SU1227713A1 - Solution for pickling electrical steels - Google Patents

Description

one

. This invention relates to the chemical treatment of parts from electrical alloys of the type 1512 (342), 1521 (344) when exposed to ultrasound after machining.

These steels are used in mechanical engineering and instrument making in the manufacture of magnetic circuits of electrical machines that provide high magnetoelectric parameters.

The purpose of the invention is to increase the dimensional accuracy and surface finish.

Example. To prepare the solution, nitric acid is added to the required amount of water, triethanolamine, sodium nitrite, isoamyl alcohol and hydrogen peroxide are added.

To obtain the composition, 5 mixtures were prepared, the composition of which is presented in Table. one.

Parts from electrotechnical alloys 1512 (342), 1521 (344), 49KF-VI, 79NM were tested.

Samples were the parts of the magnetic cores with a burr size of 110-120 µm, the surface cleanliness was 1.25.

Chemical etching was carried out in industrial ultrasonic baths of the type UZV-18m. The operating frequency of ultrasonic vibrations kHz-22; temperature of the composition is 18-20 C5 etching time 6 min.

Nitric acid4

Hydrogen peroxide (30%) 5

Triethanolamine 0.7

Sodium0,4

I Isoamyl. Alcohol1,3 Water

Ost, zl- Ostal-Ostal-Ostal-Ostnoe Nounnoe

277132.

For the tests, known compositions based on an aqueous solution of hydrogen peroxide and citric acid and a composition based on an aqueous 5 solution of hydrogen peroxide, nitric acid and alkali metal fluoride were prepared, as well as the proposed solution containing hydrogen peroxide, nitric acid, triethanolamine, sodium nitrite, 10 sodium, isoamyl alcohol and water.

The results of etching in the proposed solution are given in table. 2.

An analysis of the results obtained appears optimal. The etching process is stable, the burrs are removed completely, and the surface cleanliness is not impaired.

The results of comparative tests of etching in the known and proposed solutions are given in table. 3

Using the proposed composition effectively removes the burrs not only from the outer surfaces of the magnetic core sheets, but also opens the magnetic core sheets assembled in a package by removing the metal layer between the sheets formed during the mechanical grinding process. A small amount of removal and high precision of processing ensure the dimensions of parts according to I, II cl. accuracy.

In addition, the etching process proceeds stably, which allows the solution to be used many times, thereby reducing the consumption of chemical reagents.

Table 1

Citric acid 4.0 22 0.030 20 60 0.025 20 65

Hydrogen peroxide 2.0 (30%)

Water Else Nitric acid 6.0 22

Fluoride salt of alkali metals (NaF) 0,7

Hydrogen peroxide (30%) 10:

0.150 40 0.00 0.160 40 0.00

Water

Rest

Table 2

Table3

Nitric acid 5.0 22 0.040 1.25 0.00, 0.045 1.25 0.00

Hydrogen peroxide (30%) 6.0

Triethanolamine 0.8

Azotisysis sodium 0.5

Yzoamyl alcohol 1.5 Water Else

Continuation of table 3

Claims (2)

ELECTROTECHNICAL STEEL ETCHING SOLUTION when exposed to ultrasonic vibrations, containing nitric acid, hydrogen peroxide (30%) and water, characterized in that, in order to increase the accuracy of size and purity of treatment, it additionally contains triethanolamine, sodium nitrous acid and isoamyl alcohol in the following ratio of components, wt.%: Nitric acid 5-6 Hydrogen peroxide (30%) 6-7 Triethanolamine 0.8-1.0 Nitric acid sodium 0.5-0.7 Isoamyl alcohol 1.5-2.0 Water Rest Q 2.