SU897386A1 - Antiburnt-on coating for bottom plates and metal moulds - Google Patents

Description

(54) ANTI-SUSTAINING COATING FOR PALLETS AND COKILEES The invention relates to foundry, namely, to non-stick coating compositions used to protect the working surface on the thermal effects of liquid metal, cast iron capsule and flat pallets and chills. The coating for casting molds 1, including a refractory filler and silica, which contains a distansillimenite concentrate as a refractory filament in the following ratio of ingredients, wt.% Distensilicite concentrate 30-45 Silica sol 55-70 The disadvantage of this coating is poor adhesion to the surface , sedimentation stability is low because silica does not have much colloidality. In addition, cream-free. Sol is deficient. The closest to the proposed, the technical essence and the achieved result is the coating 2, containing in its composition, may.%: Chrome refractory filler (chromium ore) 10 Argansate {ealy 0.03 Liquid glass .5 Water85 In the known coating chromium ore is used as a filler, liquid glass is used as a binder, water is used as a solvent. The addition of potassium permanganate increases the adhesion of paint to the surface of the chill mold. Known paint has a low temperature resistance at high temperatures. With a sharp heat stroke, the strength of the coating is reduced, the casting is obtained with burnt and gas shells. In addition, there is a weld castings, which reduces the resistance of the molds. The purpose of the invention is to increase the durability of pallets and chill molds and heat resistance of the coating. To achieve this goal, the coating comprising chromium fire / refractory filler, water glass, potassium permanganate and water contains chromite as a refractory chromium filler and additionally magnesite, aerosil and an aqueous solution of phosphoric acid density

1.24-1.26 g / cm- in the following ratio of ingredients, weight,%:

Chromite6-9

Magnesite50-52

Aerosil 1,5-2

Manganese Acid 11th Potassium 0.05-0.1 Liquid Glass 20-22

Aqueous solution of orthophosphoric acid with a density of 1.24-1.26 g / cm 8-10

Chromite, magnesite and aerosil are incorporated into the coating as a filler. The combination of chromite and magnesite in such percentages provides the greatest fire resistance of the coating. Magnesite in combination with chromite m contributes to the fact that the filler is less seated and gives a good antiburning property, Aerosil increases the heat resistance and durability of the coating at high temperatures. A solution of orthophosphoric acid binds the water in the coating to a gel, which contributes to an increase in the strength of the coating, a rapid drying and a decrease in the gas creativeness. In addition, sedimentation stability is enhanced by gel formation.

The combination of liquid glass with orthophosphoric acid gives the coating a higher refractory properties, since chromophosphate oxides are formed together with the filler and give durability at high temperatures. The combination of liquid glass with a filler - aerosil provides good technological and physico-mechanical properties.

The compositions and properties of the proposed and known coatings are given in table. 1 and 2.

The coating is prepared by mixing a predetermined amount of liquid glass with aerosil and water for 1015 minutes. After mixing, the remaining chromite and magnesite is added and mixed for 20-30 minutes. Before use, a solution of orthophosphoric acid with a density of 1.24-1.26 g / cm is introduced. Then the coating is applied to the surface of the mold with a spray gun or a brush. Coating density 1.6-1.7 g / cm.

The varnish of the nonstick coating 1 has a low sedimentation stability, the increased content of the solution of orthophosphoric acid contributes to a decrease in the strength of the coating, the heat insulating properties decrease, and the burnout increases.

Composition -coating 2 has a low adhesion strength to the surface due to the low content of potassium permanganate, the curing time of the coating increases due to the low content of orthophosphoric solution. acids, gas efficiency increases due to the increased magnesite content.

Optimal are the compositions of the coating 3, 4, 5, the most well combining physicomechanical properties.

The proposed coating has a {LOW gas content, good sedimentation resistance and a covering power, satisfying strength at high temperatures.

The implementation of the invention will improve the resistance of the pallets and the chill mold to reduce the weld casting to the latter and improve the surface quality of the castings.

Table 1

Oh 2

0.01 0.05 0.07 0.1 20 22 21 20

nineteen

12 6 8 9 10 7.3 11.7 10.4 10.1 8.9

0.03 5

10 94

4 4 5.0 3.5

Resistance of chill molds, number of fillings150 180 206 206 206 160

Heat resistance, with

1200 1500 1500 1500 1500 1300

Strength

coverings

Claims (2)

, kg 0.6 0.8 1.1 1.1 1.1 1.1 0.7 The claims of the Non-stick coating for dons and molds, including chromic refractory filler, water glass, potassium permanganate and water, characterized in that with. In order to increase the resistance of pallets and chill molds and the heat resistance of the coating, it contains chromite and, additionally, magnesite, aerosil, and an aqueous solution of orthophosphoric acid with a density of 1.24-1.26 g / cm with a sparse ratio of ingredients, as chromium refractory filler, weight.. Table 2 92 3 O 92 88 b. 3 o 7.5 Chromite 6-9 Magyazit50-52 Aerosil1,5-2.0 Potassium permanganate 0.05-0.1 Liquid glass 20-22 Aqueous solution of orthophosphoric acid with a density of 1.24-1.26 g / cm 8-10 Water . The Other Sources of information, which are taken into account in the examination 1. The author's certificate of the USSR 37193, cl. B 22 C 3/00, 1976. 2. Szarka A.A. Coating of foundry m. M., Mashinostroenie, 1977, 119.