SU799893A1 - Pickup preventing coating for casting moulds and cores - Google Patents

Description

 This invention relates to foundry, in particular, to non-stick coating compositions for foundry molds and - cores of mainly iron castings. Known non-stick pokr 1 for cast iron casting the following composition, wt.%: TSH40 Concentrate sulphite yeast brew 5 Polyvinyl-solution. 55 p.o. of OT-421-23 with the disadvantages of this low 1% of its low antiburning properties. The closest in technical essence and the achieved result is a non-stick coating (containing, wt.%: Graphite, rat-crystalline (amorphous) Bentonite 5.5 Paton molasses 5.5 Keeper CB 35.0 over 10 However, this coating has not sufficient anti-stick properties in the manufacture massive castings, in thermal nodes of the molds, as well as when using molding or core mixtures with a higher degree of burn-in. The aim of the invention is to improve the nonstick properties of the coating and to improve the quality of durability of castings. This goal is achieved due to the fact that the coating additionally contains polystyrene as a carbon-containing material and an anionic surfactant at the following ingredients, wt.%: Refractory filler 45-60 Polystyrene 3-10 Anionic surfactant 0.1-1 , 0 Organic binder 1-10 Bentonite 0.2–5.0 Water Else Polystyrene GOST 20282-74 is a carbon-containing material, at the pouring temperature of the metal it emits 50% pyrocarbon, which characterizes the high antiburning properties of the polystyrene ol. To (4 components included in the composition of the film, when the mold is cast, they are destroyed to form volatile substances. Pyrolytic carbon in the form of a bonded film is deposited on the walls of the gas phase, which reduces the wettability of the material of the mold and reduces the reactivity metal-form boundary. Process (TU-38-10719 77} detergent is used as anionic surfactant. Introduction of surfactants provides better wettability by the liquid phase of polystyrene coating and obtaining single one suspension coating .. as a refractory filler can be used graphite, powdered quartz, talc, etc., as well as their combinations. As a bond, it is possible to use molasses, krepitel KB, sulfate-alcohol concentrate of brand A and R. Bentonite The proposed coating performs the function of a suspension material. The properties of the proposed coating and its compositions (1-8) are given in Tables 1 and 2. The inclination to burn is determined by a process sample illustrating the dynamic and static effect of the metal on coating when casting. As follows from the test results of the nonstick coating given in Table 2, the proposed coating has better nonstick properties than the known one. The optimum content of polystyrene is 3-10%. When introduced in a smaller amount, the effect of polystyrene is not effective, and a burnout appears on the surface of the castings. The introduction of polystyrene more than 10% is economically impractical. The optimum content of anionic surfactant. O7 substances is -0.11, 0%. A smaller amount leads to a non-uniform suspension, on the surface of which polystyrene particles float. A larger number of leads to. Foaming. The technology of cooking nonstick coating is as follows. In a mixing device, for example, in runners, a surfactant and polystyrene are mixed for 5–15 minutes. In a paddle mixer, the binder and suspension material is diluted in water, after which the composition prepared in the runners is mixed and mixed 2Q-30 min. refractory filler and mix 10-20 minutes. The resulting suspension is adjusted to the required density. The proposed coating can be used for painting molds and cores (sand, liquid glass) in individual, mass and mass production of castings.

4.5 4.5

Dusty Quartz

Graphite is hidden-crystalline (amorphous)

Polystyrene Anionic surfactant (detergent progress) 1

Bentonite Treacle molasses Krepitel KB Water

Table

9 13.5 13.5

13.5

31.5 54.6

36 31.5 31.5 6 10 10 15

0.6 5 4 4

Claims (1)

35.4 31 Suspension density, g / cm 1.35 1.34 Sedimentation stability of suspension.,% Durability of layer to abrasion, kg / mm Uniformity One- One of the suspensions native to the polyparticle particles. Burning propensity Burning tendency metal The invention claims for non-stick coating for casting molds and cores, which are mainly used in the manufacture of castings, including a refractory filler, a binder, bentonium and water, in order to improve the nonstick properties of the coating and improve the surface quality castings, it additionally contains polystyrene as a carbon-containing material and an anionic surfactant in the following ratio of ingredients, wt.%: Table 2 1.25 1.22 1.32 1.2 Uniformly-Inhomogeneous-Uniform, on the native surface with particular particles, polystyrene foam on the Prigar surface, not removed by a metal brush Refractory filler45-60 Polystyrene3-10 Anionic surfactant0 , 1-1,0 Organic binding 1 - 10 Bentonite 0.2-5-5 Water Vital, Sources of information that are taken into account during the examination 1. S. Doroshenko. et al. Obtaining a willow without a burn in sandy handicaps. M., Mechanical Engineering, 1978, p. 129. 2, Catalog Molding materials 1978, p. 46.