SU1652378A1 - Solution for cleaning surfaces of steel pipes - Google Patents

Abstract

The invention relates to the field of chemical treatment of a metal surface, in particular, solutions for cleaning the surface of steel pipes using ultrasound. The aim of the invention is to increase the cleaning efficiency. Cleaning solution contains, wt%: sulfuric acid 5-8; sodium chloride 5-15; thiourea 0.2-0.35; kerosene 0.5-2.0; pentanol-1 0.5-1.5; lauryl trimethylammonium chloride 0.1-0.3; monolaurate sorbitol 0.2-0.7 and water - the rest, the ratio of pentanol - 1, lauryl trimethylammonium chloride and sorbitol monolaurate is 65: 12; 23 wt.%. An increase in the cleaning efficiency is achieved due to the additional introduction of kerosene into the solution, as well as through the use of surface active agents, pentanol-1, as additives. lauryl trimethylammonium chloride and monolite urate sorbitol. 3 tab. yo

Description

The invention relates to the cleaning of metal surfaces, in particular to the simultaneous degreasing and etching of products from ferrous metals, mainly pipes, in solutions of mineral acids under the action of ultrasonic vibrations (UT), and can be used in ferrous metallurgy, machine building and instrument making in the aviation, automotive and shipbuilding industries in the manufacture of precision hydraulic and pneumatic systems of engines.

The purpose of the invention is to increase the cleaning efficiency.

The solution for cleaning the surface of steel pipes using ultrasound contains. wt.%:

Sulfuric acid5-8

Sodium Chloride5-15

Thiourea0.20-0.35

Kerosene 0.5-2.0

Pentanol 1,0,5-1,5

Lauritrimethylammonium chloride 0.1-0.3

Sorbitol monolaurate 0.20-0.70

WaterEverything

moreover, the ratio of pentanol - 1, lauryl trimethylammonium chloride and sorbitan monolaurate is equal to 65:12:23 wt.%.

PRI me R 1. Samples of steel pipes (f 10 mm, 1 60 mm) are loaded into the working bath, the bottom of which is the PMS-6-22 magnetostrictive transducer, or into the internal cavity CMS-8. The bath is filled with the active solution, the temperature of the solution is maintained within 40-60 ° C with the help of a thermometer controlling the moment of switching on and off

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the switch Samples are fixed in a special device in a strictly defined position. The switching on of the generator UZG-2-4M (18-20 kHz), supplying the magnetostrictor, is carried out periodically, the switch-on time is monitored by a digital watch-type stopwatch. The treatment is carried out until the soils are completely removed from the outer and inner surfaces of the samples, after which the samples are washed and dried, the cleaning quality control is visual inspection under a microscope MBS-9, and the surface is rubbed with a white cloth. The repetition of the experiment is threefold with averaging,

The compositions of the tested solutions are given in table.1.

The results of comparative tests of the known and proposed solutions are presented in table 2.

A visual inspection of the samples shows that the samples treated in the known solution are heavily etched, there are erosive oleds of destruction, the samples treated in the proposed solution do not contain soil residues and have a smooth shiny surface.

The composition of the active solution, the content of ingredients, the temperature regime of ultrasonic treatment of steel pipes are due to the need to ensure quick and high-quality removal of contaminants from external and especially internal surfaces of pipes of small diameters (less than 60 mm).

The presence in the composition of contaminants of different chemical nature of scale (inorganic compounds) and various fatty contaminants (organic compounds) requires the presence of an acid solution and an organic solvent in the composition, and the treatment in the acoustic field can significantly reduce the acid concentration (as shown by practice of ultrasonic etching, up to 5-8%). When using more dilute solutions, the rate of chemical interaction of the acid solution with the metal surface is significantly slowed. Although this solution is workable, its further use without acid correction is usually not practical. An increase in the acid concentration above 8% is undesirable, since not only the scale removal rate increases in the acoustic field by a factor of 2–3, but also the etching rate of the base metal, in connection with which pererav of the surface can occur.

Kerosene is a mixture of liquid hydrocarbons (C b-C 15), is an organic solvent of low polarity, and is effective for removing fatty contaminants. In addition, due to the low surface tension, it has a very high penetrating power.

Sodium chloride performs the function

0 pickling stimulator. Particularly vigorous stimulating effect of chlorine ions begins to affect when a concentration of 7-8% is reached. The upper limit of the salt concentration is 15%. with further

5, by increasing the NaCl concentration, the solubility of surfactants decreases, the surfactant is displaced from the aqueous phase to the organic phase due to the salting out effect, and therefore begins to fall

0 emulsifying ability of surfactants and their stabilizing properties deteriorate. In addition, the presence of sodium chloride in the solution increases the effectiveness of the inhibitor thiourea.

5Thiourea is an effective inhibitor

acid etching. When combined with surfactants, a 100% protective effect is achieved at a concentration of 0.15%, and the specific time is also reduced.

0 etching.

The need to use surfactants in an active solution, especially when combined with ultrasonic testing, is explained by their effectiveness in creating emulsifying and dispersing properties, as well as by influencing surface and interfacial tension. However, solutions containing surfactants are prone to strong foaming during their turbulization, which creates certain difficulties in the operation of ultrasonic plants with systems for circulating cleaning solution, which is especially significant when processing pipes of small diameters, in whose channels the exchange is difficult

5 waste solution at the surface being cleaned, the medium is depleted in cavitation nuclei. To reduce foaming while maintaining and even enhancing the emulsifying and dispersing effect in

0 Ultrasonic cleaning conditions use a mixture of surfactants: lauryl trimethylammonium chloride, sorbitol monolaurate and pentanol - 1 at a ratio of 63:12:23 wt.%.

The temperature of active solutions in ultrasonic cleaning processes has a complex effect on the physicochemical effect on the contamination.

As the temperature rises, the chemical activity and dissolving power increase, but the viscosity decreases,

surface tension dramatically increases the pressure of the vapor-gas mixture, which leads to a decrease in the erosive effect, i.e. the effect of using UT is reduced. However, when ultrasonic cleaning of parts that have holes, channels (for example, pipe channels) of the slit, a decrease in the surface voltage of the solution contributes to an increase in the quality of cleaning due to its better penetration into the channels. The range of temperatures (40-60 ° C) provides a combination of chemical and erosion activity, which contributes to an effective impact on pollution.

The type of contamination also affects the choice of working temperature: for chemically active and cavitation-free unstable contaminants, it is recommended to increase the temperature of the solution, for chemically inert and tacional resistant contaminants, choose a temperature that provides the maximum erosive effect on the contamination.

In tab. 3 shows the effect of the ultrasonic cleaning temperature on its effectiveness with the maximum composition of the solution components,

Thus, the use of the proposed solution for cleaning the surface of steel pipes using ultrasound reduces the removal time of the aggregates from the outer and outer surfaces of the pipes, improves the quality of the cleaned surface, and also uses biodegradable components as surfactants. x environmental protection.

Claims (1)

Formula of the Invention A solution for cleaning the surface of steel pipes, mainly by using ultrasound, containing sulfuric acid, sodium chloride, thiouresin, additives of surfactants, and leading, because it also contains kerosene to increase cleaning efficiency. , and as additives of surface-active substances - pentanol 1, lauryltrimethylammoniumchlorid-l monosorbite in the following ratio of components, mec.%: but 5-6 5-15 0.2-0.35 0.5-2.0 0.5-1.5 0.1-0.3 0.2-0.7 Else moreover, the ratio of pentanol-1 to lauoyltrimethyl ammonium chloride and sorbitan monolaurate is 65.12: 23 wt.%. Table 1 Continuation of table 1 Continued table. one Continued table. one table 2 Continued table. 2 Table 3