SU885322A1 - Master alloy - Google Patents

Description

one

This invention relates to ferrous metallurgy, in particular to the development of a complex alloy for the modification and alloying of cast iron.

Known ligature containing magnesium, calcium, barium, rare-earth metals, copper, manganese, chromium, iron, carbon, silicon Cl

The disadvantage of the ligature is that the cast iron alloyed by it has a high hardness (over 250 HB), which is why parts cast from this cast iron cannot be machined.

Closest to the proposed technical essence and the achieved effect is a ligature for the modification of cast iron, containing wt.%:

Silicon52 - 60

Calcium3 - 7

Magnesium3.5-6.5

Rare earth

metals 10.5 - 16.5 Iron Else After the cast iron is treated with this ligature, the microstructure of the metal matrix contains ferrite-perlite-cementite. After annealing, the microstructure of the metal matrix contains less than 65-70% of the pearlite component and, therefore, high-strength cast iron castings, obtained using the above master alloy, with a ra: bot for wear, exhibit lower durability than high-strength cast irons, which predominate in the microstructure pearlitic constituent / above 80%),

During normalization annealing of castings, i.e., with rapid cooling, in the microstructure of high-strength nodular cast iron after heat treatment, it is possible to increase the perishta content (approximately 80-90%), however, the formation of cement occurs, as a result plastic. The purpose of the invention is to increase the pliability of cast iron. The goal is achieved by the fact that the proposed master alloy containing silicon, calcium, magnesium, rare earth metals and iron, additionally contains copper with the following ratio of components, wt.%: Silicon 52 - 60 Calcium 3-7 Magnesium 3.5-6-6, 5 Rare earth metals 10.5 - 16.5 Copper0.5 - 9.5 Iron The Rest. The introduction of the copper ligature into the composition ensures the acceleration of the first and the inhibition of the second stage of graphitization of cast iron. Acceleration of the first graphitization stage reduces the likelihood of cementite formation, and inhibition of the second graphitization contributes to a decrease in the intensity of decomposition of pearlite. Example: A ligature was obtained in a high-frequency heartless induction furnace with a graphite crucible by silicothermic reduction of components from their oxides and fluorides. The compositions of the obtained ligatures are given in Table 1. Ligatures were introduced into synthetic cast iron in an amount of 2% by weight of the liquid metal. Received castings of high-strength nodular cast iron. The cast iron was checked for fracture. Studied the microstructure, shape of graphite and the mechanical properties of cast iron. The data obtained are given in table 2. The data show that the proposed alloy provides an increase in ductility, a decrease in the hardness of cast iron and, consequently, an improvement in its workability. Table 1

60

Known 30

table 2

ShG1-23

265

1.4

Claims (2)

59.2 5 Ligature formula containing silicon, calcium, magnesium, rare earth metals and iron, characterized in that, in order to reduce iron chyasticity, it additionally contains copper in the following ratio of components, wt.%: Silicon 52-60 Calcium 3-7 85322-in Magnesium 3.5 - 6.5 Rare-earth metals 0.5 - 16.5 Copper 0.5 - 9.5} Iron Else Sources of information taken into account during the examination I. USSR author's certificate No. 621780 , cl. C 22 C 35/00, | 978. IP 2. USSR author's certificate No. 727704, cl. C 22 C 35/00, 1978.