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CN-116559279-B - Pipe eddy current flaw detection method

CN116559279BCN 116559279 BCN116559279 BCN 116559279BCN-116559279-B

Abstract

The invention discloses a pipe eddy current flaw detection method which is characterized by comprising the following steps of S1, straightening a pipe to be detected by straightening equipment to enable the bending degree of the pipe to be detected to be smaller than or equal to 1.5 mm/m, S2, enabling the specification of a selected guide sleeve to be 2-3 mm larger than the outer diameter of the pipe to be detected, enabling the specification of a selected probe to be consistent with the specification of the guide sleeve, guaranteeing the filling coefficient of the probe to be larger than or equal to 85%, and S3, enabling the pipe to be detected to stably pass through the eddy current flaw detection equipment to finish eddy current flaw detection. The invention has the advantages of shortening the length of flaw detection blind areas at two ends of the pipe, being beneficial to reducing the production cost and the like.

Inventors

  • ZHAO WENTAO
  • LIU YUNHUI

Assignees

  • 重庆盛钢实业有限公司

Dates

Publication Date
20260508
Application Date
20230203

Claims (5)

  1. 1. The eddy current flaw detection method for the pipe is characterized by comprising the following steps of: s1, straightening a pipe to be detected by adopting straightening equipment, so that the bending degree of the pipe to be detected is less than or equal to 1.5 mm/m; s2, the specification of the selected guide sleeve is 2-3 mm larger than the outer diameter of the pipe to be detected, the specification of the selected probe is consistent with the specification of the guide sleeve, and the filling coefficient of the probe is ensured to be greater than or equal to 85%; S3, enabling the pipe to be detected to stably pass through eddy current flaw detection equipment to finish eddy current flaw detection; Before flaw detection, an eddy current flaw detection system with the following structure is firstly obtained, the eddy current flaw detection system comprises eddy current flaw detection equipment (1) and conveying roller ways (2) which are arranged at two ends of the eddy current flaw detection equipment (1) in a joint mode along the conveying direction of a pipe, the conveying roller ways (2) comprise a plurality of V-shaped conveying rollers which are arranged at intervals, and the V-shaped conveying rollers synchronously rotate through driving motors which are connected with each other; An auxiliary conveying mechanism (3) is arranged at the input end of the eddy current flaw detection device (1), the auxiliary conveying mechanism (3) comprises a guide mechanism (31) arranged along the pipe conveying direction and a sliding seat (32) slidably arranged on the guide mechanism (31), the guide mechanism (31) is also provided with a linear driving mechanism (33) arranged in parallel, the driving end of the linear driving mechanism (33) is connected with the sliding seat (32) and can drive the sliding seat (32) to move at a uniform speed along the guide mechanism (31), a baffle plate (34) which can be contracted downwards is vertically arranged on the sliding seat (32), the height of the baffle plate (34) in the vertical state is matched with the height of a pipe to be detected on the V-shaped conveying roller, and projections of the baffle plate (34) and the pipe to be detected on the V-shaped conveying roller in the axial direction are overlapped, a contraction driving mechanism (35) for driving the baffle plate (34) to contract is arranged between the sliding seat (32) and the baffle plate (34), the distance between the baffle plate (34) and the maximum eddy current flaw detection device (1) is larger than the length of the eddy current flaw detection device (1) and the length of the pipe to be detected is smaller than that of the eddy current flaw detection device (1); Two ends of the eddy current flaw detection equipment (1) are respectively provided with an auxiliary conveying mechanism (3), and the baffle (34) is provided with an electromagnet for adsorbing a pipe to be detected; During flaw detection, the baffles (34) on the two auxiliary conveying mechanisms (3) are moved towards the feeding direction of the pipe to be detected, the baffles (34) at the input end are contracted downwards through the contraction driving mechanism (35), the baffles (34) at the output end are kept in an upright state through the contraction driving mechanism (35), at the input end, the baffles (34) absorb the pipe to be detected through the electromagnets, push the pipe to be detected to enter the eddy current flaw detection equipment (1) at a constant speed until the baffles (34) move to the maximum stroke, the electromagnets are disconnected, the conveying speed of the V-shaped conveying rollers is recovered, the pipe to be detected is continuously conveyed through the V-shaped conveying rollers to detect the pipe in the middle section until the pipe to be detected is close to the baffles (34) at the output end, the baffles (34) at the output end absorb the pipe to be detected through the electromagnets, the conveying speed of the V-shaped conveying rollers is reduced, and the pipe to be detected is pulled out of the eddy current flaw detection equipment (1) at a constant speed through the baffles (34), and flaw detection is completed.
  2. 2. The pipe eddy current inspection method according to claim 1, wherein the inspection outer diameter of the eddy current inspection equipment (1) is 38-114 mm, the slope angle of the V-shaped conveying roller is 120 degrees, and the radius of the slope bottom angle is 5mm.
  3. 3. The method for eddy current inspection of pipes as claimed in claim 2, wherein the V-shaped conveying roller is made of 45 steel.
  4. 4. The pipe eddy current inspection method according to claim 1, wherein the guide mechanism (31) is two guide rods arranged along the pipe conveying direction, the two guide rods are arranged opposite to each other along the horizontal direction, the slide seat (32) is provided with two guide holes corresponding to the guide rods, the two guide rods are respectively penetrated in the guide holes, the linear driving mechanism (33) comprises a screw rod arranged between the two guide rods in parallel and a screw rod nut matched with the screw rod nut, the screw rod nut is fixedly arranged on the slide seat (32), and one end of the screw rod is connected with a stepping motor.
  5. 5. The pipe eddy current inspection method as claimed in claim 1, wherein the slide (32) is provided with a guide groove vertically penetrating, the bottom of the baffle (34) is provided with a guide post slidingly matched with the guide groove, the shrinkage driving mechanism (35) is a cylinder vertically upwards arranged below the slide (32), and a piston rod of the cylinder penetrates through the slide (32) and is connected with the guide post of the baffle (34).

Description

Pipe eddy current flaw detection method Technical Field The invention relates to the technical field of steel pipe production, in particular to a pipe eddy current flaw detection method. Background At present, the low-medium pressure boiler tube, the high-pressure fertilizer tube, the petroleum cracking tube and other boiler variety tubes produced by cold-drawing seamless steel tube enterprises need to finish eddy current flaw detection before delivery, namely, the quality of the surface and the subsurface of the tube is detected and inspected, suspicious products are removed, and the quality of the tube is ensured. When the outer diameter of the pipe is 180 mm or less, an eddy current detection system of a pass-through coil is basically adopted, and when the outer diameter of the pipe is 180 mm or more, an eddy current detection system of a rotating point probe/flat coil or a fixed point probe/flat coil can be adopted, but no matter which eddy current detection system is adopted, and the specification of the flaw detection pipe changes, an end part undetectable area, namely a flaw detection blind area, exists at two ends of each steel pipe. According to the requirements of the comprehensive performance test method (YB/T4083-2020) of the automatic eddy current testing system for steel pipes and steel bars, the undetectable area of the end part of the eddy current testing system adopting the through coil is not more than 200 mm. According to incomplete statistics, the specification of the using external diameter of the low-medium pressure boiler tube, the high-pressure boiler tube and the like is more than or equal to 180 mm, that is to say, the eddy current flaw detection of the 90% low-medium pressure boiler, the high-pressure boiler and the like adopts a pass-through coil mode, and 200 mm flaw detection blind areas are respectively arranged at two ends of the tube. Because the pipe in the flaw detection blind area is not subjected to flaw detection, in order to ensure quality, the flaw detection blind area needs to be cut off, namely, each pipe needs to be cut off for the length of 400mm in total at two ends, the yield is greatly reduced, the production cost and the income level are further influenced, and the common standard pipe 51 x 5 x 10000 mm in the middle of the 20G high-pressure boiler pipe is taken as an example, about 40 kg of waste products are increased when 1 ton of finished product is produced compared with the original standard pipe, and about 134 ten thousand yuan are reduced when 1 ten thousand tons of high-pressure pipes are produced. Therefore, how to shorten the length of flaw detection blind areas at two ends of the pipe becomes a problem to be solved. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide the pipe eddy current flaw detection method which can shorten the length of flaw detection blind areas at two ends of a pipe and is beneficial to reducing the production cost. In order to solve the technical problems, the invention adopts the following technical scheme: the eddy current flaw detection method for the pipe is characterized by comprising the following steps of: s1, straightening a pipe to be detected by adopting straightening equipment, so that the bending degree of the pipe to be detected is less than or equal to 1.5 mm/m; s2, the specification of the selected guide sleeve is 2-3 mm larger than the outer diameter of the pipe to be detected, the specification of the selected probe is consistent with the specification of the guide sleeve, and the filling coefficient of the probe is ensured to be greater than or equal to 85%; and S3, enabling the pipe to be detected to stably pass through the eddy current flaw detection equipment to finish eddy current flaw detection. Furthermore, before flaw detection, an eddy current flaw detection system with the following structure is firstly obtained, the eddy current flaw detection system comprises eddy current flaw detection equipment and a conveying roller way which is arranged at two ends of the eddy current flaw detection equipment along the conveying direction of a pipe in a joint mode, the conveying roller way comprises a plurality of V-shaped conveying rollers which are arranged at intervals, and the V-shaped conveying rollers synchronously rotate through driving motors which are connected. Furthermore, the flaw detection outer diameter of the eddy current flaw detection equipment is 38-114 mm, the slope angle of the V-shaped conveying roller is 120 degrees, and the radius of the slope bottom angle is 5mm. Further, the V-shaped conveying roller is made of 45 steel. The device comprises a V-shaped conveying roller, a guide mechanism, a slide seat, a linear driving mechanism, a baffle plate, a shrinkage driving mechanism and a temperature sensor, wherein the guide mechanism is arranged along the conveying direction of the pipe, the slide seat is slidably arranged on the guide mechanism, t