CN1088308A

CN1088308A - Magnetic detection device for detecting cracks of ferromagnetic workpiece

Info

Publication number: CN1088308A
Application number: CN93107037A
Authority: CN
Inventors: 约尔格·瓦尔丁格耶尔
Original assignee: Ted Crack Testing Plant
Current assignee: Ted Crack Testing Plant
Priority date: 1992-05-08
Filing date: 1993-05-08
Publication date: 1994-06-22
Also published as: DE4215168C2; DE4215168A1; WO1993023751A1

Abstract

The invention discloses a magnetic detection device for detecting cracks of ferromagnetic workpieces, in particular for detecting defects (especially surface defects) of long continuous materials. Wherein the work piece is sprayed with a suspension of magnetic powder, and on the other hand the work piece can be magnetized with several magnetic fields of different directions. This magnetization can be achieved by the use of two yokes which magnetize the workpiece in one plane, and which are arranged at 90 ° or substantially 90 °, if two yokes are used which magnetize the workpiece in one plane. The device is additionally provided with at least one magnetic yoke (main yoke or auxiliary yoke). The yoke is offset from the other two yokes and is located between the yokes.

Description

Detect the magnetic detection device in ferromagnetic piece crack

The present invention relates to the magnetic detection device in a kind of detection ferromagnetic piece as described in the preamble as claimed in claim 1 crack.

The invention particularly relates to the detection of microscler moving material surface crack.

This class device is known already, is GO1N27/84 at former Deutsches Reichs-Patent prospectus DE-OS3841747A1(international Patent classificating number for example) in disclose this class device.Be subjected to the effect of resultant field in this device by the workpiece of magnetic suspending liquid spray, have in this magnetic field more than an excitation body.Above-mentioned excitation body be by as magnet salient pole rotor bearing or around rotor flange or stator flange constitute.May there be phase differential in magnetization current under it.A lot of special pole cores surround a sample, and this sample can be with respect to aforementioned pole core motion.But rotor apparatus or stator-device more complicated and will preestablish the different phase shifts of magnetizing coil.

In addition, the phase shift that from the document, also has 180 ° as can be known by two excitation bodies of three-phase supply power supply., when detecting longitudinal crack and transverse crack, should make improvements with this hybrid excitation.Because this class magnetizing assembly or implement is not easy to and/or on some positions the crack do not show or have only fainter defective to show that therefore, it is obviously irrealizable that above-mentioned suggestion will easily become commodity.

Equally, a kind of checkout equipment that can detect ferromagnetic piece longitudinal crack and transverse crack simultaneously is also known, and this equipment has adopted so-called rotating magnetic field, has also utilized current excitation simultaneously, therefore can undesirable contact site occur on workpiece or burns a little.

Task of the present invention is to overcome above-mentioned shortcoming.Characteristic by claim.Described the present invention can finish above-mentioned task, when described comprehensive detection longitudinal crack of the preamble of independent claims and transverse crack, the longitudinal crack and the transverse crack of surface of the work can be detected reliably by means of better simply member and compact arrangement, the demagnetization process can also be simplified simultaneously.

The solution of finishing task of the present invention is: be provided with two each other into about the magnetization yoke of 90 ° of installations in a plane, in addition, at least also have in this device one additional, between above-mentioned two yokes, and with the auxiliary yoke of their biasings (Versetztes).

Giving priority in arranging for is that angle is about 45 ° between one or more auxiliary yokes and other two yokes, and the auxiliary yoke that perhaps is arranged between above-mentioned two yokes is added with an inflection point at the plane built-in perpendicular to the mounting plane of above-mentioned two yokes.If auxiliary yoke is 2 °-45 ° with respect to the angle of the mounting plane deflection of other two yokes then is suitable that preferably deflection is 40 °-45 ° or 45 °-50 °.

In a preferred embodiment, a yoke in the above-mentioned at least yoke (especially auxiliary yoke) be an opening, have the yoke separated from one another yoke of forming unshakable in one's determination, being positioned at this magnetic vibrating feeder yoke some coils in the heart is to link to each other on the circuit.This device is said more definitely, and the matrix that above-mentioned yoke is housed in the device is to be tunnel-like, will make assembling extremely convenient.

Describe the present invention below in conjunction with accompanying drawing.Wherein:

Fig. 1 is two and becomes the excitation body of cross setting and the top view of an additive excitation body;

Fig. 2 is the device with excitation body shown in Figure 1, but in fixing base, represents with foreshortened figure;

Fig. 3 and Fig. 4 are the top view and the front view of simplification device shown in Figure 1, wherein, also show a kind of modification selectable, that represent with bracket of apparatus of the present invention among Fig. 4;

Fig. 5 is a top view, and it shows as first and second yokes of excitation body and auxiliary yoke and magnetic line of force distribution;

Fig. 6 is the front view with Fig. 5 corresponding device thereof;

Fig. 7 is the view similar to Fig. 1 at another embodiment, but will assist the yoke additional deflection in this embodiment;

Fig. 8,9,10 illustrates part respectively and is the magnetizing assembly of prior art, and wherein: Fig. 8 shows the magnetizing field under two yokes; Fig. 9 illustrates corresponding phase shift between two yokes; Figure 10 shows two device and samples that yoke is arranged in a crossed manner.

Referring to Figure 10 in the device of a kind of known comprehensive magnetic detection longitudinal crack and transverse crack, and using under the contactless multiloop excitation condition, people have adopted setting intersected with each other, have intersected magnetization yoke or the transformer yoke (yoke of mentioning later 1 be set to 90 degrees especially approximately, 2), the operating voltage that encourages the electric coil of simply mentioning of these yokes is 220V, frequency is 50Hz, and electric current is 3A.When workpiece when being a stepped axle with artificial defect 10 (above-mentioned defective is represented with little cross in the figure), Crack Detection device and workpiece 10 are moved relative to each other, especially make workpiece pass detection means, and spray workpiece with shower nozzle in known manner.Several yoke coil feeds do not have phase shift.In this arrangement, represent the position with dial, in the position 6 With 12

The time, the crack indication that only produces more weak transverse defect and longitudinal defect, and in the position 3

With 9

There is not the longitudinal defect indication when (3 o ' clock positions and 9 o ' clock positions).The arrangement of Figure 10 and Fig. 9 is combined, and by the suitable inductance L 1 of connecting, L2 makes between the

yoke

1,2 120 ° of phase shifts, shows though can improve the crack like this, makes in the position 12 With 6

The time not only longitudinally but also all fine along horizontal demonstration, but in the position 3

With 9 Demonstration still very weak.Therefore this structure is also needed to improve.Fig. 9 be it should be noted that also the yoke 3 that dots does not belong to known detection means but a part of the present invention.

Can learn from Fig. 8 when not packing sample in

yoke

1 and 2 that the Distribution of Magnetic Field between the

yoke

1 and 2 especially can be referring to the measured value on Fig. 8 right side, it expresses DISTRIBUTION OF MAGNETIC FIELD (variation).

According to Fig. 1 to Fig. 7 at first is in the improvement of the present invention according to Fig. 1, and beginning is with Fig. 9,10 be arranged to starting point, just

yoke

1,2 is arranged into about 90 °, its magnetizing coil phase shift and inductance L 1 to each other, L2 should be 120 ° mutually.Add an auxiliary yoke 3 this moment again, as shown in fig. 1, this auxiliary yoke be arranged to

contiguous yoke

1,2 into about 45 °.

Term " coil " is interpreted as the winding that copper cash is made.

Three yokes all link with certain phase shift and power supply, and preferably each phase shift is 120 °.The inductance L 3 of yoke 3 also is coupled to 240 ° of (phase shift) parts on the t axle.Evidence with this arrangement not only can both demonstrate longitudinal defect and transverse defect (also relevant with the numeral of clock and watch) in all positions, and can also definitely demonstrate smaller defect.This point is that the end face (stirnflache) of workpiece 10 also is well suited for for sample.

Proved already that the crack that sample that extends during stretching or axle are occurred also can produce demagnetizing effect to sample.

Referring to Fig. 2, it is favourable that each

U-shaped yoke

1,2 and the auxiliary yoke 3 that is similarly U-shaped are fixed in the fixing base 11.Fixing base is by can not making by magnetized synthetic material as thermoplastic synthetic resin and so on,

yoke

1,2,3 fixedly are cast in the fixing base, their relative angular position is determined, and provide enough spaces on the other hand so that sample 10 passes through, sample is passed through along the long axis direction of matrix.Referring to the yoke field F1 that draws of with dashed lines additionally as can be seen of the direction of arrow among Fig. 2, the distribution of the magnetic field F3 of F2 and auxiliary yoke.Wherein

yoke

1 and 2 is in 3

And 9

The position, auxiliary yoke 3 is arranged on 12

To 1 Between or 6

To 7 ³⁰Between.

Fig. 3 schematically represents the top view of this structure, and Fig. 4 is front view or front elevation.The end of

reference number

1,2 and 3 geometric position and U-shaped yoke is corresponding.

The top view of Fig. 5 and the front view of Fig. 6 show the modification of the above embodiment of the present invention, magnetic field F1, F2(F3 are conformed to the principle of simplicity under there is shown),

yoke

1 and 2 intersected with each otherly is set to 90 degrees approximately, above-mentioned two width of cloth accompanying drawings also schematically show their rectangular ends separately, and the second yoke end of the auxiliary yoke 3 among Fig. 5 is hidden by top yoke end.Yoke 1 and 2 among Fig. 5 is in the plane, and arrow B is expressed the direction of packing into of sample.Yoke 1,2,3 still have phase shift, comprise in Fig. 9 the structure that dotted line represents.Yoke 1,2,3 unillustrated electric coil links to each other with three-phase ac network, can come excitatory with exchanging (AC) or half-wave DC (HWDC).

In the front view of Fig. 6, the described sample 10 that goes out is perpendicular to the figure paper plane and can move with respect to this plane, and perpendicular to the symmetry end of the auxiliary yoke 3 with complementary field distribution F3.

Fig. 7 shows another distortion of the present invention, among this figure the setting of

yoke

1,2 identical with Fig. 1, between

yoke

1,2, also be provided with an auxiliary yoke 3, as shown in the figure, this yoke is preferably at 45 approximately with above-mentioned two yokes.In order in particular cases to detect longitudinal crack and transverse crack exactly at some, can make the auxiliary yoke 3A deflection that is attached on the plane vertical with the figure paper plane, range of deflection can be from very little start angle to about 45 °.So just can generally adapt to various situations, or the detection task of just knowing after being suitable for, or be suitable for accurately detecting the interior a certain ad-hoc location of indicated range.Corresponding therewith, with

yoke

1,2,3 are cast in the situation difference in the matrix 11 regularly with shown in Figure 2, import in this example and/or the matrix of packing in auxiliary yoke 3A be deflectable.Above-mentioned yoke also can be by half-wave DC (HEDC) (linking to each other by certain phase shift) excitation, and its superiority is identical with the benefit that arrangement brought by Fig. 1 to Fig. 6.

Each embodiment that the present invention is not limited to provide in described above and/or the accompanying drawing.Can draw different pick-up units according to special circumstances, for example also can adopt a plurality of auxiliary yokes.As an example, adopt as shown in Figure 2 be equipped with three fixedly during the base member of yoke, can also in this matrix, correspondingly set in advance a guide piece or one slit, so that deflectable auxiliary yoke 3A is installed afterwards or simultaneously.

Making above-mentioned yoke is that U-shaped also is a favourable form of implementation, also can carry out some to it and change, change the curvature of big U-shaped or be other moulding, above-mentioned other pattern comprises different yokes, be the yoke of stretch-like, movable or be contained in movably in the fixing base 11 or the like.

Especially preferably, at least one yoke in the above-mentioned yoke (especially auxiliary yoke) is made the opening shape, that is to say to have the yoke iron core that is separated from each other.This yoke iron core can be parallel to each other or at an angle to each other.Be wound on the coil that this magnetic vibrating feeder yoke passes to electric current in the heart and only be connected with each other on conductivity, additional lead is not positioned at the yoke part or laterally on the yoke.The foregoing description is especially favourable for detecting elongate samples, though the magnetic field of the long final induction of length is uniform.

Referring to Fig. 2, for the ease of making pick-up unit and being convenient to install sample, it is favourable that this pick-up unit (matrix that comprises device) is made tunnel-like, and the yoke that simply illustrates among Fig. 2 can be the yoke of opening wide.

The described device of the application is particularly suited for checking chain.

Claims

1, detects the magnetic detection device that microscler moving material defective is especially detected in the ferromagnetic piece crack, be subjected to the time spent of doing of resultant field when workpiece by magnetic suspending liquid spray, two have phase shift by the excitation body of heterogeneous especially three-phase supply power supply especially yoke in the magnetic field, for example have 120 ° of phase shifts, it is characterized in that being in the plane two of uses, each other into about the magnetization yoke (1 of 90 ° of settings, 2) under the situation, this device is also additional to be provided with at least one and to be positioned at above-mentioned yoke (1,2) between and with their the biasing auxiliary yoke (3,3A).

2, device as claimed in claim 1 is characterized in that (3, angle is about 45 ° to one or more auxiliary yokes 3A) and between other two yokes.

3, device as claimed in claim 1 or 2 is characterized in that being arranged between the above-mentioned yoke (1,2), perpendicular to the auxiliary yoke (3A) in the plane of the mounting plane of above-mentioned two yokes (1,2) is additional an inflection point is being arranged.

4, device as claimed in claim 3 is characterized in that auxiliary yoke (3A) with respect to 2 °-45 ° of the scopes of the mounting plane deflection of above-mentioned two yokes (1,2), is preferably 40 °-45 ° or 45 °-50 °.

5, device as claimed in claim 1 or 2, it is characterized in that in the above-mentioned yoke at least one yoke especially auxiliary yoke by an opening, have that the yoke that is separated from each other is unshakable in one's determination to be formed, it is continuous on circuit to be positioned at this magnetic vibrating feeder yoke some coils in the heart.

6, device as claimed in claim 1 or 2 is characterized in that the matrix that will above-mentioned yoke be housed in this device and the device is tunnel-like.