SU593818A1 - Exothermal sand for raising the temperature of the riser portion, particularly, of large steel castings - Google Patents

Description

acid in the following ratio of ju-rareents, wt.%:

Aluminum wrap 11-19

Khromova ore65-72,5

Poor Acid 0.5-5.0

Liquid glass11-16

When the content of boric acid is above weight,%, the refractoriness of the candle does not increase, and defects in the form of gas shells appear on the surface of the metal. When the content of boric acid is less than 0.5 wt.% Not

its sintering effect is manifested. On the other hand, the indicated limits on the content of acid (0.5–5.0 wt;%) are determined by the amount of aluminum powder injected. When the content of the aluminum powder is closer to the upper limit, the refractoriness of the calcine is reduced, so that the amount of boric acid is also chosen to be close to the upper limit.

Examples of the compositions of exothermic mixtures are given in Table. one.

Tablipa 1

Table 2 shows the density and thermal conductivity of the proposed mixture in the initial state of the labeled states (in the form of calcine)

The density of the mixture in the original soo 3

TOYANIA, f / CM

Density of the spent mixture (in the form of calcine}, g / cm. Thermal conductivity of the mixture in its initial state, kcal / m. 4, С Thermal conductivity of the mixture in the operating state (in the form of

rt

calcine), kcal / m.h with refractoriness according to GOST). WITH

1.7-1.8

1.1-1.5

1.5-1.6

3.7-4.1

1.1-1.2

0.8-0.9

0.9-1.1

5.6–7.8 1800 17OO i For comparison, the same indicators are also given for the known mixture, chosen as the prototype,

Continuation of table 2