SU670606A1 - Etching solution - Google Patents

Description

one

The invention relates to the production of pickling solutions, in particular, for pickling steel.

A known pickling solution containing 18–20% hydrochloric acid, which is used for descaling steel products at 60–65 ° C 1.

Etching of steel in such a solution at elevated temperatures is accompanied by abundant evolution of gaseous hydrogen chloride, which leads to loss of acid, environmental pollution by aggressive vapors, which causes equipment corrosion and is unacceptable due to safety measures.

The closest to the invention in composition is a solution containing hydrogen chloride, chlorine gas and water in an amount, g / l:

Hydrogen chloride 2.5-3.0

Ferric Chloride850-875

Water Else up to 1 l 2.

Etching with such a solution is carried out at elevated temperatures (40-45 ° C), while the etching rate is not high and gassing is not completely eliminated.

The aim of the invention is the selection of such a composition of the solution, which at ordinary temperature would have a high etching rate and no gas evolution.

The goal is achieved with a solution containing ferric chloride, hydrogen chloride, water and additionally ferric chloride with the following ratio of ingredients, g / l: ferric chloride 100-200 ferric chloride 100-200 Water chloride 50-100 genus The rest is up to 1 l

Water

The presence of iron chloride in the pickling solution in an amount of 100–200 g / l at a certain ratio of concentrations of ferric chloride and hydrogen chloride causes an increased electron conductivity of the solution and, consequently, a higher etching rate, which allows the process to proceed at a temperature of 20–25 ° C. At this temperature and the above content of hydrogen chloride, the pressure of its vapor above the solution is insignificant and gas evolution does not occur.

PRI and MER.

Claims (2)

The etching solution is tested on samples of carbon steel grades Art. Oh, Art. 3, Art. 20, Art. 30, Art. 60, Art. 70, Art. 80, on which dross was obtained by calcining at 900 ° C for 3 minutes and then keeping sodium nitrate in the melt at 450 ° C for 1-2 minutes. The solution is prepared by simply mixing the components, etching is carried out at a temperature between 20-25 ° C. The degree of descaling is determined (visually and electrochemically) and the time for its complete removal is fixed. Water gauging showed that gassing does not occur during etching. The compositions of the pickling solutions and the time of complete removal of scale from the samples of the most difficult to etch the steel grade O. are presented in the table. The data in the table indicate that the time for complete descaling at a temperature of 20-25 ° C, as compared with the known composition, is reduced by a factor of three in the absence of gas evolution. The use of the proposed pickling solution for the chemical treatment of carbon steels provides, at a temperature of 20-25 ° C, an increase in the rate of etching and thereby the productivity of continuous metal processing units and the absence of release of corrosive gases, which improves working conditions and reduces equipment corrosion. DETAILED DESCRIPTION OF THE INVENTION A solution for pickling steel products containing hydrogen chloride, ferric chloride and water, characterized in that, in order to reduce the temperature and increase the etching rate, as well as to improve working conditions, op additionly contains chloride fer of the following ingredients, g / l: Chloric jelly100-200 Chloride jelly100-200 zo Chloride water 50-100 genus Remaining up to 1 l Sources of information taken into account in the examination 1.Layner V.I. and Kudr A.T.T. “Basics of electroplating, M. , Metallurgizdat 1957, Part I. 2. USSR author's certificate number 329255, cl. From 23F 1/00, 1972.