JPH10332644A - Thick magnetic-particle dispersion liquid for wet magnetic-particle testing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thick magnetic-particle dispersion liquid which prevents the precipitation and the sedimentation of magnetic particles for wet magnetic- particle testing even when the particles are left at a standstill for a long period by a method wherein the magnetic particles are composed of specific wt.% of an alkyl ether-type nonionic surface-active agent whose HLB value is specific, of specific wt.% of alcohol and of water as the remainder. SOLUTION: A thick magnetic-particle dispersing liquid for wet magnetic- particle testing is composed of 20 to 50 wt.% of magnetic particles for wet magnetic-particle testing, of 8 to 20 wt.% of an alkyl ether-type nonionic surface-active agent, of 2 to 15 wt.% of alkohol and of water as the remainder. Then, as the magnetic particles for wet magnetic-particle testing. Supermagna fluorescent magnetic particle LY-10, LY-15 or the like are used. As the alkyl ether-type nonionic surface active agent whose HLB value is 10 to 12, polyoxyethylene alkyl ether, alkyl ethylene nonyl phenyl ether, alkyl ethylene octylphenyl ether or the like is used. As the alkohol, ethanol, methanol or propyl alcohol is suitable. As the water, tap water is usually used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test.

[0002] The concentrated magnetic powder dispersion for wet magnetic particle flaw detection according to the present invention is mainly used in a wet magnetic particle flaw detection test method carried out in a production line of a steel maker or an automobile maker.

[0003]

2. Description of the Related Art As is well known, JIS G0565-199.
The wet magnetic particle flaw detection test method standardized in No. 2 is widely used for flaw detection of surface defects on steel materials such as square billets and round billets on the production line of steel manufacturers, and shafts and knuckles on the production lines of automobile manufacturers. It is also widely used for surface defect inspection of steel parts such as arms.

In the wet magnetic particle flaw detection test method, a commercially available magnetic powder for wet magnetic particle flaw test (such as triiron tetroxide particles or pure iron particles) is placed on the surface of a magnetized test object (the square billet or shaft). Lumogen Yellow S0790: trade name: BA with synthetic resin binder such as cellulose acetate-based synthetic resin and vinyl butyral-based synthetic resin
SF or Festa A: trade name: powder having an average particle diameter of 1 to 20 μm obtained by adhering a fluorescent pigment made by Swada or the like; hereinafter, simply referred to as “magnetic powder”; In this case, for the preparation of the test solution, water is used as a dispersion medium in the JIS standard, and an appropriate liquid is used as necessary. Use a test solution containing a surfactant ... ", a surfactant is used.

More specifically, the test solution used in the production line of a steel maker or an automobile maker usually contains 0.2 to 2 g of magnetic powder per liter of water containing 300 to 1000 ppm of a surfactant. The test solution is prepared by dissolving, emulsifying or dispersing a commercially available magnetic particle dispersant for wet magnetic particle flaw detection test (2 to 10% by weight of a nonionic surfactant of HLB 9 to 16 in water). A liquid containing a silicon defoaming agent and a rust inhibitor as needed; hereinafter, simply referred to as a "dispersant"), and thoroughly kneading a predetermined amount thereof with a predetermined amount of magnetic powder. A method has been adopted in which, after being made into a paste, the paste is poured into a predetermined amount of water under stirring.

When the above method is employed, weighing work and kneading work are indispensable, so that it takes time and effort to prepare a test solution.
JP-A-57-141547 discloses a technique of mixing a magnetic powder, a colorant, a pigment, a synthetic resin, an organic solvent and a surfactant, and evaporating the organic solvent to obtain a non-fluorescent magnetic powder or a fluorescent magnetic powder. As shown in the technology of obtaining a non-fluorescent magnetic powder or a fluorescent magnetic powder by coating a magnetic resin containing a coloring agent on a magnetic powder disclosed in the official gazette and obtaining a non-fluorescent magnetic powder or a fluorescent magnetic powder, the magnetic powder itself is adhered to the magnetic powder. A technique for imparting water dispersibility to water has been proposed.

However, in order to prepare a test solution in which magnetic powder is sufficiently dispersed in water, it is necessary to use a nonionic surfactant having an HLB of 9 to 16, and this surfactant is a non-volatile viscous liquid. However, since the magnetic powder to which this is attached agglomerates during storage, there is a problem that a sufficient dispersion state cannot be obtained at the time of preparation of the test solution. In fact, as far as the present inventor knows, a surfactant is attached. There is no example in which the magnetic powder is practically used in the wet magnetic particle flaw detection test method.

In view of the above problems, Japanese Patent Application Laid-Open No. 9-61
No. 404 discloses that an average particle diameter of 0.01
A powdery fluorine-based surfactant (for example, Unidyne DS) is used for 100% by weight of magnetic powder to which hydrophilic amorphous silicon dioxide fine particles (for example, Aerosil 200: trade name: manufactured by Nippon Aerosil Co., Ltd.) are adhered. -101:
(Trade name: manufactured by Daikin Industries, Ltd.) has been proposed, and the magnetic powder formulation has excellent storage stability, does not aggregate after storage for 6 months, and is stirred under a predetermined amount. In the above method, when a predetermined amount of water (containing no surfactant) is added, a dispersed state equivalent to the case where the above-described method of adding the paste is used is obtained.

Although the above-mentioned magnetic powder composition can be used practically, it requires 100% of the requirements of the wet magnetic powder flaw detection test method workers in the production lines of steel and automobile manufacturers in that the weighing work is troublesome because it is a powder. Not enough to fill.

[0010]

Steel manufacturers and automobile manufacturers in Japan have made great efforts to speed up the production line, and the speed of each second has been increased in each process. There is also a need for a method for preparing a test solution that does not require as much time and effort as possible in performing a wet magnetic particle flaw detection test method.

In response to the above-mentioned demands, the present inventor has been studying to provide a method for preparing a test solution more easily and faster than a conventional test solution preparation method. Inspired by a commercially available concentrated (conc) juice found in juices and the like, the idea of “concentrated magnetic powder dispersion” was obtained.

The present inventor prepares a “concentrated magnetic powder dispersion” in which magnetic powder is dispersed at a high concentration in an appropriate amount of a dispersant, fills the container, and prepares a predetermined amount of the concentrated magnetic powder dispersion when preparing the test solution. The method of weighing with a measuring cup or a measuring cylinder and diluting it by adding it to a predetermined amount of water under stirring can perform the weighing operation extremely quickly and accurately, and also requires the kneading work. In addition, it was thought that it was possible to disperse more quickly than in the case where a paste-like material or powder was introduced.

Therefore, the present inventor has proposed a “dense magnetic powder dispersion”
Trial production and experiments were carried out to realize.

First, when magnetic powder is added to a dispersant in a high concentration (for example, dispersant: Super Magna magnetic powder dispersant BC-6)
00: Trade name: Mark Tech Co., Ltd .: Magnetic powder in 20 ml: Super Magna fluorescent magnetic powder LY-10: Trade name: Mark Tech Co., Ltd .: When 2 g is added), the magnetic powder is obtained by standing for a very short time. It has settled.

When a test solution is prepared from a concentrated magnetic powder dispersion in which the magnetic particles settle and precipitate at the bottom of the container due to standing for a short period of time, the container is shaken sufficiently to start the precipitated magnetic particles. If it takes time and the magnetic powder is not completely raised, it is weighed with a measuring cup and poured into a required amount of water, and the required test liquid (0.2 to 2 g of magnetic powder dispersed per liter of water) is obtained. Cannot be prepared.

Next, in order to prevent sedimentation of the magnetic powder in the liquid, a magnetic powder is added to the dispersant at a high concentration and a water-soluble resin is added (for example, dispersant: Super Magna magnetic powder dispersant BC-600: Product name: Mark Tech Co., Ltd .: Magnetic powder in 20 ml: Super Magna fluorescent magnetic powder LY-1
0: Trade name: Marktec Co., Ltd .: When 2 g is added and one or more water-soluble resins selected from carboxymethyl cellulose, methyl cellulose and hydroxymethyl cellulose are added), the water-soluble resin is added. Although the viscosity of the liquid increased in proportion to the amount and the sedimentation of the magnetic powder was prevented, the viscosity of the liquid was extremely increased if the amount of addition was increased to such an extent that no sedimentation / precipitation of the magnetic powder was observed even after 30 days of standing. The magnetic powder did not disperse unless strong stirring was continued for a long time in preparing the test solution, so that it could not be put to practical use.

The inventor of the present invention has concluded that the magnetic powder does not settle or precipitate even after standing for a long period of time (at least two months or more), and the magnetic powder is easily dispersed when preparing the test solution. The present invention has been achieved as a result of repeated trial production and experiments with the realization of "liquid" as a technical problem.

[0018]

The above technical objects can be achieved by the present invention as described below.

That is, the present invention provides a magnetic powder for a wet type magnetic particle flaw detection test of 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12 to 8% by weight, an alcohol of 2 to 15% by weight, and a water balance. This is a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test consisting of:

Further, the present invention provides a magnetic powder for a wet type magnetic particle flaw detection test of 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12 at 8 to 20% by weight, an alcohol at 2 to 15% by weight, This is a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test, comprising 3 to 10% by weight of a foaming agent and the remainder of water.

Further, the present invention provides a magnetic powder for a wet magnetic particle flaw detection test in a content of 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12 in a content of 8 to 20% by weight, an alcohol in a content of 2 to 15% by weight, It is a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test, comprising 3 to 10% by weight of a foaming agent, 2 to 5% by weight of a water-soluble rust inhibitor, and the remainder of water.

The structure of the present invention will be described in more detail as follows.

The magnetic powder for a wet type magnetic particle flaw detection test used in the present invention is a well-known one, and is a supermagna fluorescent magnetic powder L.
Y-10 (described above) or Super Magna fluorescent magnetic powder LY-15
What is commercially available for magnetic particle flaw detection, such as 00 (trade name: manufactured by Mark Tech Co., Ltd.) may be used.

The HLB value used in the present invention is 10 to 12.
The alkyl ether type nonionic surfactants are also well known, and specific examples thereof include polyoxyethylene alkyl ether, alkyl ethylene nonyl phenyl ether, and alkyl ethylene octyl phenyl ether. : Trade name: Sanyo Kasei Kogyo Co., Ltd. (HLB value 10.6) or Octapol 60:
Product name: Sanyo Chemical Industry Co., Ltd. (HLB value 11.3)
There is.

As the alcohol used in the present invention, ethanol, methanol and propyl alcohol are preferred.

The water used in the present invention is usually tap water.

The mixing ratio of the magnetic powder, the surfactant and the alcohol used in the present invention is important.

Increasing the proportion of the magnetic powder is in accordance with the gist of the present invention. However, if it exceeds 50% by weight, the magnetic powder becomes difficult to disperse during the preparation of the test solution. If the ratio is reduced, the dispersibility improves, but from the viewpoint of practicality such as handleability during preparation of the test solution and the size of the container, it is preferable to add 20% by weight or more.

When the ratio of the surfactant is less than 8% by weight, the sedimentation of the magnetic powder at the time of standing is liable to occur, and as the ratio is increased, the sedimentation does not occur. The magnetic powder becomes difficult to disperse at the time of preparing the liquid, and foams easily at the time of using the test liquid. A more preferable compounding ratio is 9 to 12% by weight.

It should be noted that, among alkyl ether type nonionic surfactants, those having an HLB value of less than 10 cannot be used because they are difficult to emulsify or disperse in water, and those having an HLB value of more than 12 cannot be completely dissolved in water. Therefore, it cannot be used because the viscosity of the liquid does not increase.

When the proportion of alcohol is less than 2% by weight, sedimentation of the magnetic powder at the time of standing is liable to occur, and as the proportion increases, sedimentation does not occur, but when it exceeds 15% by weight, it will be explained in the section of "action" below. Since the pseudoplastic flow becomes too strong, bubbles entrained during the production of the product of the present invention are less likely to escape during the preparation of the test solution, and the weighing operation becomes difficult. A more preferable mixing ratio is 4 to 12% by weight.

If the product of the present invention is obtained by the mixing ratio of the magnetic powder of 20 to 50% by weight, the surfactant of 8 to 20% by weight, the alcohol of 2 to 15% by weight and the remainder of water, the achievement of the technical problem is guaranteed. Further, even when a part of the water in the compounding ratio is replaced with a silicon defoamer described below or the silicon defoamer and a water-soluble rust inhibitor, achievement of the above technical problem can be guaranteed.

The silicone antifoaming agent used in the present invention is:
Dispersant (discussed above, commercially available magnetic powder dispersant for wet magnetic particle flaw detection test)
Well-known silicone defoamer K
Commercially available products such as M-70 and KM-75 (both trade names: manufactured by Shin-Etsu Chemical Co., Ltd.) may be used, and the compounding ratio is preferably 3 to 10% by weight, and if less than 3% by weight, the prepared test is performed. When the liquid is used in a circulating manner (when the test liquid that has been sprayed on the test object and brought into contact with it is used while being transferred and circulated using a pump or the like), the foaming is increased due to insufficient defoaming power, which hinders the flaw detection work. When the content exceeds 10% by weight, a part of the film is separated to form scum. A more preferable compounding ratio is 4 to 6% by weight.

The water-soluble rust preventive used in the present invention is also a well-known one added to the dispersant (same as above), and is preferably sodium nitrite or amines.
It is preferably 5% by weight, and if it is less than 2% by weight, the required rust-preventing effect is hardly obtained, and up to 5% by weight provides a practically sufficient rust-preventing effect.

The production of the concentrated magnetic powder dispersion for the wet magnetic particle flaw detection test according to the present invention is easy.

That is, first, a prescribed amount of the remaining components except for the magnetic powder and the alcohol is weighed, placed in a container (for example, a stainless steel tank), and heated (usually 40 minutes).
After stirring sufficiently using a stirrer (e.g., a colloid mill) under heating at room temperature (about 18 to
20 ° C.), then add the alcohol and a predetermined amount of the magnetic powder, stir using a stirrer (for example, a propeller type mixer), and stop stirring when the magnetic powder is sufficiently dispersed. The desired product is obtained.

If the product of the present invention obtained by the above process is divided into appropriate amounts and filled in a container (for example, a small polyethylene tank), and used by a person engaged in a wet magnetic particle flaw detection test method, the person concerned can measure the measuring cup. A test solution can be prepared by simply weighing out a required amount of the product of the present invention from the container using a measuring cylinder or a measuring cylinder, throwing the diluted product into a required amount of water prepared in advance with stirring, and diluting it.

The product of the present invention is preferably used after being diluted 100 to 400 times with water.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the present invention is as follows.

Embodiment 1 First, 100 g of a nonionic surfactant alkylethylene nonylphenyl ether having a HLB value of 10.6 (Nonipol 60: trade name: manufactured by Sanyo Chemical Industry Co., Ltd.) and tap water 600 were placed in a stainless steel tank.
After stirring for 10 minutes using a colloid mill while heating to a liquid temperature of about 48 ° C., stop heating, cool to room temperature (about 19 ° C.), and then add 50 g of ethanol.
Was added, and 250 g of magnetic powder (Super Magna fluorescent magnetic powder LY-10: trade name: manufactured by Marktec Co., Ltd.) was added while stirring using a propeller type electric mixer. After 15 minutes, stirring was stopped and the wet magnetic particle flaw detection test was performed. 830 ml of a concentrated magnetic powder dispersion for use was obtained.

The obtained concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a static state, and then visually observed. It was confirmed that no problem occurred.

Further, 25 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder, and poured into a test liquid tank containing 10 l of water while stirring using a spatula, and the water surface was instantaneously dispersed. As a result, a uniform test solution was prepared.

The test solution prepared here contains about 300 ppm of the nonionic surfactant and about 0.75 g of the magnetic powder is dispersed per liter of water.

Embodiment 2 First, 100 g of a nonionic surfactant alkylethylene nonylphenyl ether having a HLB value of 10.6 (Nonipol 60: trade name: manufactured by Sanyo Chemical Industry Co., Ltd.) and a silicon defoaming agent were placed in a stainless steel tank. (Silicone defoamer KM-71: trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) 50 g of tap water and 550 ml of tap water were charged, and heated to a liquid temperature of about 50 ° C., using a colloid mill.
After stirring for 0 minutes, the heating was stopped and the mixture was cooled to room temperature (about 19 ° C.). Then, after adding 50 g of ethanol, magnetic powder (Super Magna fluorescent magnetic powder LY-10: commercial product) was stirred using a propeller type electric mixer. (Name: Marktec Co., Ltd.) 250 g was added, and after 15 minutes, stirring was stopped to obtain 825 ml of a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test.

The resulting concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a standing state, and then visually observed. It was confirmed that no problem occurred.

Further, 40 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed by a measuring cylinder and poured into a test liquid tank containing 10 l of water while stirring using a spatula, and the water surface was instantaneously dispersed. As a result, a uniform test solution was prepared.

The test liquid prepared here contains about 480 ppm of the nonionic surfactant and about 1.2 g of the magnetic powder dispersed per liter of water.

Embodiment 3 First, 80 g of a nonionic surfactant alkylethylene nonylphenyl ether having a HLB value of 10.6 (Nonipol 60: trade name: manufactured by Sanyo Chemical Industry Co., Ltd.) and a silicon defoaming agent were placed in a stainless steel tank. (Silicone antifoaming agent KM-71: trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) 30 g, rust inhibitor (sodium nitrite) 50 g and tap water 540 ml were charged, and heated to a liquid temperature of about 50 ° C. After stirring for 10 minutes using a colloid mill, the heating was stopped and the temperature was cooled to room temperature (about 19 ° C.). Then, 50 g of ethanol was added, and magnetic powder (Super Magna fluorescent light) was stirred with a propeller type electric mixer. Magnetic powder LY-1
(0: product name: Marktec Co., Ltd.) 250 g was added. After 15 minutes, stirring was stopped to obtain 820 ml of a concentrated magnetic powder dispersion for wet magnetic particle flaw detection test.

The resulting concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand still for 90 days, and then visually observed. It was confirmed that no problem occurred.

Further, 40 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder and poured into a test liquid tank containing 10 l of water while stirring using a spatula, and the water surface was instantaneously dispersed. As a result, a uniform test solution was prepared.

The test liquid prepared here contains about 380 ppm of the nonionic surfactant and about 1.2 g of the magnetic powder dispersed per liter of water.

Each of the test solutions prepared in the first to third embodiments and the supermagna fluorescent magnetic powder LY-10: trade name: Marktec Co., Ltd .: 12 g, supermagna magnetic powder dispersant BC-600: trade name: Marktec Co., Ltd .: A flaw detection test was carried out as follows using a test solution (hereinafter referred to as "comparative test solution") prepared by a conventional method using 100 g and 10 l of water.

(Testing ability for flaw detection) An A-type standard test piece according to the JIS standard was attached to a steel square billet to obtain an inspection object, and the test solution was applied to the surface of the test piece in a state where the square billet was magnetized by an axial current method. The test piece is scattered and irradiated with an ultraviolet lamp (black light) in a dark place, and a defect indicating pattern on the surface of the test piece is visually observed.

The above test was carried out with each test solution (including a comparative test solution)
As a result, the same clear defect indicating pattern was confirmed in any of the test solutions.

[0055]

Each of the concentrated magnetic powder dispersions according to the present invention obtained in the first to third embodiments has the effect of preventing magnetic particles from settling even though they are left standing for 90 days. It shows a remarkable behavior that it does not occur and disperses extremely easily in the preparation of the test solution, but the present inventors presume that this behavior is caused by the presence of alcohol.

That is, in the case of a Newtonian fluid such as water, the shear stress changes in proportion to the shear speed, so that the viscosity has a constant value, but an aqueous solution in which a surfactant is dissolved, emulsified or dispersed in water. Shows weak pseudoplastic flow, and in the case of pseudoplastic flow, the viscosity decreases as shear stress increases.

When alcohol is added to the aqueous solution exhibiting weak pseudoplastic flow, the pseudoplastic flow becomes stronger as the amount of addition increases.

According to an experiment conducted by the present inventors, HL was added to water.
When an aqueous solution obtained by emulsifying or dispersing an alkyl ether type nonionic surfactant having a B value of 10 to 12 is visually observed under white light, the aqueous solution shows a white color. A phenomenon of changing from white to translucent is recognized, and it is considered from this phenomenon that the colloidal particles of the surfactant emulsified or dispersed by the addition of alcohol become small and the fluidity of the aqueous solution changes. . Since the alkyl ether type nonionic surfactant having an HLB value of 10 to 12 is dissolved in alcohol, the colloid particles of the emulsified or dispersed surfactant are dissolved when the amount of the alcohol exceeds 30% by weight. As a result, the viscosity rapidly decreases.

Therefore, when the magnetic powder is dispersed in an aqueous solution in which an alkyl ether type nonionic surfactant having an HLB value of 10 to 12 is emulsified or dispersed in water and an appropriate amount of alcohol is added, a state in which the shearing speed is small (static) State) shows a high viscosity (apparent viscosity) to prevent sedimentation and sedimentation of the magnetic powder, and in a state with a high shear rate (agitated state), shows a low viscosity to facilitate dispersion of the magnetic powder. It can be estimated that

[0060]

EXAMPLES Examples and comparative examples will be described below.

Example 1 200 g of a nonionic surfactant alkylethylene nonylphenyl ether having a HLB value of 10.6 (Nonipol 60: trade name: manufactured by Sanyo Chemical Industries, Ltd.) and a silicon defoamer (silicon defoamer) were placed in a stainless steel tank. Foaming agent KM-71: Trade name: Shin-Etsu Chemical Co., Ltd.)
100 g and 450 ml of tap water were added, and the mixture was stirred at a liquid temperature of about 50 ° C. for 10 minutes using a colloid mill. Then, heating was stopped and the mixture was cooled to room temperature (about 19 ° C.). After adding 50 g of ethanol, magnetic powder (Super Magna fluorescent magnetic powder LY-10: trade name: manufactured by Mark Tech Co., Ltd.) 20 is stirred while using a propeller type electric mixer.
0 g was added, and after 15 minutes, stirring was stopped to obtain 850 ml of a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test.

The obtained concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a standing state, and then visually observed. It was confirmed that no problem occurred.

Further, 25 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder and poured into a test solution tank containing 10 l of water while stirring the water surface using a spatula, and it took about 50 seconds. Later, it was dispersed and a uniform test solution was prepared.

The test liquid prepared here contains about 590 ppm of the nonionic surfactant and about 0.6 g of the magnetic powder is dispersed per liter of water.

Comparative Example 1 A comparative magnetic powder dispersion 825 ml was obtained in the same manner as in Embodiment 2 except that the amount of tap water was 600 ml and ethanol was not added.

The obtained concentrated magnetic powder dispersion for comparison was placed in a transparent glass tank, allowed to stand still, and visually observed. After standing for 29 days, the supernatant without magnetic powder was present at the top of the tank. And precipitation of magnetic powder was observed at the bottom. Further, in this state, the tank was shaken well to start the precipitated magnetic powder, but it could not be completely started.

Comparative Example 2: A nonionic surfactant having an HLB value of 10.6, alkylethylene nonylphenyl ether (Nonipol 60: trade name: manufactured by Sanyo Chemical Industries Co., Ltd.), 50 g, and a silicon defoamer (silicon defoamer) Agent KM-7
1: 30 g of product name: Shin-Etsu Chemical Co., Ltd.)
Except that the amount of tap water was changed to 620 ml, the comparative thick magnetic powder dispersion 8
25 ml were obtained.

The obtained comparative magnetic powder dispersion was placed in a transparent glass tank, allowed to stand still, and visually observed. After standing for 30 days, the supernatant without magnetic powder was present at the top of the tank. The precipitate was observed at the bottom of the magnetic powder, and when the tank was shaken well in this state, the precipitated magnetic powder could be started up.

Example 2: 100 g of a nonionic surfactant alkylethylene octyl phenyl ether having an HLB value of 11.3 in a stainless steel tank (Octapole 60: trade name: manufactured by Sanyo Chemical Industries, Ltd.) and a silicon defoamer (silicon 50 g of defoamer KM-71 (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) and 450 ml of tap water are charged, and the liquid temperature is about 50 ° C.
After stirring with a colloid mill for 10 minutes while heating, the heating was stopped and cooled to room temperature (about 19 ° C.).
Next, after adding 150 g of ethanol, magnetic powder (Super Magna fluorescent magnetic powder LY-10: trade name: manufactured by Mark Tech Co., Ltd.) while stirring using a propeller type electric mixer.
After 15 minutes, stirring was stopped to obtain 845 ml of a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test.

The resulting concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a standing state, and then visually observed. As a result, the presence of a supernatant and a precipitate was not observed, and the sedimentation / precipitation of the magnetic powder was not observed. It was confirmed that no problem occurred.

Further, 40 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder and poured into a test liquid tank containing 10 l of water while stirring the water surface using a spatula. As a result, a uniform test solution was prepared.

The test liquid prepared here contains about 470 ppm of the nonionic surfactant and about 1.2 g of the magnetic powder is dispersed per liter of water.

Example 3: 100 g of a nonionic surfactant alkylethylene octyl phenyl ether having an HLB value of 11.3 in a stainless steel tank (Octapol 60: trade name: manufactured by Sanyo Chemical Industries, Ltd.) and a silicon defoamer (silicon 50 g of defoamer KM-71 (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) and 300 ml of tap water are charged, and the liquid temperature is about 50 ° C.
After stirring with a colloid mill for 10 minutes while heating, the heating was stopped and cooled to room temperature (about 19 ° C.).
Next, after adding 50 g of ethanol, magnetic powder (Super Magna fluorescent magnetic powder LY-10: trade name: manufactured by Marktec Co., Ltd.) 5 was stirred with a propeller-type electric mixer.
After 15 minutes, stirring was stopped to obtain 720 ml of a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test.

The resulting concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a standing state, and then visually observed. It was confirmed that no problem occurred.

Further, 25 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder and poured into a test liquid tank containing 10 l of water while stirring using a spatula, and the water surface was stirred for about 60 seconds. Later, it was dispersed and a uniform test solution was prepared.

The test solution prepared here contains about 340 ppm of the nonionic surfactant and about 1.7 g of the magnetic powder dispersed per liter of water.

Example 4: 100 g of a nonionic surfactant alkylethylene octyl phenyl ether having an HLB value of 11.3 in a stainless steel tank (Octapol 60: trade name: manufactured by Sanyo Chemical Industries, Ltd.) and a silicon defoamer (silicon Defoamer KM-71: 50 g of trade name: manufactured by Shin-Etsu Chemical Co., Ltd., 50 g of rust inhibitor (sodium nitrite) and tap water 5
30 ml and then, while being heated to a liquid temperature of about 50 ° C.,
After stirring for 10 minutes using a colloid mill, heating was stopped and the temperature was cooled to room temperature (about 19 ° C.). Then, 20 g of propyl alcohol was added, and magnetic powder (Super Magna) was stirred using a propeller type electric mixer. Fluorescent magnetic powder LY-1
(0: trade name: Marktec Co., Ltd.) 250 g was added. After 15 minutes, stirring was stopped to obtain 820 ml of a concentrated magnetic powder dispersion for wet magnetic particle flaw detection test.

The resulting concentrated magnetic powder dispersion was placed in a transparent glass tank, allowed to stand for 90 days in a standing state, and then visually observed. It was confirmed that no problem occurred.

Further, 25 ml of the concentrated magnetic powder dispersion left after standing for 90 days was weighed with a measuring cylinder and poured into a test liquid tank containing 10 l of water while stirring the water surface using a spatula. As a result, a uniform test solution was prepared.

The test liquid prepared here contains about 300 ppm of the nonionic surfactant and about 0.76 g of the magnetic powder is dispersed per liter of water.

The same test as described above (the flaw detection test) was carried out using each test solution prepared in Examples 1, 2, 3 and 4 and a comparative test solution. In the case of (Comparative test liquid), the same clear defect indicating pattern could be confirmed.

[0082]

According to the present invention as described above, as set forth in the embodiments and examples of the present invention, no sedimentation or sedimentation of magnetic powder occurs even after a long period of standing, and In the preparation, a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test in which the magnetic powder is easily dispersed can be provided.

When preparing a test solution using the concentrated magnetic powder dispersion according to the present invention, a required amount of the concentrated magnetic powder dispersion is measured using a measuring cup or a measuring cylinder,
A required test solution can be prepared only by adding the necessary amount of water prepared in advance under stirring and diluting it.

Therefore, the present invention requires a method for preparing a test solution that requires as little time and effort as possible in order to speed up the production line, and can greatly contribute to steel manufacturers and automobile manufacturers in Japan. Therefore, its industrial applicability is very large.

Claims (3)

[Claims] 1. A magnetic powder for a wet magnetic particle flaw detection test, 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12, 8 to 20% by weight, and an alcohol, 2 to 15% by weight.
And a concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test, comprising: 2. A magnetic powder for a wet magnetic particle flaw detection test, 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12; 8 to 20% by weight; an alcohol, 2 to 15% by weight; A concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test, comprising 10% by weight and the remainder of water. 3. A magnetic powder for a wet magnetic particle flaw detection test, 20 to 50% by weight, an alkyl ether type nonionic surfactant having an HLB value of 10 to 12, 8 to 20% by weight, an alcohol, 2 to 15% by weight, a silicone defoaming agent, 10% by weight, water-soluble rust inhibitor 2
A concentrated magnetic powder dispersion for a wet magnetic particle flaw detection test, comprising 5% by weight and the remainder of water.