SU550415A1 - Aqueous solution for electrochemical polishing of metals - Google Patents

Description

one

The invention relates to the electrochemical machining of metals, in particular to the polishing of carbon, high carbon, low alloyed and stainless steels.

A number of aqueous solutions for the electrochemical polishing of chromium, chromium and chromium steels, ferrous and non-ferrous metals, containing a mixture of phosphoric and sulfuric acids and various inhibitors, are known.

The closest to the described invention in terms of the composition of the components is an aqueous solution for electrochemical polishing of metals containing orthophosphoric and sulfuric acids and hexamine. However, the known solutions do not give satisfactory results when polishing carbon, high carbon low alloyed and stainless steels. In addition, polishing in these solutions is either alternating or direct current.

The proposed aqueous solution is characterized in that, in order to increase the surface cleanliness class and the ability to conduct the process with variable and direct currents, it additionally contains toluidine at the following ratio of components, weight. %:

Orthophosphoric acid 27.4-80.8 Sulfuric acid0.8-46.0

Urotropin0,3-1,2

Toluidine 1.3-7.2

WaterEverything

Toluidine is introduced into the solution in the form of its isomers — o-toluidine, m-toluidine, and p-toluidine.

The optimal composition of the solution during polishing with direct current is as follows:

Orthophosphoric acid 27.4-78.6 Sulfuric acid1.0-46.0

Urotropin0,3-1,2

Toluidine 1.3-7.2

WaterEverything

Polishing mode: temperature 18-25 ° С, anode current density 10-100 A / dm

The optimal composition of the solution when polishing with alternating current is the following:

Orthophosphoric acid 68,8-80,8 Sulfuric acid 0,8-19,6

Urotropin0,3-1,2

Toluidna1.3-7.2

WaterEverything

Polishing mode: temperature 18-25 ° C, current frequency 50 Hz, anodic current density 10-50 A / dm2.

The duration of polishing in both cases ranges from a few seconds to 20-30 minutes, depending on the requirements for cleanliness and current density. The solution is prepared as follows. Acids are first poured into the bath, then toluidine and urotropin are added. The solution is heated to boiling (no solution should be taken to avoid significant loss of water). After cooling, the solution is ready for use. The color of the cooled solution is orange.

The adjustment of the solution is carried out according to the analysis of concentrated sulfuric and phosphoric acids. The required amount of hexamine and toluidine is calculated on the basis of the volume of the added acid mixture.

The solution is stable in operation by passing 400 Ah / L, while the known solution is at 200-250 Ah / L.

Examples of solutions and their properties are shown in the table.

Claims (1)

As can be seen from the table, only the joint introduction of two inhibitors into the solution (uropro 10 pina and toluidine) improves the purity class from V 8 to V 10. The proposed electrolyte allows you to polish various steels: 40X, 40HNMA, steel 15, steel 20, steel 45, art. 3, U-8, KP-08, 15 1Х18Н9Т, 1Х18Н10Т, etc., both by constant and alternating current. Claims of the Invention Aqueous solution for electrochemical polishing of metals containing orthophosphoric and sulfuric acids and methenamine, characterized in that, in order to increase the surface cleanliness class and the possibility of conducting the process with alternating and direct currents, it additionally contains toluidine in the following ratio , %: weight. Orthophosphoric acid 27.4-80.8 Sulfuric acid0.8-46.0 Urotropin0,3-1,2 Toluidin1,3- 7,2VodaEstal