CS234794B1 - Developer for crack detection - Google Patents

Description

The invention relates to a developer for defectoscopy with improved properties and stability, the developer can be used to identify material defects with a colored or luminescent solution.

When manufacturing and repairing important parts and components, it is essential that the weld material be homogeneous. Material defects can cause destruction of the component itself, especially under load, and can cause other very high losses. Physical defects of the material can arise either directly in production or during the technical life of the part or during the renovation of the part. Defects are pores, bubbles, inclusions, but mostly micro and macro cracks that cause the most damage. There are many ways to detect material defects. Particular mention may be made of the use of X-rays in conjunction with halogen silver films, the use of ultrasound, the magnetic method, the indicating color of the luminescent and the indicating color solutions. When performing X-ray tests, it is essential to possess the necessary equipment. Said device is expensive and generally dedicated. It is used in special production and repairs. In normal practice, smaller repair shops are not used. The ultrasonic inspection is mainly of a mobile nature. A certain disadvantage is that smooth contact must be achieved. However, the equipment is difficult to secure and again poorly suited for smaller establishments. The luminescent indicator color control method is widespread in some specialized repair shops and in manufacturing. It affects defects resulting on the surface of the material. The advantage is a marked indication of material defects, the disadvantage is the need to use UV lamps and the need to shield the workplace from daylight. Magnetic field control is only extended in specialized repair shops. The disadvantage is the possibility to observe only surface defects lying just below the surface. When the indicator color is checked, the tests can be carried out without the need for the user's equipment, ie strictly in field conditions. The only prerequisites for detecting defects are the indicator color solution and developer, including adherence to the prescribed procedure. This method can detect surface defects and cracks, especially in smaller premises, repair shops or even production plants. The procedure consists in coarse cleaning of the material to which a colored solution is applied or sprayed. The solution penetrates into cracks or pores of the material. After wiping off the solution, a white developing layer is applied or sprayed on which, after about 0.5 to 2 minutes, cracks appear at the penetration of the color solution 234344 to the developer layer. When checking large pressure vessels, tubes, etc., the developer can be sprayed from one side and the colored solution from the other side of the test material. Thus, the advantages of said process using a color solution and developer are primarily in the simplicity of the test method.

In color indicator solutions, mainly fat-soluble dyes, which are sudan or resinol dyes, are used. This group of dyes mainly comprises monoazo dyes or disazo dyes dissolved in petroleum fractions of petroleum or in similar mixtures, for example with tetriahydronaphthalein. The solution can be filled into cartridges. The essence of the developer itself is the dispersion of silica in a low-boiling organic solvent. The silica used for this purpose has so far been produced by complex economically demanding processes, for example, from silica chloride by dispersion in high-performance vibration reactors. The particle size of these products is very small and can be considered almost colloidal. It is this relatively very small particle size which makes it difficult to prepare dispersions with a high solid phase concentration, since the dispersions at a concentration of SiO2 above about 1% are very dense to thixotropic and give very thin layers during coating or spraying. The injections must then be repeated, which prolongs the process and leads to excessive exhalations of organic solvents, most harmful, for example trichlorethylene. The high cost of silica produced from S1Cl4 further increases the cost of existing developing solutions, which limits their use.

A developer for defectoscopy has now been found and is the subject of the invention, characterized in that it contains 50 to 98% by weight of low boiling organic solvents, 2 to 55% by weight of SiO 2 -based pigment, 0.1 to 4% by weight of surfactant and 0.01 up to 2% by weight of the antioxidant component. Low boiling organic solvents can be light petroleum fractions to Ce, chlorofluorocarbons, chlorinated hydrocarbons, ketones to Cs, ethers to Ce or alcohols to C3 alone or in mixtures. The SiO 2 -based pigment can be silica produced by precipitation of water glass with hydrochloric acid, and further fumed silica from the production of crystalline silicon. As surfactants, abietic acid derivatives, rosin resins, mixed glycerin esters and resin acid adducts with dicarboxylic acid anhydride, mixed esters of pentaerythritol and rosin, phenol-formaldehyde resins modified with rosin, glycerine phthalic polyester modified with vegetable oil are used alone or in mixtures vegetable oils pentaeritritové polyesters modified vegetable oils, fatty acids or tall oil-modified alkyds, styrene-based rošt- _f peaty oils, vegetable oils, metal salts of higher fatty acids such as naphthenate, octoate or cobalt stearate, lead, barium »or alkali metals, higher fatty acids such as stearic, oleic, linoleic, linolenic, palmitic, polyoxyethylene lauryl ether and the like. The antioxidant components may be alone or in mixtures of alkylphenols, aralkyl- and arylphenols, aminophenols, polynuclear and polyvalent phenols, mononuclear phenols, bis and trisphenols with carbon bridge, bis and trisphenols with bridge containing heteroatoms, thiobisphenols and oxybisphenols, hydroxydiphenyls , phenol salts, phenol ethers, sulfur and selenium compounds such as mercaptans, mercaptobenzimidazole and its derivatives, mercaptoibenzthiazole, aliphatic amines, primary and secondary aromatic amines, tertiary amines, arylendiamines, amine condensation products, aromatic hydrazines, phosphines and phosphites, phosphates, phosphonates , phosphinates and thio analogues thereof, tin compounds, five- and six-membered heterocycles and the like.

The advantage of the developer for defectoscopy is, above all, an easy method of preparing highly concentrated dispersions and their good flowability allowing both coating and spraying without major problems. The antioxidant component provides sufficient dispersion stability for at least 1 year. Individual raw materials are relatively inexpensive and commonly available.

Example

A mixture of 500 ml of light petroleum fraction C6-Ce and 500 ml of 1,1,2-trichloro-1,1,2-trifluoroethane is prepared in which it is dispersed on a mixer of 130 grams of fumed silica simultaneously with 4 grams of linseed oil modified pentaerythritic polyester. and 0.8 g of 2,6-di-tert-butyl-4-methylphenol. After the dispersing, filtration through a glass cloth is carried out. The developer can be used directly or after filling into chlorofluorocarbon based propellant gas cylinders. The developer, after coating or spraying, gives homogeneous fast-drying white layers suitable for identifying both color and luminescent detection solutions.

The use of this developer is possible in workshops, factories or workshops without special equipment, to identify cracks, pores and other surface defects during welding or fatigue control and the like.

Claims (5)

A developer for flaw detection comprising 50 to 98% by weight of low-boiling organic solvents; 55% by weight of S1O2-based pigmeint, 0.1 to 4% by weight of surfactant component * and 0.01 to 2% by weight of antioxidant component. 2. The developer for flaw detection according to claim 1, wherein the low boiling organic solvents may be light petroleum fractions to Ce, chlorofluorocarbons, chlorinated hydrocarbons, ketones to C5, ethers to Ce or alcohols to C3, alone or in mixtures. 3. The developer for defectoscopy according to claim 1 or 2, characterized in that the S1O2-based pigment can be silica produced by precipitation of water glass with hydrochloric acid, further flux silica from crystalline silicon production, either self-contained or in mixtures. 4. A developer for defectoscopy according to claim 1, 2 and 3, wherein the ¹ surfactant component may be alone or in a mixture of abietic acid derivatives, rosin resins, mixed glycerin esters and dicarboxylic anhydride resin adducts, mixed pentaerythritol esters and rosin-modified acids, rosin-modified phenol-formaldehyde resins, plant oil-modified glycerine phthalic polyester, glycerine polyesters modified with vegetable oils or tall oil fatty acids, styrene-modified vegetable oil-based alkyds, vegetable oils, metal salts of higher fatty acids such as naphthenates, octoates or octoates lead, barium, or alkali metals, higher fatty acids such as stearic, oleic, linoleic, linolenic, palmitic, polyoxyethylene lauryl ether, and the like. 5. The developer for defectoscopy according to claims 1 to 4, characterized in that the antioxidant components can be alone or in mixtures of [alpha] -alkylphenols, aralkyl and arylphenols, aminophenols, polynuclear and polymorphic phenols, mononuclear phenols, bis- and trisphenols with carbon bridge, bridged bis- and trisphenols containing heteroatoms, thiobisphenols and oxybisphenols, hydroxydiphenyls, condensed ring phenols, phenol salts, phenol ethers, sulfur and selenium compounds such as mercaptans, mercaptobenzimidazole and its derivatives, mercaptobenzthiazole, aliphatic amines, aromatic and primary primary amines arylendiamines, amine condensation products, aromatic hydrazines, foisphines, phosphites, phosphates, phosphonates, phosphinates and their thio analogues, tin compounds and five-membered heterocycles.