Comparison of Probe Performance Domestic Original MFL Test Equipment

Compare and analyze the appearance, performance parameters, etc. of domestically produced probes with original imported probes. The comparison results show that the developed full tube leakage magnetic longitudinal and transverse probes have higher wave heights than domestic probes (with a maximum difference of 7%) when detecting manual grooves of N12.5 with a diameter of 139.7 mm × 7.72 mm, under the same gain (dB) value; When detecting the same artificial defect, under the same wave height, the corresponding gain value of domestic probes is greater than that of imported probes (with a maximum difference of 5.5 dB). The trial results indicate that the domestically produced probe can replace imported probes of the same type.
The function of a magnetic field measurement probe is to convert magnetic field signals, which is the core of magnetic flux leakage non-destructive testing technology and determines multiple performance indicators such as signal-to-noise ratio, resolution, and stability of the detected electrical signals. The magnetic flux leakage testing equipment for the entire pipeline of Baoji Petroleum Steel Pipe Co., Ltd. is produced by Tuboscope Testing Company in the United States. The probes used are imported from the United States and have good performance. In actual production, due to the large number of tube blanks tested per shift (about 1000 oil casing pipes tested per shift), the probes are frequently used and prone to wear, and the price of a single imported probe is expensive.   This study mainly explores the appearance, performance parameters, and other information of domestically produced probes and imported probes through the design of a trial scheme, compares and analyzes the two, observes the sensitivity differences between the two during use, and demonstrates whether their performance meets the detection requirements.
1. Demonstration Plan
The longitudinal magnetic flux leakage testing equipment for the entire pipe body has imported probe 1 and domestically produced probe 2; The 7 # probe of the transverse flaw detector is an imported probe, while the 8 # probe is a domestically produced probe. The specific demonstration plan is: ① Comparison of external dimensions. ② Comparison of appearance between domestically produced probes and original imported probes Verify whether the electromagnetic compatibility between the whole tube magnetic flux leakage detection equipment and domestic probes is good. ④ Equipment detection of artificial grooves with a diameter of 139.7 mm × 7.72 mm N12.5, observing the difference in wave height of artificial defects with the same gain (dB) value; Under the same wave height, observe the difference in gain dB values of each channel and compare them to determine the performance difference between domestic probes and imported probes.

2.1 Comparison of Appearance between Domestic and Imported Probes
Figure 1 shows a domestically produced longitudinal probe, Figure 2 shows an imported longitudinal probe, Figure 3 shows a domestically produced transverse probe used for testing a Φ 139.7 mm × 7.72 mm steel pipe, and Figure 4 shows an imported transverse probe used for non-destructive testing of a Φ 139.7 mm × 7.72 mm steel pipe.
2.2 Operation status of domestic probes
During the installation and trial use of domestically produced probes, the magnetic flux leakage detection equipment for the entire tube worked normally in all channels, and the system operated stably without signal interference
3.According to the experimental results, it can be seen that compared with the original imported probes produced by Tuboscope Testing Company in the United States, the domestically produced longitudinal and transverse magnetic flux leakage probes have a higher wave height than the domestically produced probes when detecting the manual groove of N12.5 with a diameter of 139.7 mm × 7.72 mm, under the same dB value (with a maximum difference of 7%); When detecting the same artificial defect, under the same wave height, the corresponding gain value of domestic probes is greater than that of imported probes (with a maximum difference of 5.5 dB).
In the actual magnetic flux leakage inspection of steel pipes, it is necessary to appropriately increase the sensitivity of domestic probes to ensure that the artificial defect wave height on the standard sample tube meets the requirements of the inspection. This domestic probe can replace imported probes of the same type and meet the requirements of steel pipe inspection.