SU831849A1 - Cast iron - Google Patents

Description

(54) CAST IRON

The invention relates to metallurgy, in particular, to the search for cast irons for the manufacture of parts of machines operating under the conditions of cavitation in situ of liquid media and molten metals.

Known cast iron having the following chemical composition, wt.%: Carbon 2.0-3.0

NROM18-24

Maragnets2,51-3,7.

Silicon0.4-0.13

IronErest

Known cast iron may contain phosphorus and sulfur in an amount of 0.030, 1 wt.% Each, and the total content of sulfur and phosphorus should be 0.06-0, 15. wt.%. The hardness of the cast iron is about 60 HRC, and the hardenability of 40-60 mm CQ.

However, the use of this iron for the manufacture of machine parts transporting and processing hydroabrasive pulps and molten metals, reduces the duration of their operation and reliability in operation.

The closest to the proposed technical essence and the achieved result is cast iron. The following chemical composition, in wt.%

Carbon

2.9-3.2

Chrome 20.0-22.0

Cr

0.6-1.0

Manganese 0.4-0.8

Nickel 1.2-3.2

Iron Else

The eutectic composition of this cast iron provides optimum casting properties. The relative wear resistance of cast iron is 7.9-8.0, the hardness in the cast state is 47-48 HBC G2.

The disadvantage of the known cast iron is low cavitation resistance, due to the presence in the structure of brittle carbides of the type with relatively low microhardness and large sizes (at a rate of 3. cooling of 5-25 degrees / min. Of juiHiia carbides reaches 12-A5 microns Low metal base strength reduces the resistance of the cast iron to erosive wear. The purpose of the invention is to increase the level of achievement, cavitational-erosion resistance of the bone and hardenability. The goal is achieved by the fact that the proposed Cast iron additionally contains antimony, nitrogen and one component from the group containing boron boron carbide or thorium carbide, in the following ratio of components, wt.%: 2.4-3.2 Carbon Chromium 16.0-22.0 Silicon 0.6-1, 4 Map manganese 0.4-1.4 Nickel 0.2-3.0 Antimony 0.005-0.55 Nitrogen 0.005-0.12 One component from the group containing boron 0.01-0.75 boron carbide or thorium carbide 0 , 1-1.3. Iron Else In induction electric furnaces with a quartzite crucible, a capacity of 9 × 250 kg according to the well-known technology of melting bel1e1X chromium cast iron, the proposed and known cast iron is smelted. The compositions of the alloys are given in table. 1. Boron carbide and thorn carbide are introduced at the end of the smelting using a 0.5-2.5 mm fraction. Metal times: sew 200 kg with a ladle, at the bottom of which metal antimony is introduced. The metal is poured into dry shells at 1450-1470 ° C. The results of the spontaneous tests of cavitation and erosion resistance, respectively, under the conditions of the action of hydroformed slurries and molten silumin, Hardenability and hardness of the known and proposed cast iron are given in Table. 2 As can be seen from the table, 2, the proposed white cast iron has a higher cavitational and erosion resistance than the known. The cast parts of sludge pumps and casting-dosing devices from heat-treated cast irons with austenite-martensitic base and fine carbides with microhardness of 1440-1880 kgf / mm have the maximum resistance under conditions of cavitating-erosive impact.

table 2

Claims (1)

Claim Cast iron containing carbon, chromium, silicon, manganese nickel and iron, characterized in that, in order to increase the hardness of cavitation-erosion resistance and hardenability, it additionally contains antimony, nitrogen and one component Nickel Antimony Nitrogen One component from the group consisting of boron carbide, boron or carbide τορι Iron 0.2-3.0 0.005-0.55 0.005-0.12 ' 0.01-0.75 0.1-1.3 The rest of the group containing boron, boron carbide or thorium carbide, in the following ratio of components, wt.%: Carbon '2.4-3.2 Chrome 16.0-22.0 Silicon 0.6-1.4 March ⁵⁰ Ghanaian 0,4-1,4-