RU2785668C1 - Steel corner - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, and in particular to counter-rail corners made of alloyed steel, used on turnouts of railway tracks. The angle is made of steel containing in wt.%: carbon 0.70-0.75, manganese 0.85-0.95, silicon 0.60-0.70, chromium 0.25-0.35, aluminum 0, 02-0.05, phosphorus not more than 0.030, sulfur not more than 0.030, nickel not more than 0.020, copper not more than 0.25, nitrogen not more than 0.010, iron - the rest, and has a tensile strength of not less than 1000 MPa and a relative elongation of not less 10.0%.

EFFECT: increased wear resistance, defect resistance, mechanical properties, as well as operational stability of counter-rail angles.

1 cl, 2 tbl

Description

The invention relates to the field of metallurgy, in particular to rolling production and can be used to increase the service life of the corners of the counter-rail used on railroad turnouts.

Known steel grade E68 [1] according to GOST R 55497-2013 “Railway counter-rail rails. Specifications”, having the following chemical composition (in wt.%):

carbon 0.62-0.73 manganese 0.70-1.00 silicon 0.13-0.28 vanadium 0.03-0.05 iron rest

The disadvantage of this steel is that the counter-rail corners made of E68 steel have strong lateral wear, which leads to their premature failure and an increase in the cost of maintaining turnouts.

Known steel for the manufacture of counter-rail angle [2] patent RU No. 2440436 ("Steel" application No. 2009149720 dated 12/30/2009, MPK6 V22S 38/46, publ. 10.07.2011, bull. No. 19), containing, wt.%

carbon from more than 0.60 to 0.75 manganese 0.70-1.10 silicon from more than 0.39 to 0.60 chromium 0.20-0.60 aluminum to less than 0.003 vanadium from more than 0.07 to 0.15 nitrogen from more than 0.015 to 0.020 nickel 0.03-0.20 iron and impurities rest

at the same time, as impurities, the steel contains sulfur not more than 0.020%, phosphorus not more than 0.025%, copper not more than 0.15%.

The disadvantage of this steel is that counter-rail angles made of this steel do not have increased wear resistance.

The closest analogue (prototype) to the claimed invention is steel grade K68 [3] (according to TU 0921-245-01124323-2007 “Counter-rail corner SP 850. Technical conditions), having the following chemical composition (in wt.%):

carbon 0.60-0.73 manganese 0.70-1.00 silicon 0.13-0.28 vanadium 0.03-0.07 iron rest

The disadvantage of this steel is that the counter-rail angles made of K68 steel have strong lateral wear, which leads to their premature failure and an increase in the cost of maintaining turnouts.

Most modern designs of turnouts operated on Russian railways have cross-pieces with a "rigid" cross-piece. The composition of these cross units, as an integral part of them, includes counter rails that ensure the safety of the passage of the rolling stock through the harmful space of the crosses. In most turnout projects, counter rails are used from the corner of the counter rail SP850.

In conditions of intensification of transportation, increase in axial loads of the rolling stock and speeds of trains, the loads on the track and elements of turnouts increase.

The technical result to which the claimed solution is directed is: an increase in wear resistance, defect resistance, an increase in the mechanical properties and operational stability of the control rail corner used on railroad turnouts.

The specified technical result is achieved by the fact that the counter-rail corner is made of steel containing carbon, manganese, silicon, chromium, aluminum, phosphorus, sulfur, nickel, copper, nitrogen, iron, according to the invention, all components are selected in the optimal ratio for the task being solved, wt. %: carbon 0.70-0.75; manganese 0.85-0.95; silicon 0.60-0.70; aluminum 0.02-0.05; phosphorus not more than 0.030; sulfur not more than 0.030; copper not more than 0.25; chromium 0.25-0.35; nickel not more than 0.020; nitrogen not more than 0.010; iron is the rest.

The limits of the content of the components in the claimed alloy steel obtained experimentally.

The proposed chemical composition of alloy steel for the manufacture of counter rail angle provides mechanical properties: tensile strength of 1060 MPa and relative elongation of 12.6%.

The claimed alloy steel has the following quantitative composition (wt.%) and qualitative composition:

• carbon content in the range from 0.70 to 0.75%, with the claimed

the ratio of other components of alloy steel determines its strength. With a carbon content of less than 0.70%, the required level of hardness and strength is not achieved. With a carbon content of more than 0.75%, the probability of brittle fractures increases.

• manganese content in the range from 0.85 to 0.95%, with the declared

the ratio of other components of alloyed steel determines the increase in the strength of steel. When the manganese content is less than 0.85%, it does not provide the hardness and strength of the counter-rail corner. With a manganese content of more than 0.95%, the probability of brittle fracture increases.

• silicon content in the range from 0.60 to 0.70%, with the claimed

the ratio of other components of alloyed steel is necessary for steel deoxidation and to increase strength. When the silicon content is less than 0.60%, it increases the yield strength and strength. When the silicon content is more than 0.70% leads to a decrease in ductility.

• aluminum content in the range from 0.02 to 0.05%, with the declared

the ratio of other components of alloyed steel, is a technological additive for steel deoxidation. When the aluminum content is less than 0.02%, the required deoxidation of steel does not occur. An increase in the aluminum content of more than 0.05% leads to a complication of casting and an increase in the cost of steel.

• Limiting the concentration of phosphorus, sulfur and copper due to

improving the surface quality of the finished product after rolling and improving its physical and mechanical properties.

• phosphorus content not more than 0.030% and sulfur content not more than

0.030%, with the claimed ratio of other components of alloyed steel, are a harmful impurity in steel, in an amount of more than 0.030% drastically worsens the performance properties of the product.

• the copper content is not more than 0.25%, with the claimed ratio of other components of alloyed steel, is an accompanying element, with its amount above 0.25%, it does not have a positive effect on steel.

• chromium content ranging from 0.25 to 0.35%, nickel not more than 0.020,

with the claimed ratio of other components of alloyed steel, are alloying elements that improve strength characteristics. In the present invention, the best ratio of their mass fractions is selected to maximize strength.

• Below 0.25% chromium, the strength of the steel is reduced. At

above 0.35%, plasticity decreases and brittleness increases.

• Nickel content not more than 0.020 contributes to the increase in shock

viscosity, however, when the content is less than 0.020%, its effect is insignificant, and exceeding the limit of 0.020% reduces the toughness.

• nitrogen content is not more than 0.010%, at the claimed ratio

other components of alloy steel, allows to obtain a crushed austenite grain, which provides an increase in strength properties and an increase in resistance to brittle fracture. When its amount is more than 0.010%, grain refinement is impossible and, as a result, the necessary hardening of steel is not provided, which also leads to a decrease in impact strength.

The claimed technical result is achieved using the quantitative and qualitative composition of the components, and does not depend on the sequence (order) of their addition to the melt, and also on whether they are added in pure or in the form of a ligature.

To determine the mechanical properties and impact strength, steels of experimental heats were smelted in the converter shop No. 1 of EVRAZ Nizhny Tagil Metallurgical Plant JSC with the declared boundary, beyond the boundary, as well as optimal values. The chemical composition of the obtained steels is shown in Table 1. After casting the steel on the CCM, a counter-rail angle of the SP850 type was rolled. The results of testing the mechanical properties of the obtained steels in the hot-rolled state in comparison with the prototype are presented in table 2. According to the test data, the inventive steel in comparison with the prototype has the following advantages: the mechanical properties of the angle increase and, accordingly, its operational durability

This technology for the production of rolled products, in accordance with the claimed composition of steel and the fulfillment of the specified optimal ratios between the elements, allows to obtain an increase in the mechanical properties of the corner of the counter-rail.

Table 1 shows the composition of the proposed steel and the composition of steel grades according to K68 and according to TU 0921-245-01121323-2007.

The analysis of patents and scientific and technical information revealed the absence of features similar to those inherent in the proposed technical solution, which allows us to conclude that it meets the criterion of "inventive step".

The use of the claimed alloy steel for the manufacture of the counter-rail angle allows you to provide:

1) increasing the wear resistance and defect resistance of the counter rail corner;

2) improving the mechanical properties of the counter rail corner;

3) increasing the operational stability of the corner of the counter rail.

Experimental development and use of the proposed technical solution at EVRAZ Nizhny Tagil Metallurgical Plant JSC confirms compliance with the criterion of "industrial applicability of the invention".

Table 1 Components steel Chemical composition of steel, wt.% Claimed steel Steel K68 according to TU 0921-245-01121323-2007 Steel grade K68 (prototype) Examples one 2 3 4 carbon 0.60 0.73 0.60-0.73 0.69 manganese 0.80 0.89 0.70-1.00 0.92 silicon 0.50 0.66 0.13-0.28 0.20 chromium 0.10 0.25 - 0.028 aluminum 0.01 0.032 - 0.0033 phosphorus 0.020 0.014 No more
0.030 0.018 sulfur 0.020 0.0038 No more
0.025 0.0020 nickel 0.010 0.047 - 0.048 copper 0.20 0.009 - 0.009 nitrogen 0.005 0.0041 - 0.0061 iron rest rest rest rest

table 2 Steel properties Mechanical properties Examples Steel K68 according to TU 0921-245-01121323-2007 Steel K68 (prototype) Examples one 2 3 4 Tensile strength, MPa 890 1060 Not less than
900 992.4 Relative extension, % 7.8 12.6 Not less than
eight 11.7

Sources of information

[1] E68 according to GOST R 55497-2013 “Railway counter-rail rails. Specifications";

[2] patent RU No. 2440436 (“Steel”, application No. 2009149720 dated 12/30/2009, MPK6 V22S 38/46, publ. 10.07.2011, bull. No. 19;

[3] K68 according to TU 0921-245-01124323-2007 “Counter-rail corner SP 850. Specifications.

Claims (3)

Counter-rail angle made of alloy steel, characterized in that it is made of steel containing components in the following ratio, wt.%: Carbon 0.70-0.75 Manganese 0.85-0.95 Silicon 0.60-0.70 Aluminum 0.02-0.05 Phosphorus no more than 0.030 Sulfur no more than 0.030 Copper no more than 0.25 Chromium 0.25-0.35 Nickel no more than 0.020 Nitrogen no more than 0.010 Iron rest, and has a tensile strength of at least 1000 MPa and a relative elongation of at least 10.0%.