RU2274672C1 - Cast iron - Google Patents

Abstract

FIELD: metallurgy; iron casting production.

SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular, to iron casting production and may be used for production of body castings with the various depth of walls. The cast iron contains (in mass %): Carbon - 3.0-3.5; silicon - 1.7-2.2; manganese - 0.5-0.8; chrome - 0.15-0.30; copper - 0.5-0.8; brimstone - 0.05-0.12; phosphor - 0.2; stannum - 0.5-0.1; strontium - 0.0014-0,0023; zirconium - 0.0020-0.0038; iron - the rest. The technical result is reduction of shrinkage of porosity.

EFFECT: the invention ensures reduction of shrinkage of porosity.

3 tbl

Description

The invention relates to metallurgy of foundry, in particular, to the development of cast iron compositions for case castings with different wall thicknesses.

Closest to the proposed cast iron in technical essence and the achieved result is cast iron (1) of the following chemical composition, wt.%:

Carbon 3.0-3.5 Silicon 1.7-2.2 Manganese 0.5-0.8 Chromium 0.15-0.30 Copper 0.5-0.8 Sulfur 0.05-0.12 Phosphorus 0.2 Barium 0.003-0.015 Calcium 0.007-0.025 Tin 0.05-0.1 Iron rest

The disadvantage of this chemical composition of cast iron is the tendency of complex spaced castings from this cast iron to shrink porosity in the inner walls. It is impossible to bring nourishing profits to the internal parts of these castings to feed thermal units. Therefore, it was necessary to select the chemical composition of cast iron, castings from which would not have shrinkage porosity. Table No. 1 presents the marriage of cylinder blocks according to the "leak" defect. As studies of rejected cylinder blocks showed, the cause of the leak was the shrinkage porosity in the interior of the cylinder block. The marriage of castings of cylinder blocks from this cast iron was 15% (see table No. 1).

The technical task of this invention is to reduce the marriage of cylinder blocks on the defect "leak" (shrinkage porosity).

The technical result is achieved by the fact that cast iron containing carbon, silicon, manganese, chromium, copper, tin, sulfur, phosphorus, additionally contains strontium and zirconium in the following ratio of components, wt.%:

Carbon 3.0-3.5 Silicon 1.7-2.2 Manganese 0.5-0.8 Chromium 0.15-0.30 Sulfur 0.05-0.12 Phosphorus 0.2 Tin 0.05-0.1 Strontium 0.0014-0.0023 Zirconium 0.0020-0.0038 Iron rest

Analogues containing the distinguishing features of the proposed technical solution were not found.

At GAZ, in a foundry, comparative melts were conducted with the known and proposed cast irons, with the filling of cylinder blocks.

Cast iron was smelted in a cupola with fine-tuning it by chemical composition in an electric arc furnace. As a charge, pig-iron pig irons, SCh 28 cast iron return, steel waste, cathode copper, tin and ferroalloys were used. Strontium and zirconium were introduced in the form of modifiers Supersid 75 and Supersid Extra in the amount of 0.3% by weight of the metal in the bucket. The chemical composition of the modifiers is given in table No. 1.

Table 1
Chemical composition, % Modifier Name Si Sr Zr Al Sa SuperSid 75 (t.u.) 73-78 0.6-1.0 up to 0.5 Up to 0.1 SuperSid 75 (fact) 75.0 0.75 - 0.31 0.05 Supersid Extra (t.u.) 73-78 0.6-1.0 1.0-1.5 up to 0.5 up to 0.1 Supersid Extra (fact) 74.7 0.78 1.27 0.32 0.04

The metal was overheated in an arc furnace to 1500 ° C and filled cylinder blocks with known and proposed chemical composition. Table No. 2 shows the chemical composition of the proposed and known cast irons. Table 3 shows the leakage of cylinder blocks after leakage after machining and density tests from the proposed and well-known cast irons.

table 2 Cast Iron No. FROM Si Mn Cr R S Cu Sn Zr Sr Ba Sa Fe Suggested 1 3.0 1.7 0.5 0.15 0.7 0.05 0.5 0.05 0.0015 0.0010 - - rest 2 3.0 1.7 0.5 0.15 0.7 0.05 0.5 0.05 0.0020 0.0014 - - rest 3 3.2 2.0 0.6 0.2 0.8 0.08 0.7 0.08 0.0028 0.0018 - - rest four 3,5 2.2 0.8 0.3 0.9 0.12 0.8 0.1 0.0038 0.0023 - - rest 5 3,5 2.2 0.8 0.3 0.9 0.12 0.8 0.1 0.0045 0.0025 - - rest 6 3.2 2.0 0.6 0.2 0.8 0.08 0.7 0.08 - 0.0018 - - rest 7 3.2 2.0 0.6 0.2 0.8 0.08 0.7 0.08 0.0028 - rest famous 8 3.2 2.0 0.6 0.2 0.8 0.08 0.7 0.08 - - 0.007 0.012 rest 9 3.25 2.1 0.7 0.18 0.75 0,085 0.7 0.08 - - 0.005 0.007 rest

As can be seen from tables No. 2 and 3, the proposed (cast iron No. 2-4) cast iron marriage in the "leak" is 2.5-3 times lower than that of the known (cast iron No. 6, 7), and the optimal content of strontium and zirconium are 0.0014-0.0023% and 0.0020-0.0038%, respectively.

The strontium content is less than 0.0014, i.e. 0.0010% - cast iron No. 1 is insufficient and the leakage on the “leak” of the cylinder block was 6%. The strontium content is more than 0.0023%, i.e. 0.0025% and zirconium more than 0.0038%, i.e.

table 3 Cast Iron No. Defective cylinder leakage,% Suggested 1 6.0 2 3.45 3 3.35 four 3.20 5 3.20 6 7.0 7 5,0 famous 8 8.0 9 9.0

0.0045% is unnecessary because the leakage does not decrease (cast iron No. 6, 7 of table No. 2, 3).

Entering only one element of strontium does not give a large reduction in leakage on a leak (cast iron No. 6 of tables No. 2, 3).

Entering only one zirconium element reduces leakage by “leakage” only up to 5% (cast iron No. 7, tables No. 2, 3). And the combined presence of strontium and zirconium sharply reduces the leakage of cylinder blocks along the "leak" to 3.25-3.45%.

Bibliography.

1. Yu.A. Zinoviev et al. "Cast iron" A.C. 2218442, MKI C 22 C 37/10.

Claims (1)

Cast iron containing carbon, silicon, manganese, copper, chromium, sulfur, phosphorus, tin and iron, characterized in that it additionally contains strontium and zirconium in the following ratio, wt.%: Carbon 3.0-3.5 Silicon 1.7-2.2 Manganese 0.5-0.8 Chromium 0.15-0.30 Copper 0.5-0.8 Sulfur 0.05-0.12 Phosphorus 0.2 Tin 0.05-0.1 Strontium 0.0014-0.0023 Zirconium 0.0020-0.0038 Iron Rest