SU939156A1 - Pickup preventing coating for casting moulds and cores - Google Patents

Description

This invention relates to a foundry, namely, nonstick coating compositions for casting molds and cores used primarily for manufacturing; high-manganese steel castings

A non-stick coating j is known which includes chromium iron, molasses, dextrin and water 1.

The disadvantage of this coating is the absence. In its composition of a material with high oxidizing properties, which allows the use of such nonstick coatings for castings from carbon and low alloyed steel grades.

It is also known to have a coating, including powdered quartz, manganese ore, organic binder, bentonite, podmylny lye and water G23

The coating described has a number of positive properties, but it does not provide a cast

surfaces with a zero degree of priGyra for castings from steel 110G13L and require additional cleaning and coarse works.

The closest to the proposed technical essence and the achieved result is a coating containing, mass .: kyanene-sillima-g nit 78, bentonite 2, hydrol water to a density of 1.5, 55 g / cm

However, such coverage does not provide. The method of obtaining the surface of castings from high manganese and steel grades with a siule degree of burn and requires 5 additional cleaning and chipping works. The purpose of the invention is to ensure the formation of a lightly separable grigor and improve the quality of the surface of the oi cast.

This goal is achieved by the fact that the nonstick coating, including kyanite-sillimanite, bentonite, 3 hydrol and water, additionally contains hematite ore and sodium sulfate in the following ratio of ingredients, masses, h: 73.0-78.0 Dist. Sillimanite Bentonite 2.0-2.5 Hydrol 20.0-22.0 Hematite ore 0.5-1.5 Sodium sulfate 1.0-3.5 1.8-1.9 l / water to density Coating is prepared as follows Thus, loose components are poured into the mixer and thoroughly mixed, and then water is poured to ensure a density of 1.8-1.9 g / cm, after which the resulting coating ready to use. Coating is applied to the surface of the molds and rods with a spray gun or a brush. With the introduction of hematite ore and sodium sulfate into the coating, it forms with a large amount of oxides on the surface of the mold or rod. At temperatures above 900 ° C, sodium sulfate is in a molten state, with the sulfuric acid gases being released. Na, SO Na.0.0-t-SOj 64 SOj refers to surface-active oxides, therefore the addition of sodium sulfate additives to the coating intensifies the oxidative process. This reduces the surface of contact between the casting and the mold, prevents the formation of burns and ensures the formation of easily separable burns on the surface of the castings. The compositions and properties of the proposed and known coatings are given in Tables 1 and 2. As can be seen from Table 2, the optimal properties of the coatings are 2-5. The content of hematite ore and sodium sulfate below the stated limits does not provide the necessary oxidation rate, and the content of the above specified limits does not contribute to further improvement of the coating properties. The proposed coating is recommended to be used for painting molds and cores for making castings from high-manganese steels of the type 110G13L with a wall thickness of 30-50 mm, and also will improve the surface quality of castings (purity class R220), reduce burns and reduce the amount of cleaning . Table 1

IT 77.0 78.0 77.0 75.75 73.0 77.5

2.0 2.0 2.25 2.3 2.5 2.6 2.6 20.0 20.0 20.5 21.0 22.0 22.0

0.3 0.5 1.0 1.25 1.5 1.7

0.7 1.0 2.0 3.0 3.5 3.6 To a density of 1.8-1.9 g / cm

78.0

2.0

20.0

3

Claims (3)

Up to a density of 1.5-1.55 g / cm 1.8- 1.8- .1.8 Density, g / cm 1.9 1.9 1.9 20-22 20-22 20-22 Viscosity, with Heat Resistance, c Oxidation rate, g / cm 0.0093 0.015 0.018 Good Coverage Sedimentation stability,% 90-91 90-91 90-91 Surface quality 320 320 320 castings Invention Non-stick coating for molds and cores used mainly for castings of high manganese steel, including disteno-sillimanite, bentonite, hydrol, and water, characterized in that, in order to ensure the formation of an easily detachable burn and increase surface quality of castings, further comprising a hematite ore and next sodium sulfate isootnoshenii ingredients mass.m .: Table 2 1.8-1.8-- 1.8-1.5-G, 55 1.9 1.9 1.9 20-22 20-22 20-22 20-211 0.0180.0220.0220.0085 90-9t90-9190-918 -86 320320320 Disisten-sillimanite Bentonite Hydrol Hematite ore 0.5-1.5 Sodium sulfate 1.0-3.5 1.8-: Water up to a density of 1.9 g / cm. Information sources are taken into account during the examination t. Welded A, A. Cover the foundry MM, Mashinostroenie, p.81. Tav 7. 2. The same, p.78, composition 2. 3. Tan, p.78, part 3.