SU1097655A1 - Lubricant for hot pressing of high melting metals - Google Patents

Abstract

Use of augite concentrate as a lubricant for hot pressing of refractory metals. ate with

Description

with

9 SP

ate

The invention relates to the hot working of metals by pressure and can be used in the hot pressing of profiles and pipes, in particular, from refractory metals.

Known lubricant for hot treatment of refractory metals based on borosilicate glass with the addition of boron nitride ij.

However, this lubricant, like all silicate-based lubricants, is labor intensive and includes scarce boron compounds. In addition, the melting point of the lubricant is low (630 ° C), so it sticks to the tool and press section, which requires the use of special cleaning methods (Cleaning the dies, etching the press parts in acid baths).

Known glass lubricant for hot pressing of refractory metals containing 14–40 wt.% Si02 glass fiber, E glass (54.3% SiOj; 8% 8; 14.8% AJJD; 0.5% Na20 + K20; 17.4% CaO: 4.9% MgO and 0.1% P1) or glass 475 (57.9% SiOj; 10.7% BjO; 5.9% A. 10.1% NajO; 2.9 % KjO-, 2.6% CaO; 0.4% MRO; 5.0% BaO; 3.9% ZnOj 0.6 Fg) with T.PL. 650c and 60-80% of powdered refractory (Al20, SiOg, ZrOg, borosilicate glass or mixtures thereof) with a melting point of more than 820 ° C 2.

However, this lubricant is very laborious in manufacturing and has a high cost, since the technology of its preparation includes the manufacture of special glass fiber, dispersing it in water, the introduction of pure refractory powder into this suspension, filtering and precipitating the mixture in the form. ,

The purpose of the invention is to reduce the labor intensity of production and the cost of lubrication and products made with its use, as well as ensuring the required quality of the surface to be machined and the durability of the tool in the temperature range 11501250 ° C.

This goal is achieved by using an augite concentrate as a lubricant for hot pressing of refractory metals.

When compressing refractory materials and alloys (cast and powder) in the temperature range of 1150-1250 ° C, a washer prepared from augite concentrate is used as a matrix lubricant.

Augitite concentrate is a mining and chemical raw materials of the following chemical composition, wt.%:

SiO2 42.70-46.00; Na2O 5.4-6.3; KgO 0.9-2.3; MgO, 3.1-4.5; CaO 11.814, 2; A1gOz 3.4-6.8; Fe, 0, + FeO 16.8-, 21.0; TiOg is 4.5-6.8 and PgOy is 0.02-0.85 and is the product of the processing of nepheline-apatite ores.

Apatite-nepheline rock includes apatite, nepheline, sphene, pyroxenes aegirine, augite), titanomagnetite and feldspar 3j. Breed separated (enriched by flotation). Get apatite and nepheline concentrates. The rest of the bush breed.

The augite concentrate separated from the apatite-nepheline 5 rock has not previously been recovered.

The possibility of using an augite concentrate as a lubricant at 1150-1250 ° C is due to the fact that it has an i.e. 1100-1160 С

and HIGH viscosity change with temperature. During hot pressing under conditions of short duration of contact of the hot metal with the lubricating washer and constant entrainment of the melted layers of the lubricating washer from the deformation zone, the augite concentrate washer within 1150-1250 ° C has a low viscosity liquid phase on the surface that is easily carried away by the metal from the core deformations.

Shayal of augite concentrate was tested on 1500 t horizontal hydraulic press while pressing an experimental batch of rods and profiles made of refractory metal alloys. They experienced fl lubricant - composition 1, lubricant 2 - compositions 2 and 3, respectively, based on glass E and glass 475 (Table 1), as well as augite concentrate - composition 4.

Augite concentrate lubricant was tested with the release of the finished batch of MNB alloy rods at 1150-1250 С with a degree of deformation of at least 70% on the press 1000. Over 200 kg of alloy were pressed. More than 500 compacts have been tested.

The test results are presented in Table. 2

In the process of pressing when applying the proposed lubricant, not a single finished product has been rejected. Press products fully meet the requirements for surface quality.

In comparison with the known ones, the proposed lubricant has a higher melting point and tool durability, therefore, it can be used in enterprises where hot pressing of refractory metals takes place.

The chemical composition of lubricants

Table 1

1 56 11. 12 16 4 - 3

254.3 814.8 17.4 4.9 - 0.5

357.9 10.7 5.9 2.6 0.4 5.0 10.1 2 „9 630

0.1 0, 6 3.9

table 2

Etching in the melt alkali

Claims (2)

Use of augite concentrate as a lubricant for hot pressing of refractory metals. I0Я7V55 A one 1097655 2