Rod of micro-alloy medium-carbon steel
FIELD: metallurgy, namely production of rolled bars such as calibrated round rods of medium-carbon micro-alloy steel with improved cutting ability used for making rods of automobile shock absorbers.
SUBSTANCE: rolled calibrated round rods are melted from medium-carbon micro-alloy steel containing next ingredients, mass %: carbon, 0.40 - 0.52; manganese, 0.40 - 0.95; silicon, 0.17 - 0.37; chrome, 0.01 - 0.025; sulfur, 0.020 - 0.045; vanadium, 0.005 - 0.02; aluminum, 0.03 - 0.05; calcium, 0.001 - 0.010; nitrogen, 0.005 - 0.015, nickel, no more than 0.25; copper, no more than 0.25; molybdenum, no more than 0.10; arsenic, no more than 0.08; phosphorus, no more than 0.030; iron and inevitable impurities, the balance while next relation is satisfied: calcium/sulfur is equal to 0.065 or more. Rolled piece has lamella type ferrite-pearlite structure with real size of grain 5 - 8 points and with diameter of rolled piece 10 - 30 mm. It has decarburated layer (ferrite + transition zone) consisting of no more than 1,5% of rod diameter, hardness of blank 229 - 255, temporary tensile strength no less than 640 MPa, percentage elongation no less than 6%, percentage narrowing no less than 30 %. Invention provides through calcination of rolled bars with diameter up to 30 mm.
EFFECT: improved cutting capability of steel at favorable relation of strength, ductility and viscosity, minimum anisotropy of mechanical properties at enhanced characteristics of calcination capability.
The invention relates to the field of metallurgy, in particular to the production of long-rolled steel in bars, calibrated round, of medium carbon steel of increased micro-machinability used for the manufacture of the absorber rods of the car. The objective of the invention is the provision of efficient conditions for cold massive forming geometrically-complex high-strength fasteners while providing high performance technology of plasticity and low strain hardening.
Known rolled round steel containing, wt.%: carbon range 0.38-0.47, the manganese 0,8-1,2, silicon 0,17-0,37, vanadium 0,08-0,18, boron 0,001-0,005, nitrogen from 0.005 to 0.025, sulfur being 0.036-0,080, calcium 0,001-0,010, the rest provided that the ratio of manganese to calcium is 100-1100. (USSR author's certificate SU 1689424 A1, C 22 38/60 from 07.11.1989, bull. No. 41). The disadvantage of this steel is relatively high nitrogen content and the absence in the composition of the elements that protect the boron from binding in the nitrides, which in some cases will not allow to achieve the claimed by the authors of the effect for improving the hardenability characteristics.
Known rolled round steel containing, wt.%: carbon 0,42-0,50, silicon 0,17-0,37, manganese from 0.50 to 0.80, sulfur is not more than 0,040, phosphorus does not exceed 0.035, the rest is iron. Note the si: chrome - not more than 0,25%, Nickel not exceed 0.30%, arsenic - not more than 0.08%, nitrogen not more than 0,008%, copper not exceed 0.30% (Marochnik steels and alloys, edited by A.s.zubchenko, M., engineering, 2003, p.102).
The closest in technical essence and the achieved effect of the present invention is rolled, in coils, calibrated round, of medium-carbon micro steel containing, wt.%: carbon - 0,42-0,50, silicon - 0,17-0,37, manganese - 0,50-0,80, sulfur is not more than 0,040, phosphorus does not exceed 0.035, the rest is iron. Impurities: chromium - not more than 0,25%, Nickel not exceed 0.30%, arsenic - not more than 0.08%, nitrogen not more than 0,008%, copper not exceed 0.30% (Marochnik steels and alloys, edited by A.s.zubchenko, M.: engineering, 2003, p.102).
The most important requirement of rolled steel, round, medium-carbon steel used for fabrication of absorber rods by the method of turning at normal delivery of the cutter, is, on the one hand, ensuring high performance machinability, while ensuring a favorable ratio of strength, ductility and toughness, the minimum level of anisotropy of mechanical properties and increasing hardenability characteristics while ensuring end-to-end hardenability rolled diameter up to 30 mm
The technical result of izobreteny what is the rational conditions of machining, the absorber rods of the vehicle while ensuring uniform mechanical properties across the section of the car.
The technical result is achieved by the fact that in long products rolling, calibrated round, in bars, produced from medium carbon steel micro containing carbon and alloying elements, with the defined parameters of quality steel non-metallic inclusions, structure, mechanical properties and hardenability and machinability steel contains the following ratio of components, wt.%:
|Nickel||not more than 0,25|
|copper||not more than 0,25|
|molybdenum||not more than 0.10|
|arsenic||not more than 0.08|
|phosphorus||no more than 0,030|
|iron and inevitable impurities||rest|
when performing ratio: calcium/sulfur ≥0,065,
car has a lamellar ferrite-perlite the structure, the amount of the actual grain 5-8 points, the diameter from 10 to 30 mm, the curvature is not more than 1.0 mm/m, de-carbonized layer is not more than 1.5% of the diameter of rent, hardness 229-255 HB, temporary tear resistance of at least 640 MPa, elongation not less than 6%, the relative narrowing of at least 30%.
Given the combination of alloying elements allow you to get in the finished product (the damper rod with a diameter up to 30 mm), after turning, hardening by high-frequency currents and subsequent grinding ferrite-pearlite fine structure with a favorable combination of strength and ductility.
Carbon is introduced into the composition of this steel to provide the required level of strength and hardenability. The upper limit of carbon content (0,52%) due to the need to ensure the required level of ductility of steel, and the bottom, respectively 0,40% - providing the required level of strength and hardenability of the steel.
Vanadium is introduced into the composition of this steel to ensure a fine, uniform grain structure. However, he manages the processes in the lower part of the austenitic region (determines the tendency to grain growth of austenite, stabilizes the structure during thermomechanical processing, increases the temperature of recrystallization and, consequently, affects the characterγ -α-transformation). The upper limit of the content of vanadium - 0,02%, due to the need to ensure the required level of ductility of steel, and the bottom respectively of 0.005% by providing the required strength level of the steel.
Manganese and chromium are used, on the one hand, as a solid solution hardeners, on the other hand, as elements, increasing the stability of the supercooled austenite steel. The upper levels of manganese - 0,95% and chromium - 0,25% is determined by the need to ensure the required level of ductility of steel, and the lower, manganese - 0,40% and 0.01% chromium, respectively, by the need to provide an appropriate level of strength and hardenability of the steel.
Silicon belongs to territooriumil elements. The lower limit for silicon - 0,17% caused by the deoxidation of steel. The silicon content above 0,37% will adversely affect the characteristics of ductility of steel.
Sulfur determines the level of ductility of steel. The upper limit (0,040%) due to the necessity of obtaining a given level of ductility and toughness of steel, and the lower limit (0,020%) - questions-tech production, as well as to provide a specified level of machinability of the steel.
Aluminum is used as a deoxidizer of steel and the element capable of forming a finely is dispersnoi, grain patterns. The upper limit (0,050%) due to the necessity of obtaining a given level of ductility and toughness of steel, and the lower (0,030%) - questions-tech production, as well as to ensure uniform grain structure of the steel.
Calcium is an element, modifying nonmetallic inclusions. The upper limit (0,010%) due to the necessity of obtaining a given level of ductility and toughness of steel, and the lower (0,001%) limit - questions-tech production.
Nitrogen promotes the formation of nitrides in the steel. The upper limit of nitrogen content - 0,015% due to the necessity of obtaining a given level of ductility and toughness of steel, and the lower limit -0,005% issues technology of production.
The ratio of calcium/sulfur ≥0,065% defines the conditions for the formation of globular sulfides. When you execute it, the globular sulfides, otherwise in steel are elongated sulfides, which increases the anisotropy of the properties of steel and worsens the ratio of the strength-toughness, particularly in the transverse direction of the car.
Analysis of patent and scientific and technical information not found solutions with the same set of features, which would reach a similar effect - enhancing characteristics machinability while maintaining a favorable balance of strength is the ductility and toughness of steel.
Below is an example implementation of the invention.
Smelting of the investigated steel (chemical composition, wt.%: carbon - 0,48, manganese - 0,72, silicon - 0,32, chrome - 0,10, vanadium is 0.01, sulfur - 0,034, aluminum - 0,037, calcium - 0,0025, nitrogen - 0,010) were carried out in a shaft furnace "Fuchs". Used blending melting liquid cast iron up to 40% of the total volume of the mixture. Oxidative period included a high rate of oxidation of carbon within 0,05-0,07%/min electric mode involved the shutting down of the furnace when the carbon content of 0.2-0.4 percent above the lower limit specified, dodavku the carbon produced without arcing. The temperature of the discharge from the furnace 1640-1680°C. Enter ferroalloys, steel treatment to remove non-metallic inclusions was performed on the ladle furnace equipped with an electric heating system or hinotori. The temperature of the steel before casting on 60°C above the liquidus temperature of the brand. Casting was carried out in extended to the top of the mold. The mass of the ingot a 7.85 so To provide a given nitrogen content in the casting produced a stream protection metal with argon through a special ring device. Heating of the ingots in the blooming plant produced regenerative wells before the temperature started rolling 1250-1270°C. Rolling ingots was carried out on the blooming mill (mill 1300) and then to continuous just the adjustment of the mill billet cross section of 100× 100 mm For removing the formed during heating of ingots de-carbonized layer preform was subjected to abrasive blasting." Then made hot rolling the resulting workpiece on a wire mill 150 or small-section mill 250 in diameters from 5.5 to 23 mm in coils. To ensure the value of de-carbonized layer is not more than 1% of the diameter of the limited rate of billets from the furnace is not less than 100 t/h for 150 mill and at least 56 t/h to 250 mill. The onset temperature rolling of billets 1220-1240° (C) to 250 mill and 1270-1290° (C) to 150 mill. Hot rolling of long products was finished at a temperature of 1000-1050°With, then rapid cooling to 880-900°C. Next car was subjected to calibration.
In the hot rolling and subsequent calibration of the obtained rolled ⊘22.5 mm, length 5900 mm, the curvature of the bars - not more than 0.7 mm/m lamellar Structure of pearlite, bezplatny layer depth of 0.05 mm, the score of the actual grain - 7, the hardness of the workpiece 229-241 HB, ultimate strength, 680 MPa, an elongation of 9%, a relative narrowing of 42%. The ratio of calcium/sulfur = 0,074, calcium - 0,0025%, sulfur - 0,034%.
The introduction of the proposed method of production of long-rolled products from medium carbon steel high machinability, providing a two-layer sandwich namecalling the x inclusions, ensure, on the one hand, ensuring high performance cutting, on the other hand favorable ratio between strength ductility and toughness of steel.
Rolled calibrated round, in bars, produced from medium carbon, micro steel containing carbon and alloying elements that have the specified quality parameters become non-metallic inclusions, structure, mechanical properties, hardenability and machinability, characterized in that the steel contains the following ratio of components, wt.%:
|Nickel||Not more than 0,25|
|Copper||Not more than 0,25|
|Molybdenum||Not more than 0.10|
|Arsenic||Not more than 0.08|
|Phosphorus||No more than 0,030|
|Iron and inevitable is remesi||Rest|
when executing the ratio of calcium:sulfur ≥ 0,065,
car has a lamellar ferrite-pearlite structure, the amount of the actual grain 5-8 points, the diameter from 10 to 30 mm, the curvature is not more than 1.0 mm/m, de-carbonized layer is not more than 1.5% of the diameter of rent, hardness 229-255 HB, temporary tear resistance of at least 640 MPa, elongation not less than 6%, the relative narrowing of at least 30%.
FIELD: metallurgy; production of heat-resistant steel for rotors of steam turbines.
SUBSTANCE: the invention is pertaining to the field of metallurgy. in particular to the choice of composition of the heat-resistant steel. which may be used for manufacture of the rotors. arbors and other details of the steam turbines of high and medium pressure. The heat-resistant steel contains the components in the following ratio (in mass %): C - 0.11-0.20; Si - 0.03-0.1; Mn - 0.1-0.3; Cr - 9.0-12.0; Ni - 0 0.7; Mo - 0.9-1.6; V - 0.15-0.30; W - 0-2.0; Nb 0.02-0.06; B - 0-0.02; N - 0.005-0.05; Sn - 0-0.006; Sb - 0-0.005; As - 0-0.007; S - no more than 0.015; P - no more than 0.020; Fe - the rest. The contents of the components also is defined by ratios: 0.12≤C+N≤ 0.22; 0.9≤Mo+0.5W≤2.0; 0.15≤V+Nb≤0.3; Creqv= %Cr+6(%Si) 44 (%Mo) +l. 5 (%W) +ll (%V) +5 (%Nb)-40 (%C)-30 (%N)-2 (%Mn)-4 (%Ni)> 6.5; P≤[0.l2-5(Sb+Sn)-As]/10; 10S≤ Mn ≤ 20S. The technical result of the invention is an increase of the steel resistance to the action of the supercritical temperatures of the steam, the durable strength, increased operational reliability and the service life of the turbine equipment.
EFFECT: the invention ensures an increased the steel resistance to the action of the supercritical temperatures of the steam, its durable strength, operational reliability and the service life of the turbine equipment.
FIELD: metallurgy; articles made from cold work tool steel.
SUBSTANCE: proposed article is made from tool steel containing the following components: carbon, silicon, manganese, phosphorus, sulfur, chromium, molybdenum, nickel, vanadium, tungsten, copper, cobalt, aluminum, nitrogen, oxygen, iron and unavoidable admixtures; steel is made by powder metallurgy method. After martempering, steel has hardness of 64 HRC and impact elasticity at room temperature more than 57.14 J/cm2.
EFFECT: enhanced wear resistance, hardness and ductility.
7 cl, 1 dwg
FIELD: metallurgy, in particular, alloyed tool steels for manufacture of tools for plastic formation.
SUBSTANCE: alloyed tool steel contains, wt%: carbon 0.16-0.27; silicon 0.1-1.5; manganese 0.1-1.2; chromium 12.5-14.5; nickel 0.5-1.7; molybdenum 0.2-0.8; vanadium 0.1-0.5; nitrogen 0.06-0.13; possibly at least one of sulfur max. 0.15; calcium max. 0.01; oxygen max. 0.01; iron and unavoidable contaminants the balance. Total content of carbon and nitrogen satisfies the condition of 0.3≤C+N≤0.4. Plastic formation tool is manufactured from said steel. After hardening at temperature of 1,020-1,030 C followed by tempering at temperature of 200-250 C or at temperature of 500-520 C, steel for manufacture of said tool has microstructure with matrix consisting of tempered martensite and containing 0.3-1.0 vol.% of primarily settled carbon nitrides consisting substantially of M(C,N) carbon nitrides.
EFFECT: improved hardenability, plasticity and corrosion resistance of steel and, accordingly, tool manufactured from such steel.
15 cl, 7 dwg, 2 tbl
FIELD: steels used for manufacture of heavily-loaded gears of automobile gear-boxes.
SUBSTANCE: proposed medium-alloy high machinability steel contains the following constituents, mass-%: carbon, 0.170.23; manganese, 0.65-0.95; silicon, 0.17-0.37; chromium, 0.35-0.65; nickel, 0.40-0.75; molybdenum, 0.15-0.25; sulfur, 0.020-0.040; phosphorus, 0.001-0.035; niobium, 0.005-0.02; vanadium, 0.005-0.08; calcium, 0.001-0.010; oxygen, 0.001-0.015; the remainder being iron and unavoidable admixtures. Oxygen-to-calcium ratio and calcium-to-sulfur ratio are determined as follows: oxygen/calcium =1-4.5 and calcium/sulfur ≥0.065. Steel contains the following admixtures, mass-%: copper, no more than 0.25; arsenic, no more than 0.08; nitrogen, no more than 0.015; non-metallic inclusions have double-layer structure - sulfide with oxide envelope.
EFFECT: enhanced machinability of steel; full hardenability of rolled stock up to 50 mm in diameter.
3 cl, 2 tbl, 1 ex
FIELD: metallurgy and mechanical engineering.
SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular, to production of welded pipes for oil, gas- and product pipelines and other analogous designs (containers, pressurized cylinders) working in the difficult geologic, environmental conditions and in presents of aggressive corrosive mediums. The pipe for oil, gas- and product pipelines is made out of a steel smelt using the high-purity or pure charge materials bearing carbon, manganese, silicon, chromium, nickel, vanadium, niobium, titanium, aluminum, calcium, sulfur, phosphorus, nitrogen, copper, antimony, stannous, arsenic and iron and also molybdenum at the following ratio of components (in mass %): carbon - 0.02-0.11, manganese -0.10-1.80, silicon - 0.06-0.60, chromium - 0.005-0.30, nickel - 0.005-1.0, vanadium - 0.01-0.12, niobium - 0.02-0.10, titanium - 0.01-0.04, aluminum - 0.01-0.05, calcium - 0.0005-0.008, sulfur - 0.0005-0.008, phosphorus -0.001-0.012, nitrogen - 0.001-0.012, copper - 0.005-0.25, antimony 0,0001-0,005, stannous 0,0001-0,007, arsenic 0,0001-0,008, molybdenum - 0.001-0.5, iron - the rest. At that thus the total contents of nickel and manganese depends on a concentration of molybdenum and phosphorus in mass % in the following ratio: (Ni + Mn/1 + Mo)P <0.03. The method of production of the indicated pipe includes smelting of steel with the indicated composition, its treatment in a ladle, casting, hot rolling, molding and welding. The hot rolling is conducted by a reversing rolling mill or continuous rolling mills with the following controlled accelerated chilling.
EFFECT: the invention ensures increased efficiency of production of pipes for oil, gas- and product pipelines working in the difficult geologic, environmental conditions in presents of aggressive corrosive mediums.
2 cl, 2 tbl
FIELD: metallurgy, in particular structural steel composition.
SUBSTANCE: claimed steel contains (mass %): carbon 0.42-0.54p; silicium 0.15-0.50; manganese 0.90-1.50; niobium 0.01-0.08; molybdenum 0.06-0.20; aluminum 0.005-0.060; titanium 0.019-0.045; sulfur 0.001-0.045; phosphorus 0.001-0.045; nitrogen less than 0.012; chromium, nickel and copper each not more than 0.30, and balance: iron. Steel of present invention is useful in production of pipelines for oil industry operating at temperature from 50°C to -10°C.
EFFECT: steel with optimum combination of strength and viscous properties.
2 tbl, 1 ex
FIELD: metallurgy, in particular heat resistant steel composition for forming rolls in metal hot-rolling mill.
SUBSTANCE: claimed steel contains (mass %): carbon 0.21-0.40; silicium 0.60-1.50; manganese 0.20-0.60; chromium 4.00-6.00; nickel 0.20-2.00; vanadium 0.30-0.60; titanium 0.01-0.50; tellurium 0.001-0.020; aluminum 0.01-0.50; molybdenum or molybdenum and tungsten in total 1.00-2.00; and balance: iron. Molybdenum content in steel is not less than 0.40 mass %, and one mass part of molybdenum is equivalent to two mass parts of tungsten. Steel may additionally contain (mass %) calcium up to 0.30; zirconium up to 0.35; cerium up to 0.35, and boron up to 0.015. Content of inevitable impurities in claimed steel is limited: e.g. (mass %) sulfur, phosphorous and copper each not more than 0.040; lead, arsenic, and antimony each not more than 0.010.
EFFECT: decreased crack and erosion net forming on roll surface.
FIELD: metallurgy, in particular stainless steel excellent in cutting workability useful in stick parts manufacturing with very high cutting speed.
SUBSTANCE: invention relates to resulfurizated austenitic stainless steel excellent in workability and corrosion resistance containing calcium oxide silicoaluminate inclusions of anortite and/or pseudowollastonite and/or gelenite-type, associated with inclusions of CrMnS, comprising 30-70 wt.% of chromium.
EFFECT: steel of improved corrosion resistance, in particular pitting corrosion due to presence of specific inclusions.
FIELD: ferrous metallurgy.
SUBSTANCE: invention relates to steel used in making railways. Invention proposes steel comprising the following components, wt.-%: carbon, 0.71-0.82; manganese, 0.75-1.10; silicon, 0.40-0.60; chrome, 0.70-1.20; aluminum, 0.005, not above, vanadium, 0.05-0.15; calcium, 0.0001-0.005; nitrogen, 0.005-0.015; nickel, 0.03-0.20; barium, 0.0001-0.005; strontium, 0.0001-0.005, and iron, the balance. As impurities steel can comprise, %, sulfur, 0.02, not above; phosphorus, 0.025, not above, and copper, 0.15, not above. Invention provides enhancing complex of physical-mechanical properties and exploitation strength of steel.
EFFECT: improved and valuable properties of steel.
FIELD: metallurgy; production of round bars used for manufacture of shock absorber rods.
SUBSTANCE: proposed method includes melting steel in electric furnace, off-furnace treatment, pouring into ingot molds at protection of jet, hot rolling of ingot, thus obtaining billet followed by rolling, controlled cooling and winding bars in bundles, calibration of bars at deformation degree of 20-25%, unwinding of bars, cutting and straightening and special treatment of surface. Steel contains the following components, mass-%: carbon, 0.40-0.52; manganese, 0.40-0.95; silicon, 0.17-0.37; chromium,, 0.01-0.25; sulfur, 0.020-0.045; vanadium, 0.005-0.020; aluminum, 0.03-0.050; calcium, 0.001-0.010; nitrogen, 0.005-0.015; nickel, up to 0.25; copper, no more than 0.25; molybdenum, no more than 0.10; arsenic, no more than 0.08; phosphorus, no more than 0.030; the remainder being iron and unavoidable admixtures. Calcium-to-sulfur ratio is ≥0.065; hot rolling of merchant shaped is completed at temperature of 1000-1050°C followed by fast cooling to 880-900°C and cooling in air to 300°C. Length of bars from bundle of hot-rolled shapes reaches 6 m at accuracy of cutting of ±5 mm. Finishing of shapes includes trimming, check of surfaces for flaws and ultrasonic monitoring of internal defects, selective dressing.
EFFECT: enhanced machinability of merchant shapes; enhanced ductility and toughness.
FIELD: metallurgy; production of merchant shapes for manufacture of spherical pins, end-pieces of rods and spherical supports for automobile suspensions.
SUBSTANCE: merchant shapes are molten from steel containing the following components, mass-%: carbon, 0.35-0.42; manganese, 0.50-0.80; silicon, 0.17-0.37; chromium, 0.80-1.10; sulfur, 0.020-0.040; vanadium, 0.005-0.020; calcium, 0.001-0.010; oxygen, 0.001-0.015; nickel, up to 0.25; copper, no more than 0.25; molybdenum, no more than 0.10; arsenic, no more than 0.08; nitrogen, no more than 0.015; the remainder being iron and unavoidable admixtures at oxygen-to-calcium ratio equal to 1-4.5 and calcium-to-sulfur ratio ≥0.065. Proposed merchant shapes contains nonmetallic inclusions of sulfide having double-layer structure; maximum contamination with nonmetallic inclusions pertaining to sulfides, oxides, silicates and nitrides does not exceed 3 points; it contains also structure consisting of 80% of granular pearlite; size of actual grain is 5-10 points at diameter ranging from 10 to 30 mm; provision is made for decarbonized layer not exceeding 1.5% of diameter, magnitude of cold upsetting is no less than 1/3 of height, rupture strength does not exceed 600 Mpa; relative elongation is no less than 18% and relative reduction in area is no less than 60%.
EFFECT: enhanced machinability at full hardenability of shapes up to 30 mm in diameter; retaining of technological ductility of steel.
FIELD: metallurgy; making of low-alloy steels for manufacture of articles operating in aggressive media containing hydrogen sulfide and carbon dioxide.
SUBSTANCE: proposed low-alloyed steel contains the following components, mass-%: carbon, 0.05-0.15; manganese, 0.40-0.65; chromium, 0.50-0.80; silicon, 0.30-0.80; vanadium, 0.04-0.09; aluminum, 0.02-0.05; the remainder being iron and admixtures. Content of admixtures is limited as follows, mass-%: nitrogen, no more than 0.008; nickel, no more than 0.30; copper, no more than 0.25; hydrogen, no more than 0.0002; total calcium/sulfur ratio shall be no less than 1. In particular case, proposed steel may contain titanium and niobium; total amount of vanadium, titanium and niobium shall not exceed 0.15 mass-%. Proposed steel may be used for manufacture of pipes and joints for handling aggressive media, watery oil and formation water in particular characterized by high degree of mineralization and containing H2S and CO2.
EFFECT: enhanced strength characteristics and corrosion resistance.
2 cl, 4 tbl
FIELD: ferrous metallurgy; production of rail steel.
SUBSTANCE: the invention is pertaining to the field of ferrous metallurgy, in particular, to production of steel for manufacture of railway rails. The offered rail steel contains its components in the following ratio (in mass %): Carbon - 0.83-0.5; manganese - 0.6-1.1; silicon - 0.3-0.7; vanadium - 0.08-0.15; aluminum - no more than 0.005; nitrogen - 0.012-0.02; calcium -0.0005-0.005; chromium - 0.05-0.5; one of the devices sampled from a group including zirconium and REM, namely, zirconium -0.0005-0.005; REM - 0.0005-0.005; molybdenum - 0.11-0.3; nickel - 0.05-0.3, iron and impurities - the rest. The technical result of the invention is an increased complex of mechanical properties, firmness of steel and its resistance to brittle fracture, which improves operational stability of the rails. Out of the steel of a stated composition it is possible to manufacture the rails hardened both in oil and in a compressed air with a troostite structure.
EFFECT: the invention ensures an increased complex of the rail steel mechanical properties, firmness of the steel, its resistance to brittle fracture and production of rails with a troostite structure.
FIELD: rolled stock production, possibly hot rolling of round bars of low alloy steel for cold die forging of fastening members.
SUBSTANCE: method comprises steps of heating blank up to 1100 - 1280°C; multi-pass hot rolling at reducing in grooved rolls at temperature of rolling process termination in range 950 - 1100°C; water cooling of rolled piece till 850 - 950°C. For rolled blank multi-pass rolling is realized at total elongation degree no less than 16. For cast billet multi-pass rolling is realized at total elongation degree no less than 36. Rolled bars are of alloy steel containing, mass %: carbon, 0.20 - 0.33; silicon, 0.17 - 035; manganese, 0.9 - 1.3; boron, 0.001 - 0.005; aluminum, 0.01 - 0.05; titanium, 0.01 or more; phosphorus, 0.035 of less; sulfur, 0.035 or less; chrome, 0.25 or less; nickel, 0.30 or less; copper, 0.30 or less; nitrogen, 0.012 or less; iron, the balance.
EFFECT: less loss of yield, improved quality of rolled bars.
2 cl, 3 tbl, 2 ex