A rail is a metal beam with an original cross-section. It is used to create a support on which rail transport moves. For the first time, rails began to be made in Ancient Rome, but then wood was used for their manufacture, and the distance between them was strictly 143 cm. The rails are installed in a parallel plane relative to each other. As a result, a "two-strand path" is formed.
The main task of the rail is to guide the wheels of the transport and take on the load with its subsequent distribution to the lower elements of the upper track. In the case of using trains in zones where movement is impossible without electric traction, the rails play the role of a current conductor, and for zones using automatic blocking, the rails are a conductor.
Manufacturing material
In most cases, carbon steel is used to make rails. The quality of this material is influenced by some factors, for example, the microstructure and macrostructure of steel, its chemical structure, etc. The presence of carbon makes the rail more durable and reliable.
However, excess carbon in steel can have a negative impact. When it is in excess, fragility increases significantly. That is why, when adding carbon, it is worth taking care that the structure of the steel balls is as strong as possible.
Other substances are also used to improve the quality of the starting material. Recently, more and more often they have resorted to the treatment of rails with manganese. This increases the resistance of the metal to mechanical damage, making it more durable and tough. The addition of silicon to the composition of the steel increases its wear resistance and hardness. Titanium, vanadium and zirconium can also be used. These trace elements can significantly improve the quality characteristics of steel.
In no case should sulfur and phosphorus additives be added, as they make the steel more vulnerable to breaking and increase its brittleness. Very often, cracks and breaks can be observed in parts made with the addition of these substances.
It has already been discussed above that steel has its own microstructure and macrostructure. Perlite is used as the main material for the first structure. Its shape is reminiscent of plates containing ferrite. A homogeneous steel composition can be achieved by hardening it, that is, processing it at a very high temperature. Hardening increases the wear resistance, durability, reliability, rigidity and toughness of the metal. For the macrostructure, the presence of excess substances or voids is unacceptable.
Physical characteristics of rails
The actual profile of the rails was not always like this. He suffered changes over time. History remembers angular, double-headed, mushroom-shaped, wide-bottom and other rails.
The modern wide-sole rail design includes a sole, a head and a neck that acts as a connecting element between the two parts. The central part is made slightly convex so that the load from the wheels is transferred to the central area of the rail. The joints of the neck with the sole and the head have smooth shapes. To relieve tension from the neck, it is made in the form of a curve. The wider the base of the rail foot, the higher its lateral stability.
There are several standard rail sizes. It is typical for the Russian Federation to produce rails with a length of 12.5, 25, 50, 100 m.
It is also possible to produce rails and shorter lengths. They are used on uneven railway tracks. The length of the continuous welded track is not less than 400 m and can reach the distillation length. The higher the length of the rail, the less resistance to movement of the vehicle and, accordingly, its wear. Retention of steel during the transition to a continuous welded track reaches 4 tons per 1 km of track. This is possible due to the absence of fastening elements in the area of rail joints.
When calculating the power of the material, it is necessary to take into account such a parameter as the specific gravity per 1 m of the rail. It is customary to measure it in kilograms.
Another element of the railway track is sleepers. They play the role of a fastening element. Thanks to the development of modern technologies, it became possible to produce sleepers not only from reinforced concrete and wood, but also from steel or plastic.
When calculating the cost of one rail, its specific weight, overall parameters (length and width), hardness and degree of wear resistance are taken into account.
Rail types
In order to choose the right type of rails, it is necessary to calculate the line load and the average speed at which the transport will move along it. Let's take a massive rail with a lot of weight as an example. It has a positive effect on the durability of sleepers and reduces the economic costs of maintaining the line by increasing its durability.
Today there are such types of rails:
- Railway. This type is considered the most popular and demanded. The weight of 1 meter of such a rail is 50-65 kg, the length is 12.5 or 50 m.
- Narrow gauge. They are used when it is necessary to create a narrow interrail space. This type of rail is widely used in the mining industry and other areas with limited traffic.
- Miner. With their help, continuous welded tracks are laid. They are also very popular in the industrial field.
- Tram. The name speaks for itself. Not designed for heavy line load. These rails are relatively lightweight, which leads to their rapid wear.
- Crane. They are used in those places where it is necessary to create paths for moving the crane.
- Undercrane. These rails are considered the heaviest. In some cases, laying in several rows at once is allowed.
- Framed. They are used in places where transfer mechanisms are built.
- Counter-rail. They are used when working in the upper structures of railway tracks.
- Sharp. The scope of application is similar to the counter rail type. The type of OP43 pointed rails can be distinguished separately. It is used for the construction of railway tracks.
Where to buy these types of rails? We recommend buying from reliable suppliers. In Yekaterinburg, rails can be purchased from the Rail-Komplekt trading company. The company sells high quality railway products from leading domestic factories that meet the standards of GOST.
Rail classification is carried out according to several parameters:
- Presence of holes for connecting elements (bolts).
- The method of smelting steel.
- Quality. According to this parameter, rails are divided into heat-strengthened and non-heat-strengthened.
These characteristics directly affect the cost of a rail.
Symbols
Each rail has a marking consisting of several groups of numbers and letters. Each letter means a specific parameter:
- A - rail type.
- В - quality category.
- С - grade of used steel.
- D is the length of the rail.
- E - the presence of holes for the bolts.
- F - GOST.
For example, the marking of the rail R65-T1-M76T-25-3 / 2 GOST R 51685-2000 indicates that it is a railroad type of category T1. For its manufacture, steel grade M76T was used. The length of the rail is 25 m. It has 3 bolt holes at each end. Complies with the specified GOST standard.
The invention relates to the field of ferrous metallurgy, namely the production of steel used for the manufacture of railroad 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 other impurities. 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. Strength properties of steel, plasticity and cold resistance are increased due to the formation of a dispersed structure of hardened sorbitol and an increase in the purity of steel in terms of non-metallic inclusions. 2 tab.
The invention relates to ferrous metallurgy, in particular to the production of steel for the production of railway rails.
Known pearlitic rail steel 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; not more than 0.02% A1.
The creation of high-strength rails with a ultimate tensile strength of more than 1300 N / mm 2 and a relative elongation of at least 12.0%, having increased operational reliability and high resistance to the formation of defects, presupposes a homogeneous pearlite structure, elements is difficult.
Known steels have 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 is 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 - ost ..
Significant disadvantages of these steels are low impact toughness and cold resistance, reduced reliability and service life.
In steel, this is determined by the absence of vanadium and a low nitrogen content. It has a relatively coarse austenite grain (scores 7-8). The high aluminum content in it leads to its contamination with coarse line inclusions of alumina, which significantly reduce the contact-fatigue strength of the rails.
The indicated disadvantages of steel are associated with the presence of titanium in it, low vanadium and nitrogen content. Titanium carbonitrides formed in liquid steel upon cooling sharply reduce the impact toughness and brittle fracture resistance 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, which are necessary for grinding austenite grains and simultaneously increasing the strength properties and cold resistance of steel. The austenite grain in this steel is relatively coarse and amounts to 7-8 points.
Known steel 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%; while Ca and A1 are in the ratio 1: (4-13); e - the rest.
Significant disadvantages of steel are low impact strength, increased tendency to brittle fracture and reduced operational resistance, which is due to the presence of titanium in steel, low vanadium content, high aluminum concentration. The resulting titanium carbonitrides sharply reduce the toughness and brittle fracture resistance.
A low concentration of vanadium does not provide the formation of the required amount of vanadium carbonitrides, which is necessary for additional grain refinement and an increase in the strength properties and cold resistance of steel.
The use of a large amount of aluminum for deoxidation of steel together with calcium leads to its contamination with accumulations of calcium aluminates, rich in alumina, which reduce the contact-fatigue strength.
The presence of sulfur and phosphorus in large quantities in steel leads to an increase in the red and cold brittleness of steel, respectively.
Known selected as a prototype steel 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 oil quenching at a low temperature and subsequent tempering.
Significant disadvantages of steel are the increased tendency to brittle fracture.
The desired technical result of the invention is the formation of a dispersed structure of hardening sorbitol, an increase in strength properties, plasticity, cold resistance, steel purity in terms of 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, the amount of impurities in its composition is additionally limited in the following ratio (wt%):
The claimed chemical composition is selected based on the following conditions. The selected carbon content provides, during volume quenching, a homogeneous structure of quenched sorbitol with a ultimate tensile strength of more than 1300 N / mm 2, a relative elongation of more than 0.12% and a narrowing of more than 35%.
Rails made of steel containing more than 0.84% C have a reduced impact strength at minus 60 ° C (0.15 MJ / m 2). The introduction of Mn, V, Cr is also associated with the need to increase the toughness and wear resistance of steel during the working wheel-rail contact.
The selected ratio of Mn, Si, Ni, Cr in steel containing 0.77-0.84% C provides a decrease in the transformation temperature of austenite and obtaining a more dispersed structure of quenched sorbitol.
The decrease in the content of manganese in comparison with the prototype is due to the introduction of sufficient amounts of chromium into the steel to increase the hardenability and resistance to wear. At the same time, 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%), sections 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 quenching sorbitol, which has higher mechanical properties, hardness and wear resistance.
The positive effect of small additions of chromium is that it increases wear resistance by forming carbides. In the presence of chromium, the ability of Mn and V to inhibit the growth of austenite grain increases.
The introduction of nickel within the claimed range provides, along with aluminum and vanadium, obtaining guaranteed steel impact toughness at positive and negative temperatures. Its content up to 0.15% has a positive effect on the impact strength, and at a concentration of more than 0.15%, it is possible to obtain an unacceptable upper bainite structure in the 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 claimed limits into steel leads to a 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 viscosity properties and resistance to brittle fracture (cold resistance). However, without the use of nitrogen, vanadium at high concentrations (> 0.1%) reduces the toughness and increases the cold brittleness of steel. Vanadium increases the endurance limit and improves weldability.
In steel containing at least 0.010% N, the optimum vanadium concentration is 0.06-0.10%. The lower limit of vanadium content in steel was chosen because it begins to grind grain at a concentration of more than 0.06%. The upper limit of the vanadium content is set on the basis that with an increase in its concentration above 0.10%, the relative proportion of nitrogen in vanadium carbonitride decreases, a carbonitride is formed, which is close in composition to vanadium carbide, which reduces the impact toughness.
Nitrogen concentration 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. With an increase in the content of vanadium and nitrogen in steel to the declared limits, the amount of carbonitrides in it increases, providing an increase in strength properties and cold resistance. However, with an increase in nitrogen of more than 0.018%, cases of spotted 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, phosphorus - the cold brittleness of steel.
The inventive chemical composition of the rail steel ensures the production of high-strength, wear- and cold-resistant cane rails with increased contact fatigue endurance during 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 poured into a continuous casting machine. The resulting blanks were heated and rolled according to the usual technology on rails of the P65 type, which were quenched in oil from a temperature of 800-820 ° C and tempered at 460 ° C. The data given in Table 2 show that the mechanical properties, the hardness of the volume-hardened rails made of the claimed steel are significantly higher than those of the rails made of 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 viscous properties of rails increases their wear and cold resistance, contact fatigue strength and operational reliability.
List of sources taken into account in the examination
1. GOST R 51685-2000 "Railroad 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 "Railroad rails with increased wear resistance and contact endurance".
| Table 1 | ||||||||||||
| Chemical composition of steel | ||||||||||||
| Composition | Mass fraction of elements,% | |||||||||||
| WITH | Mn | Si | V | A1 | Cr | Ni | Cu | S | R | N 2 | O 2 | |
| 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 | σt | σB | δ5 | ψ | Hardness | KCU, J / cm 2 at temperature, ° С |
|||||
| N / mm 2 | % | HB10 | HB22 | НВш | NVpod | НВпкг | +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; | |||||||||||
| HB - firmness in the outsole. |
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%:
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The shovel is an integral part of the household. The scope of this tool is wide. And since the tool is used frequently, certain requirements are imposed on it.
It must be strong, durable, easy to use, highly resistant to corrosion and durable. Rail steel shovels have proven themselves quite well on these points in the market.
1 Creation technology
The main material for such shovels is rail steel saturated with carbon. The material is characterized by high strength and low weight, which is the best option for a working tool. Often old rails or rails that do not meet the required conditions are used for such purposes. The resulting metal is packaged, after which it is processed.
1.1 Manufacturing process (video)
1.2 Advantages of Rail Steel Shovel
Of the advantages of rail steel shovels, the following should be noted:
High strength and balanced elasticity. These qualities are ensured by a durable material and a special hardening method. Moreover, the elasticity of the metal base allows the shovel to bend slightly under load, and then return to its original position. This means that deformation does not threaten such a tool.
Low weight. Despite the strength and density of the material, the high carbon content makes the shovel lighter than forged steel tools. This increases working comfort.
Resistant to wear and corrosion. Resistance to corrosive processes is provided not only by the specifics of the material, but also by anti-corrosion coatings, which cover most of the rail steel shovels.
Low price indicators. Rail steel shovels on the market are slightly more expensive than forged steel and stainless steel shovels.
Self-sharpening during operation. Rail steel shovels, due to their structure, do not lose their sharpness even when working with hard types of soil, roots, frozen ground. And the adjustment of the sharpening is carried out during operation.
2 Choosing a rail steel shovel
When choosing a shovel, the main points to look out for are the overall blade design and the ergonomics of the tool. As for the general design of the blade, it is best to select a shovel with additional stiffeners. Such a tool is much more difficult to break or bend during operation.
As for the ergonomics of the shovel, the main nuance is the ledges for the leg. They must have the correct bend angle. An edge that is too raised up will cut the leg when working, too low will cause the legs to slip. The handle at the end of the handle is also a convenient addition. It makes it easier to work with bulk materials or cut roots.
2.1 Care of the instrument
Whatever the quality of the tool, in order for it to function properly for many years, it must be properly monitored and maintained:
- After finishing work, the shovel must be immediately cleaned of soil residues.
- It is better to store the tool in a dry, well-ventilated place without access to moisture.
- It is better to paint the stalk, and this should be done periodically. This will increase the service life.
- Constantly monitor the quality of the connection between the handle and the working blade. in no case should he stagger. In this case, it must immediately be knocked out and reinforced in a new way.
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 increases these qualities and increases the viscosity. Silicon also makes rail steel harder and more wear-resistant. Rail steel can be improved with microalloying additives such as vanadium, titanium and zirconium.
A wide range of requirements for the quality of railway rails in this regard 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 technology for the production of railroad rails operating at domestic metallurgical plants ensures the required quality and durability of products. 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 for a significant and sharp increase in the quality of steel used for the production of rails.
The main reason for the low prevalence of the production of rails from electric steel is the target orientation of the construction of modern electric steel-making shops with large-capacity furnaces for the utilization of regional scrap resources and providing the regions with metal products for industrial and construction purposes. At the same time, a sufficiently high economic efficiency and competitiveness are achieved.
General characteristics of rail steels
The production of rails in our country is about 3.5% of the total production of finished rolled products, and the freight traffic of railways is 5 times higher than in the United States, and 8 ... 12 times higher than on the roads of other developed capitalist countries. This imposes particularly high demands on the quality of the rails and steel for their manufacture.
Rails are subdivided into:
By types P50, P65, P65K (for outer threads of curved track sections), P75;
Bolt holes: with holes at both ends, no holes;
Steel smelting method: M - from open-hearth steel, K - from converter steel, E - from electric steel;
The type of initial blanks: from ingots, from continuous-cast blanks (NLZ);
Anti-flake treatment: from vacuum-treated steel, which have undergone controlled cooling, have undergone isothermal holding.
The chemical composition of rail steels is presented in Table 1 in steel grades, the letters M, K and E denote the method of steel smelting, the numbers - the average mass fraction of carbon, the letters F, C, X, T - alloying of steel with vanadium, silicon, chromium and titanium, respectively.
Table 1 - Chemical composition of rail steels (GOST 51685 - 2000)
Broad gauge railroad rails of the P75 and P65 types are manufactured in accordance with 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 technology for manufacturing rails should ensure that there are no lines of non-metallic inclusions (alumina) longer than 2 mm (group I) and more than 8 mm (group II) elongated along the rolling direction, since such lines serve as a source of initiation of contact fatigue cracks during operation.
The high traffic density of the railways led to the fact that the operability of raw, non-heat-strengthened rails ceased to meet the requirements of the heavy work of the railway network.
A further increase in the service life of thermally hardened rails can be achieved by alloying the rail steel. Alloying of carbon rail steel with small additions of vanadium (-0.05%), the use of alloy steels such as 75GST, 75HGMF, etc., as well as the use of thermomechanical treatment are promising.
We sell steel rails. Check the prices with the managers. You can order a rail at the office of the "Remstroyput" company (Yekaterinburg, Taganskaya st., 55 a). Available rails P65, RP65, P50, RP50, P33, P38, T62, KP140, KP120, KP100, P80, KP70, P43, P24, P18, P11.
With the continuous replacement of rails on the main directions of the railways, two types of new ones are laid on the way, depending on the load density: P75 (GOST 16210-77) and (GOST 8161-75) (Table 7). On the tracks of industrial enterprises, rails of the types (GOST 7174-75) and (GOST 7173-54) are used. In the railway tracks there are rails of the same types, but of earlier years of laying (Table 8). The rails reused in the tracks are called.
Table 7. Main indicators of rails
| Index | P75 in accordance with GOST 16210-77 | P65 in accordance with GOST 8161-75 | P50 in accordance with GOST 7174-75 | P43 in accordance with GOST 7173-54 |
| Drawing number in album | 24 | 25 | 26 | 27 |
| Weight of 1 m rail, kg | 74,41 | 64,72 | 51,67 | 44,65 |
| Weight of one rail 25 m long, kg | 1860 | 1618 | 1292 | 1116 |
| Rail height, mm including: | 192,0 | 180,0 | 152,0 | 140,0 |
| head height | 55,3 | 45,0 | 42,0 | 42,0 |
| "neck | 104,4 | 105,0 | 83,0 | 71,0 |
| "soles | 32,3 | 30,0 | 27,0 | 27,0 |
| Rail head width, mm: | ||||
| up | 72,0 | 73,0 | 70,2 | 70,0 |
| at the bottom | 75,0 | 75,0 | 72,0 | 70,0 |
| Sole width, mm | 150 | 150 | 132 | 114 |
| 20 | 18 | 16 | 14,5 | |
| 95,04 | 82,65 | 65,99 | 57,0 | |
| Area distribution along the profile,%: | ||||
| heads | 37,4 | 34,1 | 38,1 | 42,8 |
| necks | 26,5 | 28,5 | 24,5 | 21,3 |
| soles | 36,1 | 37,4 | 37,4 | 35,9 |
| Distance from the center of gravity, mm: | ||||
| to the bottom of the sole | 88,2 | 81,3 | 70,5 | 68,5 |
| to the top of the head | 103,8 | 98,7 | 81,5 | 71,5 |
| horizontal | 4489 | 3540 | 2011 | 1489 |
| vertical | 665 | 564 | 375 | 260 |
| Moment of resistance, cm3: | ||||
| on the bottom of the sole | 509 | 435 | 285 | 217 |
| on the top of the head | 432 | 358 | 247 | 208 |
| on the side edge of the sole | 89 | 75 | 55 | 45 |
Heck. 24. Rail type P75 in accordance with GOST 16210-77 (Rails have been supplied since 1978)
Heck. 25. Rail type P65 in accordance with GOST 8161-75 (Rails have been supplied since 1976)
Heck. 26. Rail type P50 in accordance with GOST 7174-75 (Rails have been supplied since 1976)
Heck. 27. Rail type P43 in accordance with GOST 7173-54 (Rails have been supplied since 1955)
Table 8. Some indicators of rails discontinued, but used on the road
| Index | P75 | P65 | P50 | P43 | I-a | P38 (II-a) | P33 (III-a) | |||||
| GOST 16210-70 | project 751 / cp | GOST 8161-63 | GOST 8161-56 | 1950 project | GOST 7174-65 | GOST 7174-54 | GOST 3542-47 | GOST 3542-47 | OST 119 | GOST 3542-47 | GOST 6726-53 | |
| Drawing number in album | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 |
| Weight of 1 m rail, kg | 74,4 | 75,1 | 64,64 | 64,93 | 64,90 | 51,63 | 51,51 | 50,50 | 43,61 | 43,57 | 38,42 | 33,48 |
| Rail height, mm, including: | 192 | 192 | 180 | 180 | 180 | 152 | 152 | 152 | 140 | 140 | 135 | 128 |
| head height | 55,3 | 48,5 | 45 | 45 | 45 | 42 | 42 | 42 | 42 | 44 | 40 | 37 |
| "neck | 104,4 | 110 | 105 | 105 | 105 | 83 | 83 | 83 | 71 | 71 | 71 | 68 |
| "soles | 32,3 | 33,5 | 30 | 30 | 30 | 27 | 27 | 27 | 27 | 25 | 24 | 23 |
| Rail head width, mm: | ||||||||||||
| - at the top | 71,8 | 72,8 | 72,8 | 72,8 | 76 | 70 | 70 | 70 | 70 | 70 | 68 | 60 |
| - at the bottom | 75,0 | 75,0 | 75,0 | 75,0 | 76 | 71,9 | 70 | 70 | 70 | 70 | 68 | 60 |
| Sole width, mm | 150 | 160 | 150 | 150 | 150 | 132 | 132 | 132 | 114 | 125 | 114 | 110 |
| Neck thickness in the middle, mm | 20 | 20 | 18 | 18 | 17 | 16 | 15,5 | 14,5 | 13,5 | 14 | 13 | 12 |
| Cross-sectional area, cm2 | 95,1 | 95,8 | 82,6 | 82,9 | 82,9 | 65,9 | 65,8 | 64,5 | 55,7 | 55,6 | 49,1 | 42,8 |
| Distribution of metal along the profile,%: | ||||||||||||
| - head | 37,4 | 32,3 | 34,2 | 34,5 | 35,5 | 38,2 | 38,3 | 39,5 | 43,0 | 45,9 | 45,4 | 43,0 |
| - neck | 26,5 | 28,5 | 28,4 | 28,3 | 27,1 | 24,4 | 23,8 | 22,2 | 20,5 | 19,3 | 19,8 | 19,9 |
| - outsole | 36,1 | 39,2 | 37,4 | 37,2 | 37,4 | 37,4 | 37,5 | 38,3 | 36,5 | 34,8 | 34,8 | 37,1 |
| Moment of inertia relative to the axes, cm4: | ||||||||||||
| - horizontal | 4490 | 4597 | 3548 | 3573 | 3588 | 2018 | 2037 | 2016 | 1472 | 1476 | 1223 | 968 |
| - vertical | 661 | 771 | 569 | 572 | 576 | 375 | 377 | - | 257 | 284 | 209 | 167 |
| Moment of resistance, cm3 | ||||||||||||
| - on the bottom of the sole | 509 | 547 | 436 | 437 | 432 | 286 | 287 | 285 | 214 | 212 | 180 | 156 |
| - at the top of the head | 432 | 426 | 359 | 363 | 370 | 248 | 251 | 248 | 206 | 210 | 182 | 147 |
Heck. 28. Rail type P75 in accordance with GOST 16210-70
(The rails were supplied between 1966 and 1977)
Heck. 29. Rail type P75 according to project 751 / TsP
(The rails were supplied between 1958 and 1966)
Heck. 30. Rail type R65 in accordance with GOST 8161-63
(The rails were supplied between 1964 and 1975)
Heck. 31. Rail type R65 in accordance with GOST 8161-56
(The rails were supplied in the period 1956 - 1963, the holes could be oval 38´30 mm)
Heck. 32. Rail type P65 according to the design of 1950
(The rails were supplied between 1953 and 1955)
Heck. 33. Rail type P50 in accordance with GOST 7174-65
(The rails were supplied between 1965 and 1975)
Heck. 34. Rail type P50 in accordance with GOST 7174-54
(The rails were supplied between 1955 and 1966)
Heck. 35. Rail type P50 in accordance with GOST 3542-47
(The rails were supplied between 1948 and 1954)
Heck. 36. Rail type P43 in accordance with GOST 3542-47
(The rails were supplied between 1946 and 1954)
Heck. 37. Rail type 1-a according to OST 119
(The rails were supplied until 1946)
Heck. 38. Rail type Р38 (II-a) in accordance with GOST 3542-47
Heck. 39. Rail type (III-a) GOST 6726-53
(The rails were supplied until 1932)
Basic requirements for rails of types P75, P65 and P50 made of open-hearth steel in accordance with GOST 24182-80 (introduced from July 1, 1981 instead of GOST 8160-63 and GOST 6944-63)
1. The standard applies to unhardened rails of the P75, P65 and P50 types, made of open-hearth steel and intended for laying on broad-gauge railways, along the entire length.
2. The design and dimensions of the rails comply with GOST 7174-75, GOST 8161-75 and GOST 16210-77.
3. The rails of two groups are made.
4. Rails of group I are made of calm open-hearth steel deoxidized in a ladle with complex deoxidizers without the use of aluminum or other deoxidizers that form harmful line non-metallic inclusions in the steel.
5. Rails of the II group are made of calm open-hearth steel, deoxidized with aluminum or manganese-aluminum alloy.
6. The chemical composition of steel must comply with the standards specified in table. nine.
7. Mechanical properties of steel for rails of groups I and II during distance tests must comply with the standards specified in table. ten.
8. The technology for the manufacture of rails must ensure that they are free of flakes, as well as local non-metallic inclusions (alumina, carbides and nitrides of titanium or silicate cemented alumina), elongated along the rolling direction in the form of tracks - lines with a length of more than 2 mm for rails of group I and longer than 8mm for rails of group II.
9. The surface of the rail head at its ends must be hardened from rolling heating or induction heating by high-frequency currents.
Table 9. The chemical composition of rail steel
| Rail group | Rail type | steel grade | Mass fraction,% | ||||
| Carbon | Manganese | Silicon | Phosphorus | Sulfur | |||
| I | P75 | M76V | 0,71 - 0,82 | 0,25 - 0,45 | |||
| P65 | M76T | ||||||
| М76ВТ | |||||||
| М76Ц | |||||||
| P50 | M74T | ||||||
| М74Ц | 0,69 - 0,80 | 0,75 - 1,05 | 0,18 - 0,40 | Not more than 0.035 | No more than 0.045 | ||
| II | P75 | M76 | 0,71 - 0,82 | ||||
| P65 | |||||||
| P50 | M74 | 0,69 - 0,80 | |||||
| Notes. 1. In the designation of the steel grade, the letter "M" indicates the method of steel smelting (open-hearth), the numbers - the average carbon content in hundredths of a percent. 2. Rails made of steel grade М76В are classified as rails with vanadium; from steels of grades М76Т, М74Т and М76ВТ - for rails with titanium; from steels of grades M76Ts and M74Ts - to rails with zirconium. 3. The mass fraction of vanadium in rail steel, depending on the brand, ranges from 0.01 to 0.07%, titanium - from 0.005 to 0.025%, zirconium - from 0.001 to 0.050%. 4. It is allowed to manufacture rails of the P50 type of groups I and II from oxygen-converter steel. In this case, in the designation of the steel grade, the letter "M" is replaced by the letter "K". |
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Table 10. Mechanical properties of rail steel
Rails intended for welding or other special purposes, at the request of the consumer, are allowed to be made with a length of at least 6.0 m without hardening one or both ends.
10. After complete cooling, the rails can be cold straightened on roller straightening machines and stamp presses.
11. After cold straightening, the following are not allowed:
repeated cold straightening of rails on roller straightening machines in the same plane;
cold stamp straightening of the ends of the rails, if the curvature of the ends is within the location of the bolt holes;
falling of rails from a height of more than 1.0 m;
waviness and twisting of rails. A rail is considered twisted if, when measured on a control rack, it has gaps at the ends between the edge of the sole and the rack (diagonally) of more than 1/10000 of its length.
12. The ends of the rails must be milled perpendicular to the longitudinal axis of the rail. The misalignment of the ends should not be more than 1.0 mm when measured in any direction. It is not allowed to chop off and break the defective ends of the rails.
Bolt holes at the ends of the rails must be drilled perpendicular to the vertical longitudinal plane of the rail. The surfaces of the bolt holes and the ends of the rails must be free of flaws, scuffs and traces of shrinkage in the form of delamination and cracks. Burrs and beads of metal at the bolt holes and at the ends of the rails must be removed by stripping.
Heck. 40. Main markings of rails:
a - first grade rails; b- rails of the second grade; v- places of marking on the rail neck; 1 - inspection marks; 2 - the stamp of the OTK of the plant (may be in the form of a square, a triangle or the letter "K"); 3 - the place where the rail number is applied by its location in the ingot (1 and 2 - head rails, X - bottom middle rails are not marked); 4 - the place where the steel heat number is applied (the heat number for rails of the 1st group begins with the letter P); 5 - place of indication of the serial number of the rail from the head of the ingot; 6 - the place of the rolled-out (convex) marking along the length of the rail, repeated after about 2.5 m and indicating: manufacturer, month and year of rental, rail type
13. The test section of the rail for pile tests must withstand at a temperature from 0 ° to plus 40 ° C the impact test without fractures, cracks and gouges of the sole (both in the span and on the supports).
14. The test section of the rail for testing the strength of the sole must withstand the static load without cracks or fractures until an arrow deflection of 4.0 mm is obtained.
15. For laying on the main tracks of the Ministry of Railways, the following are not allowed: rails of the second grade, types Р75 and Р65 with rolled out dirt, bubbles and cracks on the middle third of the bottom of the sole with a depth of more than 0.3 mm; rails of the second grade, type P50.
16. The marking of the rails is shown in fig. 40, 41 and in table. eleven.
17. The rails shipped to the consumer must be accompanied by a document (certificate of technical suitability of the rails) signed by the manufacturer's representative and the inspector of the Ministry of Railways, certifying the compliance of the rails with the requirements of this standard, which must indicate:
Manufacturer's designation;
The numbers of the standards according to which the rails were manufactured and adopted and the order numbers;
Grade and type of rails;
Imprints or descriptions of acceptance marks and marking of rails with paints;
Carriage numbers;
The name and address of the recipient.
Heck. 41. An example of full factory markings for new rails of the first grade:
a- the rail was manufactured by the Kuznetsk (K) metallurgical plant in May (V) 1990 (90), type P65, melt A293, from ordinary standard carbon steel, with hardened ends (white stripe paint on the head), according to the carbon content "hard" ( yellow color of the sole at the end), the arrow indicates the head end; b- the rail was manufactured by the Azovstal plant (A) in March 1990 (III 90) of the P75 type, melt P356, hardened along the entire length (green stripe on the neck and green edging of the butt end); v- the rail was manufactured by the Nizhniy Tagil (T) metallurgical plant in September 1989 (IX 89) of the P50 type, melt 751Ya, hardened along the entire length, in terms of hardening quality - the first class (green edging at the end); G
The entire end of the rail is painted with blue paint, at both ends there are three cores - the rail is rejected, it is not suitable for laying on the way of the Ministry of Railways
Basic requirements for rails of types P50, P65 and P75, heat-treated by volumetric quenching in oil in accordance with GOST 18267-82
(introduced from January 1, 1984 to replace GOST 18267-72)
1. The standard applies to railway rails of types P50, P65 and P75, made of high-carbon open-hearth steel and heat treated along their entire length by volumetric oil quenching followed by furnace tempering.
2. Rails intended for heat treatment must comply with the requirements for rails of the first grade, manufactured in accordance with GOST 24182-80.
It is allowed, by agreement between the manufacturer and the consumer, to heat-treat the rails of the second grade. Hardened rails, converted to the second grade in terms of surface defects, are intended for laying on tracks that do not belong to the Ministry of Railways.
3. The hardness on the rolling surface of the head of hardened rails should be within HB 341 ... 388; the hardness of the neck and foot of the rails - no more than HB 388.
4. The macrostructure of the hardened metal of the rail head should be hardened sorbitol.
The presence of small scattered areas of ferrite is allowed.
5. The mechanical properties of hardened rails should be as follows:
Ultimate resistance, kgf / mm2 ........................................ ³120
Yield strength, kgf / mm2 ............................................ . …… .. ³81
Elongation,% .......................................... …… ³6
Relative narrowing,% ........................................... ……. . ³25
Impact strength at 20 ° С, kgf m / cm2 ................................... ³2.5
6. The test section of the rail must withstand the low-temperature impact tests under the headstock without fracture and signs of destruction.
7. In case of unsatisfactory results of repeated impact tests under a headframe, it is allowed to subject the rails to high hardness tempering HB 255 ... 302 and hand them over in accordance with GOST 24182-80 as unhardened.
8. The marking of the rails must correspond to that indicated in the drawing. 40, 41 and in table. eleven.
9. Rails must be accompanied by a document signed by a representative of the manufacturer and an inspector of the Ministry of Railways, certifying their compliance with the requirements of this standard and containing:
Manufacturer's name;
Product name and heat treatment method;
Type, class and group of rails;
Steel grade from which the rails are made;
Designation of this standard;
Imprints or descriptions of acceptance marks, as well as a description of the marking of the rails with paints;
The number of rails with an indication of their length and weight;
The name and address of the consumer.
Rail marking
Each new rail is marked on its neck and on one of the ends.
Marking is subdivided into permanent, carried out during rolling and stamping in a hot and cold state (see Fig. 40) and temporary or additional, carried out with paint (see Table 11). Marking (see Fig. 41) is necessary for the correct laying of the rails in the track.
Old-year rails are also marked (Fig. 42).
Heck. 42. An example of marking old-year rails (light paint):
a- rail of the I group, suitable for laying on the road without repair; b- Group II rail to be repaired (II-P); v- rail of group IV, not suitable for laying on the road (XXX)
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