JPH08128993A - Evaluating method of dispersant for magnetic particle solution used in wet magnetic-particle test method, and measuring instrument used for execution of this method - Google Patents

Abstract

PURPOSE: To provide an evaluating method in which a MT(Magnetic-Particle Test) dispersant added to a magnetic particle solution in wet MT method can be quantitatively evaluated with a numeric value. CONSTITUTION: The standard surface 71 of a surface roughness standard piece 7 for comparison and the plate surface 61 of a transparent plate 6 are fixed opposite to each other with a space 3, the lower end parts are dipped in a magnetic particle solution to which a MT dispersant is added in the attitude where both the surfaces are vertical, the value of ascending height of the magnetic particle solution ascending in the clearance 3 by capillary phenomenon is measured, and the MT dispersant is evaluated by the measured value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating a dispersant for a magnetic powder liquid used in a wet magnetic particle flaw detection test method and a measuring instrument used for carrying out the method. INDUSTRIAL APPLICABILITY The present invention is used not only by a manufacturer of a magnetic powder liquid dispersant but also by a wet magnetic powder particle flaw detection test method in a steel industry, an automobile industry, or the like.

[0002]

As is well known, in the steel industry, steel materials such as square billets and round billets are inspected, and in the automobile industry, steel parts such as knuckle arms and shafts are inspected. JI for flaw detection
The “wet magnetic particle flaw detection test method” specified in S G 0565 is widely used. The above-mentioned test method is a defect indicating magnetic powder pattern by bringing a magnetic powder liquid in which non-fluorescent magnetic powder or fluorescent magnetic powder is dispersed into water into contact with the surface of the inspection object, and by assembling / adhering the magnetic powder to the surface defect portion of the inspection object. Is formed, and the defective portion is detected by the pattern.

In preparation of the above-mentioned magnetic powder liquid, the above-mentioned JIS standard "... In the wet method, ... A test liquid containing water as a dispersion medium and a suitable surfactant as necessary is added. As stated in "Use ...", a surfactant is to be used, and in the industry, a surfactant is added to water, and if necessary, an emulsion type silicon defoaming agent or a rust preventive (sodium nitrite). , Triethanolamine, etc.), which is a commercially available dispersant for magnetic powder liquids.

Typical examples of commercially available dispersants for magnetic powder liquids include:
"Magnetic powder dispersant BC-600 (trade name: manufactured by Mark Tech Co., Ltd.)" can be mentioned. Further, as a typical prior art document relating to a magnetic powder liquid dispersant, Japanese Patent Publication No. 2-594267 and Japanese Patent Publication No. 2-594267 which disclose a composition comprising water, a nonionic surfactant, a silicon defoaming agent, a rust preventive agent and soap are disclosed. Japanese Patent Publication No. 26057/1992 discloses water, a nonionic surfactant, a silicone defoaming agent, soap and alcohol.

The purpose of use of the commercially available magnetic powder liquid dispersant and the magnetic powder liquid dispersants disclosed in the above publications is to sufficiently disperse non-fluorescent magnetic powder or fluorescent magnetic powder in water and to inspect the magnetic powder liquid. This is for uniformly wetting the surface of the object when it is brought into contact therewith. Each manufacturer of commercially available magnetic powder liquid dispersant shows the recommended concentration that the above purpose of use can be achieved to the user, and the user prepares the magnetic powder liquid according to the recommended concentration, and the standard use concentration in the industry is: "When dispersing 0.5 g of fluorescent magnetic powder in 1 liter of water, a dispersing agent for magnetic powder liquid 20
cc is to be added ”.

In the preparation of the above magnetic powder liquid, the concentration of the magnetic powder liquid dispersant used is extremely important. If the concentration is not proper, sufficient dispersibility cannot be obtained or sufficient wettability cannot be obtained. As a result, the accuracy of flaw detection decreases. Further, even when using the prepared magnetic powder liquid, the concentration of the magnetic powder liquid dispersant in the liquid must be maintained at an appropriate concentration, and the magnetic powder liquid is used in a deteriorated state. If it is present, sufficient dispersibility and sufficient wettability cannot be obtained, and the flaw detection accuracy also deteriorates.

The usage of the dispersant for the magnetic powder liquid, which is usually adopted at the site of the wet magnetic powder flaw detection test method, is as follows.

First, at the time of preparing the magnetic powder liquid, the magnetic powder liquid is prepared using a commercially available magnetic powder liquid dispersant according to the concentration recommended by the dispersant manufacturer. Then, add SU to the prepared magnetic powder solution.
S Wet the polishing plate, pull it up, and evaluate the wettability by visually observing the wet state of the surface. If the wettability is poor (the magnetic powder liquid does not uniformly adhere to the surface of the SUS polishing plate, In the case of breaking), an appropriate amount of a commercially available magnetic powder liquid dispersant is added, the SUS polishing plate is again immersed and pulled up, and the wet state of the surface is visually observed to evaluate the wettability. This evaluation work is repeated until sufficient wettability is obtained (until the magnetic powder liquid is uniformly attached to the surface of the SUS polishing plate).

Incidentally, the wettability of the liquid in which only the commercially available magnetic powder liquid dispersant is added is evaluated in the same manner as above using a SUS polishing plate, and then the non-fluorescent magnetic powder or the fluorescent magnetic powder is dispersed. In some cases.

Next, when the magnetic powder liquid is used, the magnetic powder liquid at an appropriate time after the start of use is evaluated using a SUS polishing plate in the same manner as above, and the wettability is deteriorated. For that, add an appropriate amount of commercially available magnetic powder liquid and continue to use.

[0011]

As described above, a non-fluorescent magnetic powder or a fluorescent magnetic powder (usually the latter is used) is dispersed in water using a magnetic powder liquid dispersant, and The concentration of dispersant is extremely important. In detail,
If the concentration of the magnetic powder liquid dispersant is not appropriate, sufficient dispersibility cannot be obtained, and the magnetic powder will agglomerate, resulting in a decrease in flaw detection accuracy and sufficient wettability. Since the magnetic powder is not obtained, the magnetic powder liquid is repelled on the surface of the object to be inspected (a defect existing at a portion where the magnetic powder liquid is repelled cannot be detected), so that the flaw detection accuracy is deteriorated. With respect to dispersibility, the dispersed state can be visually confirmed, and since the magnetic powder liquid is usually used in a stirred state, there are few problems.

However, regarding the wettability, the above-mentioned SUS
There are the following problems when evaluation is performed by the method using a polishing plate. That is, sensory evaluation (SU
S: It is empirically evaluated by observing the wet state of the polishing plate. The comparison between the evaluation results when the magnetic powder solution is prepared and the evaluation results when the magnetic powder solution is used is inaccurate because it is left to the observer's memory. Since the concentration itself of the magnetic powder liquid dispersant cannot be measured, there is a problem that the amount of the magnetic powder liquid dispersant to be added must be empirically determined. Further, in relation to, at the time of preparing the magnetic powder solution, the evaluation by the SUS polishing plate can be repeated, but since it is difficult to repeat the evaluation by the SUS polishing plate when using the magnetic powder liquid, it is difficult in terms of work efficiency, The fact is that we evaluate it once or twice during the work, and add it to the eyes that are empirically high each time.
There is also the problem of being uneconomical because an excessive amount is added to the required amount.

It should be noted that it is necessary to add a dispersant for the magnetic powder liquid when the magnetic powder liquid is used because the contaminants adhering to the object to be inspected are mixed into the magnetic powder liquid during use. Performance is deteriorated, and because part of the magnetic powder liquid in use adheres to the object to be inspected and is carried out to the outside, water, non-fluorescent magnetic powder or fluorescent magnetic powder, and a dispersant for magnetic powder liquid can be used. Because it is necessary to add.

Despite the inherent problems as described above, as far as the present inventor knows, a method for quantitatively evaluating a dispersant for magnetic powder liquid added to water or magnetic powder liquid is still proposed. It has not been. The present inventor conducted research to solve the above problems by embodying a method capable of quantitatively evaluating a dispersant for a magnetic powder liquid added to water or a magnetic powder liquid.

The present inventor, in the process of research,
Attention was paid to the measurement method using the spreading wetting phenomenon. The above-mentioned measuring method is used in various technical fields. For example, in Japanese Patent Laid-Open No. 60-182018, a standard wetting reagent is provided on a magnetic surface of a magnetic recording medium held at an angle of 90 ° or less with respect to a horizontal plane. Disclosed is a method of evaluating the surface wettability of the magnetic surface of the magnetic recording medium by measuring the flow length of the wetting reagent at a predetermined time or measuring the time required to flow the predetermined flow length by dropping. Japanese Patent Laid-Open No. 63-167239 discloses that a standard wetting reagent is dropped on the surface of a magnetic medium held horizontally, and then the magnetic surface is rotated and fixed at a predetermined angle. A method of measuring the flowing length and evaluating the surface wettability of the magnetic surface of the magnetic recording medium by the measured value is disclosed, and further, it is disclosed in JP-A-6-148056.
As described in the scope of the patent claims, "Claim 1 defines a V-shaped body having an opening whose cross section extends in a wedge shape, and a pair of wall surfaces of which at least one is a solid to be evaluated are opposed to each other. The horizontal cross section of the opening is immersed in the liquid to be evaluated in a wedge-shaped posture, and the value of the height of rise of the liquid to be evaluated from the liquid surface to the wall surface between the pair of wall surfaces is measured. Is used as an evaluation value of surface wettability of a solid to be evaluated with respect to a liquid. The method for evaluating the surface wettability of a solid liquid is characterized in that the wall surface of is a transparent plate.

The present inventor utilizes the extended wetting phenomenon to
S With the polishing plate surface and the glass plate surface facing each other with a fixed interval and fixed, and the both surfaces being vertical, the lower end portion thereof is exposed to water or magnetic powder liquid to which a dispersant for magnetic powder liquid is added. A large number of experiments were carried out by measuring the rising height of the water or magnetic powder liquid that is immersed and increasing the interval, and quantitatively evaluating the magnetic powder liquid dispersant added to the water or magnetic powder liquid by the measured value. As a result, it was found that the measured values also vary depending on the variation in surface roughness of the SUS polished plate surface. Then, they faced the difficult problem that it is very difficult to continuously and economically obtain a large number of SUS polished plates having a constant surface roughness.

Therefore, the present inventor, while proceeding with various investigations, can solve the above-mentioned problems by using the Japanese Industrial Standards-Comparative Surface Roughness Standard Piece, and moreover, the surface of the object to be inspected which is the object of the wet magnetic particle flaw detection test method. However, it has been found that a rough surface having a rough surface similar to that of a cast surface and a rough surface having a rough surface similar to a grinder (thunder) surface can be easily obtained.

The surface roughness standard piece for comparison with Japanese Industrial Standards is specified in JIS B 0659 and is "... variation in standard surface ... must be within ± 15% ..." Roughness is almost constant, and since there are commercially available products, many can be obtained continuously and economically.

[0019]

[Means for Solving the Problems]
This can be solved by the present invention I and II as follows. That is, the present invention I provides a standard surface roughness standard piece for comparison with Japanese Industrial Standards (hereinafter referred to as “surface roughness standard piece”) and a transparent plate, wherein the standard surface of the surface roughness standard piece and one surface of the transparent plate are 0.1
Fix in a state of facing each other with an interval of ~ 1 mm, and in a posture in which both sides are vertical, the lower end is immersed in water or a magnetic powder solution to which a dispersant for a magnetic powder solution is added, and the interval To measure the value of the rising height of the water or magnetic powder liquid, the wet magnetic powder flaw test method characterized by evaluating the magnetic powder liquid dispersant added to the water or magnetic powder liquid by the measured value Is a method for evaluating a dispersant for a magnetic powder liquid used in.

The present invention II is a facing surface 2 of a central opening 2 of a concave substrate 1 in a plan view made of a thick plate material used in a method for evaluating a dispersant for a magnetic powder used in the above-mentioned wet magnetic powder flaw detection test method.
The gap 3 between the slits adjacent to 1, 21 'is 0.1 to 1
A transparent plate 6 is inserted and fixed in a holder H having two slits 4, 4'and 5, 5'symmetrically formed so as to have a width of mm, straddling the slits 4, 4'on the opening 2 side. A measuring instrument formed by inserting and fixing the surface roughness standard piece 7 across the other slits 5 and 5'so that the standard surface 71 faces one surface 61 of the transparent plate 6 (FIGS. 1, 2 and 3). See).

The structures of the present inventions I and II will be described in more detail below. Standard surface roughness is JIS B
The one specified in 0659 is used. There are various types of commercially available products according to the standard, but it is preferable to select and use one that is close to the surface of the object to be inspected targeted for the wet magnetic particle flaw detection test method. ",
“Precision casting surface roughness standard piece” and “Steel plate surface finish surface roughness standard piece (there are two types, a comparative grinder surface finish surface standard piece and a comparative sander surface top surface standard piece)” are particularly suitable. Each of these standard pieces is commercially available, for example, from "Nippon Metal Electroforming Co., Ltd."

As the transparent plate, a glass plate or a plastic plate (for example, an acrylic resin plate) having excellent transparency and having a smooth surface is used.

The required standard surface roughness standard piece selected and the required transparent plate body selected have a standard surface of the standard surface roughness sheet and one surface of the transparent plate body of 0.1 to 1 mm, preferably 0.2.
It is fixed and used while facing each other with a space of ~ 0.5 mm. In the case of 0.1 mm or less, due to the size of the available surface roughness standard piece, the sample (water or magnetic powder liquid) that rises the interval by capillary phenomenon at the time of use reaches the upper end and the height rises. May not be possible, and when it is 1 mm or more, the height of the sample which rises due to the capillary phenomenon at the time of use may be low, which makes it difficult to measure the rise height.

The inventor of the present invention, by setting the interval to 0.1 to 1 mm, uses various commercially available surface roughness standard pieces described above and various commercially available dispersants for magnetic powder solutions and the magnetic powder solutions disclosed in the above-mentioned respective publications. It has been confirmed by a number of experiments that each sample to which the dispersant for use has been added can be used to clearly measure the rising height of each sample in which the interval is increased by the capillary phenomenon.

The means for setting / fixing the interval is not particularly limited, and various means can be adopted. For example, the standard surface of the surface roughness standard piece and one surface of the transparent plate face each other, and the inside of both side parts thereof are arranged. Spacers of the required thickness (this thickness is the spacing) are installed on each of them, and the required spacing can be set / fixed by fixing the outer sides of both sides with clips, but the most desirable spacing setting / fixing means. Are means adopted in the measuring instrument according to the present invention II.

The surface roughness The standard surface of the standard piece and the one surface of the transparent plate are fixed in a state of facing each other with a required gap, and the lower end portion is immersed in the sample in a posture in which both surfaces are vertical. In order to measure the rise value of the sample that raises the interval, the sample is placed in a shallow bat up to a height of about 3 to 5 mm from its bottom surface, and the both sides are made vertical so that the lower end portion is on the bottom surface of the bat. The rising height from the liquid surface of the sample may be measured when the sample is raised upright and the rising of the sample that rises in the interval is stopped.

In the above measurement, the scale height can be easily read by placing a scale scale on the transparent plate surface on the side not facing the standard surface of the surface roughness standard piece. Usually, the reading can be done visually, but the CCD
It is also possible to read by a camera and perform automatic measurement. Also, automatic measurement can be performed using an optical sensor such as a photoelectric tube.

In quantitatively evaluating the magnetic powder liquid added to water or the magnetic powder liquid by the measurement value obtained by measuring the rising height of the sample, the following evaluation can be performed.

A. A non-fluorescent magnetic powder or fluorescent magnetic powder is dispersed in water using a commercially available magnetic powder liquid dispersant to prepare a magnetic powder liquid having sufficient dispersibility and sufficient wettability with respect to an object to be inspected (usually, It may be prepared according to the concentration recommended by the manufacturer of the magnetic powder liquid dispersant), the sample is taken from the magnetic powder liquid, and the measured value of the rising height is recorded and stored, and the wet magnetic powder flaw detection test is performed using the magnetic powder liquid. After carrying out the method, a sample is taken from the magnetic powder liquid in use at an appropriate time after the start of use, and the measured value of the rising height measured for this sample is compared with the previously recorded measurement value. If there is a variation between the measured values, a commercially available magnetic powder liquid dispersant is added to the magnetic powder solution in use so that the measured value matches the previously recorded and recorded value.

B. Using the target dispersant for a magnetic powder solution in advance, magnetic powder samples having different concentrations of the dispersant were prepared (usually, 0.5%, 1%, 2%, and 3% were prepared. The measured value of the rising height of each magnetic powder sample is plotted on a graph with the rising height (mm) on the vertical axis and the dispersant concentration (%) on the horizontal axis, Magnetic powder liquid dispersant concentration calibration curve is created and placed, at the time of preparation of the magnetic powder liquid prepared using the same magnetic powder liquid dispersant as the target magnetic powder liquid dispersant, or at an appropriate point during use, A above
The concentration of the magnetic powder liquid dispersant at each time point is obtained by comparing the measured value of the rising height measured in the same manner as in the above case with the above calibration curve. Instead of the above magnetic powder liquid sample, water containing only a magnetic powder liquid dispersant may be used.

It is also possible to measure the time from the time of immersion to the time when the rising of the sample for increasing the interval is stopped, and the same evaluation as in A and B can be carried out by the measured value.

Next, the measuring instrument shown in FIGS.
As shown, it has a very simple structure. A plan view of a thick plate material that constitutes the holder H (see FIG. 3)
The concave substrate 1 is manufactured by cutting it out of a brass block body into a required size and shape, or by molding it into a required size and shape using a plastic material (for example, ABS resin). At the time of manufacture, the distance between the slits 4 and 4'and the slits 5 and 5 '(the arrow 3 in the figure) should be a required dimension selected from the range of 0.1 to 1 mm, preferably 0.2 to 0.5 mm. Must be careful. As the transparent plate 6 and the surface roughness standard piece 7, those as described above are used.

The width of the slits 4 and 4'is the transparent plate 6 to be used.
And the widths of the slits 5 and 5'are adapted to the thickness of the surface roughness standard piece 7 to be used, or are made wider. When the width is wide, the transparent plate 6 and the standard surface roughness piece 7 can be easily inserted and removed, but the spring mechanism 4 for fixing at the time of insertion.
1, 41 'and spring mechanisms 51, 51' need to be provided in the slits 4, 4'and the slits 5, 5 '.

Spring mechanisms 41 and 41 'are provided in the slits 4 and 4'to press the transparent plate 6 toward the surface roughness standard piece 7, and in the slits 5 and 5', the surface roughness standard piece. Spring mechanisms 51 and 51 'are provided so as to press 7 toward the transparent plate 6 (see FIG. 2). As the spring mechanisms 41, 41 ′, 51, 51 ′, it is preferable to use a leaf spring shown in FIG. 2 that is bent in a zigzag shape (folded in 99), but is not limited to this. Instead, it may be replaced with another shape (for example, a leaf spring having an arcuate shape in side view).

A surface graduation 63 is provided on the surface 62 of the transparent plate 6 on the side not facing the standard surface 71 of the surface roughness standard piece 7.
Is preferably added, and the scale width is 1 mm width, preferably 0.5 mm width.

[0036]

The operation of the present invention having the above-described structure is as follows. The present invention I utilizes the expansion wetting phenomenon to measure the value of the rising height that changes depending on the surface tension of the water or the magnetic powder liquid to which the magnetic powder liquid dispersant to be evaluated is added. That is, the wetting phenomenon of the surface of a liquid depends on the interfacial tension between the solid and the liquid, and in the case of expansion wetting, the surface tension of the solid (γs), the surface tension of the liquid (γl) and the interfacial tension of the solid and the liquid ( It has long been known that the relationship between the three parties of
Surface Chemistry (enlarged version), P51-52, Sankyo Publishing Co., Ltd., issued November 10, 1968).

Ws (work of expansion) = γs −γl −γsl

In the above equation, if γs is the surface tension of the surface roughness standard piece and γl is the surface tension of the water or the magnetic powder liquid to which the dispersant for the magnetic powder liquid is added, γs does not change and
Since l and γsl change depending on the concentration and type of the magnetic powder liquid dispersant, Ws also changes. Therefore, if the surface tension is measured, in other words, water or magnetic powder liquid that increases the interval by capillary action is used. If the rising height is measured, the change in concentration can be evaluated by the measured value.

In the present invention II, the distance 3 between the standard surface roughness standard single surface 71 and the transparent plate body surface 61, which is the most important in the measurement of the rising height, is kept constant. Further, the scale graduation 63 attached to the transparent plate surface 62 facilitates accurate measurement of the rising height.

[0040]

EXAMPLES Examples of the present invention are as follows. The surface roughness standard pieces used in each example are all JIS B 0659 standard products manufactured by Nippon Metal Electroforming Co., Ltd.

Example 1 For comparison, a standard surface was cut out from a ground surface roughness standard piece classification value of 16 μ (surface roughness) to a size of 25 mm × 30 mm and a standard surface of a slide glass (glass plate) for microscopic observation. Face each other, and the width of the plate is 8 mm on the inside of both sides.
A thickness gauge having a plate thickness of 0.2 mm was inserted into each side, and the outer sides of both sides were fixed with turn clips to manufacture a measuring tool having a facing distance of 0.2 mm.

Commercially available magnetic powder liquid dispersant BC-300 (trade name: manufactured by Mark Tech Co., Ltd.) was added to water to give a mixture of 0.
Four kinds of magnetic powder solution dispersant aqueous solutions having various concentrations of 5%, 1%, 2% and 3% were prepared, and 100 cc of each aqueous solution was put into a 200 mm x 250 mm x 40 mm SUS bat (from the bottom of the bat). Height to liquid level is 3mm).

With the standard surface of the standard piece and the surface of the slide glass being perpendicular to each other, the lower end of the measuring tool is set upright on the bottom surface of the vat, and at the same time, the rising of the aqueous solution which raises the interval by the capillary phenomenon is stopped. For each of the above aqueous solutions, the time until the measurement was performed was measured with a stopwatch, and the rising height from the liquid surface to the rising stop position was measured with a scale of 0.5 mm width scale. The measurement results are shown in Table 1.

Example 2 Table 1 shows the results measured in exactly the same manner as in Example 1 except that the thickness of the thickness gauge was changed to 0.3 mm.

Example 3 Table 1 shows the results measured in exactly the same manner as in Example 1 except that the thickness of the thickness gauge was changed to 0.5 mm.

[0046]

[Table 1]

Example 4 Table 2 shows the results measured in exactly the same manner as in Example 1 except that the comparative sander surface roughness standard piece standard value was changed to 36 μ (surface roughness).

Example 5 Table 2 shows the results measured in exactly the same manner as in Example 4 except that the thickness of the thickness gauge was changed to 0.3 mm.

Example 6 Table 2 shows the results measured in exactly the same manner as in Example 4 except that the thickness of the thickness gauge was changed to 0.5 mm.

[0050]

[Table 2]

Example 7 For comparison, the sander finish surface roughness standard piece standard value was changed to 26 μ (surface roughness) and the thickness of the thickness gauge was set to 0.
Change to 4 mm, and further commercial dispersant for magnetic powder liquid BC-700
Table 3 shows the results measured in exactly the same manner as in Example 1 except that the product name was manufactured by Mark Tech Co., Ltd.

[0052]

[Table 3]

Example 8 Comparative grinder finished surface roughness standard piece classification value 70-s
The standard surface of 25 mm x 30 mm is cut out from the (surface roughness), and the standard surface and one surface of the microscope observing slide glass (glass plate) are made to face each other, and inside the both side parts,
Thickness gauges each having a plate width of 8 mm and a plate thickness of 0.3 mm were inserted, and the outsides of both side portions were fixed with turn clips, respectively, to manufacture a measuring tool having a facing distance of 0.3 mm.

Commercially available magnetic powder liquid dispersant BC-600 (trade name: manufactured by Mark Tech Co., Ltd.) was added to water to prepare a dispersion of 0.
Four kinds of magnetic powder solution dispersant aqueous solutions having various concentrations of 5%, 1%, 2% and 3% were prepared, and 100 cc of each aqueous solution was put into a 200 mm x 250 mm x 40 mm SUS bat (from the bottom of the bat). Height to liquid level is 3mm).

With the standard surface of the standard piece and the surface of the slide glass being perpendicular to each other, the lower end portion of the measuring tool is erected on the bottom surface of the vat, and at the same time, the rising of the aqueous solution which raises the interval by the capillary phenomenon is stopped. For each of the above aqueous solutions, the time until the measurement was performed was measured with a stopwatch, and the rising height from the liquid surface to the rising stop position was measured with a scale of 0.5 mm width scale. Table 4 shows the measurement results.

Example 9 Table 4 shows the results measured in exactly the same manner as in Example 8 except that the casting surface roughness standard piece classification value was changed to 35-s (surface roughness).

[0057]

[Table 4]

As seen in Examples 1 to 9 above, there is a difference in the rising height depending on the concentration of the magnetic powder liquid dispersant aqueous solution and the type of the magnetic powder liquid dispersant used. By using the measured value, the dispersant for magnetic powder liquid in water or magnetic powder liquid can be quantitatively evaluated numerically, as in A and B above.

Example 10 (Production of Measuring Instrument) Sander Finished Surface Roughness Standard Piece for Comparison Standard value is cut out from the section value 26 μ (surface roughness) to a size of 25 mm × 30 mm and the standard surface roughness 7 (thickness 2 mm).
Then, a transparent acrylic resin plate having smooth front and back surfaces was cut into the same size as the standard piece 7 to form a transparent plate 6 (thickness 2 mm). A scale 62 having a width of 0.5 mm is attached to the surface 62 of the transparent plate 6 (a part of the scale 63 is omitted in FIG. 1). On the other hand, a holder H having a shape shown in FIGS. This holder H
The width of the slits 4 and 4'is 6 mm, and the slits 5 and 5 '
Width is 6mm, slits 4 and 4'and slits 5 and 5 '
The interval (arrow 3 in the figure) between and was 0.4 mm. Further, in the slits 4 and 4'and the slits 5 and 5 ', spring mechanisms 41, 41' and 51, which are formed by bending stainless steel leaf springs into a zigzag shape, respectively, are formed.
51 'is provided (see FIG. 2).

The slit 4 on the opening 2 side of the holder H
The transparent plate 6 is inserted across 4'and the surface 62 faces the opening 2, and the standard piece 7 is crossed over the other slits 5 and 5 ', and the standard surface 71 is the transparent plate. Inserted and fixed so as to face one side 61 of 6 and facing distance 0.4mm
The measuring instrument of The transparent plate 6 is pressed toward the standard piece 7 by the spring mechanisms (leaf springs) 41 and 41 ', and the standard piece 7 is pressed by the spring mechanism (leaf spring) 5.
Interval holding portions 3 which are pressed toward the transparent plate 6 by 1, 51 'to form intervals (arrows 3 in the figure).
Since they are fixed in pressure contact with 1, 31 ', the facing distance (spacing) between the one surface 61 of the transparent plate and the standard surface 71 of the standard piece 7 is
It is always held at 0.4 mm (see Fig. 2).

(Preparation of Dispersant Concentration Calibration Curve for Magnetic Powder Liquid) 1l
Beaker Fluorescent magnetic powder for commercial flaw detection LY-4700
(Product name: Mark Tech Co., Ltd.) 0.5 g and commercial magnetic powder liquid dispersant BC-700 (Product name: Mark Tech Co., Ltd.) 5 cc were put and kneaded well, then tap water was added to make 1 liter. A magnetic powder liquid having a magnetic powder concentration of 0.5 g / l and a magnetic powder liquid dispersant concentration of 0.5% was prepared. Similarly, the magnetic powder concentration was kept constant at 0.5 g / l, and magnetic powder liquids having magnetic powder liquid dispersant concentrations of 1%, 2%, and 3% were prepared.
Each of the four types of magnetic powder liquid 100 cc, 200 mm x 2
Put in a 50 mm x 40 mm SUS bat (height from bat bottom to liquid level 3 mm), and for each bat, make the above-mentioned measuring device vertical and make the lower end of the holder H stand upright on the bat bottom and at the same time The time until the rise of the magnetic powder liquid that rises by 3 due to the capillary phenomenon stops is measured by a stopwatch, and the rise height from the liquid level to the rise stop position is measured by the scale graduation 63. The measurement value of each rising height of the magnetic powder liquid was obtained.

FIG. 4 is a graph in which the vertical axis represents the rising height (mm) and the horizontal axis represents the dispersant concentration (%), and the measured values of the respective rising heights obtained here are plotted. 4 is a graph of a dispersion agent concentration calibration curve for the magnetic powder liquid.

(Evaluation) 0.5 g of the same fluorescent magnetic powder as described above and 20 cc of the same magnetic powder liquid dispersant as described above per liter of tap water
A magnetic powder solution 60 l (dispersant concentration 2%) was prepared.

60 l of the magnetic powder liquid was charged into the SUS tank 10 (volume 90 l) of the circulation agitator shown in FIG. 5, and the pump 20 was operated with the liquid temperature maintained at about 25 ° C.
The magnetic particle liquid was circulated through the pipe 30 as indicated by the arrow in the figure, and spraying, recovery, and spraying from the shower 40 were continuously performed for 168 hours.

The tank 1 is placed every 24 hours from the time of adding the magnetic powder liquid.
Five kinds of samples were obtained by sampling 100 cc of sample from 0. For each of these samples, the rising height was measured and the rising stop time was measured in exactly the same manner as above using the same SUS bat and measuring instrument as above, and the measured value of rising height and the magnetic powder solution of FIG. 4 were measured. Table 5 shows the results of determining the concentration of the magnetic powder liquid dispersant of each sample by collating it with the standard dispersant concentration calibration curve.

[0066]

[Table 5]

From Table 5, it can be confirmed that the change with time of the concentration of the dispersant for magnetic powder liquid added to the magnetic powder liquid can be quantitatively evaluated numerically.

[0068]

INDUSTRIAL APPLICABILITY According to the present inventions I and II, it is possible to easily quantitatively evaluate a dispersant for a magnetic powder liquid added to water or a magnetic powder liquid, and particularly at a site for carrying out a wet magnetic powder flaw detection test method. Since it is possible to easily evaluate the change with time of the concentration of the dispersant for the magnetic powder liquid added to the magnetic powder liquid during continuous use, it is possible to always maintain a constant flaw detection accuracy.

Further, the measuring instrument according to the present invention II has a simple structure, is easy to use, and is inexpensive to manufacture.

Therefore, the industrial applicability of the present invention is great, and it can be said that the present invention greatly contributes to the steel industry and the automobile industry.

[Brief description of drawings]

FIG. 1 is a perspective view of a measuring instrument according to the present invention.

FIG. 2 is a sectional view taken along the line AA ′ of FIG.

FIG. 3 is a plan view of a measuring instrument according to the present invention.

FIG. 4 is a graph showing a concentration standard curve of a dispersant for a magnetic powder according to the present invention.

FIG. 5 is a partial vertical cross-sectional explanatory view of a circulation stirring device used in Example 5 of the present invention.

[Explanation of symbols]

1 concave base 2 central opening 21, 21 'facing surface 3 spacing 31, 31' spacing holding portion 4, 4 ', 5, 5' slit 41, 41 ', 51, 51' spring mechanism 6 transparent plate 61, 62 Transparent plate surface 6
3 Scale Scale 7 Surface Roughness Standard Piece 71 Standard Surface H Holder 10 Tank 20 Pump 30 Pipe
40 shower

Claims (5)

[Claims] 1. A surface roughness standard piece for comparison with the Japanese Industrial Standards (hereinafter referred to as "surface roughness standard piece") and a transparent plate, wherein the standard surface of the surface roughness standard piece and one surface of the transparent plate are 0. It is fixed in a state of facing each other with an interval of 1 to 1 mm, and in a posture in which both sides are vertical, the lower end is immersed in water or a magnetic powder solution to which a dispersant for a magnetic powder solution is added. Wet magnetic particle flaw detection test characterized by measuring the value of the rising height of the water or magnetic powder liquid that increases the interval, and evaluating the magnetic powder liquid dispersant added to the water or magnetic powder liquid by the measured value. A method for evaluating a dispersant for a magnetic powder used in the method. 2. The two slits 4, so that the distance 3 between the slits adjacent to the facing surfaces 21, 21 'of the central opening 2 of the concave base body 1 made of a thick plate material in plan view is 0.1 to 1 mm. In a holder H having 4'and 5,5 'symmetrically provided,
The transparent plate 6 is inserted and fixed across the slits 4 and 4'on the opening 2 side, and the surface roughness standard piece 7 and the standard surface 71 of the transparent plate 6 are crossed over the other slits 5 and 5 '. The measuring instrument used in the method for evaluating a dispersant for a magnetic powder used in the wet magnetic particle flaw detection test method according to claim 1, wherein the measuring tool is inserted and fixed so as to face one surface 61. 3. A transparent plate 6 has a scale graduation 6 on a surface 62 of the surface roughness standard piece 7 on the side not facing the standard surface 71.
The measuring instrument according to claim 2, which is labeled with 3. 4. A spring mechanism 4 for pressing the transparent plate 6 in the slits 4, 4'towards the surface roughness standard piece 7 side.
The measuring instrument according to claim 2, wherein 1, 41 'are provided. 5. A spring mechanism 5 for pressing a standard surface roughness piece 7 into the slits 5, 5'toward the transparent plate 6 side.
The measuring instrument according to claim 2, wherein the measuring instrument is provided with 1, 51 '.