SU1416513A1 - Method of modifying gray iron - Google Patents

Abstract

The invention relates to metallurgy and can be used in the modification of gray iron. The purpose of the invention is to stabilize the mechanical properties of the iron during the full casting of the modified melt. A new method of modifying: gray iron includes the simultaneous introduction of a silicobar into an iron melt at equal intervals of time and an amount of 0.05-0.15% by weight and pitch in an amount of 0.10-0.25% by weight of the modifier introduced. The use as a pitch inhibitor, as well as a batch injection of a silikobar, ensures the stabilization of the tensile strength at stretching in the range of MPa, at bending in the range of 520–551 MPa and hardness of HB in the range of 220–224. (/)

Description

Od

SP

The invention relates to metallurgy, in particular to the development of methods for the modification of gray iron.

The purpose of the invention is the stabilization of the mechanical properties of cast iron during the complete casting of the modified melt.

The essence of the invention lies in the batch injection of silicobars and leks during the casting process of the modified iron melt. The choice of the boundary limits for the consumption of the modifier and inhibitor is determined by the following.

With the introduction of a silikobar into the melt of less than 0.05 wt.%, The density of microinhomogeneous silicon and barium floes is not sufficient, and the introduction of more than 0.15 wt.% Is impractical, iTEK leads to over-expenditure of the modifier.

: To maintain the microscopic density of silicon and barium constant Over time, it is necessary to introduce a silicobarium every min.

 Thus, the addition of 0.05– OjlS wt.% of the modifier to the melt every 5 O min leads to an increase in the structural stability, and hence to the stability of the mechanical properties.

When introduced into cast iron simultaneously with a pitch modifier in an amount of less than 0.1% by weight of the modifier, the partial pressure of CO vapor is insufficient to form a non-oxidizing atmosphere, which leads to an increased oxidation of the modifier and an increase in its consumption. The introduction of more than 0.25% of the pitch by weight of the modifier is not feasible, since this interval completely ensures the creation of a non-oxidizing atmosphere,

PRI im p Modified cast iron of the following chemical composition, wt.%: Carbon 2.8; silicon 1.45; manganese 1.0; sulfur 0.07; phosphorus 0.09. When modifying, a silikobarium with 15% barium was used at a rate of

0.7% of molten iron and a modifying effect duration of 8 min. Liquid iron was poured into a 1-ton drum bucket, in a special {sumera of which was placed silico barium and pitch (chemical composition of pitch,%: C 62, Hj 8, Oj 10, N4 U T 78-215 ° C), which is the residue after the sublimation of the resins obtained as a side product in the gas generators. Every 5 minutes, samples for mechanical properties were poured. In the second ladle, treatment with silicobarium was performed every 5 min with pouring samples for mechanical properties.

Cast iron, modified in a known manner, had the characteristics given in the scoreboard5 "

The mechanical properties of cast iron modified by the proposed method are given in Table 2o.

As can be seen from Table 2, batch treatment with silicobarium and the use of pitch as an inhibitor ensure stabilization of the ultimate tensile strength in the range of 34.0–34.6 kG / mm, bending 52.0–55.1 and hardness HB 220-224.

Claims (1)

Invention Formula A method for modifying gray iron, including the simultaneous introduction of a silicobar modifier and an inhibitor into liquid iron, which is intended to stabilize the mechanical properties of the iron during the complete casting of the modified melt, into the melt before the casting process in portions of 0.05-0.15 wt.% at equal intervals of time, and as a inhibitor it is used as a inhibitor with a flow rate of 0.1-0.25% by weight of the input modifier portion. Table 1