RU2353648C1 - Lubrication for cold metal deformation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to lubricant and grease lubricant, used for cold metal deformation, inclined to pickup on form tool, while treatment, for instance titanium ad its alloys. Lubrication for cold metal deformation, contains in wt %: nonionic emulsifiers 28 - 50, animal fats 48 - 70, water not more than 2.

EFFECT: improvement of surface condition of rolled pipes.

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Description

The invention relates to lubricating coatings and technological lubricants used in the cold deformation of metals, prone to sticking to the forming tool, when processing, for example, titanium and its alloys.

Known lubricant for cold rolling pipe composition, wt.%:

Sodium Nitrate 35-40 Talc ground 20-25 OP-10 45-35

(Alexandrov V.K., Anoshkin N.F., Belozerov A.P. et al. Semi-finished products from titanium alloys. - M.: VILS, 1996, p. 350).

A disadvantage of the known lubrication is the indentation of solid particles of talc and sodium nitrate into a deformable metal and, as a result, a low surface roughness is formed on the pipes.

The composition of the same purpose closest to the claimed invention for the totality of features is “Lubricant for cold rolling of pipes without preheating (TI-SGM-011-7-99-Rolling of pipes from titanium and its alloys at KhPT and KhTPR mills, cutting of titanium pipes) "- prototype.

Ground Talc, GOST 21234 2.0-3.0 - volume fractions Sodium nitrate, GOST 828 3.5-4.0 - volume fractions Wetting agent OP10, OP7 GOST8433 3.0-4.5 - volume fractions Water content allowed up to 5%

In a known lubricant, due to surface-active substances (surfactants), the components of the lubricant are held on the surface of the pipe. The use of talc in the lubricant reduces the friction stress and, accordingly, shear deformations in the surface layers of the deformable metal. Sodium nitrate in the zone of metal deformation decomposes at a temperature of 380 ° C with the release of atomic oxygen, which oxidizes the juvenile surfaces of titanium, which reduces the setting on the contact surface of the tool and the deformable metal and prevents metal from sticking to the tool. In addition, the endothermic decomposition of nitrate promotes additional heat removal from the deformation zone.

A disadvantage of the known lubrication is the indentation of solid particles of talc and sodium nitrate in a deformable metal, which is manifested in high roughness on the pipes and reduces their quality. A sufficiently high friction stress leads to microdestruction in the surface layers of high-strength titanium alloys, for example: OT4-0, OT4-1, OT4, PT7M, Ti3Al2.5V.

The technical result in the implementation of the invention is to improve the quality of the surface.

The specified technical result during the implementation of the invention is achieved by the fact that in the lubricant for cold deformation of metals, consisting of water, a nonionic emulsifier and fillers, animal fat is used as a filler in the following components, wt.%:

nonionic emulsifiers 28-50 animal fats 70-48 water no more than 2

Nonionic emulsifiers OP-10 (GOST 8433-57) - products of the processing of mono- and dialkylphenols with ethylene oxide, an oily liquid or paste, contain up to 0.5% water. Nonionic compounds do not dissociate in aqueous solutions, but have significant solubility. Among nonionic compounds, the products of long chain fatty acid hydroxyethylation are of greatest importance.

A content of non-ionic emulsifiers in the lubricant of less than 28% does not impair the lubricating properties, however, it leads to difficulty in removing grease after cold rolling, more than 50% leads to sticking of the emulsifier to the pipes, which also makes it difficult to remove grease after rolling.

Animal fats are mixtures of esters formed by glycerol and higher fatty acids. All fatty acids are surfactants. Getting on a metal surface, they wet it well, adjoin it with active groups, forming ordered boundary layers. Having a large length of molecules, such layers significantly reduce the friction forces.

With a decrease in the percentage of animal fat less than 48, the friction forces in the deformation zone increase, respectively, the tool warms up and its durability decreases, as well as metal sticking to the tool, at more than 70, the remaining amount of emulsifier does not provide lubricant removal after cold rolling, the lubrication continuity is violated .

An increase in the amount of water in the lubricant of more than 2% leads to boiling of water, discharge of the lubricant from the surface of the deformable metal and its setting with the tool.

Lubricants were tested during rolling of tube billets from Ti3Al2.5 alloy along the route: 85 × 17 mm → 65 × 11 mm → 50 × 7.5 mm → 35 × 3.9 mm on cold rolling mills KhPT 90 and KhPT 3 1/2 ''.

Known lubricant composition:

Ground Talc, GOST 21234 2.5 volume fractions Sodium nitrate, GOST 828 4 volume fractions Wetting agent OP10, OP7, GOST8433 4.5 volume fractions Water 5%

Suggested grease composition:

nonionic emulsifiers 38% animal fats 60% water 2%

The proposed grease in the form of a paste is applied with a spatula to the surface of the semi-finished products before cold rolling or brushing.

During the tests, surface quality was evaluated (measurement of surface roughness, Ra).

The technological scheme of pipe production.

1. The pressed billet was machined to a size of 85 × 17 mm.

2. Heat treatment applied an oxide layer to the inner and outer surfaces of the pipes.

3. Cold rolling at the KhPT mill 90 two batches (one of which rode on a known lubricant, and the other on the proposed one).

4. Etching in hydrochloric acid to conduct a visual assessment of the surface quality of the pipes.

5. Heat treatment for stress relieving, recrystallization and applying a lubricating oxide film at intermediate sizes.

6. Cold rolling at the HPT mill 3 ^1/2 _of two parties (one of which rode on a known lubricant, and the other on the proposed one).

7. Etching in hydrochloric acid to conduct a visual assessment of the quality of the surface of the pipes.

8. Vacuum heat treatment and etching in hydrochloric hydrofluoric acid at the finished size.

The test results are shown in the table. The data on the results of measuring the surface roughness of pipes rolled on a known and proposed lubricant show that at all stages the surface quality of pipes rolled on a proposed lubricant significantly increases in comparison with the surface quality of pipes rolled on a known lubricant.

The proposed lubricating coating significantly improves surface quality.

Table Technological operation pipe size mm The surface roughness Ra, microns Famous grease Suggested grease Original machined pipe 85 × 17 1.1-1.5 1.1-1.6 Pipe, heat treated, pickled 65 × 11 1.3-1.8 1.1-1.4 Pipe, heat treated, pickled 50 × 7.5 1.7-2.6 0.9-1.3 Pipe, heat treated, pickled at finished size 35 × 3.9 1.8-2.9 0.6-1.3

Claims (1)

Grease for cold deformation of metals, including water, a nonionic emulsifier and fillers, characterized in that animal fat is used as a filler in the following components, wt.%:
nonionic emulsifiers 28-50 animal fats 70-48 water no more than 2