Rails are iron profiled rolled products in the form of strips, fastened with beams and intended for the movement of rolling stock of railways and subways, trams, trains and trolleys of mining transport and monorails and in general any mobile, turning and rotating structures.

Rails are parts of the upper structure of the road, laid on supports and fastened to them and to each other to form a rail track. The rails directly take the pressure of the wheels of the rolling stock.

We present railway rails produced by the Novokuznetsk Metallurgical Plant of the following types:

Railway rails - rails intended for sectional and continuous railway tracks and for the manufacture of turnouts, are produced in accordance with GOST R 51685-2000.

Rails are divided into types: P50, P65 (for external threads of curved sections of the road, GOST 8161-75) and P75.

Railway rails are made from steel grades K78ХSF, E76, E78ХSF, М76Ф, К76Ф, E76Ф, К76Т, М76Т, E76Т, М76, К76.

Rail designation scheme: rail type, quality group, steel grade, rail length, presence of bolt holes, designation of this standard.

Rails for industrial railway tracks - wide gauge rails intended for railway tracks and switches of industrial enterprises are produced in accordance with GOST R 51045-97 and are divided into 3 types: PP50, PP65 and RP75.

This type of rail is made from carbon steel grade 76 and special carbon microalloy steel grades 76T, 76F and 76Ts.

Rail designation scheme: rail type, rail length, bolt grooves (2 - on both ends, 0 - without holes), rail hardening (T - heat-strengthened, H - non-heat-strengthened), steel grade, standard designation.

Broad gauge railway rails made of open hearth steel - broad gauge railway rails of types P75, P65 and P50 made of open hearth steel are manufactured in accordance with GOST 24182-80. The design and dimensions of the rails are calculated according to GOST 7174-75, GOST 8161-75 and GOST 16210-77.

Rails are manufactured in 2 accuracy groups:

Group 1: rails are made of mild open-hearth steel, deoxidized with complex deoxidizers without the use of aluminum. Such rails are marked blue.

Rails R75, R65 are made from steel M76V, M76T, M76VT, M76Ts;

Rails P50 - made of steel M74T, M74Ts.

Group 2: rails are made from mild open-hearth steel, deoxidized with aluminum or, as it is often called, manganese-aluminum alloy. Such rails are indicated by white markings.

For the manufacture of rails R75, R65, M76 steel is used;

For P50 rails, M74 steel is used.

The length of the rails is 24.92; 24.84; 12.42; 12.46 meters.

Railway rails, heat-treated by volumetric hardening in oil - rails P50, P65, P75 made of open-hearth high-carbon steel. Such rails are subjected to heat treatment in accordance with GOST 18267-82 along the entire length using the method of volumetric hardening in oil followed by furnace tempering. The range and chemical composition of such rails is specified in GOST 24182-80.

Hardened rails are divided into first and second grade. Rails of the 1st grade are divided into rails of the first group of classes 1 and 2 and the second group of classes 1 and 2. Rails are sorted into groups and grades according to GOST 24182-80.

Based on materials from the site http://www.corunamet.ru/produkcia/relsi/

The invention relates to the field of ferrous metallurgy, namely to the production of steel used for the manufacture of railway rails. Steel contains carbon, manganese, silicon, vanadium, aluminum, chromium, nickel, nitrogen, iron and impurities in the following ratio of components, wt.%: carbon 0.77-0.84, manganese 0.90-0.95, silicon 0 .20-0.35, vanadium 0.06-0.10, aluminum no more than 0.004, nitrogen 0.010-0.018, chromium no more than 0.15, nickel no more than 0.15, iron and impurities the rest. As impurities, steel contains, in wt.%: sulfur not more than 0.015, phosphorus not more than 0.020, copper not more than 0.20 and oxygen not more than 0.0018. The strength properties of steel, ductility and cold resistance are increased due to the formation of a dispersed structure of hardening sorbitol and an increase in the purity of steel based on non-metallic inclusions. 2 tables

The invention relates to ferrous metallurgy, in particular to the production of steel for the production of railway rails.

Pearlitic rail steel is known containing 0.71-0.82% C; 0.75-1.05% Mn; 0.25-0.60% Si; 0.05-0.15% V; no more than 0.025% P; no more than 0.030% S; no more than 0.02% A1.

The creation of high-strength rails with a tensile strength of more than 1300 N/mm 2 and a relative elongation of at least 12.0%, with increased operational reliability and high resistance to the formation of defects, assumes a homogeneous pearlite structure, which can be ensured by volumetric quenching in oil at a specified wide range of chemical concentrations elements is difficult.

Steels are known having the following chemical composition (wt.%):

0.65-0.8 C; 0.18-0.40 Si; 0.6-1.2 Mn; 0.001-0.01 Zr; 0.005-0.04 A1; 0.004-0.011 N one element from the group containing Ca and Mg 0.0005-0.015; 0.004-0.040 Nb; 0.05-0.3; Fe - oc..

0.69-0.82 C; 0.45-0.65 Si; 0.6-0.9 Mn; 0.004-0.011 N; 0.005-0.009 Ti; 0.005-0.009 Al; 0.02-0.10 V; 0.0005-0.004 Ca; 0.0005-0.005 Mg; 0.15-0.4 Cr; Fe - rest..

Significant disadvantages of these steels are low impact strength and cold resistance, reduced reliability and operational resistance.

In steel, this is determined by the absence of vanadium and low nitrogen content. It has a relatively large austenite grain (points 7-8). The high aluminum content in it leads to its contamination with coarse streak inclusions of alumina, which significantly reduce the contact fatigue strength of the rails.

These disadvantages of steel are associated with the presence of titanium and low vanadium and nitrogen content. Titanium carbonitrides formed in liquid steel during cooling sharply reduce the impact strength and resistance to brittle fracture of rails.

The relatively low content of vanadium and nitrogen does not ensure the formation of the required amount of aluminum nitrides and vanadium carbonitrides necessary to refine the austenite grain and simultaneously increase the strength properties and cold resistance of steel. The austenitic grain in this steel is relatively large and scores 7-8.

Steel is known containing 0.65-0.89% C; 0.18-0.65% Si; 0.6-1.2% Mn; 0.004-0.030% N; 0.005-0.02% A1; 0.0004-0.005% Ca; 0.01-0.10% V; 0.001-0.03% Ti; 0.05-0.4% Cr; 0.003-0.1% Mo; vanadium carbonitrides 0.005-0.08%; in this case, Ca and A1 are in the ratio 1:(4-13); e - the rest.

Significant disadvantages of steel are low impact strength, increased susceptibility to brittle fracture and reduced operational durability, which is due to the presence of titanium in steel, low vanadium content, and high concentration of aluminum. The resulting titanium carbonitrides sharply reduce impact strength and resistance to brittle fracture.

A low concentration of vanadium does not ensure the formation of the required amount of vanadium carbonitrides necessary for additional grain refinement and increasing the strength properties and cold resistance of steel.

The use of a large amount of aluminum to deoxidize steel together with calcium leads to its contamination with accumulations of calcium aluminates rich in alumina, which reduce contact fatigue strength.

The presence of sulfur and phosphorus in steel in large quantities leads to an increase in the red and cold brittleness of steel, respectively.

The steel selected as a prototype is known, containing (wt.%): 0.78-0.88 C; 0.75-1.05 Mn; 0.25-0.45 Si; 0.03-0.15 V; no more than 0.02 Al; no more than 0.020 R; no more than 0.015 S.

Rails made of E83F steel are subjected to volumetric hardening in oil at low temperatures and subsequent tempering.

Significant disadvantages of steel are its increased susceptibility to brittle fracture.

The desired technical result of the invention is the formation of a dispersed structure of hardening sorbitol, increasing the strength properties, ductility, cold resistance, and purity of steel for non-metallic inclusions.

To achieve this, steel containing carbon, manganese, silicon, vanadium, aluminum additionally contains chromium, nickel, nitrogen in the following ratio of components (wt.%):

In addition, its composition additionally limits the amount of impurities in the following ratio (wt.%):

The claimed chemical composition was selected based on the following conditions. The selected carbon content provides, during volumetric hardening, a homogeneous structure of hardening sorbitol with a tensile strength of more than 1300 N/mm 2, elongation of more than 0.12% and contraction of more than 35%.

Rails made of steel containing more than 0.84% ​​C have reduced impact strength at minus 60°C (0.15 MJ/m2). The introduction of Mn, V, Cr is also associated with the need to increase the toughness and wear resistance of steel at the working wheel-rail contact.

The selected ratio of Mn, Si, Ni, Cr in steel containing 0.77-0.84% ​​C ensures a decrease in the austenite transformation temperature and a more dispersed hardening sorbitol structure.

The reduction in manganese content compared to the prototype is due to the introduction of sufficient amounts of chromium into the steel to increase hardenability and resistance to wear. Moreover, the claimed concentrations of Ni and Cr exclude the formation of upper bainite in the microstructure, which is not allowed in the working part of the rail head. However, with a carbon content of 0.77-0.84% ​​and a high concentration of manganese (>0.95%), areas of upper bainite are observed in the structure of heat-strengthened rails.

As a result, the claimed contents of Mn, Si, Cr, Ni provide the required reduction in the transformation temperature of austenite and the formation of a structure of dispersed hardening sorbitol, which has higher mechanical properties, hardness and wear resistance.

The positive effect of small additions of chromium is that, by forming carbides, it increases wear resistance. In the presence of chromium, the ability of Mn and V to inhibit the growth of austenite grains increases.

The introduction of nickel within the stated limits ensures, along with aluminum and vanadium, the guaranteed impact strength of steel at positive and negative temperatures. Its content up to 0.15% has a positive effect on impact strength, and at a concentration of more than 0.15% it is possible to obtain an unacceptable upper bainite structure in rails.

The use of vanadium in steel is due to the fact that it, like Cr and Mn, increases the solubility of nitrogen in the metal, binding it into strong chemical compounds (nitrides, vanadium carbonitrides), which refine the austenite grain and reduce its tendency to grow when heated.

The introduction of V, N within the stated limits into steel leads to refinement of the austenite grain to points 9-12 and a decrease in its tendency to grow when heated due to the formation of dispersed particles of vanadium carbonitrides, to an increase in strength and toughness properties and resistance to brittle fracture (cold resistance). However, without the use of nitrogen, vanadium at high concentrations (>0.1%) reduces the impact strength and increases the cold brittleness of steel. Vanadium increases the endurance limit and improves weldability.

In steel containing at least 0.010% N, the optimal concentration of vanadium is 0.06-0.10%. The lower limit of vanadium content in steel was chosen because it begins to refine grain at a concentration of more than 0.06%. The upper limit of vanadium content is set based on the fact that when its concentration increases above 0.10%, the relative proportion of nitrogen in vanadium carbonitride decreases, and a carbonitride is formed, similar in composition to vanadium carbide, which reduces impact strength.

A nitrogen concentration of less than 0.010% in steel containing less than 0.06% vanadium does not provide the required level of strength properties, impact strength at minus 60°C and austenite grain refinement. When the vanadium and nitrogen content in steel increases to the stated limits, the amount of carbonitrides in it increases, providing an increase in strength properties and cold resistance. However, when nitrogen increases above 0.018%, cases of spotty segregation and “nitrogen boiling” (bubbles in steel) are possible.

Limiting the content of copper, sulfur and phosphorus was chosen to improve the surface quality and increase the ductility and toughness of the steel. In addition, the concentration of sulfur determines the red brittleness, and the concentration of phosphorus determines the cold brittleness of steel.

The claimed chemical composition of rail steel ensures the production of high-strength, wear- and cold-resistant cane rails with increased contact fatigue endurance through volumetric quenching in oil followed by tempering.

Steel of the claimed composition (Table 1) was smelted in a 100-ton electric arc furnace DSP-100 I7 and cast onto a continuous casting machine. The resulting billets were heated and rolled using conventional technology onto P65 type rails, which were subjected to oil quenching from a temperature of 800-820°C and tempering at 460°C. The data given in Table 2 show that the mechanical properties and hardness of volumetrically hardened rails made from the inventive steel are significantly higher than those of rails made from E83F steel. The claimed chemical composition of rail steel also provides a high level of plastic properties and high resistance to brittle fracture (KCU-60°C≥0.2 MJ/m 2). Increasing the hardness, strength, plastic and viscosity properties of rails increases their wear and cold resistance, contact fatigue strength and operational reliability.

List of sources taken into account during the examination

1. GOST R 51685-2000 "Railway rails. General technical conditions."

2. A.s. USSR No. 1435650, M. class. С22С 38/16, 1987

3. A.s. USSR No. 1239164, M. class. С22С 38/16, 1984

4. RF Patent No. 1633008, M. class. С22С 38/16, 1989

5. TU 0921-125-01124328-2001 "Railway rails with increased wear resistance and contact endurance."

Table 1
Chemical composition of steel
Compound	Mass fraction of elements, %
WITH	Mn	Si	V	A1	Cr	Ni	Cu	S	R	N 2	O2
1	0,77	0,90	0,31	0,06	0,004	0,05	0,05	0,05	0,006	0,007	0,012	0,0014
2	0,87	0,95	0,39	0,09	0,002	0,08	0,10	0,10	0,009	0,012	0,014	0,0014
3	0,83	0,95	0,30	0,10	0,004	0,15	0,12	0,12	0,006	0,017	0,017	0,0018
4	0,84	0,90	0,20	0,08	0,004	0,25	0,15	0,15	0,012	0,013	0,015	0,0014
5	0,81	0,95	0,30	0,07	0,002	0,11	0,15	0,15	0,006	0,010	0,020	0,0014
6	0,85	0,90	0,35	0,10	0,003	0,05	0,10	0,10	0,008	0,014	0,018	0,0013
7	0,78	0,91	0,31	0,08	0,003	0,06	0,05	0,05	0,013	0,010	0,013	0,0016
8	0,79	0,95	0,25	0,07	0,003	0,10	0,12	0,12	0,006	0,009	0,015	0,0013
9	0,80	0,93	0,21	0,06	0,002	0,10	0,10	0,10	0,010	0,011	0,018	0,0012
10	0,84	0,94	0,20	0,07	0,004	0,12	0,11	0,11	0,012	0,013	0,020	0,0014
Prototype TU-0921-01124328-2001 Steel E83F	0,78-0,88	0,75-1,05	0,25-0,45	0,03-0,15	no more than 0.02	≤0,15	≤0,15	≤0,20	≤0,025	≤0,25	-	-

table 2
Mechanical properties of rails
Option	σт	σB	δ5	ψ	Hardness	KCU, J/cm 2 at temperature, °C
N/mm 2	%	HB10	HB22	Nvsh	NVpod	NVpkg	+20	-60
1	900	1313	13	40	388	378	352	378	390	49;47	25; 26
2	930	1300	12	39	388	373	363	363	388	47;43	24; 28
3	980	1333	12	43	385	363	352	352	388	45;45	25; 25
4	980	1320	13	42	388	375	363	363	389	44;42	29; 24
5	950	1312	14	43	388	363	375	363	388	45;40	27; 28
6	890	1312	13	40	388	375	375	363	390	44;41	27; 26
7	920	1323	12	39	383	372	363	370	395	41;42	26; 27
8	980	1343	12	33	385	373	363	352	390	37;38	25; 27
9	990	1340	12	39	388	375	375	363	390	36;35	24; 25
10	1000	1350	12	43	388	375	375	363	401	36;35	23; 22
prototype	880	1274	7	26	≥352	≥341	≤401	≤401	≥363	0,2	0,15
Note: НВпкг - hardness on the rolling surface of the rail head;
HB10, HB22 - hardness at a distance of 10 and 22 mm, respectively;
НВш - hardness in the neck;
HBpod - hardness in the sole.

Rail steel containing carbon, manganese, silicon, vanadium, aluminum and iron, characterized in that it additionally contains chromium, nickel, nitrogen in the following ratio of components, wt.%:

at the same time, the amount of impurities in it is additionally limited at
the following ratio, wt.%:

Similar patents:

The invention relates to the field of metallurgy, namely to structural cast steels used in various industries, including in the automotive industry in the manufacture of large-sized castings for mining dump trucks with particularly large load-bearing capacity, operating under high shock loads and in extreme climatic conditions.

The invention relates to the field of metallurgy, namely to steel compositions that can be used for the manufacture of machine parts and equipment operating in harsh conditions, in particular for rolling rolls of pipe electric welding mills.

The invention relates to the field of metallurgy and can be used in the manufacture of welded structures from double-layer rolled products that are operated for a long time at subzero temperatures under conditions of intense mechanical, corrosion-erosion effects of powerful ice fields and sea water, in particular the hulls of nuclear icebreakers, ice-sailing vessels, sea ice-resistant stationary and floating platforms for hydrocarbon production on the Arctic shelf

The invention relates to the field of metallurgy, namely to the production of large hot-rolled sections and shaped products from low-carbon low-alloy steel. Steel contains components in the following ratio, wt.%: carbon 0.08-0.12, manganese 1.30-1.80, silicon from more than 0.50 to 0.80, phosphorus up to 0.030, sulfur from more than 0.01 up to no more than 0.030, chromium up to 0.3, nickel up to 0.3, copper up to 0.3, aluminum more than 0.01, vanadium 0.05-0.10, calcium 0.0001-0.005, nitrogen up to 0.008 and iron rest. The required value of the yield strength of 345 N/mm2 is ensured during the production of large hot-rolled sections and shaped steel without the use of an accelerated cooling system after rolling. 1 ave.

The invention relates to the field of metallurgy, namely to steel used for the manufacture of cutting tool parts. Steel contains, in wt.%: from 0.28 to 0.5 C, from 0.10 to 1.5 Si, from 1.0 to 2.0 Mn, maximum 0.2 S, from 1.5 to 4 Cr, 3.0 to 5 Ni, 0.7 to 1.0 Mo, 0.6 to 1.0 V, trace amounts to a total maximum of 0.4% wt. rare earth metals, the rest is essentially just iron and impurities. After softening annealing, the steel has a matrix comprising overaged martensite containing up to about 5 vol.% of substantially round, uniformly distributed carbides, the matrix being substantially free of grain boundary carbides. The steel has improved machinability, wear resistance and hardenability. 7 n. and 15 salary files, 21 ill., 6 tables.

The invention relates to the field of metallurgy, more specifically to rolling production, and can be used to produce weldable strips of strength category X100 according to API 5L-04 standard, used in the construction of high-pressure oil and gas pipelines. The technical result is to increase the strength properties of strips while ensuring the proportion of the fibrous component in the sample fracture is at least 90%. To achieve a technical result, after steel smelting, continuously cast slabs are obtained, heated to the austenitization temperature, multi-pass rough and finishing rolling is carried out with a regulated temperature at the end of rolling and the strips are cooled with water, while after rough rolling the strips are cooled to a temperature of 720-800°C, finishing rolling are carried out with a relative reduction per pass of 8-25% and a rolling end temperature of 740-790°C, after which the strips are cooled at a rate of at least 17°C/s. Steel is smelted with the following chemical composition, wt.%: 0.06-0.11 C, 0.02-0.04 Si, 1.45-1.95 Mn, 0.15-0.28 Mo, 0.01- 0.06 Nb, 0.01-0.09 Ti, 0.15-0.35 Ni, 0.10-0.30 Cr, 0.002-0.009 N, no more than 0.20 V, the rest Fe. 2 tables

The invention relates to the field of metallurgy, namely to high-strength structural steels, hardened primarily in air, used for the manufacture of axisymmetric body parts. Steel contains carbon, silicon, chromium, manganese, nickel, molybdenum, vanadium, copper, sulfur, phosphorus, iron and inevitable impurities in the following ratio of components, wt.%: carbon 0.18 - 0.24, manganese 1.0 - 1 .5, silicon 0.20 - 0.40, sulfur not more than 0.010, phosphorus not more than 0.015, chromium from more than 3.00 to 3.20, nickel 0.90 - 1.20, molybdenum 0.50 - 0.70 , vanadium 0.10 - 0.20, copper no more than 0.25, iron and inevitable impurities - the rest. After thermomechanical treatment, steel has high plasticity, allowing it to be deformed by rotary drawing in a cold state with degrees of deformation of 50-70% and providing mechanical properties in a strengthened state above 155 kgf/mm2 with a relative elongation of at least 7%. 3 tab., 2 pr.

The invention relates to the field of metallurgy, namely to structural complex-alloyed high-strength steels that are hardened in air, and can be used in the production of axisymmetric parts operating under pressure. Steel contains, in wt.%: carbon from 0.18 to less than 0.2, manganese 1.00-1.3, silicon 0.20-0.40, sulfur not more than 0.010, phosphorus not more than 0.015, chromium 2, 90-3.20, copper no more than 0.25, nickel 2.20-2.50, molybdenum 0.70-0.90, vanadium from 0.15 to less than 0.20, iron and inevitable impurities the rest. After hardening in air and thermomechanical treatment, the temporary tensile strength σB is at least 170 kgf/mm2, and the relative elongation δ5 is at least 6%. 1 ill., 5 tab., 1 pr.

The invention relates to the field of metallurgy, namely to a high-strength steel sheet having a yield strength to tensile strength ratio of 0.6 or more. The sheet is made of steel of the following composition, in wt.%: 0.03-0.20% C, 1.0% or less Si, from more than 1.5 to 3.0% Mn, 0.10% or less P, 0.05% or less S, 0.10% or less Al, 0.010% or less N, one or more kinds of elements selected from Ti, Nb and V, the total content of which is 0.010-1.000%, 0.001-0.01 Ta, the rest Fe and inevitable impurities. The structure of the sheet includes ferrite and a secondary phase including martensite. The area ratio of ferrite is 50% or more, and the average crystal grain size is 18 μm or less. The area fraction of martensite in the secondary phase ranges from 1 to less than 7%. The required strength and formability are ensured while reducing the weight of the sheet. 12 n. and 8 salary files, 6 tables, 1 pr.

The invention relates to the field of ferrous metallurgy, namely to the production of steel used for the manufacture of railway rails

RAIL STEEL

In the USSR, heavy type rails (R75, R65 and R50, 25 m long) are made of high-carbon steel with a high manganese content (Table 36.1). This carbon content is typical for rail steel in the USA and Canada. In other countries it is slightly lower, for example in England 0.50-0.60%, in Japan 0.60-0.75%, in Germany 0.40-0.60% with an increased manganese content (up to 1.2- 1.3%). Abroad, rail steel is smelted in open-hearth furnaces (USA, Canada), oxygen converters (Japan, Germany, England), electric furnaces (Germany), and Thomas converters (France). When smelting rail steel in converters, the quality of the rails decreases due to the increased content of harmful impurities (up to 0.07% P and 0.06% S).

Over the years, the improvement of the chemical composition of rail steel has been carried out in the following main directions:

1. Reducing the content of harmful impurities (sulfur, phosphorus, oxygen, hydrogen) in rail steel in order to increase its purity and metallurgical quality.

2.Increasing the carbon content in steel to eliminate the soft component in its structure - ferrite and increase the amount of solid particles of the second phase - cementite, which is part of thin-plate pearlite. With an increase in the content of rail steel from 0.5 to 0.8% C, its strength, wear and crush resistance increased significantly.

Table 36.1

3. Alloying of rail steel, i.e. increasing its content to more than 1.0% Mn, more than 0.4% Si and introducing into its composition such elements as Cr, Ni, Mo, V, Nb, Ti, etc. This also includes attempts to improve the complex properties of rail steel through modification and microalloying, which amounts to adding small amounts of elements such as Mg, B, Ce and rare earth elements.

The carbon content in rail steel is currently brought to the eutectoid level, above which structurally free cementite is formed. One of the promising directions for modifying rail steel aims to increase the upper permissible limit of carbon content in rail steel to 0.85-0.87% without the release of structurally free cementite.

The best options for non-heat-treated rails made of low-alloy steel made it possible to increase their operational durability on domestic railways by no more than 25%.

In the hot-rolled state (end rolling temperature 1000-1050°C), the grain size in rail steel corresponds to 2-3 points according to GOST 5639-65, after hardening (heating temperature 830-850 °C) it corresponds to 7-8 points. The structure of rail steel in the hot-rolled state is a sorbite-like fine-plate pearlite, sometimes with individual thin ferrite deposits. The hardenability of rail steel is low: when determined by the end hardening method (GOST 5657-69), it is 4-6 mm.

In the USSR, rail steel is mainly smelted in heavy-duty open-hearth furnaces with a capacity of 380-450 tons at the Kuznetsk Metallurgical Plant (KMK), Nizhny Tagil Metallurgical Plant (NTMK) and the Azovstal plant. It is partially smelted in Bessemer converters at the Dnieper Metallurgical Plant named after. Dzerzhinsky (DMZ). A diagram of the technological process of rail production at four domestic rail rolling plants is shown in Fig. 36.3. It shows that in the production of railway rails three types of heat treatment are used: anti-floc heat treatment; thermal hardening of ends; thermal hardening along the entire length.

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Posted on http://www.allbest.ru/

• Introduction
• 1. General characteristics of rail steels
• 2. Chemical composition and quality requirements for rail steel
• 3. Rail steel production technology
• 4. Production of rail steel using modifiers
• Conclusion
• List of sources used

Introduction

Rail steel is a carbon alloy steel that is alloyed with silicon and manganese. Carbon gives steel characteristics such as hardness and wear resistance. Manganese enhances these qualities and increases viscosity. Silicon also makes rail steel harder and more wear-resistant. Rail steel can be made even better with the help of micro-alloying additives: vanadium, titanium and zirconium.

The wide range of requirements imposed in this regard on the quality of railway rails requires the improvement of technological processes, the development, testing and implementation of new technologies and the use of progressive processes in the field of rail production.

The main reason for the low prevalence of production of rails from electric steel is the targeted focus of the construction of modern electric furnaces with large-capacity furnaces to utilize regional scrap resources and provide regions with metal products for industrial and construction purposes. At the same time, fairly high economic efficiency and competitiveness are achieved.

1. General characteristics of rail steels

The production of rails in our country is about 3.5% of the total production of finished steel, and the freight load on railways is 5 times higher than in the USA, and 8...12 times higher than on the roads of other developed capitalist countries. This places particularly high demands on the quality of rails and steel for their manufacture.

Rails are divided into:

- according to types P50, P65, P65K (for external threads of curved track sections), P75;

- quality categories: B - heat-strengthened rails of the highest quality, T1, T2 - heat-strengthened rails, N - non-heat-strengthened rails;

- the presence of bolt holes: with holes at both ends, without holes;

- method of steel smelting: M - from open hearth steel, K - from converter steel, E - from electric steel;

- type of initial billets: from ingots, from continuously cast billets (CCB);

- anti-floc treatment method: made of evacuated steel, subjected to controlled cooling, subject to isothermal exposure.

The chemical composition of rail steels is presented in Table 1. In steel grades, the letters M, K and E indicate the method of steel smelting, the numbers indicate the average mass fraction of carbon, the letters F, C, X, T indicate the alloying of steel with vanadium, silicon, chromium and titanium, respectively.

Table 1 - Chemical composition of rail steels (GOST 51685 - 2000)

Wide gauge railway rails of types P75 and P65 are manufactured according to GOST 24182-80 from open hearth steel M76 (0.71...0.82% C; 0.75...1.05% Mn; 0.18...0 .40% Si;< 0,035 % Р и < 0,045 % S), и более легкие типа Р50 - из стали М74 (0,69...0,80 % С). После горячей прокатки все рельсы подвергают изотермической обработке для удаления водорода с целью устранения возможности образования флокенов. Рельсы поставляют для эксплуатации на железных дорогах незакаленными (сырыми) по всей длине и термоупрочненными по всей длине. Концы сырых рельсов подвергают поверхностной закалке с прокатного нагрева или с нагрева ТВЧ. Длина закаленного слоя от торца рельса 50...80 мм, а твердость закаленной части IIB 311...401. Сырые рельсы из стали М76 должны иметь ов >Ј 900 MPa and 5 > 4%. The rail manufacturing technology must ensure that there are no lines of non-metallic inclusions (alumina) extended along the rolling direction with a length of more than 2 mm (group I) and more than 8 mm (group II), since such lines serve as a source of initiation of contact fatigue cracks during operation.

The high load intensity of railways has led to the fact that the performance of raw, non-heat-strengthened rails no longer meets the requirements of the heavy work of the railway network.

Further increase in the operational resistance of thermally strengthened rails can be achieved by alloying the rail steel. Promising is the alloying of carbon rail steel with small additions of vanadium (-0.05%), the use of alloy steels such as 75GST, 75KhGMF, etc., as well as the use of thermomechanical processing.

2. Chemical composition and quality requirements for rail steel

rail steel chemical carbon

Steels that do not have a grade or code are designated by the number (code) of the corresponding standard and the serial number in this standard. For example, steels in the US standard ASTM A1 are designated as ASTM/1, ASTM/2, etc., steels in the Canadian standard are designated as CN/1, CN/2, etc., steels in Australian standards in accordance with the code standard are designated as AS/1 (standard AS 1085 p.1) and AS/11 (standard AS 1085 p.11).

The carbon content in rail steel is determined depending on the cross-sectional dimensions of the rail. In general, the dimensions of a rail are usually characterized by the mass of its linear meter (kg/linear m). The greater the mass of a linear meter, the higher the carbon content in rail steel should be.

Manganese acts like carbon, increasing the strength and wear resistance of hot-rolled rails. In this regard, in the Australian standard AS 1085 p.1, along with the content of carbon and manganese separately, the total indicator of their content (C+Mn/5) is also standardized. In the ASTM A1 standard, with a high manganese content, the content of nickel, chromium and molybdenum is limited, which is necessary to obtain a uniform structure of rail steel by ensuring a given level of hardenability. In steel grades B, 3B and 90B (standards BS 11, ISO 5003 and UIC 860), the decrease in carbon content is compensated by an increase in manganese content.

In Russian standards (GOST 24182, 18267), in addition to the limits for the content of basic chemical elements - carbon, silicon, manganese, phosphorus and sulfur, standardized in most foreign standards, limits for the content of micro-alloying additives are established: vanadium (steel grades M76V and M74V), zirconium (grades steel M76Ts, K74Ts and M74Ts), titanium (steel grades M76T, K74T and M74T) and vanadium together with titanium (steel grade M76VT), arsenic content is limited< 0,15% для сталей из керченских руд.

Domestic rail steels are similar in the content of manganese, silicon, phosphorus and sulfur. Grades of rail steels for a certain dimensional type of rail differ in microalloying additives. Such steels are practically analogues, therefore in the Consolidated List they are placed one after another with the corresponding foreign analogues indicated in each line. The repetition of one steel grade in two or more lines of the Consolidated List is due to the fact that there is more than one analogue in the standards of one country. For example, the first line of the Consolidated List indicates the domestic steel grade M76 and its analogues: according to the US standard ASTM A1 - ASTM/1, according to the Japanese standard JIS 1124-1124, according to the Australian standard AS 1085 r.11 - AS/11, according to the Canadian standard CNR1 - CN/1 and according to the international standard ISO 5003 - 2A. The second line of the Consolidated List for the same grade of M76 steel indicates other foreign analogues: according to the US AREA standard, the steel is designated AREA/1, according to the Australian standard AS 1085 r.1 - AS/1 and according to the Canadian standard CNR12 - CN/2. Steels CN/1 and CN/2 differ in silicon content, which depends on the method of steel smelting.

A significant improvement in the purity of rail steel and an increase in its metallurgical quality in Russia was achieved as a result of the transition from ladle deoxidation of steel with aluminum to its deoxidation with complex vanadium-silicon-calcium, silicon-magnesium-titanium and calcium-zirconium alloys. Complex deoxidation of rail steel with the listed alloys without the use of aluminum made it possible to eliminate the formation of lines of alumina inclusions in the rail head, which were centers of initiation of contact fatigue damage to the rails. The absence of stitched non-metallic inclusions in the rail head has led to an increase in their operational durability.

In most current standards, the right to choose the method of steel production is given to the manufacturer, and information about the method of steel production is communicated to the consumer through special markings of the rails. There are cases when, depending on the method of casting steel, different limits for the content of chemical elements are set. Thus, in the Canadian standard, the silicon content in steel when casting into ingots is 0.10-0.25%, and during continuous casting of steel - 0.16-0.35%.

An important element of the technological chain for the production of railway rails is anti-floc treatment, which consists of a special cooling mode for heavy-type hot-rolled rails (40 kg/linear m), which ensures the removal of hydrogen. or in vacuum degassing of liquid rail metal before casting. The Canadian Government Railways standard sets the maximum permissible hydrogen content in evacuated steel.

Control of the production technology of rail steel in the hot-rolled state is carried out by determining the mechanical properties during tensile testing of samples cut from the rail head and measuring Brinell hardness. In tensile tests, in most cases, temporary tensile strength (tensile strength) and relative elongation are determined, sometimes - relative transverse contraction.

The macrostructure of hot-rolled rails is also monitored with quality assessment using specially developed macrostructure scales.

The quality of rails is also assessed by the absence or presence of signs of destruction of rail sections as a result of being hit by a falling load. The weight of the falling load (usually 1000 kg), the height of the drop of the load and the distance between the supports on which the tested section (sample) of the rail is installed in a horizontal position are specified depending on the standard size of the rail using an equation or a special table given in the relevant standard. The impact is made in the middle between the supports of the rail sample.

The properties of thermally strengthened rails are assessed in standards by mechanical characteristics: when testing tensile specimens cut from the rail head, impact strength at room and low (-40°C, -60°C) test temperatures and hardness measured by Brinell, Rockwell, Vickers and Shora. The microstructure and depth of the hardened layer are also standardized, which depend both on the chemical composition of the rail steel, which determines the level of its hardenability, and on the heat treatment technology.

3. Rail steel production technology

In top and combined blast oxygen converters, dephosphorization begins from the first minutes of purging. However, at a carbon content of about 0.6 - 0.9%, the phosphorus content in the metal stabilizes or even increases slightly. A further decrease in phosphorus concentration is observed at significantly lower carbon content. Therefore, when the phosphorus content in cast iron is high and blowing is stopped at the grade carbon content, the concentration of phosphorus in the metal is usually higher than the required content in steel.

To obtain the required phosphorus content in high-carbon steel, which is smelted with the cessation of blowing at the grade carbon content, slag renewal is used. At the same time, the productivity of steel-smelting units decreases, and the consumption of slag-forming materials and cast iron increases.

At different plants, the converter is dumped to drain the slag at a carbon content of 1.2 - 2.5%. When the phosphorus content in cast iron is 0.20 - 0.30%, the slag is renewed twice at a carbon content of 2.5 - 3.0% and 1.3 - 1.5%. After downloading the slag, freshly burnt lime is added to the converter. The FeO content in the slag is maintained within 12 - 18% by changing the level of the tuyere above the bath. To liquefy the slag, fluorspar is added during blowing in an amount of 5 - 10% by weight of lime. These measures make it possible to obtain a phosphorus concentration of no more than 0.010 - 0.020% by the time the blowing is completed to the grade carbon content in the steel.

During tapping, the metal is deoxidized in a ladle with ferrosilicon and aluminum. In this case, a mandatory operation is cutting off the converter slag. Getting it into the ladle leads to rephosphorization of the metal during deoxidation and, especially, during out-of-furnace processing under reducing slag for desulfurization.

Blowing the metal in the converter to a low carbon content allows for its deep dephosphorization. In this regard, the technology of smelting rail and cord steel in oxygen converters has become somewhat widespread, which involves the oxidation of carbon to 0.03 - 0.07% and subsequent carburization of the metal in a ladle with petroleum coke, anthracite, etc. The use of such technology requires the availability of clean materials harmful impurities and gases from carburizers. This necessitates special training, the organization of which can create significant difficulties.

Some enterprises use the technology of producing rail and cord steel in oxygen converters by smelting low-carbon metal and then carburizing it with liquid cast iron, which is poured into a steel-pouring ladle before releasing the melt from the converter. Its use requires the presence of cast iron with sufficiently pure phosphorus content. To obtain the carbon content in steel within the required limits, the final carburization of the deoxidized metal is carried out with solid carburizers during vacuum processing.

Due to the low oxygen content in high-carbon rail steel, a high degree of purity for oxide inclusions can be obtained without the use of such relatively complex types of out-of-furnace processing as vacuuming or processing at the UKP. Usually, this is achieved by blowing the metal in the ladle with an inert gas. At the same time, in order to avoid secondary oxidation of the metal, ladle slag must contain a minimum amount of iron and manganese oxides.

For this purpose, when smelting rail steel in arc steel-smelting furnaces, the design of which does not provide for a bay window release of metal, it is recommended to carry out a shortened melting recovery period. To do this, after obtaining the required phosphorus content in the metal, the slag from the oxidation period of the smelting is drained from the furnace. Preliminary deoxidation of steel is carried out with silicon and manganese, which are introduced into the furnace in the form of ferrosilicon and ferromanganese or silicomanganese. Then new slag is placed in the furnace, which is deoxidized with ground coke or scrap electrodes and granulated aluminum before release of the melt. It is also possible to use powdered ferrosilicon for this purpose. The final deoxidation of steel with silicon and aluminum is carried out in a ladle during tapping. After being released into the ladle, the metal is purged with an inert gas for homogenization and, mainly, to remove accumulations of Al2O3. During operation of rails, accumulations of Al2O3 cause delamination in the working part of the rail head. The consequence of delamination can be the complete separation of the peeled plates on the rail head and its premature failure.

A more effective way to prevent the formation of delaminations in rail steel, smelted both in converters and in arc steel-smelting furnaces, is to modify non-metallic inclusions by treating the steel with calcium. Typically, silicocalcium is used for this purpose, which is introduced into the metal as part of a flux-cored wire or blown in a stream of argon through tuyeres immersed in the melt.

4. Production of rail steel using modifiers

Rails fail due to defects of contact fatigue origin. In a single shift, up to 50% of the rails are taken out of service due to these defects. The reason for the formation of defects is high-hard non-metallic inclusions such as alumina (A12 O 3) and aluminosilicates, stretched into lines along the rolling direction. In cast metal they form clusters, which, during rolling, are crushed and stretched, forming lines whose length can reach tens of millimeters. The very size of individual inclusions of alumina (corundum) also affects the magnitude of stresses and deformations in microvolumes of metal. It has been shown that the greatest danger in rail steel is 30 micron corundum inclusions [I]. According to other data, line inclusions of corundum become dangerous, reducing fatigue properties already at a value of 7-100 micromicrons.

Therefore, all work in the production of rail steel is aimed at reducing both the size of acute-angled inclusions and finding solutions to reduce the length of their lines in the rolled metal.

To some extent, metal contamination can be reduced by blowing the metal in the ladle with an inert gas, evacuation, and using (simultaneously with blowing) the introduction of new slag with solid slag mixtures with cutoff during the release of metal from the steel-smelting unit of furnace slag [3]. However, the problem can be solved more fundamentally by using modifiers for processing rail steel.

At NTMK, in the first stages of experiments, modifiers containing calcium and zirconium were used. At the same time, on experimental melts, when filling a ladle with metal (open hearth melting 440 tons) to 1/5 of its height, FeSiCa (3.2 kg/ton) was introduced in portions, and after that SiZr was introduced in portions - 0.45 kg/ton. The supply of ferroalloys was completed when 2/3 of the ladle was filled. It was discovered that on the experimental metal there were no stitch lengths of 4 mm, on ordinary metal - more than 20% of the samples had stitches of 4-16 mm.

In the future, when using complex alloys based on silicocalcium with zirconium and aluminum, the consumption is 1.9 kg/t. The optimal composition of the modifier used is 6-7% Zr and 5-7% A1. At the same time, it was possible to ensure a level of impact strength of the rails of at least 0.25 Mg 7 / M 2, and no lines longer than 2 mm were found.

Ukrainian researchers have carried out work on testing master alloys with Mg and Ti in the smelting of rail steel in converters and open-hearth furnaces [b]. The use of alloys with Mg, Ti and A1 (55-58% Si, 4-5% Mg, 4-7% Ti) for modifying rail steel in the ladle made it possible to localize shrinkage defects in the profitable part of the ingot, to reduce the segregation of elements by 27-32 %o increase the wear resistance of the metal, but the length of the alumina lines was significant, on average 5.3 mm. After using alloys without aluminum, it was possible to reduce the number of alumina inclusions and the length of the lines. The addition of complex master alloy SmTi to a ladle without additive A1 ensured a reduction in the prevalence of rails with surface defects, mainly in films, by 5-8%, and an increase in the yield of grade 1 rails by 1.8-4.5%. The length of the lines did not reach 2 mm, the operational durability and reliability of the experimental rails were, respectively, 20-25% higher than those made from steel deoxidized with aluminum.

The next attempt to reduce the contamination of rails with streak oxide inclusions was the use of an alloy containing barium alumina to modify steel. At the same time, a deeper deoxidation of the metal was achieved, the total oxygen content from 0.0036-0.006%o to 0.0026%o and a decrease in the anisotropy of plastic properties. The modifier was added to the ladle.

The fourth group of attempts to improve the quality of rail steel is associated with the appearance of vanadium in the composition of modifiers used for processing liquid metal in a ladle. Moreover, the metal is microalloyed with vanadium (its content is 0.005-0.01%) from containing alloys (the content of components in such alloys has not been established) and from natural cast iron alloyed with vanadium. The same work provides data on the microalloying of vanadium-containing metal with zirconium. This achieves an increase in the ultimate contact endurance of heat-strengthened rails by 7.2% and a reduction in their wear by 23%. It is noted that rails made of steel deoxidized with a calcium-containing master alloy containing vanadium have the highest reliability and durability.

The experience of using complex ferroalloys with vanadium and adding them to a ladle when producing rail steel is described in work carried out at the Kuznetsk Metallurgical Plant.

Microalloying in the ladle, due to existing and unregulated processes when introducing modifiers into the ladle (metal oxidation, temperature, additive moment), is unstable, the absorption of easily oxidized components of alloys (magnesium, calcium, zirconium, vanadium) is low, and their consumption is 3 -4 kg per ton, so a group of researchers at the Azovstal OJSC plant, when producing rail steel, changed the modification by introducing wire with a KMKT alloy (the content of elements is not reported).

Thus, the problem of increasing the absorption of easily oxidized elements introduced into liquid metal in the composition of complex alloys exists. Therefore, the development and application of new methods for introducing modifiers, in particular at casting, is of current importance.

Conclusion

The railway rail production technology used at domestic metallurgical plants ensures the required quality and durability of the product. However, for a number of reasons, rail steel in the Russian Federation is smelted in open-hearth furnaces, which limits the technological capabilities of metallurgists to significantly and dramatically improve the quality of steel used for the production of rails.

Rail steel containing 0.60 - 0.80% C and cord steel similar in composition are smelted in oxygen converters and arc steel-smelting furnaces. The most difficult task in the production of these grades of steel is to obtain a low phosphorus content in the metal when blowing is stopped at the grade of carbon content.

In arc steel-smelting furnaces, rail and cord steel are smelted using conventional technology, using measures for intensive removal of phosphorus from the metal - adding iron ore to the charge and at the beginning of a short oxidation period with continuous removal of slag and its renewal with lime additives. In this case, measures are also necessarily taken to prevent furnace slag from entering the steel-pouring ladle.

The International Union of Railways (UIC) has developed the international standard UIC 860 concerning the quality and methods of manufacturing rail steels and the conditions for acceptance of rails of different weight categories, non-heat-treated, made from ordinary and wear-resistant steels. The properties of rail steels are determined primarily by the carbon content. It was taken as the basis for determining analogues of steels in various standards.

Rail steel must have high strength, wear resistance and not have local stress concentrates of metallurgical origin. In the middle third of the width of the sole and on the upper plane of the head, single gentle stripping of pockets, nicks, scratches with a depth of up to 0 5 mm is allowed, and in other places - up to 1 mm.

List of sources used

1) Kudrin, V.A. Technology for producing high-quality steel [Text] // V.A. Kudrin, V.M. Parma. - M: Metallurgy, 1984. 320 p.

2) Povolotsky, D. Ya. Electrometallurgy of steel and ferroalloys [Text] / D. Ya. Povolotsky, V. E. Roshchin, M. A. Ryss and others - M.: Metallurgy, 1984. - 568 p.

3) Simonyan, L.M. Metallurgy of special steels. Theory and technology of special electrometallurgy: A course of lectures [Text]. / L.M. Simonyan, A.E. Semin, A.I. Kochetov. - M.: MISIS, 2007. - 180 p.

4) Kudrin, V.A. Theory and technology of steel production: Textbook for universities. - M.: “Mir”, LLC “ACT Publishing House”, 2003.- 528 p.

5) Goldstein, M.I. Special steels: textbook for universities [Text] / M.I. Goldstein, Grachev S.V., Veksler Yu.G. - M.: Metallurgy, 1985. - 408 p.

6) Paderin, S.N. Theory and calculations of metallurgical systems and processes [Text]. / S.N. Paderin, V.V. Filippov. - M.: MISIS, 2002. - 334 p.

7) Bratkovsky, E.V., Electrometallurgy of steel and special electro-metallurgy [Text] / E.V. Bratkovsky, A.V. Zavodyany. - Novotroitsk: NF MISiS, 2008.

8) Kudrin, V.A. Theory and technology of steel production: a textbook for universities [Text] / Yu.V. Kryakovsky, A.G. Shalimov. - M.: "Mir", LLC "AST Publishing House", 2003. - 528 p.

9) Voskoboynikov, V.G. General metallurgy: textbook for universities [Text] / V.G. Kudrin, A.M. Yakushev. - M.: ICC "Akademkniga", 2002. - 768 p.

10) Alperovich, M.E. Vacuum arc remelting and its economic efficiency / M.E. Alperovich. - M.: Metallurgy, 1979. - 235 p.

Posted on Allbest.ru

Similar documents

Steel production in oxygen converters. Alloy steels and alloys. Alloy steel structure. Classification and marking of steel. The influence of alloying elements on the properties of steel. Thermal and thermomechanical treatment of alloy steel.

abstract, added 12/24/2007


Steel metallurgy as production. Types of steel. Non-metallic inclusions in steel. Deoxidation and alloying of steel. Charge materials for steelmaking. Converter, open-hearth steel production. Steel smelting in electric furnaces.

test, added 05/24/2008


Classification and marking of steel. Characteristics of steel production methods. Fundamentals of steel smelting technology in open-hearth, arc and induction furnaces. Universal unit "Conarc". Domestic ladle-furnace units for out-of-furnace steel processing.

course work, added 08/11/2012


Basic methods of steel production. Converter method. Open-hearth method. Electric steelmaking method. Steel casting. Ways to improve the quality of steel. Processing of liquid metal outside the steelmaking unit. Steel production in vacuum furnaces.

course work, added 01/02/2005


Structure and properties of steel, source materials. Steel production in converters, open-hearth furnaces, and electric arc furnaces. Steel smelting in induction furnaces. Extra-furnace refining of steel. Steel casting. Special types of electrometallurgy steel.

abstract, added 05/22/2008


History of the development of steel smelting in electric arc furnaces. Technology of steel melting on fresh carbon mixture with oxidation. Steel smelting in a two-tub steelmaking unit. Off-site metal processing in the workshop. Casting steel on section continuous casters.

practice report, added 03/10/2011


Areas of application of tool carbon steel and its consumer properties. Separation of tool carbon steel by chemical composition into high-quality and high-quality. Production technologies and technical and economic assessment.

course work, added 12/12/2011


Analysis of world experience in the production of transformer steel. Technology for smelting transformer steel in oxygen converters. Bucket processing of transformer steel. Construction and equipment of continuous casting machine. Continuous casting of transformer steel.

thesis, added 05/31/2010


Mechanisms for strengthening low-alloy steel HC420LA. Dispersion hardening. Production technology. Mechanical properties of high-strength low-alloy steel of the studied grade. Recommended chemical composition. Parameters and properties of steel.

test, added 08/16/2014


Application and classification of steel pipes. Characteristics of pipe products made from various grades of steel, steel quality standards in its manufacture. Methods for protecting metal pipes from corrosion. Composition and application of carbon and alloy steel.

The basis of the Russian railway network is made up of P 65 rails - linear structures of I-beam cross-section, which serve to absorb loads from rolling stock, their elastic “processing” and subsequent transfer to the support - sleepers. The characteristics of these “steel beams” are regulated by GOST R 8161-75. It establishes the design and dimensions of hardened and unhardened rails and rail bars of type P65.

Rails R 65

Any rails are designed to solve several problems. Firstly, they perceive and transmit the train load. This is necessary to maintain the durability of both the subgrade and the wheels. Secondly, they set the direction of movement of the rolling stock. And finally, they create a platform with the least resistance for the wheels to roll. The contact surface of the working elements is several centimeters (3-5 depending on the class of the track).

The scope of application of the presented linear structures is quite extensive. Thus, the P 65 rails, as well as the P50 and P75, are used for laying sectional and continuous wide gauge tracks. They are also used to create turnouts. In the latter case, linear products with a modified profile (RK65) are used.

Rail elements

P65 rails, like any other types, cannot be called an ordinary I-beam.

Experts identify several conventional parts in its design:

1. Head - its shape ensures reliable adhesion of the rolling stock wheel to the rail itself.
2. Neck - resists bending loads and also transfers them to the support
3. Sole - ensures stability of the entire linear structure, distributes stress over the entire surface of the sleeper. It consists of a right and left pen.

In addition, two areas are distinguished within the rail, located on the left and right sides of the neck and occupying the space from the lower edge of the head to the middle part of the sole. These are the so-called left and right sinuses. They contain wedge-shaped linings that fasten the P 65 rails together in some sections of the track.

P65 rail dimensions

Few people have wondered why the P 65 rail has this particular shape. Meanwhile, each radius of curvature, level area and slopes were specially selected experimentally or by calculations in order to create optimal conditions for interaction with rolling stock.

Most of us know that the P 65 rail has a weight of 65 kg, which is actually incorrect. The exact weight of a linear meter is 64.72 kg. Other parameters have the following meaning:

• the radius of the head (R500) ensures centering of the load, that is, it forces the longitudinal axis of the wheel to coincide with the axis of the rail;
• The R80 creates a smooth transition to the R15, which creates tight contact with the wheel flange;
• the head slope of 1:20 corresponds to the slope of the wheel flange, which is necessary for mating with the wheel flange;
• the sharp edge of the head is rounded with a radius of R3, which is done to eliminate stress concentrators;
• transition radii R15 and R370 are introduced in order to ensure smooth mating of the head with the neck and eliminate areas with dangerous stresses;
• transition radius R400 at the base of the neck is necessary for smooth transfer of load to the sole;
• the slopes of the upper edge of the sole and the lower part of the head are the same (1:4), which is necessary for installing wedge-shaped pads, which at the same time act as a spacer.

The P 65 rail is subjected to colossal loads every day. Its weight in Russian industry cannot be underestimated. But if not for the special design, it would not be able to cope with its task, it would quickly become deformed and need to be replaced.

Rail steel

All railway rails (R 65, RK65, R75, R50) are made exclusively from rail steel. It is characterized by high bending strength, hardness and wear resistance, which is achieved by a high carbon content (0.82%) and the addition of alloying additives - manganese, vanadium, zirconium, silicon, titanium.

M76VT is the main steel grade used in the production of rail lashes. Depending on the method of production, it can be of the first group (smelted exclusively in open-hearth furnaces) or of the second group. A cast or rolled “blank” undergoes a complex multi-stage heat treatment stage. This is largely why the price for the P 65 rail is at such a high level - from 50 thousand rubles per ton.