SU1827376A1 - Charge for graphite-containing refractory materials making - Google Patents

Description

The invention relates to the production of refractories and can be used for the manufacture of metal wires, including metal wires for casting steel.

The purpose of the invention is to increase the strength and heat resistance.

This goal is achieved in that the mixture for the manufacture of graphite-containing refractories containing a refractory filler, graphite, an antioxidant additive, carbon fiber and a binder, contains a high molecular weight carbon fiber with an organic coating with a ratio of its length to the largest grain size of the filler l / d = 5-3 / d with the following content of components, wt.%:

Graphite 15-35

Antioxidant supplement

Carbon Fiber Binder Refractory Filler

6-20

0.5-2.0

4-9

Rest

Samples are made as follows. The mixture is mixed in laboratory mixing runners in the following order: refractory filler is loaded, moistened with a binder, mixed, the remaining components are introduced, mixed again, and then moistened with the rest of the binder and mixed completely.

As a filler with a grain size of 0.1 -3 mm, electrofused corundum, high alumina chamotte, fused zirconia, and stabilized calcium oxide are used. Also used are crystalline silicon with a fraction of less than 0.066 mm, silicon carbide with a grain size of 100-180 mm, and refractory clay of the DN-2 grade. graphite grade GT-2, technical lignosulfonate (LST), bakelite varnish grade LVS-1 and binding phenolic powder brand SFP. A high-modulus fiber with an elastic modulus E> 100 GPa is used as carbon fiber. for example, evlon ”with a diameter of 10-30 mm, coated with phenol-formaldehyde resin. The fiber length is selected depending on the grain composition of the filler used.

1827376A1, based on the empirical ratio: l / d * 5t3 / d, where I is the fiber length, d is the largest grain size of the filler, thus: if the fraction is 0.1 mm, then the fiber length is 3.5 mm (35 times ), if the fraction 5 is 3 mm, then the fiber length is 18 mm (6 times longer), that is, the fiber length lies in the range from 3.5 to 18 mm.

The composition of the mixture are given in table. 1.

Laboratory samples (cylinders Ф36 W mm, height 40 mm and parallelepipeds 10x10x100 mm) were formed at a specific pressure of 80 MPa. Drying and firing of all samples was carried out under identical conditions. The maximum firing temperature is 15. 1350 ° C. The reducing medium was formed by coke filling.

The test results are shown in table.2. The bending strength was determined on rectangular samples 20 according to the existing methodology at the institute (bending at three points). Thermal resistance was estimated by the loss of compressive strength after three times thermal loading (sharp heating at 1300 ° C for 5 min - water). 25 The loss of strength characterizing heat resistance was calculated by the formula:

P - Fri P

• 100, where T is the loss of strength,%;

P is the compressive strength of the initial samples, MPa;

Fri - ultimate compressive strength of the samples after three thermal loads. MPa

Claims (2)

Claim A mixture for the manufacture of graphite-containing refractories, including a refractory filler, graphite, an antioxidant additive, carbon fiber and a binder, characterized in that, in order to increase strength and heat resistance, it contains a high-modulus carbon fiber with an organic coating with a ratio of its length I and the largest grain size d filler l / d - 5 + 3 / d in the following content of components, wt.%: G rafite antioxidant supplement Specified Carbon Fiber Binder Refractory filler 15-35 6-20 0.5-2.0 4-9 Else Table 1 - · Material ¢ 4 charges 1 2 3 . 4 5 6 7 8 9 10 eleven 12 · Corundum fifty . 35 48 ¹ - ^: • 52  : ' 20 25 High Alumina Fireclay - - 33 < thirty  - 25 - 58 20 fifteen Zirconium dioxide 34 thirty 48 . 25 fifty • 8 fifteen. Antioxidant Supplement: 20 ¹⁸ 11.5 20 6 18.5 18 fifteen 16.5 8 19.5 16 silicon crystalline .4 4 3 3 2 5.5 :5. 5 5 8 G 8 -silicon carbide 6 4 2.5 5 -. 3 3 3.5 '- 4.5 8 refractory clay 10 Yu 6: 12 4 thirteen 10 1.0 _: 8 • 10 - Graphite 35 24 fifteen : 24 29th 24 24 ..24 25 25 24 23 Carbon High Fashion. 5: 1  -  - 1.0 . - - . - - organic fiber coating 6: 1 * - 0.5 2.0 1.5 ; · • - · - fiber length / 'max 8: 1 2.0 '-. - - • grain size 11: 1- -: - 1.0 · . 1.0 2.0 35: 1 1.5 1.0 • * years ' 9 - . - 8 4  - 6: - 5  - · - - - 4 Bakelite varnish + SFP (1: 1) 7 4 9 6 8 8 • Notes. 1. In the examples, the 3.8-maximum size is true of the filler -0.1; and examples 4.10.12 - 0.5 mm; e examples 1, 2.11-1 mm: in examples 5.6.7 - 3 mm; · 2. In accordance with the ratio l / d - 5 * 3 / d specified in the claims, the fiber length is: and in the examples of 3.8-3.5 mm; in examples 4.10.12 - 5.5 mm: · examples 1.2.11 -8 mm: in examples 6.7 - 18 mm: and in example 5 - 15 minutes. Table) SaoAstaa samples Seoistm charge 4-i 1 2 3 4 5 6 7 IN 9 eleven 12 proto- Tensile strength l rm bending. MPa 9L 11.6 13.0 OF 8.0 9.6 10.5 9.5 10.5 ϊό.ο 9.5 10.0 3.2-6 Heat resistance. % (loss "strength) 22 20 22 22 32 24 32 36 22 18 20 22 32-40 Meta-resistance. % fifteen fifteen 16 20 20 21 20 21 14 20 18 20-28