SU551401A1 - Liars - Google Patents

Description

(54) LIGATURE

one

This invention relates to metallurgy, in particular to ferroalloy production. At present, various modifiers and ligatures are used for modifying the steel, wt%:

Known ligature, consisting of wt.%: Vor 2.0-20.0

РЗМ5,0-35,0

Chrome5.0-20

Silicon6, O-40, O

Aluminum0,2-8,0

Calcium0,2-2,0

Iron1, O-12.0

Carbon0, OZ-O, 3

Nickel is the rest.

However, in this ligature the content of boron, REM and chromium is increased, which leads to marriage to chill. The high boron content leads to the formation of coarse-dispersed inclusions and complex triple ER-tectics containing boron, which leads to a decrease in the flexural strength and deflection arrows. The increased boron content in the complex with chromium and the high concentration of rare-earth metals leads to the appearance of free-structured cementite in thin sections of castings.

The increased content of aluminum in the ligature leads to the appearance of interdendritic graphite in the structure of cast iron, and, as a result, to a decrease in the physicomechanical properties of the metal.

The aim of the invention is to obtain castings with an isotropic structure that provides an increase in the tensile strength of the metal and bending while reducing chill.

The goal is achieved by introducing into the composition of a master alloy copper, cobalt, zirconium and niobium in the following ratio of components, wt.%:

2.0-8.0

0.001-4.5

0.01-15.0

4.0-12.0

0.1-3.5

0.1-2.5

O ,, o

0.05-0.4

Claims (2)

0.5-45.0 Cobalt 0.5-7.0 Zirconium 0.01-10.0 Niobium 0.1-25.0 Nickel the rest. Copper is introduced into the composition of the ligature as a graphitizing and perlite-forming element. When the copper content is less than 0.5%, its action is insufficient: the amount of pearlite in the structure does not increase, the depth of chill is not reduced. The upper limit of 45% copper concentration is due to the fact that when it is exceeded in the structure of cast iron in the ligature, it is released as an independent phase along the boundaries of graphite inclusions, which reduces the fi-mechanical properties of cast iron. Cobalt is a B-iron graphitizing element. When its content in the ligature to 0.5%, the modifying effect of cobalt is insignificant. With an increase in the content in the ligature to 7%, cobalt reduces the tendency of pig iron to chill, promotes the appearance of a narrower transition zone with a crushed structure, increases the tensile strength of the iron. When cobalt content in the ligature of more than 7%, no increase in the properties of the cast iron is observed. Pyrconium is introduced to grind grain, prevent chill, and improve the physicomechanical properties of cast iron. The modifying effect of zirconium is achieved when its concentration in the alloy is not lower than 0.01%. With an increase in the zirconium content of more than 1O%, it enhances the carbide forming action of chromium and boron. This leads to bleaching and a reduction in the physical and mechanical properties of cast iron. Niobium is introduced into the composition of cast iron to increase the quasi-hautropic nature of the metal structure. When the content in the ligature is less than 0.1% niobium, its action as a modifier is insignificant. With up to 25% niobium in the ligature, it contributes to the grinding of the primary structure of iron and results in smaller inclusions of graphite in the microstructure, which increases the physicomechanical properties of the metal. With an increase in the niobium content of more than 2%, a further increase in the properties of the cast iron is not observed. Niobium, moreover, in gray cast iron reduces the tendency to chill. Calcium in the composition of the ligature is needed to desulfurize the metal, aluminum to increase the melting point of the complex modifier, increase its modifying effect, and also stabilize pearlite. The effect of carbon and silicon on graphitization of cast iron in the eutectoid interval, as well as on the nature of graphite and the size of the eutectic grain, is that carbon and silicon contribute to graphitization in both temperature ranges. Carbon enlarges graphite, prevents its interdendritic distribution, and crushes the eutectic grain. Nickel is a graphite element in cast iron, and, alloying a metal matrix, improves the physicomechanical properties of the metal. Along with copper, it also stabilizes perlite. The concentration of iron is determined by the technological conditions for smelting the master alloy and the processability of modifying the iron and steel. The effectiveness of the proposed ligature on the structure and physicomechanical properties of cast iron is confirmed by the following example. The original cast iron is melted in an induction furnace. The chemical composition of cast iron is as follows. wt.%: carbon 3.17; silicon 1.93; manganese 0.63; sulfur 0.05; phosphorus O, O2; the modification temperature is 1370-1410 C. The amount of the introduced ligature in all cases is 0.2–5% of the weight of the liquid metal. In total, three compositions of ligatures and one composition of known ligatures were tested. The chemical composition of the ligatures is given in table. 1, 15.33 3.12 12.45 37.74 7.32 1.74 113.72 5.35 2.35 11.72 2.27 1.97 22.54 0.4 2.5 1 0 are known , 35 0.5 38.4 2 2.6 10 3.2 3 To assess the physicomechanical properties of cast iron, special samples are poured. The tendency of pig iron to chill out in thin sections of x castings is determined on special ones. From the presented data it is clear that the properties of the initial cast iron corresponded approximately to the mark C4 18-36. Modified cast iron with ligatures of the described composition has enhanced physical and mechanical properties that are superior to the analytical properties of cast iron with a composition that corresponds to the prototype by 10-15%, while simultaneously reducing the tendency to chill by 2-3 times. Claims for modifying steel and cast iron containing boron, rare-earth Table 1 11.02 0.21 OST 7.35 0.17 0.49 0.087 0.02 0.02 -1.5.5 0.5 45.5 2, 6 7.6 11.15 0.25 8.25 5.4 4 5 step wedge samples with a cross section ° d D ° 2.0 mm. The main results of testing samples experienced heats are given in Table. 2. Table 2, metals, chromium, silicon, aluminum, calcium, iron, carbon, nickel, characterized in that, in order to obtain an isotropic structure in castings, it additionally contains copper, cobalt, niobium and zirconium in the following ratio of components, wt.%: 2.0-8.0 0.001-4.5 0.01-15.0 4.0-12.0 Silicon O, 1-3.5 Aluminum 0.1-2.5 Calcium 0.5 -8,0 Iron O, 05-O, 4 Carbon 7 jV enb0,5-45,0 Cobapt0,5-7,0 Zirconium 0.01-10.0 Niobium 0.1-25.0 Nickel-oleo. l .x, H 551401Q ® The source of information taken into account during the examination: 1. USSR Copyright Certificate No. 424903, M.C. C 22 C 35 / OO. 5 O2.06.72.