SU668967A1 - Master alloy - Google Patents

Description

LIGATURE

(54)

The invention relates to ferrous metallurgy, in particular, to alloys intended for the alloying of steel and cast iron. A ligature is known in the following ratio of components, wt.%: Calcium8-18 Iron20-35 Copper0.5-20.0 Tin0.25.25.0 Aluminum 0.2-2.5 Silicon Else 1. However, aluminum and silicon included in the composition of the ligature , along with the positive qualities of the grafitiator, at the same time they contribute to the increase in the size of graphite inclusions in the crystallization of iron-carbon alloys. This reduces the tensile strength and bending strengths, as well as reduces the hardness of the castings. So, for example, gray cast iron of the grade SCh-18-36 doped with this ligature swarm has the following mechanical properties; tensile strength, 0 kgf / mm bending strength, iZb, ® kgf / mm Hardness HB Part 73, the size of graphite inclusions - 50 -55 MKM. The purpose of the invention is the transformation of the mechanical properties of gray cast iron by decreasing the graphite graphite inclusions. It is achieved that antimony is additionally introduced into the known ligature, and the components are taken in the following ratio, wt.%: Silicon 40-75 Aluminum 0.3-0.8 Tin 0.05-0.2 Antimony 0.1-0, 5 Iron. The rest. Antimony in this composition of the ligature reduces the graphitizing effect of silicon and aluminium.h, contributes to the grinding of graphite inclusions in the process of crystallization of carbon alloys. The content of antimony and other components (aluminum and silicon) at the lower limit provides for obtaining the pearlite structure of cast iron, which has enhanced mechanical properties. With an increase in the content of graphitizers, their action is localized by an increase in the content of antimony to the upper limit. Example. To prepare the ligature, four mixtures of ingredients were prepared, each containing 55 wt.%. . t., "66". ir frf 4 silicon, 0/5 Be.% aluminum, 0.1 wt.% tin, but differing from each other in antimony, equal in each mixture to 0.1 wt.%, 0.3 wt.%, 0, 5 wt.% And 0.7 wt.%, As well as the iron content, was u-. We can add up to 100% of the J mixture to the mixture.

20.8 22.3 24.8 18.1

As can be seen from the table, the highest mechanical properties of gray iron are observed when the melt is treated with a ligature containing 25% antimony in it 0.1-0.5 wt.%. This forms a fine pearlite structure with dimensions of graphite inclusions of 25-30 microns. The mechanical properties of cast iron treated with a ligature of a pre-30 composition are increased by an average of 1.2-1.4 times. An increase in the content of cypbNM in the ligature of more than 0.5 weight;% leads to a decrease in the tensile strength of the cast iron during bending due to the excessive jigging effect of antimony.

Improving the mechanical properties of gray iron by treating with additives with the proposed ligature makes it possible to increase the structural reliability of -.,.

kindergartens and improve their quality. The processing technology of gray iron with the proposed ligature does not complicate

general technological process and does not cause other changes.

Claims (1)

1. USSR author's certificate 395481, cl. C 22 C 35/00, 1971. 74 Gray cast iron is treated with vyieuk-j with a ligature in the amount of 0.3% by weight of the molten metal by inserting pieces of ligature measuring 5-10 mm to the bottom of the casting ladle. The obtained test data are shown in the table.