SU523135A1 - Lubricant for hot metal processing - Google Patents

Description

(54) GREASE FOR HOT METAL TREATMENT

one

The invention relates to process lubricants for hot metal forming and can be applied when pressing pipes on vertical mechanical presses.

At present, graphite-based lubricant with the addition of sodium chloride is used in vertical mechanical pipe presses. However, this lubricant leads to the carburization of the surface of the products, which is unacceptable and requires an additional operation, heat treatment, to remove the carburized layer. At the same time, metal losses due to scale formation yield up to 3%.

It is also known that when using lubricants with a high content of graphite, combined additives are introduced that contribute to a more complete oxidation of graphite and limit its contact with the metal. In addition to graphite and pyrolusite additives, these lubricants contain bentonite clay, polystyrene, trichlorethylene. These lubricants, although somewhat reduce the degree of carbonization of pressed products, however, cannot completely prevent it, since they contain in their composition the main carburizing component — graphite in large quantities.

Lubricants based on condensed phosphates, as well as sodium tripolyphosphate, are known for hot metal forming processes, in particular, tube pressing. These lubricants do not cause carbonization of the metal. However, they are aggressive towards the metal and are low-tech, since they are recommended to be applied in a powder-like state. With the required

The method of supplying the lubricant directly at the beginning of the pressing process to the end of the preform heated to ISO-1200C does not ensure uniform distribution of such lubricants in the deformation zone, which leads to scraping of pressed products.

Also known lubricant for hot metal treatment, containing, by weight. %

Sodium tripolyphosphate 64-75

Iron oxides4-8

Mineral oil

"Vapor 15-25

Salt eutectic,

containing 31% NaCl,

54% NasCOs, 15% NaF. 1.5-1.7

Sawdust2-3,8

When pressing thin-walled pipes (wall from 2.5 to 5 mm) using this lubricant, an increase in compression forces, an increase in the wear of mandrels and the appearance of scratches on the inner surface of the pipes is observed. In order to extend the temperature range of lubrication and improve the quality of pressed thin-walled pipes, sodium tripolyphosphate-based lubricant, mineral oil, iron oxides, sawdust, salt eutectic containing sodium chloride and carbonate additionally contain graphite and sodium chloride and sodium carbate in salt eutectic contained in the amount of 45 and 55 weight. %, respectively. The composition of the proposed lubricant weight. %: Iron oxides4-8 Mineral oil18-25 Sawdust2-4 Eutectic salt1-2 Graphite8-10 Sodium tripolyphosphate Up to 100 The presence of graphite in the lubricant improves its antifriction properties at lower temperatures (400-800 ° C), as a result of which the force decreases removing the mandrels increases their durability and improves the quality of the inner surface of the pipes. At the same time, graphite, being in a lubricant in an amount not exceeding 10%, in combination with tripolyphosphate has a low activity. The results of lubricant testing for pressing the pipes are given in Table 2.

As you can see, the well-known lubricant does not provide the stability of the mandrels and the quality of the inner surface of thin-walled pipes.

Table 1

table 2

Claims (1)

The proposed lubricant reduces pressing forces, increases tool life and improves the quality of the pressed fineness and does not cause carburization of the surface of the pressed metal. Improving the anti-friction properties of the lubricant allows the use of a slightly more refractory, but simple two-component salt eutectic with mp. 620 ° C, which lowers the melting point of the lubricant as a whole from 930 to 760 ° C. Thus, the proposed lubricant has a wider range of applications and allows us to successfully produce high-quality pipes on vertical mechanical presses. The preparation of the proposed lubricant consists in the thorough mixing of the components in a mechanical mixer for 45 minutes while simultaneously heating to 60-80 ° C. A portion of lubricant in the amount of 250-300 g is fed to the end of the heated billet in a container of a vertical pipe-profile press before each pressing. Under production conditions on a vertical press with a force of 1500 tons, pipes of 42X2.8 mm in size from steel 12X1MF were extruded from blanks with a diameter of 160X290 mm using lubricants, the compositions of which are presented in Table. 1. (m. Pl. The proposed lubricant 760 ° C, known - 720 ° C). 5 oukh pipes. This expands the range of application of lubricants for pipes produced on vertical mechanical presses. Claim 5 Lubricant for hot treatment of metals based on sodium tripolyphosphate, iron oxides, mineral oil, sawdust and salt eutectics containing chloride and sodium carbonate, characterized in that, in order to extend the operating temperature range of the lubricant and the quality of the surface to be treated, eutectic salt containing 561 5645 wt.% sodium chloride and 5S weight.% sodium carbonate, and the lubricant contains graphite in the following ratio of components, wt. %: Iron oxides 4-8 Mineral oil 18-25 Sawdust 2-4 Eutectic salt containing 45 wt. % sodium chloride and 55 wt. % sodium carbonate 1-2 Graphite 8-10 Sodium tripolyphosphate Up to 100