SU1320003A1 - Composition for alloying surface of casting in mould - Google Patents

Abstract

The invention relates to foundry, and HMeHHQ to the production of castings with a doped surface layer. The purpose of the invention is to increase the thickness and wear resistance of the alloyed layer and improve its surface quality. The composition includes boron carbide, boron sodium, titanium powder, iron powder, cryolite and hydrolyzed ethyl silicate in the following ratio of ingredients, wt.%; boron carbide 10.8-14.4; nitride. selection 2.7-3.6; titanium powder 13.5-18.0; iron powder 3.0-4.0; cryolite 1.0-3.0; hydrolyzed ethyl silicate - the rest. Carbide and boron nitride increase the hardness and wear resistance of the alloyed casting layer. The titanium powder provides for the formation of a layer of titanium carbide particles in the alloyed 4, which leads to an additional increase in its hardness and wear resistance. The exothermic nature of the reaction of the formation of titanium carbide leads to a better heating of the composition on the surface of the casting mold, a more intensive process of formation of the doped layer and an increase in its thickness. Cryolite is a process activator, c. its presence in the composition produces boron and titanium subfluorides, which in the form of gas are easily transported to the surface of the casting and provide a thicker doped layer. The iron powder melts and spreads over the surface of the carbide and nitride particles, sintering them and bonding them to one another and casting. The sintering of particles contributes to the formation of a doped layer with a smooth surface on the casting. Hydrolyzed ethyl silicate plays the role of a binder. 2 tab. W from 00 to with

Description

113

The invention relates to foundry (production, namely, to obtain

castings with a doped surface layer.

The purpose of the invention is to increase the thickness and wear resistance of the doped layer and improve its surface quality.

The essence of the invention is as follows. The composition for alloying the surface of castings contains hydrolyzed ethyl silicate, boron nitrite, boron carbide, iron powder, cryolite and doped metal, titanium powder in the following ratio of ingredients, wt.%: Carbide 0.8 to 14.4; boron nitride 2.7-3.6; titanium powder 13.5-18.0; iron powder 3.0 4.0; cryolite 1, hydrolyzed ethyl silicate - the rest.

Boron carbide and boron nitride are the hardeners of the surface layer of the casting, increasing its wear resistance. The titanium powder, when interacting with boron carbide in the presence of other ingredients of the composition, forms titanium carbide, which additionally hardens the doped surface layer. The reaction of formation of titanium carbide proceeds c. heat release, This contributes to a more complete uniform heating of the composition on the surface of the mold, intensifies the processes of formation of the doped layer on the surface of the casting and provides an increase in its thickness. Cryolite plays the role of an activator of the surface alloying process: in its presence, gaseous boron and titanium subfluorides are formed in the composition, which are easily delivered to the surface of the casting. There, they disproportionate with the formation of atomic boron and titanium, which dissolve in the metash of the casting, contributing to an increase in the depth of the doped layer. The iron powder melts due to the heat of the casting and the exothermic reaction and spreads over the surface of the carbide and nitride particles, ensuring their sintering and bonding of the particles to each other and to the casting. The sintering of particles contributes to the formation of a doped layer with a smooth surface on the casting. Hydrolyzed ethyl silicate plays the role of a binder.

Variants of the composition are given in table. 1, and indicators of the properties of the alloyed casting layer - in Table. 2. As can be seen from these tables, the composition provides an increase in the thickness of the doped layer by 1.4-2.3 times, a reduction in roughness by 1.5-2 times, an increase in hardness and wear resistance by a factor of.

Using the proposed composition ™

in comparison with the known, it allows to increase the resistance of surface-doped castings by a factor of 3-4.

5 account poviyeni service life cast

details, as well as reducing the consumption of alloying materials in obtaining the same thickness) of the alloyed layer on the casting.

Claims (1)

0 Claims of the invention The composition of the day is the alloying of the surface of castings in the mold, the contents of boron carbide, hydrolyzed ethyl silicate and alloying metal 3 characterized in that, in order to increase the thickness and 2-resistivity of the doped layer and improve the quality of its surface, it additionally contains nitride 0 boron, iron powder and fiolit, and as an alloying metal - titanium powder with the following ratio of ingredients, wt.%: Boron carbide five Boron nitride Titanium powder Iron powder Cryolite Hydrolyzed 10.8 2.7 13.5 3.0 1.0 1-4.4 3.6 18. C 4.0- 3.0 Hydrolysis he anny ethyl silicate 69.0 .63.0 57.0 Seditional stability,% The thickness of the doped layer, mm The surface roughness of the alloyed cast layer, fij70-80 Hardness alloyed-v-. „Of the layer, HV910-950 980-1020 Wear resistance relative to the prototype 1.45 Editor E. Sligan Compiled by E.Ten Tehred V.Kadar Order 2558 / П Circulation 740. Subscription of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, st. Project, 4 table 2 94  90 87 3.5-4.5 4.0-5.0 4.5-5.5 85-90 90-95 1.75 1.98 Proofreader M.Sharoshi