SU1712444A1 - Method of producing cast iron with vermicular graphite - Google Patents

Abstract

The invention relates to methods for producing iron with vermicular graphite. The purpose of the invention is to increase the strength of cast iron. The method consists in introducing into the ladle a modifier containing 40-60% by weight of LCKK-4P ligature. CCE-MISh-1 ligatures (the rest) 6 as a mechanical mixture in the amount of 1.0-1.1% of the weight of the melt processed together with 0.45-0.55% silicocalcium. As a result of processing by the proposed method of producing pig iron, containing,%: C3.6-3.9: Si 2.0-2.3; Mp 0.4-0.8. its strength was 430-460 MPa. 1 h. p, f-ly, 1 tab.

Description

The invention relates to foundry, in particular, to methods for producing castings from iron with vermicular graphite accelerated crystallization, a; also by sand casting without noc / ie heat treatment.

The purpose of the invention is to increase the strength of cast iron.

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The cast iron is melted in a YV-100 induction furnace in a crucible with an acid lining; To process cast iron, a mixture of ligatures is laid at the bottom of the ladle under a stream of metal. The initial cast iron before the modification has a chemical composition /%: C 3.6-3.9; St 2.0-2.3; MP 0.4-0.8; P less than 0.1; S 0.02 &. The cast iron is modified at. 1420–1480 ° C. After modifying the cast iron, experimental castings of wedges of 120x100x30 size and stepped cylindrical samples with a diameter of 30 and 60 MNH are cast, which are poured over metal and lined molds

Noah 10 mm). For comparison, the same castings are poured into sand molds.

The investigated compositions of modifiers for cast iron are given in the table.

Test specimens are cut from 60 mm diameter cylindrical specimens cast in sand molds. Test samples for rupture carried out on cylindrical samples D 10 mm according to GOST 1497-84. For comparison, cast iron is treated with LCKK-ZR ligature (prototype).

The modes of the process and the strength of cast iron, processed by the proposed and known methods are shown in the table.

As follows from the data presented in the table, the treatment of cast iron according to the proposed method can significantly increase the strength of cast iron. At the same time, the analysis of the microstructure of the cast samples showed the absence of cementite in the structure and the predominant production of graphite of a vermicular shape against the background of a perlite-ferrite matrix.

F o rm u l a i 3 o b ri e n 1 l 1. A method for producing iron with vermicular graphite, including the introduction of a modifier into the ladle containing a JShK-4R ligature in the amount of 1.0-1.1% of the mass of the melt to be processed, characterized in that, in order to increase the strength of the iron, the modifier additionally contains the ligature SCSRISH-1 in the following ratio of components, wt.%:

ZhKMK-4R, 40-60

SCEMISH-1Everything Else

and together with it, silicocalcium in the amount of 0.45-0.55% of the mass of 5 melts is introduced into the ladle.

2. The method according to p. 1 ,. This is due to the fact that the modifier is a mechanical mixture of ligatures. ten

Claims (2)

Claim 1. A method of producing cast iron with vermicular graphite, comprising introducing into the ladle a modifier containing ZhKMK-4P ligature in an amount of 1.0-1.1% by weight of the processed melt, characterized in that, in order to increase the strength of cast iron, the modifier is additionally contains ligature SCEMISH-1 in the following ratio of components, wt.%: ZhKMK-4R. 40-60 SCEMISH-1 The rest and, together with it, silicocalcium is introduced into the ladle in the amount of 0.45-0.55% by weight of melt 5. 2. The method of claim 1, wherein the modifier is a mechanical mixture of ligatures. Way Modifier Composition Input amount of modifier,% The entered amount of silicocalcium,% a _{V /} MPa Ligature ZhKMK-4R Ligature SCEMISH-1 Offering 40, 60 1.0 0.5 435 my Also fifty fifty 1.0 0.45 430 60 40 1,1 0.5 460 fifty fifty 1,0 0.55 460 Famous Ligature Modification ZhKMK-ZR together with 0.2-0.3% Al I 428