SU924186A1 - Solution for electrochemically polishing titanium and its alloys - Google Patents

Description

The invention relates to the electrochemical treatment of metals, in particular for polishing and BT1-0 Gitana type alloys, RT-4, VT-6, BT-16, and can be used in medical, engineering, aviation and dru- ⁵ GIH industries.

Known solution for electrochemical polishing of the guitar, containing sulfuric, hydrofluoric and nitric acid [1]. ^ten

However, the known solution is intended for polishing titanium foil (thickness 0.01-0.015 mm), having an initial roughness of 8 8, and cannot be used for polishing surfaces with a complex geometric configuration, for example, tracheotomic tubes.

In addition, currently marketed _m while rolling, as well as tubes, izgotov'lennye titanium alloy has an initial roughness V: 7, and therefore the known solution can not be used without

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pretreatment of the surface to increase its purity Ηονδ.

The closest to the proposed is a known solution for the electrochemical polishing of titanium and its alloys, containing sulfuric and hydrofluoric acid, hexamine and water £ 23.

However, the operation of this pickup is associated with significant energy consumption caused by the relatively high density of the applied current of 50-65 A / dm. Processing of titanium products in this solution also leads to significant metal removal.

In addition, the preparation and operation of a known solution is complicated by the presence of fuming hydrofluoric acid, which impairs sanitary and hygienic working conditions.

The purpose of the invention is the reduction of removal

metal while maintaining high quality polishing and energy savings.

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This chain is achieved by the fact that the solution containing sulfuric acid, a source of fluorine ions, hexamine and water, as a source of fluoride ions contains ammonium fluoride acid, in the following ratio, wt.%:

Sulphuric acid 82.5-87.5 Ammonium fluoride sour 9.0-9.5 Urotropin 0.3-0.5 Water Rest

The solution is prepared as follows.

Ammonium acid fluoride is dissolved in water, urotropine is added to the resulting solution, after it is completely dissolved, sulfuric acid is introduced in small portions with stirring. The polishing process is recommended to be carried out at 25–50 ° C, anodic dense current flow of 30–45 A / dm ^g for 5–10 min. 20

After polishing, the products are washed and dried.

When polishing in a solution such alloys as OT-4 and VT1-0, the removal of metal is 22.7-45.1 and 20-45.7 μm 25, respectively, at the frequency of polished

surfaces 0,18-0,36 and 0,21-0,32 microns

respectively.

Efficiency (stability)

the solution is 100 A h / l.

The table presents comparative data on the proposed and known compositions of the solution, modes and results of processing.

As can be seen from the table, the use of the invention allows to reduce the overall removal of the metal while maintaining high quality polishing (purity class, reflectivity) and use a lower current density, which leads to a significant reduction of energy consumption.

In addition, the replacement of volatile and fuming hydrofluoric acid with its salt greatly simplifies the process of preparation and operation of the solution.

The economic effect from the introduction of the proposed invention for polishing tracheotomy tubes for an annual productivity of 100,000 pcs per year is 50,000 r. in year.

The composition of the solution mode and the results of processing Famous solution The proposed solution one 2 * 3 Content, wt.%: Sulfuric acid 600–650 ml 82.5 85.7 87.5 Hydrofluoric acid 200-25 0 ml - - - Ammonium Fluoride Sour 9.5 9.3 9.0 Urotropin 8-12 g 0.5 0.4 0.3 Water Up to 1 l 7.5 4.6 3.2 Anode current density, A / dm 50-65 thirty 40 _ 45 Voltage, V 12-18 ten ten ten Solution temperature, ⁰ С 20-60 25 50 50 Duration, min 5-7 ten five five Anode material OT-4, OT-4, BT '1-0, W 1-0, W 1-0 W 1-0 OT-4 OT-4 Cathode material W 1-0 W 1-0 W 1-0 VT1-0 Cleanliness class, before polishing ^ν 7a-8a 7c 76 7c Cleanliness class after polishing ^ν 8a-10a 9c BB 96

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Table continuation The composition of the solution mode and the results of processing Famous solution The proposed solution one 2 3 Roughness, Ya, micron, before polishing 0.54-1.22 0.65 0.76-0.84 0.75 Roughness, um, after polishing, 0.16-0.48 0.18 0.34 0.24 General metal removal, mkm 49-72 30.9 . 27 36 Removal rate, micron / min 7-12 3.1 5.4 7.2 About griglable ability,% 55-62 59-62 63-65 61-63 Electricity consumption, KVH Θ75Ο 4500 6000 6750

Claims (1)

Claim A solution for electrochemical polishing of a guitar and its alloys, containing sulfuric acid, a source of fluoride, urotropin and water, about which, in order to reduce metal removal while maintaining high polishing quality and save electricity, as a source fluoride it contains ammonium fluoride acid, in the following ratio, wt.%: Sulfuric acid 82,5-87 ^ 5 Ammonium fluoride „ sour 9.0-9.5 Urotropin. 0.3-0.5 Water Rest