SU1355350A1 - Binding compound for making moulds and cores - Google Patents

Abstract

The invention relates to a foundry, in particular, to compositions of binder compositions based on liquid glass used in the manufacture of molds (F) and rods (C) of mixtures according to C02 process or self-hardening. The purpose of the invention is to improve the quality of F and C by increasing the speed of their curing in the tooling and strength at the initial stages of curing and reducing their adhesion to the tooling. Composition, wt.%: Liquid glass (module 2.6, density 1.42 g / cm) 80.0- 97.5, hexamethylenetetramine (HMTA) 2.5-20.0. In the mixing process, sand is mixed with water glass, then LMTA is added, preferably in powder form. Due to the introduction of HMTA, F and C are cured with carbon dioxide 1.5-2 times faster and 1.5-2 times higher. whether the strength with the complete elimination of the adhesion of the mixture to the snap. 2 tab. with (L oo ate ate

Description

 13

This invention relates to a foundry, in particular, liquid glass-based binder compositions used in the manufacture of molds and cores from mixtures by a COi process or self-hardening.

The purpose of the invention is to improve the quality of the molds and cores by increasing the speed of curing in the base and strength at the initial stages of curing and reducing their adhesion to the equipment.

The essence of the invention is as follows.

The chemical formula of hexamethylene tetramine (CH) N. .

Hexamethylenetetramine (HMTA) is envisaged to be used mainly in the form of a powder, however, it can also be introduced into the mixture as a previously prepared solution.

An example. The described mixture was prepared as follows.

The sand was mixed with a calculated amount of liquid glass, and then with the addition of HMTA. Two methods of curing were used: purging with carbon dioxide and self-hardening due to HMTA in combination with the action of ferro-pshak. When testing samples treated with carbon dioxide, the curing rate was controlled by their compressive strength after 5, 10, 15 and 20 s, and the samples with ferroslag were controlled by strength after exposure to air for 10, 20 and 30 minutes.

Adhesion was controlled by. the amount of the adhering mixture to a wooden liquid soda glass (modulus 2.7, density 1.42 g / cm)

Hexamethylenetetramine

53502

in the box referred to the sample surface. The strength was controlled after 1 h exposure to air.

The compositions of the binder compositions 1-5 of the invention are listed in Table. one.

For the preparation of mixtures according to the process, 93% by weight of quartz necka K0315A and 7% by weight of binder compositions were used according to Table 1. A self-hardening mixture was prepared from 89% by weight of the indicated quartz sand, 4% by weight of ferroslag and 7% by weight binder composition No. 1 (see Table 1).

five

ten

The properties of the mixtures with binding compositions No. 1-5 are listed in Table. 2

The mixture with the binder composition according to the invention is cured with carbon dioxide, 1.5-2-2 times faster with gas and 1.5-2-2 times higher strength, and its sticking to the tooling is completely eliminated.

F, formula of invention

The binder composition for the manufacture of casting molds and cores containing liquid glass and amine is, in order to improve the quality of the molds and cores by increasing the speed of their curing in the rigging and durability and reducing their adhesion to the rigging The composition as an amine contains Hexamethylenetetramine in the following ratios of ingredients, in wt%:

Liquid glass 80.0-97.5 Hexamethylenetetramine 2.5-20.0

Table 1

95

90

85

80

ten

15 . 20

 For the mixture cured by ferrochromic slag.

Table l

Claims (1)

Claim A binder composition for the manufacture of foundry molds and cores containing liquid glass and an amine, characterized in that, in order to improve the quality of the molds and cores by increasing the speed of their curing in the tool and strength and reduce their adhesion to the tool, the binder composition as an amine contains hexamethylenetetramine in the following ratios of ingredients, wt.%: Liquid glass 80.0-97.5 Hexamethylenetetramine 2.5-20.0 Table! Ingredients The content of the ingredients of the binder composition, wt.% In composition No. 1 . 2 3 4 5 Liquid glass co. dovoe (module 2.7, density 1.42 g / cm ³ ) 97.5 95 90 85 80 Hexamethylene tetra- min 2,5 5 10 fifteen · 20 Table Ζ Properties Property indicators for mixtures with binder compositions, No. j 1 *) Compressive strength after blowing COj in: 5 s 0.007 0.009 0.012 0.018 0.022 - 10 s 0,112 0.137 0.158 0.167 0.174 - ^{15 s} 0.296 0.282 ' 0,304 0.298 0.287 g 20 s ‘ 0.296 0.290 0,300 '0.295 0.285 - 60 min 0.288 0.267 0.274 0.317 0.327 - Compressive strength, MPa, mixture with ferrochrome slag through, min: 10 0.018 20 - - - - 0.253 thirty - - - - - 0,306 * 60 - - - - 0.348 Adhesion g / 100 cm ² 0 about 0 0 0 0 * For a mixture cured by ferrochrome slag.