SU1216261A1 - Solution for electrochemical polishing of carbon steel - Google Patents

Description

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The invention relates to the electrochemical treatment of metals, in particular to the polishing of carbon steels, and may find application in mechanical engineering,

The aim of the invention is to increase the surface cleanliness class.

A positive effect is achieved by introducing polishing based on phosphoric and sulfuric acids and formamide into the electrolyte.

Polishing is carried out at an anode current density of 70-100 A / dm, electrolyte temperature 60-80 ° for 5-7 minutes.

The solution for electrochemical polishing is prepared as follows.

The required amount of phosphoric and sulfuric acids is added to the water in small portions with stirring, after which the formamide is added. Density of solutions of 1.69 g / cm

Electrolyte stability is 390-410 Ah / l.

The introduction of formamide in concentrations below the minimum limit value and above the maximum limit value leads to a deterioration in the quality of the polishing.

Phosphoric acid

Sulfuric acid

Chromic anhydride

Formamide Water

Roughness,

RO J microns:

Before polishing

After polishing

Cleanliness class, 7:

62612

Introduction to the electrolyte less than Oj 2% formamide does not increase the polishing ability of the solution and can lead to etching of individual, surface areas.

The introduction of more than 0.9% formamide into the electrolyte is impractical, since a subsequent increase in its content does not lead to a further improvement in the quality of the polished surface.

The introduction of formamide into the electrolyte solution improves the quality of polishing by adsorbing it on the anode surface, leading to the formation of a passivation layer that suppresses the etching of the metal.

Table 1 presents the results of Q testing samples of steel 08 KP.

The choice of the optimal polishing mode for the optimal electrolyte composition is illustrated by the data in Table. 2,

S As can be seen from the data of Tables 1 and 2, the electrolyte provides a high polishing ability compared to the known polishing electrolyte (reducing the surface roughness Q to 0.11-0.12 μm) and increasing the class of surface cleanliness to v lOoriVlO b.

Table 1

53.3 53.2 52.6 52.0 50.7 46.5 46.6 46.0 46.6 44.3

0.2 0.6 0.3 0.8

0.9 1.5

1.3 3.7

1.22 1.21 0.12 0.125

1.2 1.28 0.11 0.24

Compiled kg.Pozdeeva Editor S.Patrusheva Tehred T.Tulik Proofreader M.Demchik

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VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

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Branch ShSh Patent, Uzhgorod, ul, Project, 4

Table i

Claims (1)

SOLUTION FOR ELECTROCHEMICAL POLISHING OF CARBON STEEL containing phosphoric and sulfuric acids and water, characterized in that, in order to increase the class of surface cleanliness, it additionally contains formamide in the following ratio of components, wt.%: Phosphoric acid Sulfuric acid Formamide Water 52.0-53.2 45.6-46.3 0.2-0.9 0.3-1.5> ί