely used. The ultrasonic detection method uses the characteristics of ultrasonic energy entering the interior of ferromagnetic materials. When the ultrasonic wave passes from one section to another, it will produce reflection, which is used as the basis for detection to detect the internal damage of the cable. However, this method is difficult to detect specimens with complex and irregular structural shapes, and there are large differences in the detection results of the defect position and shape. At the same time, the material of the material will also affect the detection results. As a new detection method of green non-destructive testing, magnetic leakage detection method is based on the non-destructive testing technology of the magnetism of ferromagnetic materials. When the internal magnetic field of ferromagnetic materials passes through the defect, the magnetic resistance increases and a leakage magnetic field is generated. The magnetic signal at the defect of the ferromagnetic material is detected to judge the internal damage of the cable. Magnetic flux leakage detection has the following advantages: (a) The entire detection process has the characteristics of fast speed, simple process, convenient operation, high efficiency and low cost; (b) There are multiple detection methods, such as external wear type, internal wear type and probe type, which are suitable for various types of ferromagnetic material detection such as pipes, rods, wires, etc.; (c) The damage degree and damage location of the cable can be intuitively judged by collecting the magnetic flux leakage signal, and its detection accuracy is high; (d) The probe type detection method can be used. In the actual bridge inspection process, the magnetic flux leakage detection device can be fixed on the climbing cable equipment, and the internal damage of the cable can be autonomously detected, identified and located through the movement of the climbing cable equipment. However, the existing magnetic flux leakage detection method does not consider the change law of the magnetic signal under the holding force state and the detection of cable damage magnetic flux leakage signal under the fatigue-corrosion coupling state, and there are certain limitations. Therefore, it is urgent to develop a high-strength steel wire magnetic flux leakage detection method that considers the corrosion-fatigue coupling effect to solve the above technical problems.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a high-strength steel wire leakage magnetic flux detection method taking into account the corrosion-fatigue coupling effect. No external excitation magnetic field is required as a magnetic source. The natural geomagnetic field is used to magnetize the ferromagnetic material. No pretreatment of the surface of the test piece is required. Early prevention and diagnosis of test piece defects can be performed. The changing characteristics of the leakage magnetic flux signal under the cable operation state are more comprehensively explored, which can provide new ideas and solutions for bridge health detection. It has broad application prospects and is conducive to popularization and application.

[0005] In order to achieve the above object, the present invention provides a high-strength steel wire magnetic flux leakage detection method considering the corrosion-fatigue coupling effect, comprising the following steps:

[0006] S1: Take 55 galvanized high-strength steel wires to make a simple cable;

[0007] S2: Use electrochemical corrosion to produce high-strength steel wires with different corrosion degrees to simulate the corrosion of the cable body under the operation state;

[0008] S3: Use a universal fatigue testing machine to perform fatigue loading on the cable body to simulate the action state of alternating stresses such as vehicle loads on the bridge and wind, rain and earthquakes;

[0009] S4: The fatigue and corrosion conditions are interactively applied to the simple cable, and pre-fatigue-corrosion-fatigue and pre-corrosion-fatigue-corrosion interactive conditions are performed to simulate the joint action of cable body corrosion and alternating stress under real conditions;

[0010] S5: Place the treated cable on a magnetic flux leakage detection platform to collect magnetic signal data, perform three-dimensional magnetic flux leakage signal detection through axial and circumferential routes, and determine cable damage through magnetic flux leakage signal analysis.

[0011] Preferably, in S1, the manufacturing method of the simple cable is: the interior of the cable is composed of 55 parallel galvanized high-strength steel wire bundles, which are arranged in accordance with the specification of "Parallel Steel Wire Cables for Large-Span Cable-Stayed Bridges" JT / T775-2016, and polyethylene tape is wrapped around the outer periphery of the steel wire to maintain the arrangement of the steel wire, and a high-density polyethylene sheath is used for protection on the outside to make a simple cable.

[0012] Preferably, the specific steps of S2 are: making a homemade electrochemical accelerated corrosion device for galvanized steel wire, controlling the stable current at 0.5A, controlling the degree of corrosion by the corrosion time, connecting the high-strength steel wire to the positive electrode of a DC regulated power supply through a wire, connecting the negative electrode of the DC regulated power supply to the carbon rod through a wire, using a 5% sodium chloride solution as the electrolyte solution, and using insulating tape to wrap and cover the parts of the steel wire that do not participate in the corrosion to isolate them from contact with the electrolyte solution, and controlling the corrosion process of the galvanized steel wire by adjusting the current size and corrosion time of the DC regulated power supply.

[0013] Preferably, the specific steps of S3 are: according to the specification "Hot-dip galvanized or zinc-aluminum alloy steel wire for bridge cables" (GB / T 17101-2019) and "Parallel steel wire cables for large-span cable-stayed bridges" (JT / T 775-2016), a fatigue loading test of the steel wire specimen is carried out, with a stress amplitude of 360MPa, a maximum tensile force of 23.09KN, a minimum tensile force of 9.24KN, a maximum stress of 600MPa, and a minimum stress of 240MPa. The 50mm length range on the left and right ends of the specimen is the clamping end of the fatigue test. The cyclic loading mode in the fatigue test is a constant-amplitude sinusoidal waveform. Combined with the specification "Axial force control method for fatigue test of metal materials" and the specimen and equipment conditions of this test, the stress ratio R is set to 0.4 and the loading frequency f is 8Hz.

[0014] Preferably, the specific steps of S4 are: in order to explore the influence mechanism of fatigue stress caused by vehicle load on the distribution of leakage magnetic signal, a pre-fatigue-corrosion-fatigue interaction working condition is carried out, and the high-strength steel wire of the cable is first subjected to pre-fatigue loading of F1=1000, 5000, and 10000 times and used as the initial state, and then electrochemically corroded to different degrees, and the corrosion time is T=1, 3, 6, and 9h, and then fatigue loads of F2=1000, 5000, and 10000 times are applied; a pre-corrosion-fatigue-corrosion interaction working condition is carried out, and the high-strength steel wire of the cable is first electrochemically corroded to different degrees, and the corrosion time is T1=1, 3, 6, 9 h, followed by fatigue loading of F=1000, 5000, and 10000 times, and then corrosion time of T2=1, 3, 6, and 9 h; all corrosion T fatigue F with different gradients are combined, for example: under the pre-fatigue-corrosion-fatigue interaction condition, condition ① F1 (1000 times)-T (3h)-F2 (1000 times), condition ② F1 (1000 times)-T (6h)-F2 (5000 times)…; under the pre-corrosion-fatigue-corrosion interaction condition, condition ① T1 (3h)-F (1000 times)-T2 (3h), condition ② T1 (3h)-F (5000 times)-T2 (6h)….

[0015] Preferably, the specific judgment method of S5 is: the collected cable leakage magnetic signal will form a waveform diagram. When there is a defect in the high-strength steel wire inside the cable, the magnetic field line at the defect will bend, deform and mutate. The average amplitude value of the normal waveform in the intact state of the cable is set to K. When the amplitude of the abnormal waveform is greater than 10% of K, it can be determined that the cable is internally damaged.

[0016] The present invention provides a high-strength steel wire magnetic leakage detection method taking into account the corrosion-fatigue coupling effect, which has the following beneficial effects.

[0017] 1. As a new method in the field of green non-destructive testing, the present invention is essentially a magnetic detection technology based on the relationship between magnetic signal changes. Its spontaneous magnetic leakage signal is caused by the change in its microstructure, which causes the change in signal characteristics. There is a huge correlation between this signal and material properties. Compared with traditional magnetic leakage detection technology, this technology does not require an external excitation magnetic field as a magnetic source. It uses the natural geomagnetic field to magnetize ferromagnetic materials, and does not require pretreatment of the test piece surface, so that defects in the test piece can be prevented and diagnosed early.

[0018] 2. The present invention takes into account the impact of corrosion-fatigue coupling on cable operation, and more comprehensively explores the changing characteristics of the leakage magnetic signal under the cable operation state, which can provide new ideas and solutions for bridge health detection. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific embodiments to help understand the content of the present invention.

[0020] The present invention provides a high-strength steel wire magnetic flux leakage detection method considering the corrosion-fatigue coupling effect, comprising the following steps:

[0021] S1: Take 55 galvanized high-strength steel wires to make a simple cable;

[0022] The manufacturing method of the simple cable is as follows: the inside of the cable is composed of 55 parallel galvanized high-strength steel wire bundles, which are arranged in accordance with the specification of JT / T775-2016 "Parallel Steel Wire Cables for Large-span Cable-stayed Bridges". Polyethylene tape is wrapped around the outside of the steel wire to maintain the arrangement of the steel wire, and a high-density polyethylene sheath is used on the outside to protect the simple cable.

[0023] S2: Use electrochemical corrosion to make high-strength steel wires with different corrosion degrees to simulate the corrosion of the cable body under the operating state of the cable; the specific steps are: make a homemade electrochemical accelerated corrosion device for galvanized steel wire, control the stable current at 0.5A, control the corrosion degree by corrosion time, connect the high-strength steel wire to the positive pole of the DC regulated power supply through a wire, and connect the negative pole of the DC regulated power supply to the carbon rod through a wire. The electrolyte solution uses a 5% sodium chloride solution, and use insulating tape to wrap and cover the parts of the steel wire that do not participate in the corrosion to isolate them from contact with the electrolyte solution. The corrosion process of the galvanized steel wire is controlled by adjusting the current size and corrosion time of the DC regulated power supply.

[0024] S3: Use a universal fatigue testing machine to perform fatigue loading on the cable body to simulate the action state of vehicle loads on the bridge and alternating stresses such as wind, rain and earthquake; the specific steps are: According to the specifications "Hot-dip galvanized or zinc-aluminum alloy steel wire for bridge cables" (GB / T17101-2019) and "Parallel steel wire cables for large-span cable-stayed bridges" (JT / T 775-2016), a fatigue loading test of the steel wire specimen is carried out, with a stress amplitude of 360MPa, a maximum tensile force of 23.09KN, a minimum tensile force of 9.24KN, a maximum stress of 600MPa, and a minimum stress of 240MPa. The 50mm length range on the left and right ends of the specimen is the clamping end of the fatigue test. The cyclic loading method in the fatigue test is a constant-amplitude sinusoidal waveform. Combined with the specification "Axial force control method for fatigue test of metal materials" and the specimen and equipment conditions of this test, the stress ratio R is set to 0.4 and the loading frequency f is 8Hz.

[0025] S4: The fatigue and corrosion conditions are interactively applied to the simple cable, and pre-fatigue-corrosion-fatigue and pre-corrosion-fatigue-corrosion interactive conditions are performed to simulate the joint action of cable corrosion and alternating stress under real conditions; the specific steps are: in order to explore the influence mechanism of fatigue stress caused by vehicle load on the distribution of leakage magnetic signal, pre-fatigue-corrosion-fatigue interactive conditions are carried out, and the high-strength steel wire of the cable is first subjected to pre-fatigue loading of F1=1000, 5000, and 10000 times and used as the initial state, and then electrochemical corrosion of different degrees is carried out, and the corrosion time is T=1, 3, 6, 9h, and then F2=1000, 5000, and 10000 times of fatigue load are applied; pre-corrosion-fatigue-corrosion interactive conditions are carried out, and the cable is first subjected to pre-fatigue loading of F1=1000, 5000, and 10000 times of pre-fatigue loading of F1=1000, 5000, and 10000 times of pre-fatigue loading of F2 ... The high-strength steel wire was subjected to different degrees of electrochemical corrosion, with corrosion time of T1=1, 3, 6, 9h, followed by fatigue loading of F=1000, 5000, 10000 times, and then corrosion time of T2=1, 3, 6, 9h; all different gradients of corrosion T fatigue F were combined, for example: under the pre-fatigue-corrosion-fatigue interaction condition, condition ①F1(1000 times)-T(3h)-F2(1000 times), condition ②F1(1000 times)-T(6h)-F2(5000 times)…; under the pre-corrosion-fatigue-corrosion interaction condition, condition ①T1(3h)-F(1000 times)-T2(3h), condition ②T1(3h)-F(5000 times)-T2(6h)….

[0026] S5: Place the treated cable in the magnetic flux leakage detection platform to collect magnetic signal data, perform three-dimensional magnetic flux leakage signal detection through axial and circumferential routes, and judge the cable damage through magnetic flux leakage signal analysis. The specific judgment method is: the collected cable magnetic flux leakage signal will form a waveform. When there is a defect in the high-strength steel wire inside the cable, the magnetic field line at the defect will bend, deform and mutate. The average amplitude of the normal waveform in the intact state of the cable is set to K. When the amplitude of the abnormal waveform is greater than 10% of K, it can be judged as internal damage of the cable.

[0027] As a new method in the field of green nondestructive testing, the present invention is essentially a magnetic detection technology based on the relationship between magnetic signal changes. Its spontaneous magnetic leakage signal is caused by the change in its microstructure, which causes the change in signal characteristics. There is a huge correlation between this signal and the material properties. Compared with traditional magnetic leakage detection technology, this technology does not require an external excitation magnetic field as a magnetic source. It uses the natural geomagnetic field to magnetize ferromagnetic materials. It does not require pretreatment of the surface of the test piece, and can perform early prevention and diagnosis of test piece defects. The present invention takes into account the impact of corrosion-fatigue coupling on cable operation, and more comprehensively explores the changing characteristics of the magnetic leakage signal under the cable operation state, which can provide new ideas and solutions for bridge health detection.

[0028] The invention concept is described in detail using specific examples herein, and the description of the above embodiments is only used to help understand the core idea of ​​the invention. It should be pointed out that any obvious modification, equivalent substitution or other improvement made by a person of ordinary skill in the art without departing from the invention concept should be included in the protection scope of the present invention.

Claims

1. A high-strength steel wire magnetic flux leakage detection method considering the corrosion-fatigue coupling effect, characterized in that: The steps include: S1: Take 55 galvanized high-strength steel wires to make a simple cable; S2: Use electrochemical corrosion to produce high-strength steel wires with different corrosion degrees to simulate the corrosion of the cable body under the operation state; S3: Use a universal fatigue testing machine to perform fatigue loading on the cable body to simulate the action state of alternating stresses such as vehicle loads on the bridge and wind, rain and earthquakes; S4: The fatigue and corrosion conditions are interactively applied to the simple cable, and pre-fatigue-corrosion-fatigue and pre-corrosion-fatigue-corrosion interactive conditions are performed to simulate the joint action of cable body corrosion and alternating stress under real conditions; S5: Place the treated cable on a magnetic flux leakage detection platform to collect magnetic signal data, perform three-dimensional magnetic flux leakage signal detection through axial and circumferential routes, and determine cable damage through magnetic flux leakage signal analysis.

2. A high-strength steel wire magnetic flux leakage detection method considering the corrosion-fatigue coupling effect according to claim 1, characterized in that: In S1, the manufacturing method of the simple cable is as follows: the interior of the cable is composed of 55 parallel galvanized high-strength steel wire bundles, which are arranged in accordance with the specification of JT / T775-2016 "Parallel Steel Wire Cables for Large-Span Cable-Stayed Bridges", polyethylene tape is wrapped around the outer periphery of the steel wire to maintain the arrangement of the steel wire, and a high-density polyethylene sheath is used for protection on the outside to make a simple cable.

3. The method for detecting magnetic flux leakage of high-strength steel wire considering the corrosion-fatigue coupling effect according to claim 1 is characterized in that: The specific steps of S2 are: making a self-made electrochemical accelerated corrosion device for galvanized steel wire, controlling the stable current at 0.5A, controlling the corrosion degree by the corrosion time, connecting the high-strength steel wire to the positive pole of a DC regulated power supply through a wire, connecting the negative pole of the DC regulated power supply to a carbon rod through a wire, using a 5% sodium chloride solution as the electrolyte solution, wrapping and covering the parts of the steel wire that do not participate in the corrosion with insulating tape to isolate them from contact with the electrolyte solution, and controlling the corrosion process of the galvanized steel wire by adjusting the current size and corrosion time of the DC regulated power supply.

4. The method for detecting magnetic flux leakage of high-strength steel wire considering the corrosion-fatigue coupling effect according to claim 1 is characterized in that: The specific steps of S3 are: according to the specification "Hot-dip galvanized or zinc-aluminum alloy steel wire for bridge cables" (GB / T17101-2019) and "Parallel steel wire cables for large-span cable-stayed bridges" (JT / T775-2016), a fatigue loading test of the steel wire specimen is carried out, with a stress amplitude of 360MPa, a maximum tensile force of 23.09KN, a minimum tensile force of 9.24KN, a maximum stress of 600MPa, and a minimum stress of 240MPa. The 50mm length range on the left and right ends of the specimen is the clamping end of the fatigue test. The cyclic loading method in the fatigue test is a constant-amplitude sinusoidal waveform. Combined with the specification "Axial force control method for fatigue test of metal materials" and the specimen and equipment conditions of this test, the stress ratio R is set to 0.4 and the loading frequency f is 8Hz.

5. The method for detecting magnetic flux leakage of high-strength steel wire considering the corrosion-fatigue coupling effect according to claim 1, characterized in that: The specific steps of S4 are: in order to explore the influence mechanism of fatigue stress caused by vehicle load on the distribution of leakage magnetic signal, a pre-fatigue-corrosion-fatigue interaction condition is carried out, and the high-strength steel wire of the cable is first subjected to pre-fatigue loading of F1=1000, 5000, and 10000 times and used as the initial state, and then subjected to electrochemical corrosion to different degrees, and the corrosion time is T=1, 3, 6, 9h, and then fatigue loads of F2=1000, 5000, and 10000 times are applied; a pre-corrosion-fatigue-corrosion interaction condition is carried out, and the high-strength steel wire of the cable is first subjected to electrochemical corrosion to different degrees, and the corrosion time is T1=1, 3, 6, 9h, Afterwards, fatigue loading of F=1000, 5000, and 10000 times was performed, and then corrosion time of T2=1, 3, 6, and 9h was applied; all corrosion T fatigue F with different gradients were combined, for example: under the pre-fatigue-corrosion-fatigue interaction condition, condition ① F1 (1000 times)-T (3h)-F2 (1000 times), condition ② F1 (1000 times)-T (6h)-F2 (5000 times)…; pre-corrosion-fatigue-corrosion interaction condition, condition ① T1 (3h)-F (1000 times)-T2 (3h), condition ② T1 (3h)-F (5000 times)-T2 (6h)….

6. The method for detecting magnetic flux leakage of high-strength steel wire considering the corrosion-fatigue coupling effect according to claim 1, characterized in that: The specific judgment method of S5 is as follows: the collected cable leakage magnetic signal will form a waveform diagram. When there is a defect in the high-strength steel wire inside the cable, the magnetic field line at the defect will bend, deform and mutate. The average amplitude value of the normal waveform in the intact state of the cable is set to K. When the amplitude of the abnormal waveform is greater than 10% of K, it can be determined that the cable is internally damaged.