SU1617030A1 - Alloying composition for treating cast iron - Google Patents

Abstract

The invention relates to foundry and can be used to produce castings for cylinder liners of diesel engines. The purpose of the invention is to increase the hardness and wear resistance of the processed iron. This goal is achieved due to the fact that the mixture additionally contains oxides of niobium, phosphorus and limestone in the following ratio of components, wt.%: Carbon-containing material 10-30, oxides of niobium 2-6, oxides of phosphorus 2-10, known to 2-5 FS75 rest. 1 tab.

Description

(Ls

The invention relates to foundry and can be used to produce castings of cylinder liners for diesel engines.

The purpose of the invention is to increase the hardness and wear resistance of processed cast iron.

The proposed mixture additionally contains oxides of niobium, phosphorus and limestone in the following ratio of components, wt.%:

Carbon content

material

Niobium oxides

Phosphorus oxides

Known to

Ferrosilicon FS75

The presence of

10-30 2-6 2-10 2-5

The rest:; mixture of carbon-containing material and ferrosilicon FS75 provides a more complete course of redox reactions with oxides of niobium and phosphorus. Moreover, silicon is more active at low temperatures up to, and carbon - at. higher. In addition, the reaction products in the form of oxides are activated by carbon and are effective additional crystallization centers when the melt is cooled.

As carbonaceous material, coking or electrode chips can be used.

Entering niobium oxides into the mixture allows the doping of pig iron due to the effective reduction of niobium by carbon and silicon during the melt processing. This in turn increases the hardness of cast iron due to the use of metal Cft.

sl

About 00

ical basis. The content of niobium oxides in a mixture of 2–4% was chosen based on the need to provide additional alloying of the liner iron with niobium in the range of 0.08– 0.25%. When the concentration of niobium oxides in the mixture is below 2%, the required level of doping is not achieved. Exceeding the oxide content of more than 4% due to excessive doping significantly reduces the workability of the iron.

The presence of phosphorus oxides in the mixture provides an additional 15 doping of the pig iron with phosphorus, which is very important for the cylinder liners of diesel engines in terms of improving the wear resistance of the part. The limits of the content in the mixture of phosphorus oxides were chosen from 20 of the following considerations: the lower concentration limit (2%) is due to the level of phosphorus doping of pig iron, in which a phosphide eutectic in the form of a 25 broken mesh is formed in the structure of the alloy, which significantly improves its wear resistance.

The upper limit of the content of phosphorus oxides in the mixture (10%) is limited due to a reduction in the tensile strength of cast iron. The presence of lime in the mixture makes it possible to liquefy slag, thereby accelerating the flow of acid-reducing reactions between the components of the mixture and the melt. The lower limit of the content of limestone in the mixture (2%) is due to the production of a hydraulic fluid that improves diffusion processes. The upper limit of lime content (5%) is limited due to the reduced lining resistance of the melting furnace.

Example. Under production conditions, cast iron is produced, containing - j,%: carbon 3.2; silicon 2.0; manganese 0.8; chromium 0,3; copper vanadium 0.1; iron else. The molten melt with a dispensing bucket is re-burning a arc electric furnace with a simultaneous introduction of an alloying mixture in it in an amount of 3% and containing, in wt.%: Niobium oxides 1-7-, phosphorus oxides 1-11; known to 1-6; carbon-containing material 9 - 32-; the rest is ferrosilicon FS75.

Then, the pig iron is superheated to a temperature of 1460 ° C, holding for 5 minutes to average the metal by chemical composition. Cast iron out

 it is produced into a bottling ladle with its subsequent modification with a complex ligature FSZORZMZO.

Pour samples in to study hardness and wear tests.

The wear tests are carried out under boundary lubrication conditions on an MT-2 machine. High-strength cast iron HF50-2o is used as a counterbody. The amount of wear is estimated by the gravimetric method (g / 1000 m of the sample run).

The results of comparative tests of the known and proposed mixtures for the treatment of cast iron and their properties are given in table. 1 and 2o

The use of the proposed mixture for the treatment of cast iron improves the hardness and wear resistance and, when producing castings for cylinder liners, provides an increase in the motor life of the cylinder-piston group of diesel engines. In addition, it is possible to eliminate the surface hardening of HDTV sleeves and thereby reduce their cost. manufacturing.

The alloying mixture is prepared by mixing the components previously crushed on the runners.

about rm y

the invention

Cutting a mixture of pig iron for processing, including carbonaceous material and ferrosilicon FS75, is different from that, in order to increase the hardness and wear resistance of the pig iron, it additionally contains oxides of niobium, phosphorus and limestone in the following ratio of components, wt.

Carbon.containing

material10 - -30.

Niobium oxides 2-6

Oxides of phosphorus 2-10

Known k2 - 5.

Ferrosilicon

FS75Everything Else

1617030

 6 Table 1

table 2

Claims (1)

Claim The alloying mixture for processing cast iron, including carbon-containing material and FS75 ferrosilicon, characterized in that, in order to increase the hardness, wear resistance of the treated cast iron, it additionally contains niobium, phosphorus and limestone oxides in the following ratio, wt.%: Carbon containing material 10 - -thirty Niobium Oxides 2 - 6 Phosphorus oxides 2 - 10 Limestone 2 - 5 Ferrosilicon FS75 Rest Table 1 Mixture Component Content Limits The composition of the mixture,% Carbon material Niobium Oxides Phosphorus oxides Limestone Ferrosilicon FS75 Molybdenum Oxides Known Offer Average . 20 - - Rest 20 gay Lower 10 2 2 2 Also ·. Average 20. 4 6 3,5 - Upper Lower Bottom thirty b 10 5 - him Above top 8 1 1 1 - him 32 7 eleven 6 - table 2 Mixture Component Content Limits Hardness, HB Depreciation, g / 1000 comrade Famous naya Average 210 0,045 Offers Lower 217 0,040 gay Average 229 0,032 Upper 241 0,026 : Below the bottom him 212 0,044 Above top him 248 0,022