Method of production of skelp steel for pipes of underwater sea gas pipe lines of high parameters

FIELD: metallurgy; production of low-alloyed cold-resistant steel for underwater sea gas lines at working pressure up to 19 Mpa working at low temperatures.

SUBSTANCE: proposed method includes production of steel blank, heating it to temperature above As3, deformation in controllable mode at specific reduction processes and at total reduction of 50-60% followed by controllable cooling; proposed steel has the following composition, mass-%: carbon, 0.05-0.9; manganese, 1.25-1.6; silicon, 0.15-0.30; chromium, 0.01-0.1; nickel, 0.3-0.6; molybdenum, 0.10-0.25; vanadium, 0.03-0.10; aluminum, 0.02-0.05; niobium, 0.01-0.06; copper, 0.2-0.4; calcium, 0.001-0.005; sulfur, 0.0005-0.005; phosphorus, 0.005-0.015; the remainder being iron; preliminary deformation of blanks is performed at temperature of 950-850°C at total reduction of 50-60%; then, blank is cooled down to temperature of 820-760°C at rate of cooling of 15°C/s on controllable cooling unit and final deformation is performed additionally at temperature of 770-740°C to required thickness of skelp at total reduction of 60-76%; further cooling is performed at higher rate of 35-55°C/s to temperature of 530-350°C, after which skelp is cooled in jacket to temperature of 150±20°C and then in the air. New stage of the proposed method makes it possible to manufacture tubes of 1067-1420 mm in diameter at thickness of walls of 24-40 mm which are used for sea gas pipe lines working at pressure of up to 19 Mpa.

EFFECT: enhanced strength, ductility and cold resistance; enhanced operational reliability; increased service life.

2 tbl, 1 ex

 

The invention relates to metallurgy, and more specifically to the production of stepsaway steel pipe offshore pipelines diameter 1067-1420 mm with working pressure up to 19 MPa strength class K60.

Currently increased demand for large diameter pipes for subsea pipelines in connection with the development of new fields located in areas with severe climatic conditions.

The construction of pipelines pipes of Russian production for submarine pipelines high settings, not inferior in quality to foreign analogues, is one of the most promising directions.

Wide use has similar technology strapcova steel CAP on THE 14-1-1950-89 using normalization, normalization and tempering, quenching and tempering, and controlled rolling. This steel contains a mass fraction of elements of the following composition: carbon 0.15 to 0.20 per cent; manganese 1.3 to 1.6%; silicon, 0.3 to 0.5%; chromium - not more than 0.3%; vanadium 0,08-0,12%, nitrogen 0,015-0,025%, sulfur not more than 0.02%of phosphorus - not more than 0.02%, iron - rest. Steel has the following mechanical properties: tensile strength ≥590, yield strength ≥410 MPa, elongation ≥22% and KCU at -40°C - 59 j.

However strapcova steel CAP category strength K60 is produced in thicknesses of about 8.5-10.5 m is, that ensures operation at an operating pressure in the pipes is not more than 7 MPa, and is intended for the production of pipes for onshore pipelines.

Also the disadvantage of this stepsaway steel is the inability to use it for underwater pipelines and the absence of requirements for large diameter pipe, as approved by OAO Gazprom in the ratio of fracture toughness:

To ensure requirements for pipes for subsea pipelines, namely the category of strength K60, 24-40 mm thickness to provide a working pressure of 19 MPa and Pcm below 0,22%, the required mode of production stepsaway steel using the method of thermomechanical processing.

The closest technology is a method of production of sheet steel of the following chemical composition (wt.%) carbon 0.05 to 0.15; manganese - 1,2-2,0; silicon - 0,2-0,6; niobium - 0,01-0,10; titanium - 0,005-0,03; aluminum - 0,01-0,10; chrome - 0,03-0,50; Nickel - 0,03-0,50; copper - 0,03-0,50; nitrogen - 0,005-0,020, iron rest, using the method of thermomechanical processing (RF patent 2062795, class C 21 D 9/46, 8/02, 1995 - prototype), which consists in obtaining sheet, austenization are determined, the strain with the total degree of reductions of 50-80% to 14 mm thickness, the cooling from the temperature of the end of the deformation 760-900°soon with the TEW 10-60° C/C to a temperature of 300-20°With in re-heated to the temperature 590-740°With a delay of 0.2 to 3.0 min/mm and the final cooling.

The technical result of the invention is to develop a production method stepsaway steel in thicknesses 24-40 mm while providing superior weldability of Sequ≤0.44 per cent and requirements for large diameter pipes by the coefficient of criminologist Pcm≤0,22%, and requirements, ensuring the manufacturability of the tube defined by the ratio of σof 0.2in≤0,90, guaranteed temporary resistance more than 565 MPa, the yield strength of more than 482 MPa KV and-40more than 50 joules.

The technical result is achieved in that in the method of production stepsaway steel pipes submarine gas pipelines of high parameters, including the production of billets of steel, heating to temperatures above AU3the deformation in a controlled manner with private reductions in the total compression 50-60% and subsequent controlled cooling, according to the invention the workpiece is produced from a steel of the following composition, wt.%:

Carbon0,05-0,09
Manganese1,25-1,6
Silicon0,15-0,30
Chromeof 0.01-0.1
Nickel0,3-0,6
Molybdenum0,10-0,25
Vanadium0,03-0,10
Aluminum0,02-0,05
Niobium0,01-0,06
Copper0,2-0,4
Calcium0,001-0,005
Sulfur0,0005-0,005
Phosphorus0,005-0,015
IronThe rest,

preliminary deformation of the workpiece is carried out at a temperature of 950-850°With total reductions of 50-60%, then cooling it to a temperature 820-760°With cooling rate 4-15°With the installation of controlled cooling (UCO), additionally produce the final deformation at a temperature 770-740°to the desired thickness of the strip, with a total compression 60-76%, further cooling leads rapidly to UCO with speed 35-55°C/s to a temperature 530-350°s, then the strip is cooled in the caisson up to 150±20°and forth in the air.

Application of thermomechanical processing provides an increase in the number of nuclei of ferrite and promotes the formation of a developed substructure at the completion of the deformation at a temperature close to the point Ar3and uniform allocation supermultiplet carbide phase over the entire area of ferritic grains.

Deformation PR the temperatures of 850-950° With total reductions of 50-60% is required for the development of cast structure of the workpiece and forming a pre-metal structure.

The cooling temperature 760-820°With cooling rate 4-15°/produce to form a solid metal surface layer, which allows for further fine deformation to obtain a fine-grained structure throughout the cross section of the car.

The end of the deformation mode of thermomechanical treatment at a temperature of 740-770°With close to Ar3that leads to an increase in the number of nuclei of ferrite and uniform selection of fine carbide phase.

Accelerated cooling of rolled steel in the temperature range from 725-750°to 350-530°increases the dispersion of the structural components.

Subsequent slow cooling in the caisson helps to relieve thermal stresses.

To get high quality and stable properties stepsaway steel produced by this method, it is necessary to provide high metallurgical quality of the workpiece, including low sulfur content (0,0005-0,005%).

The sulfur content in the claimed range when the modification of the sulphides of calcium allows to obtain more homogeneous structure, to minimize defects, thereby to increase the resistance of the metal in the acidic environment of the gas, and increases nicotine atorney viscosity of steel.

Low carbon content along with improved weldability, increasing the low temperature viscosity favorably and to reduce segregation in continuously cast slab.

With the high carbon content decreases the segregation of manganese, which helps avoid banded ferrite-pearlite structure.

In steel with a carbon content of less than 0,09% peritectically reaction when crystallization does not occur, decreases the interval of crystallization, expanding the interval of existence δ-ferrite, which allows homogenizing solid solution, thereby increasing the uniformity of distribution of elements.

The addition of manganese, molybdenum and Nickel in the claimed limits provides terrastone hardening metal and promotes better hardenability during thermomechanical processing.

When microregion aluminum, niobium and vanadium is grinding grain due to the formation of fine carbides, which hinders the grain growth of austenite during heating, which increases the yield strength and gladstonos stepsaway steel.

Tests stepsaway steel, manufactured by the proposed method showed that the selected modes and chemical composition provide along with the required strength high job impact at -60°With (not less than 50 j), and the desired ratio σof 0.2the ≤0,90.

Example. The steel was melted in a Converter with secondary processing, refining and pouring in continuously cast billets h mm

Chemical composition shown in table 1.

The billet was subjected to heating above the temperature AU3that corresponded 1130°C, then subjected to preliminary deformation at a temperature of 950 and 850°with a total compression 56 and 60%, and then cooled to a temperature of 820 and 760°With speeds of 4 and 15°C/C, the final deformation on stripsody car width is 24, 31 and 40 mm was carried out at a temperature of 770 and 740°with a total compression 60 and 76% with subsequent accelerated cooling in UCO up to temperatures of 350 530 and°and passed the car in the caisson to cool to 150±20°C. Further cooling was performed on the air.

Mechanical properties of rolled stepsaway steel was determined on transverse specimens: explosive type W No. 4 according to GOST 1497, shock type 11 according to GOST 9454. The results are presented in table 2.

Technical efficiency of the present invention will be expressed in the possibility of manufacturing a domestic mainline pipes for offshore pipelines 1067-1420 mm, to increase their reliability and durability by improving the operation of the punch and criminologist steel strip, as well as reducing the complexity of the manufacture of welded pipes by increasing the nological steel.

Table 1
Chemical composition of steel
SteelConditional number of trunksMass fraction of elements,%PcmWithEQ
SiMnPSCrNiCuAlVNbMoTiCANFe
10,070,301,60,0100,0050,010,300,300,050,0650,0350,10-0,001-REST0,200,41
Offer20,050,151,430,0150,00250,100,600,200,020,0300,0100,25-0,005-0,170,42
30,09 0,231,250,0050,00050,060,450,400,0350,10to 0.0600,17-0,003-0,210,42
Known40,110,301,60--0,200,500,400,004-0,06-0,005-0,005--

td align="center"> 285
Table 2
Method and mechanical properties rental
SteelUsl No. PLA CaiTol soup for about kataThe parameters of the methodMechanical properties
Preliminary rollingCooling UCOFinal rollingCooling UCOThe temperatures of the cooling gap Denia in the caisson, °Temporary resistance σin, MPaConditional limit fluid is STI σ of 0.2, MPaσof 0.2inElongation δ3Job blow KV-20, JJob blow KV-60, J
Temperature of atur, °Compression, %, not less thanTemperatures, °Speed °/sTemperatures, °Compression, %Temperature, °Speed °/s
Offer14095050760477076530351505904870,8225288273
40850608201574060350551506105020,8227269268
23195050820477060530551505804900,8427299
31850607601574076350351506104980,8226291287
32495050820477076530351505704760,8428299253
24850607601574060350551506155000,8127277264
Known41495050--7606030030-596455-337885
Note. 1. Values of mechanical properties are given for the test results of three samples per pixel.

2. The mechanical properties determined after thermomechanical processing.

Method of manufacturing stepsaway steel pipes submarine gas pipelines of high parameters, including the production of billets of steel, heating above the temperature AU3the deformation in a controlled manner with private reductions in the total compression 50-60%, controlled cooling, characterized in that the workpiece is produced from a steel of the following composition, wt.%:

Carbon0,05-0,09
Silicon0,15-0,30
Manganese1,25-1,6
Chromeof 0.01-0.1
Nickel0,3-0,6
Molybdenum0,10-0,25
Copper0,2-0,4
Calcium0,001-0,005
Aluminum0,02-0,05
Niobium0,01-0,06
Vanadium0,03-0,10
Sulfur0,0005-0,005
Phosphorus0,005-0,015
IronRest

preliminary deformation is carried out at a temperature of 950-850°with a total compression of 50-60%, then cooled to a temperature of 820-760°With speed 4-15°C/C, the final deformation is carried out at a temperature of 770-740°to the desired tol the ins strip with a total compression 60-76%, further cooling leads rapidly with speed 35-55°C/s to a temperature 530-350°s, then the strip is cooled in the caisson to a temperature (150±20)°and forth in the air.



 

Same patents:

FIELD: ferrous industry; production of stainless steel of the martensitic-austenitic class.

SUBSTANCE: the invention is pertaining to the field of ferrous industry, to production of stainless steel of the martensitic-austenitic class intended for manufacture of the high-loaded components working on twisting and bending under a dynamic loading in corrosive acid mediums having a high content of salts of alkaline and alkaline-earth metals, salts of nitrogenous acid and sulfuric acid, ions of chlorine and hydrogen sulfide. The steel contains the following ingredients(in mass %): Carbon - 0.005 - 0.07; silicon - no more than 1.0; manganese - no more than 1.8; chrome - 12.5 - 17.0; nickel - 2.0 - 8.0; molybdenum + 3 · tungsten - 0.05 - 5-4.5; nitrogen - 0.005 - 0.15; boron - 0.0001 - 0.01; at least one the following ingredients: aluminum, titanium, niobium, vanadium - 0.01 - 5.0; iron and impurities - the rest. At that Thus (Mo+3·W)≤(kl-Cr·al), where kl=15.9, a1 = 0.87, and alsoNi=k2-a(Cr+Mo+W), wherek2 = 16.25 ± l.5, a2=0.7 ± 0.l. The method of manufacture of the product provides for ingots casting or blanks continuous casting, rolling and thermal treatment. The technical result of the invention is an increased steel plasticity, its corrosion resistance in hydrosulfuric mediums with a simultaneous increase of stability of the steel mechanical properties.

EFFECT: the invention ensures an increased steel plasticity, corrosion resistance in hydrosulfuric mediums, stability of the steel mechanical properties.

25 cl, 2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: stainless steel comprises, in mass %, 0.01-0.07 of C, 0.3-1.8 of Mn, up to 1.0 of Si, 14-18 of Cr, 2.0-5.0 of Ni, 1.0-4.0 of Cu, 0.01-1.0 of Nb, 0.01-0.12 of N, 0.01-2 of AL+Ti, Fe, and accompanying admixtures the remainder. At least one of the components (aluminum or titanium) forms intermetallic compounds with nickel.

EFFECT: enhanced strength and resistance to corrosion.

9 cl, 1 dwg, 1 tbl

FIELD: steel making.

SUBSTANCE: invention relates to steels for pipe-welding industry, whose produce is appropriate in food-processing industry, chemical industry, agriculture, and motor car construction, for example in manufacture of teet cup cartridges and automotive muffler parts. Steel contains following components, wt %: carbon 0.01-0.05, silicon 0.01-0.8. manganese 0.1-0.8. chromium 13.0-18.0, titanium 0.05-0.5, aluminum 0.01-0.1, calcium 0.001-0.02, zirconium 0.005-0.035, nitrogen 0.001-0.025, boron 0.0003-0.005, barium 0.001-0.1, magnesium 0.001-0.02, rare-earth metals 0.001-0.05, nickel 0.1-0.95, vanadium 0.01-0.35, molybdenum 0.01-0.5, tungsten 0.01-0.3, and iron - the balance.

EFFECT: increased plasticity and yield limit thereby contributing to increased pipe-welding productivity.

2 tbl

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.28-0.35, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, molybdenum 0.001-0.10, nickel 0.001-0.10, niobium 0.005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.055 ≤ 2.0; 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.001 ≥ 0.33, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 23 mm in diameter; point of maximum load not higher than 640 MPa; relative elongation at least 18%; and relative contraction at least 55%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing carbon and alloying elements, having specified parameters of metallurgical quality, structure, mechanical properties, hardenability, and in-process plasticity and characterized by being composed of, wt %: carbon 0.17-0.25, manganese 0.90-1.40, silicon 0.01-0.17, sulfur 0.005-0.020, chromium 0.001-0.35, vanadium 0.001-0.07, nickel 0.001-0.10, copper 0.001-0.10, molybdenum 0.001-0.10, titanium 0.01-0.04, boron 0.0005-0.0050, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 22 ≤ 12/C-Mn/0.055 ≤ 47Ni/10Ti+Al ≤ 0.039; 10B-0.01C/N ≥ 1.80, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-25 mm; carbon-free layer not exceeding 1.5% diameter; cold setting value at least 1/3 height; throughout (90%) hardenability in circles up to 19 mm in diameter; point of maximum load not higher than 580 MPa; relative elongation at least 18%; and relative contraction at least 60%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from steel containing, wt %: carbon 0.10-0.15, manganese 0.90-1.40, silicon 0.001-0.37, sulfur 0.005-0.020, chromium 0.001-0.35, nickel 0.005-0.10, niobium 0,005-0.02, titanium 0.01-0.04, boron 0.0005-0.0050, aluminum 0.02-0.06, nitrogen 0.005-0.015, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 500(Ti/24-N/7)+0.2 ≥ 0; 40 ≥ C/0.01+B/0.0001 ≥ 3.0, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% perlite; effective grain size 5-10 points; diameter of wire 10-23 mm; carbon-free layer not exceeding 2.5% diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 15 mm in diameter; point of maximum load not higher than 520 MPa; relative elongation at least 20%; and relative contraction at least 65%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

FIELD: metallurgy, in particular composition of dispersion-hardening martensite stainless steel for air-spaceships.

SUBSTANCE: claimed steel contains (mass %) carbon ≤0.030; manganese ≤0.050; silicium ≤1/00; phosphorus ≤ 0.030; sulfur 0.007-0.015; chromium 14.00-15.50; nickel 3.50-5.50; molybdenum ≤1.00; copper 2.50-4.50; niobium + tantalum = (carbon content)x5-0.25; aluminum ≤0.05; boron ≤0.010; nitrogen ≤0.030; and balance: iron and inevitable impurities.

EFFECT: steel excellent in workability.

21 cl, 14 tbl, 2 ex

Steel // 2243288
The invention relates to metallurgy, in particular to low-alloy plate welded structural steels intended for the manufacture of platforms, heavy-duty trucks operating in the Far North

Steel // 2243287
The invention relates to metallurgy, and in particular to compositions of steels used in the production of cold rolled strips, tapes and sheets intended for the manufacture of articles by deep drawing

Rail steel // 2241779
The invention relates to ferrous metallurgy, in particular to the production of steel for rails

FIELD: steel making.

SUBSTANCE: invention relates to such type of steel that is employed in welded structures such as gas conduits, petroleum pipelines, as well as in high-pressure vessels. Steel according to invention contains, wt %: C 0.02-0.10, Si up to 0.6, Mn 1.5-2.5, P up to 0.015, S up to 0.003, Ni 0.01-2.0, Mo 0.2-0.6, Nb below 0.010, Ti up to 0.030, Al up to 0.070, N up to 0.0060, Fe and unavoidable impurities - the rest, provided that parameter P = 2.7C+0.4Si+Mn+0.8Cr+0.45(Ni+Cu)+2V+Mo-0.5 is within a range of 1.9 to 3.5. Microstructure of steel is mainly composed of martensite and bainite. Steel sheet is manufactured by heating casting to at least Ac3, subjecting it to hot rolling, and cooling sheet at a rate 1°C/sec to temperature not exceeding 550°C. Sheet is further used to manufacture a tube. When laying multilayer welding joint, energy absorbed in the Charpy impact test at -40°C is at least 200 J.

EFFECT: achieved elongation strength at least 800 MPa.

21 cl, 1 dwg, 9 tbl, 5 ex

FIELD: ferrous metallurgy; motor-car industry; production of steels intended for manufacture of items of a complex configuration with the help of cold sheet stamping.

SUBSTANCE: the invention is pertaining to the field of ferrous metallurgy and motor-car industry, in particular, to methods of production of steels intended for manufacture by cold sheet stamping of items of a complex configuration, predominantly details for motor cars. The technical problem is to boost steel stamping, to improve the quality of a surface of a steel strip and hence to improve adhesion of a protective cover. The method includes a steel smelting, casting, hot rolling, strips reeling in rolls, a cold rolling, a recrystallization annealing and a temper rolling. The steel contains components in the following ratio (in mass %): Carbon - 0.002 - 0.008, silicon - 0.005-0.025, manganese - 0.05-0,20, phosphorus - 0.005-0.025, sulfur - 0.003-0.012, aluminum - 0.02-0.07, titanium - 0.02-0.05, niobium - 0.001 0.080, iron and imminent impurities - the rest. The hot rolling is completed at the temperature determined from the ratio: Tf.r≥ 7300 / (3.0-Ig [Nb] [C]) - 253, where Tf.r - temperature of the end of the rolling, °C; [Nb] and [C] - the shares of niobium and carbon in the steel accordingly in mass %, and the recrystallization annealing is carried out in a pusher-type furnace at the temperature assigned depending on the contents of niobium in steel according to the equation: Tan= (750+ 1850 [Nb]) ± 20, where Tan - a temperature of the thermal treatment, °C; [Nb] - the contents of niobium in the steel, in mass %.

EFFECT: the invention allows to boost the steel stamping, to improve the quality of the steel strip surface and adhesion of a protective cover.

4 ex, 1 tbl

FIELD: metalwork operating in cold climates at static loads.

SUBSTANCE: proposed iron-based cold-resistant alloy includes the following components, mass-%: titanium, 1-2; carbon, 0.009 max; silicon, 0.1 max; aluminum, 0.003 max; copper, 0.03 max; nickel, 0.2 max; the remainder being iron. Proposed alloy possesses high strength at retained ductility; embrittlement of this alloy at cooling to temperature below minus 78°C is excluded; content of carbon is considerably reduced due to increased content of titanium, thus enhancing resistance to cold.

EFFECT: enhanced efficiency; enhanced cold resistance.

1 dwg, 1 tbl

Structural steel // 2251587

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; production of important rolled stock for oil-well tubing of increased service life.

SUBSTANCE: proposed method includes making steel of definite chemical composition in electric furnace, tapping metal from furnace into ladle, treatment of metal in ladle and teeming steel into ingot molds. Alloying with molybdenum is performed by introducing molybdenum-containing materials into furnace in making steel. After teeming, ingots are rolled, cooled and heated for rolling in preset temperature range and are subjected to preliminary and final deformation; process is completed by final cooling of rolled blanks to surrounding temperature.

EFFECT: improved strength characteristics and cold resistance of metal; enhanced reliability of metal products.

1 ex

FIELD: metallurgy; high-titanium-bearing foundry alloy production.

SUBSTANCE: the invention is dealt with the field of metallurgy, in particular, with production of the foundry alloy containing mainly titanium and also a small amount of other useful metals reduced from oxides of a charge together with the basic components of a foundry alloy. The method includes the following stages: after melting-down of the first portion of the charge representing an ilmenite concentrate formed on the rotating melt of the high-titanium-bearing foundry alloy and reduction by titanium and silicon of a part of oxides from the melted portion of ilmenite they use aluminum to reduce all oxides in a cinder melt. The obtained slag is added with the first portion of calcium oxide in the amount ensuring fluidity of the cinder. The second portion of the charge is introduced in the melt in the amount corresponding to the possibility of to reduce oxides by titanium. The produced titanium oxide is merged with the earlier produced cinder. A determined part of the produced melt in conditions of its rotation is poured out through a side tap hole. Using aluminum reduce titanium oxide from the merged cinder and the reduced titanium merge with the rest metal melt. In the formed final cinder enter the second portion of calcium oxide. A part of the produced foundry alloy is poured out through a side tap hole. Then a final cinder is also poured out and they feed a new portion of ilmenite onto the residue of the foundry alloy. The invention allows to reduce at least twice the power input used for reprocessing of the ilmenite concentrate, as in the process of reduction of the metals from oxides there are no endothermic reactions but exothermic reactions; to use ilmenite concentrates with a share of titanium oxide up to 45% and a strong metal reductant - aluminum, and also to realize a progressive technology of the liquid-phase reduction of metals from oxides in conditions of rotation of the melt by an electromagnetic field.

EFFECT: the invention allows to reduce at least twice the power input used for reprocessing of the ilmenite concentrate, to use ilmenite concentrates with a share of titanium oxide up to 45% and a strong metal reductant - aluminum, to realize a progressive technology of the liquid-phase reduction of metals from oxides.

5 cl, 1 ex, 1 dwg

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from low-carbon steel composed of, wt %: carbon 0.17-0.25, manganese 0.30-0.65, silicon 0.01-0.17, sulfur 0.005-0.020, vanadium 0.005-0.07, niobium 0.005-0.02, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: 12/C-Mn/0.02 ≥ 27; 0.46 ≥ 6V+8Nb ≥ 0.22; Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 80% grainy perlite; effective grain size 5-10 points; diameter 10-25 mm; carbon-free layer not exceeding 1.5% of diameter; cold setting value at least 1/3 height; point of maximum load not higher than 550 MPa; relative elongation at least 20%; and relative contraction at least 60%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously ensured improved characteristics of in-process plasticity and low level of stray hardening.

FIELD: ferrous metallurgy.

SUBSTANCE: invention provides round-profiled iron smelted from alloyed steel composed of, wt %: carbon 0.06-0.11, manganese 0.30-0.9, silicon 0.001-0.15, boron 0.0005-0.0050, vanadium 0.005-0.08, aluminum 0.02-0.06, titanium 0.01-0.04, sulfur 0.005-0.020, nitrogen 0.005-0.015, calcium 0.001-0.010, iron and unavoidable impurities - the balance. When following relationships are fulfilled: Ti/48+Al/27-N/14 ≥ 0.6 x 10-3; Mn+5.0C ≥ 0.80; Ca/S ≥ 0.065, rolled iron has following characteristics: maximum degree of pollution with nonmetal inclusions, in particular sulfides, oxides, silicates, and nitrides, does not exceed 3 points for each type of inclusions; longitudinally uniform spheroidized structure composed of at least 60% grainy perlite; effective grain size 5-10 points; diameter 10-16 mm; carbon-free layer not exceeding 1.0% of diameter; cold setting value at least 1/3 height; throughout hardenability in circles up to 16 mm in diameter; point of maximum load not higher than 500 MPa; relative elongation at least 22%; and relative contraction at least 70%.

EFFECT: ensured optimal conditions for cold die forging of high-strength geometrically complex fastening members and simultaneously improved steel hardenability characteristics.

The invention relates to metallurgy, and more particularly to rolling production, and can be used in the manufacture of welded pipes for oil pipeline construction in seismic zones

The invention relates to metallurgy, and more particularly to rolling production, and can be used in the manufacture of the sheet reversing mills low alloy steel for the construction of offshore platforms

FIELD: metallurgy; production of rolled sheets for manufacture of electrically welded straight-seam tubes of larger diameter.

SUBSTANCE: proposed method includes melting of steel, alloying, ladle treatment, teeming steel into ingots or continuously cast blanks; as a result, steel of definite composition is obtained at ratio of [Manganese] x [Niobium] = (2.5-3.5) 10-2. After teeming, ingots are rolled into slabs and are cooled down; continuously cast blanks are cooled down and are subjected to preliminary and final deformation to required sizes of rolled sheets (final deformation is completed in preset temperature range). Heat treatment of rolled sheets is proposed as version. Heat treatment is performed at definite mode and is followed by cooling to surrounding temperature.

EFFECT: enhanced efficiency; enhanced strength characteristics and cold resistance of metal; enhanced corrosion resistance.

3 cl, 1 ex

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