JP3728307B2 - Contact medium for ultrasonic nondestructive inspection - Google Patents

Description

  The present invention relates to a contact medium for nondestructive inspection of various materials and structures, that is, ultrasonic flaw detection or thickness measurement. More specifically, the present invention relates to a rust-proof contact medium for ultrasonic flaw detection or thickness measurement having high thixotropic properties, good handleability, and excellent ultrasonic transmission.

  In ultrasonic flaw detection and ultrasonic thickness measurement methods, which are a type of nondestructive inspection, ultrasonic pulses are sent inward from the surface of the sample to be inspected, and reflected waves from the interface, scratches, lattice defects, etc. Instead of this, an electric signal is displayed on the cathode ray tube, so that it is possible to know the thickness of the sample, the presence or absence of defects in the sample, the presence or absence of a defect, the position, the size, and the like.

  Conventionally, measurement was performed with a contact medium such as oil, glycerin, or water in order to eliminate the air gap between the transmitting and receiving surfaces of the ultrasonic oscillator and the sample to be inspected, and to reduce the attenuation of the transmitted wave. I was doing. However, since oil, glycerin and water have low viscosity, a contact medium layer with sufficient thickness cannot be obtained when used in a flaw detection method such as an automatic flaw detection method. There are drawbacks such as sagging when performing surface flaw detection. In addition to stickiness and sagging, at high temperatures there is a disadvantage that gelation and solidification occur and work for a long time cannot be done, and even after wiping after use, rust occurs after several hours or days, There was a problem of degrading the sample to be inspected.

  As a contact medium that improves these drawbacks, a contact medium mainly composed of polyvinyl alcohol (PVA) and a contact medium composed of an aqueous solution containing carboxymethyl cellulose (CMC) are known. Recently, a contact medium made of an aqueous solution containing a carboxyvinyl polymer and a surfactant is known (for example, see Patent Document 1). However, even when this medium is left at a high temperature for a long time, there is a drawback that sagging occurs due to a decrease in viscosity or the like, causing deterioration. For example, if left in a sunny place under the hot summer sun or left in a car, the viscosity of the contact medium decreases and the thixotropic property is lost.

JP-A 61-105459

  The object of the present invention is to improve the above-mentioned drawbacks, thixotropic, so that no sagging occurs even when applied to a vertical surface or ceiling surface, no problems such as gelation or solidification occur even at high temperatures, and the sample to be inspected by rust It is an object of the present invention to provide a contact medium that is excellent in ultrasonic wave transmission without sagging due to a decrease in viscosity even when left at a high temperature for a long time.

As a result of intensive studies to solve the above problems, the present inventors have found that an aqueous solution containing a carboxyvinyl polymer, a nonionic surfactant, and an amine compound has excellent characteristics, and is for ultrasonic nondestructive inspection contact. The present invention was completed by finding that it can be used as a medium.

That is, the present invention relates to a contact medium for ultrasonic nondestructive inspection comprising an aqueous solution containing a carboxyvinyl polymer, a nonionic surfactant and an amine compound.

The present invention also relates to a contact medium for ultrasonic nondestructive inspection comprising a glycerin aqueous solution containing a carboxyvinyl polymer, a nonionic surfactant and an amine compound.

  A major feature of the contact medium of the present invention is that the viscosity does not decrease even when left for a long time at a high temperature. In other words, with a conventional contact medium that does not contain an amine compound, when it is left for a long time in hot weather such as summer, the viscosity decreases, the thixotropic property is lost, and when applied to a vertical surface or a ceiling surface, it flows and sagging occurs. According to the present invention, by containing an amine compound, a contact medium having thixotropic properties even when left at a high temperature for a long time and free from sagging in any part can be obtained.

  Next, another feature of the contact medium of the present invention is that even if there is an oil film, it is not repelled like water or glycerin, and the probe is slippery and the flaw detection work is easy.

  Another feature of the contact medium of the present invention is that it does not cause gelation or solidification even at high temperatures, and therefore does not cause any trouble in the flaw detection operation. In flaw detection work under hot weather, the object to be inspected such as a steel pipe immediately becomes a high temperature exceeding 70 ° C, and the conventional contact medium mainly composed of PVA and CMC is immediately gelled and solidified, so that its function is no longer possible. I couldn't do it. However, since the contact medium of the present invention does not gel or solidify even at such a high temperature and does not sag, the operation at a high temperature can be easily performed as at the normal temperature. Further, since it does not solidify even at a low temperature (for example, -20 ° C), it can be used in a very wide temperature range.

  Yet another feature of the present invention is that rust is not generated on the sample to be inspected after use. Therefore, post-treatment after use is very simple and only needs to be wiped off with a waste cloth.

  In addition, the contact medium of the present invention has good wettability to the surface of the object to be inspected, and as described above, the contact medium of the present invention is advantageously used for manual, semi-automatic and automatic ultrasonic flaw detection or thickness measurement. In addition, it performs an excellent function as a contact medium in any part or working environment, and does not leave any problems after use, and can have an excellent effect in nondestructive inspection. is there.

  The contact medium for rustproof nondestructive inspection of the present invention is obtained by mixing and stirring water, carboxyvinyl polymer, nonionic surfactant and amine compound.

  The blending amount of the carboxyvinyl polymer varies depending on the target viscosity, but is usually 0.1 to 25 parts, preferably 100 parts by weight of water (hereinafter, “parts by weight” is simply referred to as “parts”). Is 0.2 to 10 parts, particularly preferably 0.3 to 5 parts. If the amount of carboxyvinyl polymer is less than 0.1 part, the thickening effect is small, so the viscosity tends to be low and dripping tends to occur, and if it exceeds 25 parts, the thickening effect tends to be almost unchanged.

  As the carboxyvinyl polymer, those having a molecular weight of 1,000,000 to 3,000,000 are used, and may be used in the form of its ammonium salt. Specific examples include Carbopol (trade names) 934, 941, 940, 960, and 961 manufactured by BF Goodrich Chemical.

  The nonionic surfactant blended in the contact medium of the present invention serves to suppress the generation of rust. Moreover, viscosity and thixotropic properties are not lost. And it does not gel.

  The amount of the nonionic surfactant is usually 0.1 to 15 parts, preferably 0.3 to 10 parts, and particularly preferably 0.7 to 7 parts with respect to 100 parts of water. If the blending amount of the nonionic surfactant is less than 0.1 part, the antirust effect tends to be hardly obtained, and if it exceeds 15 parts, the antirust effect tends to hardly change.

  Preferred nonionic surfactants include, for example, ether type nonionic surfactants such as polyoxyalkylene alkyl ether, ether ester type nonionic surfactants such as polyoxyethylene glycerin fatty acid ester, and esters such as polyethylene glycol fatty acid ester. Type-containing nonionic surfactants, nitrogen-containing type nonionic surfactants such as cycloalkylamine ethylene oxide, and the like.

  The amine compound blended in the contact medium of the present invention improves the thickening by adding it to the carboxyvinyl polymer and has stable viscosity characteristics over a wide temperature range, so it can control deterioration such as a decrease in viscosity. There is an effect, and thixotropic property is not lost even if left at a high temperature for a long time.

  The compounding quantity of the said amine compound is 0.1-17 parts normally with respect to 100 parts of water, Preferably it is 0.2-12 parts, Most preferably, it is 0.5-6 parts.

  Preferred amine compounds include primary, secondary and tertiary amines such as mono-, di-, tri-isopropanolamine, mono-, di-, tri-ethanolamine, mono-, di-, tri-ethylamine, There is ammonia etc. and it is effective for deterioration.

  Although the contact medium of the present invention is based on water, glycerin may be further added when particularly good ultrasonic transmission is required.

  When blending glycerin, glycerin 20-1100 parts, preferably 68-1050 parts, carboxyvinyl polymer 0.1-25 parts, preferably 0.2-10 parts may be blended with 100 parts of water. If the blending amount of glycerin is less than 20 parts, good ultrasonic permeability tends to be not obtained, and if it exceeds 1100 parts, the ultrasonic permeability tends to hardly change.

  Further, if necessary, a preservative, a neutralizing agent and the like may be added as appropriate.

The contact medium of the present invention has thixotropic properties, and when applied to a vertical surface or a ceiling surface, the yield value at 20 ° C. is usually 98 dyn / cm ² or more, particularly 118 to 700 dyn / cm ² . the 80 yield value at ℃ is 98dyn / cm ² or more, and particularly preferably from 107~665dyn / cm ^2.

  The contact medium of the present invention is used by being applied to the surface of a sample to be inspected in nondestructive inspection such as ultrasonic flaw detection and thickness measurement. Samples to be inspected include, for example, architectural steel frames, bridges, shipbuilding, industrial tanks and piping, spherical tanks, railway bodies and rails, and the like.

  In applying the contact medium of the present invention to the surface of the sample to be inspected, it may be applied using a brush, a spatula or the like.

  Next, the contact medium of the present invention will be described with reference to examples and comparative examples.

Examples 1-5 and Comparative Examples 1-5
A contact medium having the composition shown in Table 1 was prepared. As carboxyvinyl polymer, carbopol 941, carbopol 940, carbopol 934 (manufactured by BF Goodrich Chemical) is used, and as nonionic surfactant, polyethylene glycol fatty acid ester, cyclohexane is used. Alkylamine ethylene oxide and polyoxyalkylene alkyl ether were used, and triisopropanolamine and triethanolamine were used as amine compounds.

  Comparative Examples 1-5 were prepared with compositions having no amine compound of Examples 1-5.

  Using the prepared contact medium, viscosity and yield values were measured and a sagging test was performed by the following method. Table 1 shows the measurement results of the viscosity and yield value, and Table 2 shows the results of the sagging test.

(Viscosity, yield value)
Using a conical plate rotational viscometer (E type viscometer, manufactured by Tokyo Keiki Co., Ltd.), the viscosity and yield value of the contact medium at 20 ° C. and 80 ° C. were measured. The temperature of the contact medium is adjusted by placing the contact medium in a glass bottle and keeping the temperature constant in a thermostatic bath. The viscosity and yield value at 80 ° C. are the temperatures after the contact medium reaches 80 ° C. Measurement was carried out after holding for 3 hours.

  As shown in Table 1, the contact medium of the present invention had a viscosity almost equal to that at 20 ° C. even at a high temperature of 80 ° C. The yield value is almost the same as that at 20 ° C. even at a high temperature of 80 ° C., and the thixotropy is not lost.

(Sag test)
After each contact medium was applied to a part of the steel plate so as to have a thickness of 1 mm, the steel plate was set up vertically, and the time required to drop 200 mm on the steel plate was measured. This test was carried out for two cases of steel plate temperatures of 20 ° C. and 80 ° C., respectively. Each contact medium was also set to 20 ° C. and 80 ° C., and in the case of 80 ° C., the test was performed after maintaining the state at 80 ° C. for 3 hours.

  Further, after each contact medium was applied to steel plates of 20 ° C. and 80 ° C. as described above, the state of the contact medium on the ceiling surface was examined by turning the steel plate upside down.

  As is apparent from Table 2, the contact medium of the present invention does not cause sagging regardless of where it is used.

  Next, contact media prepared in Examples 1-5 and Comparative Examples 1-5, glycerin as Comparative Example 6, 75% glycerin aqueous solution as Comparative Example 7, general oil (machine oil) as Comparative Example 8, comparison Using water as Example 9, 5% CMC aqueous solution as Comparative Example 10, and 40% glycerin aqueous solution as Comparative Example 11, the following sagging test, high-temperature treatment test, slip property test, and rust prevention test were carried out. The results are shown in Table 3.

(Sensitivity test)
Each contact medium was applied to a steel plate (100 mm × 200 mm) having a surface roughness of 0 to 10 μm, 30 μm, 60 μm, and 100 μm to a thickness of 13 mm so as to have a thickness of 0.3 mm. Sensitivity was measured (5 MHz in the vertical direction) using FD-610S manufactured by Co., Ltd.

  Evaluation is based on the sensitivity when the bottom echo height is 80% when using glycerin (Comparative Example 6), which is considered to have the highest ultrasonic transmission, as the reference (zero), and the same bottom echo height The sensitivity (-dB) required to obtain the thickness (80%) was examined.

(High temperature treatment test)
Each contact medium was kept at 80 ° C. for 30 minutes, and its gelation (solidification) state was examined.

(Slip test)
Each contact medium was applied to a thickness of 0.3 mm on the surface of a steel plate having a surface roughness of 20 μm, and the slipperiness of the probe was examined.

(Rust prevention test)
Each contact medium is applied to a flat steel plate with a surface roughness of 50 μm by shot blasting to a thickness of 0.5 mm, left in a thermostatic bath at a temperature of 40 ° C. and a humidity of 100% for 14 days, and the number of days until rusting is observed did.

  As is apparent from Table 3, the contact medium of the present invention has performance equivalent to that of a contact medium not containing an amine compound, is excellent in ultrasonic transmission and flaw detection workability, and has a rust prevention effect.

Claims (2)

A contact medium for ultrasonic nondestructive inspection comprising an aqueous solution containing a carboxyvinyl polymer, a nonionic surfactant and an amine compound. A contact medium for ultrasonic nondestructive inspection comprising a glycerin aqueous solution containing a carboxyvinyl polymer, a nonionic surfactant and an amine compound.