KR100544877B1 - Billet Hmm - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a billet flaw detection method. In particular, after coating a magnetic powder containing iron powder, a fluorescent pigment, titanium dioxide, and a water-soluble polymer on the surface of the billet, it is irradiated with lamps of both visible and infrared light sources simultaneously. The present invention relates to a billet flaw flaw detection method which can improve the quality of billet by improving the flaw detection performance.

Billet flaw detection, magnetic powder, visible light, ultraviolet ray, iron molecule, fluorescent pigment, titanium dioxide, water-soluble polymer

Description

Billet blemish method {METHOD OF SURFACE DEFECT DETECTION OF BILLET}

The present invention is a method of coating the surface of the billet, iron powder, fluorescent pigments, titanium dioxide, and a magnetic powder containing a water-soluble polymer, and then irradiating the lamp of the visible light and the external two light sources at the same time to detect the defect of the billet surface It is about.

In general, billet flaw flaw detection using dry magnetic powder forms magnetic field by flowing alternating current through billet which is a ferromagnetic material, and magnetic powder is attracted to the flaw by the leakage magnetic field formed near the flaw when the ferromagnetic material is flawed. to be.

Magnetic particle inspection utilizes the leakage magnetic flux generated from a flaw by saturating the ferromagnetic material.If there is no flaw in the billet, the magnetic flux flows to the inner surface of the billet almost without leaking even if the saturation magnetic field is applied. If any, the magnetic particles are evenly attached to the surface of the billet because they are almost uniform throughout. However, if there is a flaw on the surface of the billet, the magnetic flux is changed by the flaw, and the amount of magnetic flux increases inside the magnetic material around the flaw, and some of them are pushed out. The strength of the magnetic field formed by the magnetic flux pushed out is much greater than that of the flawless portion, so the magnetic particles gather and adhere to the flaw portion.

As such, the role of magnetic particles can be considered very important in magnetic particle detection. Usually, magnetic powder uses fine iron powder, which is a ferromagnetic material, as a core, and a polymer material for fixing a pigment, which exhibits color or fluorescence, to the magnetic powder has a form surrounding the core in combination.

Magnetic particle inspection can be classified into a method of identifying a defect under visible light and a method of determining a defect under ultraviolet light. Magnetic particles that detect flaws under ultraviolet rays are coated with a polymeric binder with a fluorescent substance that emits light when ultraviolet rays are irradiated on the surface of ferromagnetic particles such as iron and alloys. The pigment of the color contrasted with the color of is coated with a polymeric binder.

As a pigment that shows color, there is generally titanium dioxide (TiO ₂ ) having excellent whiteness. The reason why titanium dioxide is used is that white is preferable in order to visually identify magnetic particles attached to the flaw because the surface of the billet is a dark color close to black.

Titanium dioxide is currently the most commonly used white pigment, and various grades of products are commercially available depending on its purity. Whiteness also depends on purity. Therefore, the highest whiteness can be obtained by using high purity titanium dioxide, but in reality, high purity titanium dioxide of 99.99% or more is 10 times more expensive than general titanium dioxide of 99% or more, and its use is limited. For the above reason, when manufacturing white magnetic powder, high purity titanium dioxide and general grade titanium dioxide are mixed and used at a level capable of obtaining desired whiteness.

In the case of fluorescent pigments, many kinds can be purchased commercially, and when exposed to ultraviolet rays, they are colored according to the characteristics of the material.

As a prior art regarding magnetic powder, US Patent No. 5,350,558 discloses magnetic powder production and application methods such as the change of the type of ferromagnetic material used for the production of magnetic powder, the type of polymer used as the coating binder, and the optimum coating conditions. Japanese Patent Application Laid-open No. 9,368,792 discloses an optimum magnetization method in magnetic particle detection. In addition, U.S. Patent No. 4,433,289 discloses a method of preparing magnetic powder using only a water-soluble polymer such as gum arabic as a binder, but this can detect flaws only in a dark room and degrade the performance of the binder. There is this.

When only fluorescent pigments are used, a dark room is required, and the visible light lamp often blinks because the lamps of the visible light and the ultraviolet light source cannot be used at the same time, which causes a problem of severe eyestrain of the worker. In addition, the conventional technology for producing water-soluble fluorescent particles is not only limited to the field application test, but especially the human eye needs time to adapt when the brightness of the structure is severely changed. There is a problem that the fatigue is so severe that it interferes with the health of the worker.

Therefore, it is possible to use the lamps of both light sources at the same time, so that not only the flaw surface flaw can be easily inspected, but also the study of the flaw flaw flaw flaw flaw detection method can improve the work efficiency.

In order to solve the problems of the prior art, the present invention is to provide a billet flaw flaw detection method that can easily detect flaws of the billet by irradiating the lamps of both visible light and ultraviolet light to the magnetic powder coated on the surface of the billet at the same time.

In order to achieve the above object, the present invention relates to a billet flaw detection method, in particular, after coating the magnetic powder containing iron powder, fluorescent pigments, titanium dioxide, and water-soluble polymer on the surface of the billet, both visible light and ultraviolet light A billet flaw flaw detection method comprising irradiating a lamp of a light source at the same time.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention, while studying the method of improving the flaw detection rate and the working efficiency in the billet flaw detection method, billet the magnetic powder containing iron powder, fluorescent pigments, titanium dioxide, and water-soluble polymer After coating on the surface of, and irradiated with lamps of both visible and ultraviolet light sources at the same time, it was confirmed that the flaw of the surface of the billet can be easily inspected, and based on this, the present invention was completed.

In the present invention, the magnetic powder is characterized in that it comprises 50 to 72.72% by weight of iron powder, 1.8 to 20% by weight of fluorescent pigment, 10 to 20% by weight of titanium dioxide and 5 to 30% by weight of water-soluble polymer. .

The iron powder is preferably 30 μm or less, and all commercially available ones can be used, but in the present invention, iron powder of Hoshigen, which is generally available for purchase, was used. The iron powder is preferably contained in 50 to 72.72% by weight based on the total magnetic powder, when less than 50% by weight does not adhere well, when it exceeds 72.72% by weight of the pigment and polymer content is small There is a difficult problem in manufacturing.

The fluorescent pigments are all commercially available can be used, more preferably Basic red 001, dispersed yellow 082 solvent yellow 044 (Disperse yellow 082 solvent yellow 044), and green pigment 007 (Pigment green007) It is preferable that at least one selected from the group consisting of. Fluorescent pigments of the present invention are yellow and green systems. The fluorescent pigment is included in the amount of 1.8 to 16% by weight based on the whole magnetic powder, the inclusion of the fluorescent pigment content of less than 1.8 parts by weight does not significantly improve the flaw detection performance, if it contains more than 16% by weight There is a problem that the improvement effect of no longer increases.

As the titanium dioxide, titanium dioxide for pigments of general grade or fine titanium dioxide excellent in high purity whiteness is preferable. High purity titanium dioxide has a purity of 99.99% or more, and titanium dioxide having a purity of less than that may be a general grade titanium dioxide. In addition, it is possible to use a mixture of titanium dioxide for pigment and high purity titanium dioxide in a 50: 50 to 80: 20 weight ratio. Preferably, the magnetic powder contains 10 to 20 wt% of titanium dioxide, and most preferably 15 wt%.

The water-soluble polymer is preferably at least one selected from the group consisting of gum arabic, carboxy methyl cellulose, polyacrylic acid, polyvinyl alcohol and polyethylene glycol, and most preferably polyvinyl alcohol or polyethylene glycol. This is because polyvinyl alcohol and polyethylene glycol are colorless and transparent and it is easy to control physical properties such as viscosity according to the change of molecular weight. The water-soluble polymer is preferably included in the magnetic powder in 5 to 30% by weight, when the content is less than 5% by weight, the amount of the binder is insufficient to make the production difficult, and when it exceeds 30% by weight, the performance of sticking to the billet is reduced.

In addition, in the present invention, the magnetic powder may further comprise 0.001 to 5% by weight of a fluorescent brightener. Fluorescent brighteners preferably use conventional fluorescent brighteners.

The magnetic powder production method of the present invention comprises the steps of (a) mixing iron powder, fluorescent pigment, titanium dioxide, and water-soluble polymer in water, (b) drying the mixed liquid prepared in (a) in a rotary evaporator, and (c Pulverizing the dry matter, characterized in that it comprises the step of adjusting the particle size.

In addition, the method for preparing magnetic powder of the present invention comprises the steps of (a) mixing iron powder, fluorescent pigment, titanium dioxide, and a water-soluble polymer in water, (b) dissolving a fluorescent brightener in methanol, (c) the mixing the solution prepared in (a) and the solution prepared in (b), (d) drying the mixed solution prepared in (c) in a rotary evaporator, and (e) grinding the dried product It further comprises the step of adjusting.

In this invention, it is preferable that the said magnetic powder contains 60% or more of particles which are 40-100 micrometers, and contains 40% or less of particles of 100-200 micrometers.

The method for flaw detection of billet flaw of the present invention is to flaw the billet of the billet by irradiating the above-described magnetic powder-coated billet surface with a high-intensity ultraviolet lamp showing brightness of 4,000 to 6,000 uW at 600 mm position in visible light and filter.

In the present invention, the whiteness measuring device of Minolta Co., Ltd. was used to measure the whiteness related to the visibility of magnetic powder, and the HUNTER mode is easy to distinguish by showing the largest difference in value according to the change of whiteness among the modes of CIE, HUNTER, and ASTME313. Was used.

According to the present invention, by simultaneously applying the lamps of visible light and ultraviolet light to the magnetic powder coated on the billet, the defects on the surface of the billet can be easily inspected, and the flaw detection capability of the magnetic powder is significantly improved compared to the white magnetic powder, thereby providing a fine surface. The flaw can be inspected and the work efficiency can be improved by reducing the fatigue of the worker's eyes. In addition, the present invention by using a digital camera to acquire the image of the flaw detected flaw, by processing the image feed back to the image processing technology that cataloged the size and location information of the flaw to prevent the occurrence of the flaw and at the same time the billet quality You can also improve.

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are provided only to more easily understand the present invention, and the present invention is not limited to the following examples.

EXAMPLES 1-7. Magnetic powder manufacturing]

Example 1

In 1 L of water, 100 g of polyethylene glycol (molecular weight 5,000 to 10,000) was dissolved with a water-soluble polymer as a binder. 50 g of fluorescent pigment (FZ-2000 GREEN of SINLOIHI) and 150 g of titanium dioxide (low purity titanium dioxide: high purity titanium dioxide = 70:30) with white pigment and 800 g of iron powder were mixed in a polyethylene glycol solution. 1 solution was prepared. In addition, 3 g of Ubitex, a fluorescent brightener, was dissolved in 1 L of methanol, mixed with the first solution, and water and methanol were evaporated in a rotary evaporator to prepare magnetic powder. The dried magnetic powder was pulverized to a desired particle size, and sieved to adjust the particle size so that 40 to 100 µm of particles were 60% or more and 100 to 200 µm of particles were 40% or less.

Example 2

Except for using polyvinyl alcohol 100 g as a water-soluble polymer as a binder in Example 1 was carried out in the same manner as in Example 1.

Example 3

Except for using 100g of gum arabic as the binder water-soluble polymer in Example 1 was carried out in the same manner as in Example 1.

Example 4

The same procedure as in Example 1 was conducted except that 20 g of fluorescent pigment and 180 g of titanium dioxide were used in Example 1.

Example 5

Except for using 100g fluorescent pigment, 100g titanium dioxide in Example 1 was carried out in the same manner as in Example 1.

Example 6

Except for using 200g fluorescent pigment, 100g titanium dioxide in Example 1 was carried out in the same manner as in Example 1.

Example 7

Except for using a fluorescent pigment 200 g, titanium dioxide 200 g in Example 1 was carried out in the same manner as in Example 1.

Example 8. Billet flaw flaw detection

Using the magnetic powders prepared in Examples 1 to 7, the flaw surface was inspected under the condition that the ultraviolet lamp and the incandescent lamp were simultaneously illuminated. As a result, flaw detection performance was improved significantly compared to white powder, so that the amount of spraying magnetic powder could be reduced by about 20% compared to white powder, and it was possible to inspect without the need of dark room and flickering of incandescent lamps. I could make it.

According to the present invention, by simultaneously applying the lamps of visible light and ultraviolet light to the magnetic powder coated on the billet, the defects on the surface of the billet can be easily inspected, and the flaw detection capability of the magnetic powder is significantly improved compared to the white magnetic powder, thereby providing a fine surface. Can flaw. In addition, the present invention has an effect that can significantly improve the work efficiency by reducing the fatigue of the operator's eyes.

Claims (8)

In the method for flaw detection by coating magnetic powder on the surface of billet, 50 to 72.72 wt% iron powder, 1.8 to 20 wt% fluorescent pigment, 10 to 20 wt% titanium dioxide and 5 to 30 wt% water-soluble The billet flaw flaw detection method which irradiates the lamp | ramp of both visible light and an ultraviolet-ray at the same time to magnetic powder containing a polymer. delete The method of claim 1, The magnetic powder is billet flaw flaw detection method further comprises 0.001 to 5% by weight of a fluorescent brightener. The method of claim 1, Billet flaw characterized in that the fluorescent pigment is selected from the group consisting of Basic red 001, Disperse yellow 082 solvent yellow 044, and Green pigment 007 (Pigment green007) Scanning method. The method of claim 1, The water-soluble polymer is billet flaw flaw detection method, characterized in that at least one selected from the group consisting of gum arabic, carboxy methyl cellulose, polyacrylic acid, polyvinyl alcohol and polyethylene glycol. The method of claim 1, The titanium dioxide is a bile flaw flaw detection method, characterized in that the use of titanium dioxide for the pigment and titanium dioxide having a purity of 99.99% or more in a 50: 50 to 80: 20 weight ratio. The method of claim 1, And a high-brightness ultraviolet lamp having a brightness of 4,000 to 6,000 ㎼ at 600 mm from visible light and a filter. The method of claim 1, A billet flaw flaw detection method comprising 60% or more of particles having a magnetic powder of 40 to 100 µm and 40% or less of particles of 100 to 200 µm.