Methods for manufacturing and inspecting high-strength tubular products made of steel, as well as inspection probes and tubular products.

Abstract

A method for manufacturing and inspecting a pipe product (1) made of steel, the method comprising the steps of: a) providing a steel pipe, b) modifying the steel pipe into the pipe product (1), the steel pipe being modified in at least one of the end regions (10-1, 10-2) of the steel pipe, c) inspecting for defects in the inner wall (7) and outer wall (8) of at least one modified end region (10-1, 10-2) of the pipe product (1) by means of an inspection probe (9), the inspection probe being adapted to at least one modified end region (10-1, 10-2), the inspection probe having at least one eddy current sensor (12) for inspecting the inner wall (7) of at least one modified end region (10-1, 10-2) of the pipe product and at least one eddy current sensor (13, 14, 15) for inspecting the outer wall (8), a plurality of sensors (13, 14, 15) being provided on at least one arm (2, 3) and / or a plurality of sensors (12) being provided on an internal component (4).

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing and inspecting a high-strength tube product and an inspection probe, in particular for use in the method, and a tube product manufactured according to the method. BACKGROUND

[0002] High-strength or ultra-high-strength tube products made of steel are used in many technical and industrial applications. The manufacture of such high-strength or ultra-high-strength tube products made of steel is described, for example, in EP 3 233 577 B1, DE 10 2018 106 546 A1, DE 10 2018 123 316 A1 and DE 10 2019 103 502 A1 for different applications. In particular, airbag tubes are described there as such tube products.

[0003] Due to the loads of such high-strength or ultra-high-strength tube products made of steel in the technical and / or industrial applications for which they are intended, the tube products must be inspected for their defect freedom, in particular in the region of the reforming during the manufacture of the tube product from the raw steel tube. Here, the reforming of the tube can be achieved by a large number of common reforming processes, such as hot reforming and cold reforming.

[0004] In the framework of the present application, in particular the inspection of the end region of the reforming of the high-strength tube product is dealt with. Here, different possibilities are provided in order to carry out the inspection. On the one hand, an ultrasonic inspection of the tube product can be carried out in a liquid (coupling medium), however it must be taken into account here that after the inspection the inspected tube product needs to be cleaned and dried again in order to be further processed, which means a higher energy or time expenditure in the manufacture and inspection of the tube product. Furthermore, due to the used liquid, corrosion on the high-strength tube product can occur. Furthermore, not all relevant defect types can be reliably detected by this inspection technique.

[0005] Another possibility for checking the surface in the end region of a modified tube product consists in using an eddy current examination by means of a corresponding eddy current sensor. Here, the eddy current examination is not only contactless, but also non-destructive, however, can only be used for checking electrically conductive materials, which is the case in the case of tube products made of steel. In the case of the eddy current examination, use is made of the effect that impurities and damages in electrically conductive materials also have a different electrical conductivity or magnetic permeability than the original material. Here, the measurement signal is related to three parameters, namely the electrical conductivity, the magnetic permeability and the distance between the probe and the material surface, so that on the one hand a damage to the surface of the object to be examined can be determined from this. On the other hand, a layer thickness measurement and a check of the material properties, in particular a material structure examination, can also be carried out by means of the eddy current examination. In the framework of the present application, in the present case, essentially the defect examination of the surface or wall surface of the manufactured tube product in the end region thereof which is modified is emphasized.

[0006] In the examination of the damage to the surface or wall surface, the corresponding eddy current sensor is moved over the object to be examined. Here, as long as the electrical resistance is uniform and the eddy current thus flows unhindered in the material, the material or the surface has no damage. Not only in the case of a damage to the material or the surface, but also in the case of an inclusion of foreign material in the sample wall to be examined, the electrical resistance and the eddy current intensity change. The change can be detected by means of the eddy current examination and can be made visible or recognizable by means of a corresponding imaging method by means of an evaluation logic. Here, the coils of the eddy current sensor used are connected in such a way that small changes in the material properties or the distance between the eddy current sensor and the material surface can be largely compensated.

[0007] For example, DE 196 41 888 A1 discloses an examination of the weld seams of a reactor control rod sleeve by means of a corresponding eddy current probe on the inside of the reactor control rod sleeve. Furthermore, WO 99 / 04253 A1 shows an internal examination of the inner wall of a tube by means of an eddy current examination. An internal tube examination by means of an eddy current examination is also disclosed in US 10,788,456 B2.

[0008] In all known methods, defects of the surface of the tube interior region are examined. However, when a steel tube is modified into a tube product, not only damages can occur on the inner wall of the tube product, but also on the outer wall of the tube product. Even if the inner wall of the tube product is configured to be defect-free, a surface damage on the outer wall of the tube product, in particular in the end region thereof which is modified, can lead to malfunctions when the tube product is used correctly or can also lead to damage to the tube product itself. Although such an examination of the outer wall of the tube product in the end section thereof which is modified is also possible, this relates to an increased time expenditure, material consumption and cost expenditure. SUMMARY

[0009] It is therefore the task of the present invention to provide a method for manufacturing and inspecting a high-strength or ultra-high-strength pipe product made of steel, which enables a cost-advantageous and time- and material-saving inspection of a modified end region of a high-strength or ultra-high-strength pipe product made of steel. Furthermore, it is the task of the present invention to provide a corresponding inspection probe for use in the method according to the invention and finally to provide a corresponding pipe product.

[0010] The task in the method aspect is solved by a method having all the features of the technical solution of the present invention. With regard to the inspection probe, the task is solved by an inspection probe having all the features of the technical solution of the present invention and with regard to the pipe product, the task is solved by a pipe product having all the features of the technical solution of the present invention.

[0011] The method for manufacturing and inspecting a high-strength pipe product made of steel according to the present invention has here the following steps:

[0012] a. providing a steel pipe, which can be implemented not only as seamless, but also as having a weld seam,

[0013] b. modifying the steel pipe to a pipe product, wherein the steel pipe is modified at least in one of the end regions of the steel pipe,

[0014] c. inspecting the inner wall and the outer wall in the at least one modified end region of the pipe product for defects by means of an inspection probe, which is adapted to the at least one modified end region, which has at least one eddy current sensor for inspecting the inner wall of the at least one modified end region of the pipe product and at least one eddy current sensor for inspecting the outer wall of the at least one modified end region of the pipe product, wherein a plurality of sensors is provided on at least one arm and / or a plurality of sensors is provided on an inner part.

[0015] By means of the method according to the application it is possible in a simple manner to achieve that not only the outer wall of the modified end region of the pipe product made of steel is examined for defects and damage by means of eddy current examination, but also the inner wall of the modified end region of the pipe product is examined for defects and damage, without additional time and additional examination stations being required due to additional examination of the surface in the outer region of the end product of the pipe product. The examination probe is configured in such a manner that it has an eddy current sensor which simultaneously examines the inner wall surface and the outer wall surface of at least one modified end region of the pipe product. However, by means of the method according to the application not only is the time expenditure for the examination of the outer wall and the inner wall surface optimized, rather even in the case of additional examination of the outer wall surface of at least one modified end region of the pipe product the same evaluation electronics can be used for the evaluation of the inner wall of at least one modified end region of the pipe product. Thereby it is achieved that the measurement resolution and the detection rate are improved overall or even reliably achieved for certain defect types compared to a separate examination by means of ultrasound or a single-sided eddy current examination. Finally, it is also possible thereby to minimize the instrument expenditure for the examination of the inner wall and the outer wall of at least one modified end region of the pipe product. Here, a plurality of sensors is provided on the at least one arm and / or a plurality of sensors is provided on the inner part, such that the examination is performed for example at different measurement frequencies and / or sensitivities in order to detect different defect types and / or defects in different depths of the pipe wall, or in order to be able to detect for example larger pipe length sections simultaneously.

[0016] In the framework of the application, the inner wall is to be understood as the inner wall surface or the portion of the pipe wall which proceeds from the inner wall surface. At the same time, in the framework of the application, the outer wall is to be understood as the outer wall surface or the portion of the pipe wall which proceeds from the outer wall surface.

[0017] An advantageous first configuration of the method according to the application proposes that the inner wall and the outer wall are examined simultaneously. By means of this parallel examination it is possible to halve the examination duration at least compared to a serial examination.

[0018] Here, it has been found to be particularly advantageous that the inner wall and the outer wall of at least one modified end region of the pipe product are examined in such a manner that the pipe product is fixed and the examination probe is moved in a rotational manner axially over at least one modified end region of the pipe product, wherein not only the inner wall but also the outer wall of at least one modified end region of the pipe product is examined by means of the eddy current sensor. By means of the axial movement and the rotational movement of the examination probe it is ensured that the eddy current probe is moved over the entire surface of the inner wall and the outer wall of at least one modified end region of the pipe product, such that it is possible to ensure that not only the inner wall but also the outer wall of at least one modified end region is examined completely.

[0019] It has proven to be particularly advantageous according to an embodiment of the method according to the application that the simultaneous examination of the inner wall and the outer wall in the end region of the at least one modification of the pipe product is carried out directly after the last manufacturing step, in particular after the modification according to step b) and in particular in a manner linked to the modification cycle. By this measure, it is possible to examine the surfaces of the inner wall and the outer wall of the end region of the modification in the manufacturing step or directly after the manufacturing step without having to reserve a separate examination station. In this respect, too, the logistics expenditure for supplying the manufactured pipe product together to a separate examination station is saved.

[0020] In a further embodiment of the method according to the application it is proposed that the examination is carried out after the demagnetization of the end region of the at least one modification. Thereby, false detections due to magnetic properties possibly present in the end region of the modification are avoided.

[0021] In a further advantageous configuration of the method according to the application, the steel pipe provided consists of a steel alloy having, in addition to iron and unavoidable impurities due to melting, the following alloying elements in percent by mass, wherein the following percentage data in this document always refer to percent by mass:

[0022] C (0.07 to 0.50%; preferably 0.08 to 0.15%), Si (0.01 to 0.60%; preferably 0.01 to 0.50%), Mn (0.3 to 1.7%; preferably 1.0 to 1.7%), Cr (up to 1.2%; preferably 0.2 to 0.9%), Mo (up to 1.2%; preferably up to 0.2%), Ni (up to 0.4%; preferably 0.15 to 0.4%), Al (0.01 to 0.10%), V (up to 0.15%), Nb (up to 0.06%) and Ti (up to 0.06%).

[0023] The impurities due to melting are in particular impurities which enter into the steel alloy when manufacturing the steel, in particular when producing the melt and when handling the materials added to the melt.

[0024] According to the application, carbon (C) is present in the steel in an amount in the range of 0.07 to 0.50%. With a carbon content of 0.07%, it is also possible to ensure sufficient strength and to keep the cementite formation Fe3C in the steel low. Furthermore, sufficient toughness can be guaranteed. In contrast, with too high a carbon content, the formation of carbides in the steel is promoted, thereby reducing the notch impact toughness. Therefore, according to the application, the carbon content is preferably limited to at most 0.15%. According to one embodiment, the carbon content can lie in the range of 0.08 to 0.15%.

[0025] Preferably, silicon (Si) is present in an amount in the range of 0.01 to 0.60%, preferably in the range of 0.01 to 0.50%. Silicon increases the tensile strength and the yield limit of the provided steel pipe.

[0026] Preferably, manganese (Mn) is present in an amount in the range of 0.3 to 1.7%. Manganese increases the yield limit and the strength of the steel alloy. Furthermore, manganese improves the weldability as a substitute for carbon. According to one preferred embodiment, manganese is present in an amount in the range of 0.5 to 1.7% and particularly preferably in the range of 0.6 to 1.7%.

[0027] Preferably, chromium (Cr) is present in an amount of maximum 1.2%. Chromium increases the toughness and the tensile strength of the steel alloy. According to one preferred embodiment, chromium is present in an amount in the range of 1.0% and particularly preferably in the range of 0.2 to 0.9%.

[0028] Preferably, molybdenum (Mo) is present in an amount of maximum 1.2%, in particular maximum 0.2%. Molybdenum in particular improves the tensile strength and the weldability of the steel alloy.

[0029] Preferably, nickel (Ni) is present in an amount of maximum 0.4%, preferably in an amount between 0.15 and 0.4%. Nickel increases the tensile strength and the yield limit.

[0030] Preferably, aluminum (Al) is present in an amount in the range of 0.01 to 0.10%.

[0031] Preferably, vanadium (V) is present in an amount of maximum 0.15%. Vanadium increases the tensile strength of the alloy.

[0032] Preferably, niobium (Nb) is present in an amount of maximum 0.06%.

[0033] Preferably, titanium (Ti) is present in an amount of maximum 0.06%.

[0034] In another configuration of the method according to the application, the pipe product has a microstructure consisting of stretched, annealed martensite, which in particular has a mean martensite lath size of d avg <3 pm. This property of the pipe product can be achieved, for example, by a quenching and tempering treatment, i.e. by hardening and subsequent annealing, and a cold drawing after the quenching and tempering treatment, in particular before the examination in step b).

[0035] According to another embodiment of the method according to the application, the pipe product, in particular the airbag tube, has a microstructure consisting of stretched, annealed martensite. Preferably, this microstructure is achieved in particular by a heat treatment with subsequent cold drawing.

[0036] According to an alternative embodiment, the tube product, in particular the airbag tube, can also be composed of an air-hardenable steel alloy as disclosed, for example, in EP 1 474 538 A1. Here, the steel alloy and the tube manufacturing steps disclosed therein form part of the present disclosure in respect of step a) of claim 1, i.e. the provision of the steel tube.

[0037] Preferably, the tube product has a transition temperature of less than 233.15 K. Preferably, the transition temperature is determined by means of a Ring-Charpy-Versuch. For example, the transition temperature is determined here by sampling in the respective length section as a notched impact specimen in the form of a ring, i.e. as a narrow tube section with a desired notch introduced for testing purposes. After cooling to the low-temperature conditions of the test, the specimen is subjected to an axial impact. The transition temperature refers to the temperature at which the specimen changes from a plastic to a brittle breaking behavior. It is understood that, in order to determine this transition temperature, a plurality of specimens for characterizing the length section must be tested.

[0038] In addition to airbag tubes, the following further tube applications can be manufactured by means of the method according to the application or used in the method. Drive shafts, stabilizers and axle components made of air-hardenable steel alloys, as disclosed in DE 10 2017 297 369 A1, DE 10 2016 107 143 A1 and DE 10 2015 1 1 1 150 A1, for example. The steel alloys and tube manufacturing steps disclosed therein form part of the present disclosure here in respect of step a) of claim 1, i.e. the provision of the steel tube, and step b) of claim 1, i.e. the profiling of the steel tube into a tube product.

[0039] It is further preferred that the wall thickness of the tube product and / or of the provided steel tube is less than 4 mm. Such a wall thickness can also be used, in particular in the case of airbag tubes.

[0040] It is particularly advantageous to check the transition region in the tube product for defects by means of the movement of the eddy current sensor in the recess in the transition region of the inner wall or of the outer wall. Thereby, it is ensured that the eddy current sensor can be guided in the transition region to the recess, so that the eddy current sensor has a spacing there to the wall of the transition region, which the eddy current sensor can detect and thus check. This "guiding to" (Heranführen) can be realized by means of corresponding mechanisms in the arm and / or the inner part. Here, only exemplarily a forked sensor holder, a laterally moving sensor holder or a segmented inspection probe are mentioned, which list is not exhaustive.

[0041] In principle, it is also possible to integrate a distance compensation in the framework of the method according to the application. Thereby, for example in the defect evaluation, the electronics and / or the used software, a change in the distance between the eddy current sensor and the wall surface due to the rotation and / or clamping is compensated.

[0042] The inspection probe according to the application is characterized in that it has a web which connects the first arm and the second arm to each other, at least one eddy current sensor being arranged on the inner wall of the first arm and the second arm, respectively, wherein a holding element is mounted on the web between the first arm and the second arm for receiving the at least one eddy current sensor. With the inspection probe thus configured, the outer wall and the inner wall of a tubular element, in particular a tubular product, manufactured according to the method explained above can be inspected simultaneously in a simple manner. The outer wall surface of the end region of the tubular product can be inspected in a simple manner by means of the eddy current sensors arranged on the inner wall of the first arm or the second arm, which are arranged on the web, whereas the at least one eddy current sensor arranged on the holding element is configured for checking the inner wall of the end region of the tubular product. Thus, by means of the rotation of the inspection probe and the movement in the axial direction above the end region of the tubular product, the entire surface of the inner wall and the outer wall can be checked for defects and damages by means of the inspection probe.

[0043] It is particularly advantageous here that the holding element is mounted on the web in such a way that it is equidistant to the first arm and the second arm. With this configuration of the application, it is ensured that both arms have the same distance to the outer wall of the tubular product when the arms are rotated above the end region of the tubular product. In this respect, the eddy current sensors directly opposite on both arms will also provide exactly the same signal, thus enabling a comparison of the signals with each other and a redundant inspection. However, an opposite arrangement of the eddy current sensors on both arms is not provided, because a malfunction of the eddy current sensors can also be determined in another way or will immediately draw attention. Here, the geometry of the inner walls of both arms can be adapted to the geometry of the end region of the tubular product to be checked, so that by means of the correspondingly arranged eddy current sensors, it always has the same distance to the surface to be checked of the modified end region of the tubular product.

[0044] According to a particularly advantageous configuration of the application, the inspection probe is configured as a body of rotation about a central longitudinal axis, wherein the web is configured as a disc, the two arms together are configured as a hollow cylinder arranged on the edge of the disc, and the holding element is configured as a solid cylinder arranged on the disc about the center of the disc. Such an inspection probe can be formed in a simple manner from a solid metal body, in particular by milling, wherein it proves to be particularly advantageous that such a solid body has a high weight and is therefore relatively insensitive to slight imbalances occurring upon rotation. This is particularly important because the individual eddy current sensors of the inspection probe are arranged at different positions on the body of rotation and therefore imbalances occur upon rotation. Thus, in the case of a solid inspection probe made of metal in particular, the weight of the eddy current sensors is reduced, so that slight imbalances occurring upon rotation of the inspection probe configured as a body of rotation by the eddy current sensors are untroublesome. Such an inspection probe configured as a body of rotation is sometimes also referred to below as a pot probe.

[0045] Alternatively, it can be that the inspection probe does not have the geometry of a body of rotation at all. This is in particular the case when the inspection probe has only one arm for inspecting the outer wall. The holding element for inspecting the inner wall can likewise be configured as an arm which projects from the web of the inspection probe and can be introduced into the interior of the pipe to be inspected.

[0046] Here, the inspection probe can be moved in a manner perpendicular to the axis of rotation of the pipe to be inspected, so that the arm for inspecting the outer wall and the holding element for inspecting the inner wall are moved toward the side recess on the end of the pipe to be inspected. Here, the geometry of the arm and of the holding element is adapted to the geometry of the end of the pipe to be inspected. If the inspection of the end of the pipe is now carried out, the axis of rotation of the inspection probe corresponds to the central longitudinal axis of the pipe to be inspected. BRIEF DESCRIPTION OF DRAWINGS

[0047] Further objects, advantages, features and application possibilities of the application result from the following description of exemplary embodiments according to the drawings. Here, all features described and / or illustrated, individually or in any meaningful combination, constitute the subject matter of the application, independently of their generalization in the claims or their reference relationships.

[0048] which shows:

[0049] Figure 1 : a view at the beginning of the inspection step of the method for inspecting the end region of two modifications of the pipe product according to the application by means of the inspection probe according to the application,

[0050] Figure 2 : a view of the inspection of the end section of the pipe product at the end of the inspection Figure 1

[0051] ​Figure 3 diagram of the examination of the end section of a further tube product by means of a further examination probe according to the application at the end of the examination,

[0052] Figure 4 diagram of the examination of the end section of a further tube product by means of a further examination probe according to the application at the end of the examination,

[0053] Figure 5 diagram of the examination of the end section of a further tube product by means of a further examination probe according to the application at the end of the examination, and

[0054] Figure 6 diagram of different defect types that can occur in a tube product according to the application. DETAILED DESCRIPTION

[0055] The diagram in Figure 1 shows a tube product 1 according to the application, in particular an airbag tube, which has a modified end region 10-1, 10-2, which should be examined for defects in the inner wall 7 and the outer wall 8 in the modified end region 10-1, 10-2 of the tube product 1 by means of a corresponding examination probe 9. The end region has a transition region 11-1, 11-2 between the modified or reduced cross section of the tube product 1 and the cross section of the provided steel tube. Figure 1 The diagram shows the beginning of the examination. Here, the tube product 1 is configured such that during its manufacture the end region 10-1, 10-2 of the tube product is constricted. It is also conceivable in other embodiments, which are not shown here, that the end region of the tube product has been expanded. The modification when manufacturing the tube product from a steel tube can here be carried out according to known methods, which are not explained in detail here.

[0056] Here, the end regions 10-1 and 10-2 of the tube product 1 are configured in a rotationally symmetrical manner with an inner wall 7 and an outer wall 8. In order to examine the inner wall 7 and the outer wall 8 on the end regions 10-1 and 10-2 of the tube product 1 for defects, two examination probes 9 are used in the present case. Here, the examination probe 9 consists of a web 16, which connects the first arm 2 and the second arm 3 to one another, wherein a holding element 4 is arranged on the web 16, which is spaced equidistantly from the two arms 2 and 3. Arranged on the two arms 2 and 3 are eddy current sensors 13, 14 and 15, which are positioned such that they can examine different diameter regions of the end regions 10-1, 10-2 of the tube product 1, wherein the spacing between the eddy current sensors 13, 14 and 15 and the respective region of the outer wall 8 essentially has the same spacing. Also arranged on the holding element 4 is an eddy current sensor 12, by means of which defects in the inner wall 7 of the end regions 10-1 and 10-2 of the tube product can be examined.

[0057] because Figure 1 The diagram is shown in cross-sectional view. Regarding the inspection probe 9, it should also be noted that the inspection probe is a solid element made of metal, in the form of a rotating body, such that the contact piece 16 is constructed as a disk, while the two arms 2 and 3 together form a hollow cylinder and are arranged on the edge of the disk-constructed contact piece 16. Similarly, the retaining elements 4 are each constructed as solid cylinders on the disk-constructed contact piece 16 and are arranged at the center of the contact piece. Although, according to Figure 1 The end regions 10-1 and 10-2 are identical after modification and have the same cross-section and the same transition regions 11-1 and 11-2. However, the cross-sectional geometry, length, and width of the transition regions 11-1 and 11-2 can also be different. Correspondingly, although the inspection probe 9 has the same reference numerals, it can be constructed differently in detail, especially to adapt to the geometry of the end regions 10-1 and 10-2. Furthermore, the inspection probe 9 according to the invention is not necessarily constructed as a rotating body. However, when the inspection probe is constructed as a rotating body, it does not necessarily have to be made of a solid element made of metal. For example, a hollow element made of a plate wall made of metal can also be conceived. In addition, the material constituting the inspection probe is not limited to metal.

[0058] As mentioned above, Figure 1 The diagram illustrates the situation at the beginning of the inspection of defects in the end regions 10-1 and 10-2 of the tube product 1. The inspection probe 9 is already rotating at this point, with arrow 5 indicating the direction of rotation, and this rotation occurs about the central longitudinal axis 19. In addition to the rotational motion 5, the inspection probe 9 also undergoes axial motion, indicated by arrow 6.

[0059] During the axial movement of the inspection probe 9, the inspection probe continues to rotate about the central longitudinal axis 19, so that defects and damage to the surfaces of the outer wall 8 and inner wall 7 in the end regions 10-1 and 10-2 of the tube product 1 can be inspected over the entire area by means of eddy current sensors 12 to 15.

[0060] Here, the movement of the inspection probe 9 in the axial direction is prolonged until the inspection probe 9 reaches the... Figure 2 The position is shown in the diagram. In this position, the tube product 1 is fully immersed in the inspection probe 9 with its end regions 10-1 and 10-2, so that the outer and inner walls 8 and 7 of the tube product 1 have been fully inspected once. This inspection is then complete, and the inspection probe 9 can be moved again to the position indicated by the inspection probe. Figure 1In its initial position. Here, it is now possible to omit the rotation of the inspection probe 9, since the surfaces of the outer wall 8 and inner wall 7 in the end regions 10-1 and 10-2 of the tube product 1 have already been fully inspected. Alternatively, it is possible to perform a second surface inspection on the inner wall 7 and outer wall 8 of the tube product 1 while the inspection probe 9 is being removed from the end regions 10-1 and 10-2 of the tube product 1.

[0061] If no defects are identified during the inspection of the end regions 10-1 and 10-2 of tube product 1, tube product 1 is supplied to its further application. However, if defects or damage are detected during inspection, the corresponding tube product 1 is rejected.

[0062] exist Figure 3 The diagram illustrates the inspection of the end section of another tube product 1 at the end of the inspection process using a separate inspection probe 9 according to the invention. The inspection probe 9 is substantially corresponding in construction to... Figure 1 and Figure 2 The inspection probes are therefore labeled with the same reference numerals. However, Figure 3 The tube product 1 in its end region 10-1 with Figure 1 and Figure 2 The end regions of the tubular products differ, and although the transition region 11-1 is also constructed in a tapered manner, it also has an outwardly convex ridge. The inspection is to be consistent with... Figure 1 and Figure 2 The inspection is conducted in a similar manner as described in the text, so I will omit the explanation here.

[0063] Figure 4The diagram illustrates the inspection of the end section of another tube product 1 by means of another inspection probe 9 according to the invention at the end of the inspection. This time, the tube product there is not tapered in its end region 10-2, but has a bulge pointing inwards in the transition region 11-2. This time, the inspection probe 9 used here is not rotationally symmetrical about its axis of rotation, which corresponds to the central longitudinal axis 19 of the tube product. More specifically, the inspection probe 9 has a tab 16, on one end of which an arm 3 is arranged, the arm having three eddy current sensors 13, 14, and 15 on its inner wall 17 for inspecting the outer wall 8 of the tube product in the region of the bulge. Furthermore, the inspection probe has a retaining element 4, which is also constructed as an arm and arranged relative to the arm 3 on the tab 16. The retaining element 4 is equipped with an eddy current sensor 12 for inspecting the inner wall 7 of the tube product 1 in the region of the bulge in the end region 10-2. Here, the arm 3 and the retaining element 4 are spaced apart from the rotation axis of the inspection probe 9, such that when the inspection probe 9 rotates, the retaining element 4 is guided along the outer wall 8 of the tube product 1 in the end region 10-2 of the tube product, while the retaining element is guided along the inner wall 7 of the tube product 1 in the end region 10-2 of the tube product.

[0064] Figure 5 The diagram illustrates the inspection of the end section of another tube product 1 by means of another inspection probe 9 according to the invention at the end of the inspection. This time, the tube product there is not tapered in its end region 10-1, but has a raised portion pointing outwards in the transition region 11-1. This time, the inspection probe 9 used here is not constructed rotationally symmetrically about its axis of rotation, which corresponds to the central longitudinal axis 19 of the tube product. More specifically, the inspection probe 9 has a tab 16, on one end of which an arm 3 is arranged, the arm having an eddy current sensor 13 on its inner wall 17 for inspecting the outer wall 8 of the tube product in the region of the raised portion. Furthermore, the inspection probe has a retaining element 4, which is also constructed as an arm and arranged relative to the arm 3 on the tab 16. The retaining element 4 is equipped with three eddy current sensors 12, 12', and 12" for inspecting the inner wall 7 of the tube product 1 in the raised region of the end region 10-1. Here, the arm 3 and the retaining element 4 are spaced apart from the rotation axis of the inspection probe 9, such that when the inspection probe 9 rotates, the retaining element 4 is guided along the outer wall 8 of the tube product 1 in the end region 10-1, while the retaining element is guided along the inner wall 7 of the tube product 1 in the end region 10-1.

[0065] The invention is examined in the following manner. Figure 4 and Figure 5The implementation described herein. Before and / or during the inspection of the tube product 1, the inspection probe 9 is moved to or above the end region 10-1 or 10-2 to be inspected, such that it is simultaneously or successively guided radially along the central longitudinal axis 19 of the tube product 1 and relative to the tube axis 19, so as to reach the side recess constructed through the transition region 11-1 or 11-2 in a collision-free manner with the arm 3 and the retaining element 4. After the measurement is completed, the inspection probe 9 is guided away from the end region 10-2 in a collision-free manner, correspondingly parallel to and transverse to the central longitudinal axis 19.

[0066] exist Figure 6 The present invention exemplarily and non-exhaustibly illustrates defects in the wall of a pipe product 1 according to the invention, which can be detected by means of inspection (the inspection is performed by means of the method according to the invention). Here, it is possible to reliably detect not only different surface defects A, B, C, and D, but also inclusion defects E during inspection, and to visualize them on a known imaging device (e.g., a screen) using known methods.

[0067] Regarding inclusion defects E, the detection rate also depends on the power of the eddy current sensor used to inspect tube product 1. In principle, higher power results in greater detection depth.

[0068] Surface defect A is a more or less vertical crack on the surface of pipe product 1, while surface defect B is a crack whose direction changes more frequently with increasing penetration depth. Surface defect C is a more or less linearly extending crack; however, unlike surface defect A, this crack is not perpendicular to the surface of the pipe product. Surface defect D is less likely to involve cracks on the surface of the pipe product because its penetration depth is relatively smaller compared to surface defects A, B, and C. Instead, surface defect D has a crater-like surface defect structure.

[0069] exist Figure 6 All surface defects shown can be reliably and accurately detected using the method according to the invention. The advantage of eddy current inspection compared to ultrasonic inspection is that it can be performed in a dry manner. In this respect, compared to ultrasonic inspection, the rapid surface inspection within a few seconds included in eddy current inspection not only saves time, but more precisely, it also eliminates the time spent drying the pipe products, where corrosion problems can occur in the pipe products due to the "wet" inspection method in the case of ultrasonic inspection, problems that can be avoided in the case of eddy current inspection.

[0070] List of reference numerals

[0071] 1 tube product

[0072] 2 First Arm

[0073] 3 Second Arm

[0074] 4. Holding element

[0075] 5. Rotational motion

[0076] 6. Axial movement

[0077] 7. Inner wall

[0078] 8 outer wall

[0079] 9. Check the probe

[0080] 10-1 End Region

[0081] 10-2 End Region

[0082] 11-1 Transition Zone

[0083] 11-2 Transition Zone

[0084] 12 Eddy Current Sensors

[0085] 13 Eddy Current Sensor

[0086] 14 Eddy Current Sensor

[0087] 15 Eddy Current Sensor

[0088] 16 stitched images

[0089] 17. Inner wall

[0090] 18 Inner Wall

[0091] 19. Central longitudinal axis

[0092] A surface defect

[0093] B Surface defects

[0094] C Surface defects

[0095] D Surface defects

[0096] E. Inclusion defects.

Claims

1. A method for manufacturing and inspecting pipe products (1) made of steel, the method comprising the following steps: a) Provide steel pipes, b) Modify the steel pipe into the pipe product (1), wherein, The steel pipe is modified in at least one end region of the end area of ​​the steel pipe, wherein the at least one end region has a transition region with varying diameters on both the inner and outer surfaces between the reduced cross-section of the modified pipe product and the cross-section of the provided steel pipe. c) Inspecting for defects in the inner wall (7) and outer wall (8) of at least one modified end region of the tube product (1) using at least one inspection probe (9), the inspection probe being adapted to at least one modified end region, the inspection probe having at least one eddy current sensor (12) disposed on an internal component (4) for inspecting the inner wall (7) of the at least one modified end region of the tube product and at least one eddy current sensor disposed on at least one arm for inspecting the outer wall (8) of the at least one modified end region of the tube product, the inspection probe further comprising a tab (16) connecting the at least one arm to the internal component, the method further comprising the steps of: moving the at least one arm together with the internal component from an initial position outside the tube product axially to a transition region through the at least one modified end region of the tube product, and rotating the at least one arm together with the internal component about the central longitudinal axis (19) of the tube product, and d) Inspect the defects in the transition region.

2. The method according to claim 1, characterized in that, In step c), both the inner wall and the outer wall are inspected simultaneously.

3. The method according to claim 1 or 2, characterized in that, The inner wall (7) and the outer wall (8) of the end region of the at least one modified tube product (1) are inspected, such that the tube product (1) is fixed, and the inspection probe (9) is rotated and moved axially above the end region of the at least one modified tube product, wherein defects are inspected not only on the inner wall (7) of the end region of the at least one modified tube product, but also on the outer wall (8) by means of the eddy current sensor.

4. The method according to claim 1 or 2, characterized in that, After the final manufacturing step, the inner wall (7) and the outer wall (8) in the at least one modified end region of the tube product (1) are inspected.

5. The method according to claim 1 or 2, characterized in that, The inspection is performed after the end region of the at least one modified type has been demagnetized.

6. The method according to claim 1 or 2, characterized in that, The provided steel pipe is made of a steel alloy, which, in addition to iron and impurities due to melting, contains the following alloying elements in percentages by mass: C: 0.07% to 0.50%, Si: 0.01 to 0.60%, Mn: 0.3% to 1.7%, Cr: up to 1.2%, Mo: up to 1.2%, Ni: up to 0.4%, Al: 0.01% to 0.10%, V: Maximum 0.15%, Nb: up to 0.06%, and Ti: Maximum 0.06%.

7. The method according to claim 1 or 2, characterized in that, The tube product (1) has a microstructure consisting of stretched, annealed martensite.

8. The method according to claim 1 or 2, characterized in that, The tube product (1) has a tensile strength of at least 900 MPa and a transition temperature of less than 233.15 Kelvin.

9. The method according to claim 1 or 2, characterized in that, The eddy current sensor (15) of the inspection probe (9) is positioned such that after the inspection probe moves into the end region, the position of the eddy current sensor corresponds to the position of the transition region.

10. The method according to claim 1 or 2, characterized in that, The inspection is performed at different measurement frequencies or with different sensitivities to determine different defect types and / or defect depths.

11. The method according to claim 1 or 2, characterized in that, Defects in the transition region are inspected by moving an eddy current sensor in the side recess of the transition region of the inner wall (7) or the outer wall (8).

12. The method according to claim 4, characterized in that, After the modification according to step b), the inner wall (7) and the outer wall (8) in the end region of the at least one modification of the tube product (1) are inspected in a manner linked to the modification rhythm.

13. The method according to claim 1 or 2, characterized in that, The provided steel pipe is made of a steel alloy, which, in addition to iron and impurities due to melting, contains the following alloying elements in percentages by mass: C: 0.08% to 0.15%, Si: 0.01 to 0.50%, Mn: 1.0 to 1.7%, Cr: 0.2% to 0.9% Mo: up to 0.2%, Ni: 0.15 to 0.4%, Al: 0.01% to 0.10%, V: Maximum 0.15%, Nb: up to 0.06%, and Ti: Maximum 0.06%.

14. The method according to claim 7, characterized in that, The martensite has d avg The average martensitic lath size is <3μm.

15. An inspection probe (9) for use in the method according to any one of the preceding claims, characterized in that, The inspection probe has a tab (16) that connects at least one arm and a retaining element (4) to each other. At least one eddy current sensor is arranged on the inner wall (17) and / or outer wall (18) of the arm, respectively. The retaining element is used to receive at least one eddy current sensor (12).

16. The inspection probe (9) according to claim 15, characterized in that, The retaining element (4) is mounted on the tab (16) at an equidistant distance from the first arm (2) and the second arm (3).

17. The inspection probe (9) according to claim 16, characterized in that, The inspection probe is constructed as a rotating body about a central longitudinal axis (19), wherein the contact piece (16) is constructed as a disk, the first arm (2) and the second arm (3) together are constructed as a hollow body with a circular inner surface, and the retaining element (4) is constructed as a body with a circular outer surface.

18. A tube product (1), said tube product being manufactured by the method according to any one of claims 1 to 14 and inspected by means of an inspection probe according to any one of claims 15 to 17.

19. The pipe product (1) according to claim 18, characterized in that, The tube product (1) is an airbag tube.

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