SU910829A1 - Cast iron - Google Patents

Description

() CAST IRON

The invention relates to metallurgy, in particular to the development of the composition of cast iron for molds. Cast iron G is known to have the following chemical composition, weight 3.1-3.8 Carbon. 2,3-3,2 Silicon 0.45-0.9 Manganese. 0.1-0, i + Chrome 0.01-0.1 Calcium 0.02-0.08 Magnesium. Rare-earth metals (REM) 0.003-0.1 0.005-0.2 Strontium .0.005-0.2 Aluminum Remaining Iron Cast iron is intended for thin-walled cast products used in power engineering. In this iron, strontium and aluminum are introduced to increase the density and growth of the castings. However, for castings with a thickness of 20, 50 and 100 mm, it does not apply. The closest in technical form and effect to be achieved is cast iron 2 of the following chemical composition, wt.%: Carbon. 2.7-, 3 Silicon 1 ,, 5 Magnesium 0.01-0.0 Calcium 0.08-0.3 Rare-earth metals 0.01-0, T2 Iron Else As impurities, cast iron sorrer, weight: Manganese, not more than 0 , 3 Chromium is not more than 0.1 Sulfur is not more than 0.02 Phosphorus is not more than 0.14 The disadvantage of the known cast iron is the ductility, ductility, and the chump is high. Reducing the degree of churning and obtaining a stable structure of cast iron was achieved as a result of the receipt of elements of graphitizatsoboa3. 91082 ri and strontium. Possessing a high affinity for sulfur, these elements desulfurize cast iron and contribute to an increase in the assimilation of graphite-globalizing elements — magnesium, rare-earth metals. The purpose of the invention is to increase the plasticity, reduce the degree of chill, while maintaining the strength properties. To achieve this goal, the pig iron containing carbon, silicon, magnesium research institute, calcium, rare earth metal and iron, additionally contains barium and strontium with the following ratio of components, weight: carbon 2,7-f, 2 silicon 1s5-3, 0 Magnesium 0.01-0.05 Calcium 0.02-0.09 Rare-earth metals 0.01-0.12. barium 0.02-0.09 Strontium 0.01-0.06 Iron Iron Pig iron in the form of impurities also contains sulfur no more than 0.02 wt. and phosphorus not more than 0.18 wt., aluminum and manganese in the sum not more than 1, Pig iron is smelted into 50 kg of an induction furnace. In tab. Figure 1 shows the chemical composition of the known and proposed chows. Samples of these cast irons in castings with diameters of 20, 50 and 100 mm are poured into sand molds. Cast iron is bent. Known2,2 2, k 0.03 0.05 0.05 ny Proposed 2.7 3.0 0.005 0.09 0.01 3.5 2.1 0.03 0.05 0.06 4.2 1, 5 0.01 0.02 0.12 5

Table 1 The data on the characteristics of graphite forms, the microstructure of the metal matrix and the mechanical properties (jgPHa strength, elongation and hardness without heat treatment are given in Table 2. As can be seen from Table 2, castings with a diameter of 50 mm and The above cast iron according to the proposed invention has an insignificant degree of a white with a good combination of strength and plastic properties, and castings from known cast iron require heat treatment to eliminate chillbones. To eliminate chill in a casting with a diameter of 20 mm cast iron normalized annealing (heating to E50C, holding for 1.3 and 5 hours in a furnace and cooling in air. Table 3 summarizes the characteristics of the shape of graphite, the microstructure and the mechanical properties of castings 20 mm thick after heat treatment. It can be seen from Table 3, after heat treatment of castings with a diameter of 20 mm, even when operating at 950-1 hours, there is no cementite in the microstructure of the metal matrix, whereas even after 6 hours exposure in the furnace, up to 2% of cementite remains in the microstructure of known iron. The expected economic effect from the use of nodular cast iron due to an improvement in the quality of the metal may be 7.5–9.0 rubles per ton of iron. The rest 0, 02 0.01 The rest 0.06 0.0 - 0, 09 O, About

table 2

while maintaining the strength properties, it additionally contains barium and strontium in the following ratio of components, weight:

Carbon 2.7-, 2

Silicon1,, 0

910829. eight

Continued table. 3

Sources of information taken into account in the examination

1, USSR Author's Certificate No. 602591, cl. C 22 C 37 / 1P, 1976.

2. USSR author's certificate number 361217, cl. C 22 C 37/00, 1973.

Claims (1)

Claims' .25 Cast iron containing carbon, silicon, magnesium, calcium, rare-earth metals and iron, distinguished by the fact that, in order to increase ductility, reduce the degree of bleached ³⁰ while maintaining strength properties, it additionally contains barium and strontium in the following ratio of components , weight.%: Carbon 2.74.2 ³⁵ Silicon 1.53.0 Magnesium - 0.01-0.05 Calcium 0.02-0.09 Rare earth metals Barium Strontium Iron 0,0.1 - 0,12 0.02-0.09 0.01-0.06 Rest