SU806785A1 - Solution for pickling iron and carbon steels - Google Patents

Description

The invention relates to the chemical treatment of a metal surface, in particular to the etching of jellies and carbon steels. A known solution for the etching of iron and carbon steels, containing hydrochloric and nitric acid, thiourea B as an inhibitor, and aluminum sulphate 1. However, the treatment process with this solution is characterized by a low rate of removal of dense scale, and a large removal of 1 metal. The purpose of the invention is to prevent the dissolution of the base metal. The goal is to achieve that the solution as an inhibitor contains benzenesulfonic acid and urea-carbomethylenethriphenyl chloride in the following ratio of components, g / l: hydrochloric acid (19 g / cm) 180-250 nitric acid (34 g / cm) 60-180 Benzenesulfonic Urea-6-carbometry Lentriphenylphosphonium 0.5-2.0 Urea Chloride-Methylene Trifenyl Phosphonium Chloride is a phosphorus-containing product of the synthesis of the structure formula H Nq-NH-c -ca-j-pphjlci, where Ph is CgHg. Only the combined use of both additives prevents etching of the treated surface. The electrolyte is prepared as follows. The components are added to water in the following sequence: hydrochloric acid, benzenesulfonic acid, nitric acid; Urozinocarbomepentriphenylphosphonium chloride can be introduced into the electrolyte both before the addition of benzenesulfonic acid and nitric acid, and after the introduction of the first or acids. The electrolyte is prepared at room temperature. The proposed electrolyte allows high-quality cleaning of the surface from scale and rust in a short time (5-7 minutes), practically not a solution of the base metal. Thanks

This process of etching proceeds without the release of hydrogen or nitrogen oxides. And that eliminates hydrogenation of the metal and improves working conditions,

The electrolyte is stable. In one liter of the solution, it is possible to process 8 m of surface quality.

The solution must be replaced when the content in the solution is 60 g / l of iron.

The results of etching the surface of carbon steel, coated with scale, formed as a result of heat treatment at temperature with subsequent stamping, are presented in the table.

Hydrochloric acid (weight 1.19)

Nitric acid (unit weight 1.34)

Ureavivocarbomethylenetriphenyl chloride) 2

18Nowsay, Fo10 kis "ota

Salt on kitty; 1O. (unit weight 1.19)

Nitric acid (unit weight 1.34)

Mochvinokarbometilentriphenylphosphonium chloride

Ben zolsulfot acid

250 180

25

2

ten

25

35

40 0.5

2.0

The sample surface is covered with a thick layer of dross

188

0.2

The surface of the samples is covered with scale with signs of rust.

0.25

135

The surface of the samples is covered with a dense layer of scale

0.55

135

Claims (1)

After two hours of contact of the electrolyte with the surface of the metal, areas with scale remain on the surface, the dissolution rate of the base metal 10. 580 The claim of the solution for pickling iron and carbon steels containing salted and nitric acids and an inhibitor, characterized in that, in order to prevent dissolution of the base metal, it contains benzenesulfonic acid and urea-carbomethylenethenylphosphonium chloride as an inhibitor in the following ratio of components, g / l : Solic acid (19 g / cm) 180-250 7856 Nitric acid (34 g / cm) 60-180 Benzylsulfonic acid 8-10 Urea chloride rbomethylenetriphenylphosphonium0, 5-2.0 Sources of information taken into account during ex pertise 1. Anoschenko I.I. About dissolving. iron in a mixture of hydrochloric and nitric acids, - Works of the Third International Congress of Corrosion of Metals. M ,, Mir, 1968, t, 2, p. 203-208,