Hot-pressed thick-sheet steel, product moulded by stamping, and method of manufacturing products moulded by stamping

FIELD: metallurgy.

SUBSTANCE: steel contains, wt %: C: 0.15 to 0.5, Si: 0.2 to 3, Mn: 0.5 to 3, P: 0.05 or less (except 0), S: 0.05 or less (except 0), Al: 0.01 to 1, B: of 0.0002 to 0.01, N: 0.001 to 0.01%, Ti: in the amount equal to or greater than 3.4[N]0.01% and equal to or less than 3.4[N]0.1%, where [N] is the content (wt %) N, the rest are iron and unavoidable impurities. The average diameter of the equivalent circle of Ti-containing inclusions having an equivalent circle diameter of 30 nm or less among the Ti-containing inclusions contained in the steel sheet is 3 nm or more. The amount of Ti in the inclusions and the total amount of Ti in the steel satisfy the ratio: (the amount of Ti in the inclusions (wt %)-3.4[N])≥0.5×[(total amount of Ti (wt %))-3.4[N]], where [N] is the content (wt %) N in the steel. The share of ferrite in the metallographic microstructure is 30% or more.

EFFECT: required balance between high strength and elasticity is provided.

6 cl, 1 dwg, 16 tbl, 2 ex

 



 

Same patents:

Steel // 2556449

FIELD: metallurgy.

SUBSTANCE: steel contains, wt %: carbon - 0.1-0.15, silicon - 0.2-0.3, manganese - 0.45-0.65, vanadium - 0.2-0.25, nitrogen - 0.0001-0.00015, calcium - 0.005-0.009, aluminium - 0.05-0.1, boron - 0.1-0.15, zirconium - 0.4-0.6, selenium - 0.002-0.003, ferrum - balance.

EFFECT: steel corrosive resistance enhancement.

1 tbl

FIELD: metallurgy.

SUBSTANCE: steel contains the following elements, wt %: C 0.05-0.07, Cr 18.0-20.0, Ni 5.0-7.0, Mn 8.0-10.0, Mo 1.4-1.8, Si 0.25-0.35, N 0.25-0.28, Al 0.0015-0.0035, rare earth elements 0,005-0,008, the rest is Fe and impurities. Steel contains the following components as impurities, wt %: Cu 0.05, S 0.0025, P 0.010, Sn 0.005, Pb 0.005, Bi 0.005, As 0.005.

EFFECT: required strength parameters at room temperature, resilience at cryogenic temperatures and weldability ensured.

2 cl, 1 tbl

FIELD: metallurgy.

SUBSTANCE: steel contains components in wt %: 0.32-0.42 C, max. 0.35 Si, 1.4-1.8 Mn, max. 0.04 P, 0.08-0.4 S, max. 0.03 Al, 0.03-0.12 Bi, 0.002-0.020 O, Fe and admixture - rest. Steel has uniformly distributed lightly deformed sulfide inclusions of ellipsoidal shape of 2.1-2.2 points.

EFFECT: manufactured steel has increased strength and increased cutability.

6 dwg, 2 tbl

FIELD: metallurgy industry.

SUBSTANCE: molten steel, doped with silicon, is continuously cast into a preform having a thickness in the range from 50 to 100 mm, and subjected to hot rolling in multiple unidirectional rolling mills for obtaining rolls of a finished hot rolled strip having a thickness ranging from 0.7 to 4.0 mm, followed by continuous annealing of the hot rolled strip, by cold rolling, continuous annealing of the cold rolled strip for the initiation of primary recrystallisation and optionally decarburisation and/or nitriding, applying of a coating on the annealed strip, annealing the strip wound in the roll to initiate secondary recrystallisation, continuous thermal levelling by annealing of the annealed strip and application on the annealed strip of the coating for electrical insulation, and the product thus obtained.

EFFECT: improvement of magnetic properties.

13 cl, 3 tbl, 3 dwg

FIELD: metallurgy.

SUBSTANCE: method involves making of steel containing the following components, wt %: C≤0.0040, Si 0.1-0.8, Al 0.002-1.0, Mn 0.10-1.50, P≤0.2, Sb 0.04-0.08, S≤0.0030, N≤0.0020, Ti≤0.0020, and Fe and inevitable impurities are the rest, casting of steel rods, heating of rods to the temperature of 1100-1150°C, hot rolling of rods, which involves finish rolling at the temperature of 860-920°C so that a hot-rolled strip is obtained, cooling of the hot-rolled strip by air during time t (sec) when the following ratio is met: (2+30×Sb%)≤t≤7, coiling of the strip at the temperature of ≥720°C, cold rolling of the strip at the crimping degree of 70-78% so that a cold-rolled strip of the required thickness is obtained, annealing of the cold-rolled strip by heating to the temperature of 800-1000°C at the heating rate of ≥15°C/sec and exposure time of 10-25 seconds.

EFFECT: method allows making electrical steel at comparatively low costs so that high magnetic properties are maintained.

2 cl, 4 tbl, 4 dwg

FIELD: metallurgy.

SUBSTANCE: manufacturing method of textured electrical plate steel involves manufacture of a steel slab, in which content of inhibitor components is reduced, i.e. content of Al of 100 ppm or less and content of N, S and Se of 50 ppm respectively, hot rolling of steel, and then, one cold rolling or two or more cold rolling operations with intermediate annealing operation(s) between them to obtain a steel plate of final thickness; annealing of the steel plate for primary recrystallisation and then annealing for secondary recrystallisation; besides, annealing for the primary recrystallisation includes heating of a steel plate to the temperature that is equal or higher than 700°C, at the heating rate of at least 150°C/s, cooling of the steel plate to the temperature of 700°C or lower, and then, heating of the steel plate to the exposure temperature at average heating rate of not more than 40°C/s in the next heating zone.

EFFECT: reduction of losses in steel iron.

6 cl, 7 tbl, 3 dwg

Steel // 2530909

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to steels for automotive industry. Proposed composition contains the following substances, in wt %: carbon 0.1-0.15, silicon 0.15-0.2, manganese 0.3-0.5, chromium 0.1-0.15, aluminium 0.4-0.6, copper 1.0-1.3, barium 0.0008-0.0012, zirconium 0.1-0.15, vanadium 0.3-0.4, tellurium 0.0008-0.0012, iron making the rest.

EFFECT: higher strength.

1 tbl

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly to production of hot-stamped part that feature high corrosion resistance. Two plies are successively applied on steel substrate surface: plating ply I containing 60 wt % and more of Ni, Zn and unavoidable impurities making the rest. Note here that coating mass varies from 0.01 to 5 g/m2; and plating ply II, containing 10 to 25 wt % of Ni, Zn and unavoidable impurities making the rest. Note coating mass varies from 10 to 90 g/m2.

EFFECT: higher resistance to perforating corrosion.

8 cl, 3 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: in compliance with this invention, slab contain the following components in wt %: 0.01-0.10 C, 2.5-4.5 Si, 0.02-0.12 Mn, 0.005-0.10 Al, 0.004-0.015 N, 0.005-0.06 S and/or 0.005-0.06 S. Steel sheet temperature is controlled to satisfy the equation T(t)<FDT-(FDT-700)×t/6 (where T(t) is steel sheet temperature (°C), FDT is finishing temperature of rolling (°C) and t is time interval (s) after termination of finish rolling) over the entire roll length at cooling after finish hot rolling. Besides, temperature of steel sheet roll end section making 10% of roll length is controlled to make at least 650°C in 3 seconds after termination of hot rolling.

EFFECT: higher magnetic properties over the entire coil length.

2 cl, 2 dwg, 2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: proposed composition contains the following substances, in wt %: carbon - 0.02-0.05, silicon - 0.10-0.80, manganese - 0.10-0.50, chromium - 13.0-16.0, boron - 2.01-3.5, vanadium - 0.15-0.35, cerium - 0.03-0.07, aluminium - 0.15-0.80, titanium - 4.02-8.50, nickel - 0.05-0.50, sulphur - 0.005-0.02, phosphorus - 0.005-0.03, lead - not over 0.005, bismuth - not over 0.005, iron making the rest.

EFFECT: higher process plasticity at hot deformation temperature, decreased disposition to intercrystalline corrosion and cracking at stress.

Steel // 2556442

FIELD: metallurgy.

SUBSTANCE: steel contains, wt %: carbon 0.17-0.23, manganese 0.9-1.1, silicon 0.8-1.4, tungsten - 1.0-1.4, boron 0.04-0.06, nickel 1.6-2.0, titanium 0.002-0.004, iron - the rest.

EFFECT: steel strength improvement.

1 tbl

FIELD: metallurgy.

SUBSTANCE: chemical composition of steel includes in wt %: C from 0.03 to 0.10, Si from 0.01 to 0.50, Mn from 0.5 to 2.5, P from 0.001 to 0.03, S from 0.0001 to 0.0030, Nb from 0.0001 to 0.2, Al from 0.0001 to 0.05, Ti from 0.0001 to 0.030, B from 0.0001 to 0.0005, and iron and inevitable impurities are the rest. Steel plates are held for pre-set time period between rolling runs within recrystallization temperature range, and cooling after hot rolling is performed by two stages. Steel structure in central part through strap thickness has effective size of crystal grains from 3 to 10 microns. Sum of areas of beinite and needle ferrite is from 60 to 99%. Strap thickness is from 7 to 25 mm, and absolute difference A-B of sums of areas of beinite and needle ferrite at any two sections of the strap is from 0 to 30%, where sums of areas of the beinite and needle ferrite at these two sections are designated as A and B, respectively.

EFFECT: reduced strength deviation at common temperature and increased low temperature impact toughness.

7 cl, 2 dwg, 6 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention can be used during structures arc welding in shielded gas using flux cored electrode wire. Weld metal contains specified chemical components and 20% or more particles of Ti-containing oxide. The equivalent diameter of the specified particles diameter is 0.15-1.0 mcm. Their quantity is at least 5000 per mm2. Quantity of vanadium presenting in form of the compound in the weld metal as calculated to total weight of the weld metal is 0.002% or more. Average equivalent diameter of circle of V-containing carbide presenting in the weld metal is 15 nm or below.

EFFECT: weld metal has high strength and high resistance to cold cracking due to decreasing of the hydrogen diffusion.

2 cl, 5 dwg, 6 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Sheet is made of steel containing in wt %: 0,040≤C<0.065, 1.4≤Mn≤1.9, 0.1≤Si≤0.55, 0.095≤Ti≤0.145, 0.025≤Nb≤0.045, 0.005≤A1≤0.1, 0.002≤N≤0.007, S≤0.004, P≤0.020, iron and unavoidable impurities making the rest. Sheet microstructure consists of granular beinite, ferrite, cementite, titanium and niobium carbonitrides. Ratio between drain size dl measured parallel with rolling direction and gain size dn perpendicular to rolling direction makes less than or equals 1.4.Method of sheet production includes heating of semi-finished product to 1160-1300°C, hot rolling with rolling end temperature of 880-930°C. Note here that reduction degree of next to last pass is smaller than 0.25, reduction degree of last pass is smaller than 0.15 while the sum of both reduction degree is smaller than 0.37. Initial temperature at next to last is smaller than 960°. Cooling is performed at the rate of 50-150°C/s. Sheet is wound at winding temperature of 470-625°C.

EFFECT: production of sheet with ductility stress over 690 MPa and less or equal to 840 MPa, strength of 780-950 MPa, elongation over 10% and bore expansion factor larger than or equal to 50%.

26 cl, 6 tbl, 1 dwg

FIELD: metallurgy.

SUBSTANCE: steel contains the following, wt %: C: 0.008 or more and 0.040 or less, Si: 5.0 or less, Mn: 2.0 or less; Al: 2.0 or less; P: 0.05 or less; N: 0.003 or less, Ti: 0.04 or less; Fe and inevitable impurities are the rest. Contents of components included in steel meet expressions (1) and (2): 30085[Si%]+16[Mn%]+40[Al%]+490[P%]430(1), 0,008Ti*<1,2[C%](2), where Ti∗=Ti-3.4[N%].

EFFECT: steel has high magnetic and mechanical properties, low price and high quality of the manufactured steel plate.

6 cl, 3 dwg, 6 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: metal of a weld contains the following, wt %: C 0.02 to 0.12; Si 0.10 to 2.0; Mn 0.90 to 2.5; Ni 0.20 to 3.5; Mo 0.05 to 1.5; Ti 0.040 to 0.150; N not more than 0 and less than or equal to 0.015; and O 0.030 to 0.10, Fe and inevitable impurities are the rest. Particles of residual austenite are present at number density of 2500 per square millimetre or more and at total volume ratio of 4.0% or more in terms of total volume of all structural components of metal of a weld.

EFFECT: metal of a weld has high resistance to hydrogen embrittlement and is resistant to cracking at low temperatures.

6 cl, 5 dwg, 9 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: pipe is made from a parent material of a steel plate folded into a pipe-shaped form and welded by seam welding so that a weld and a large-grained heat-affected zone (HAZ) are formed. The parent material of the steel plate has the following chemical composition, wt %: C 0.03 to 0.085, Mn 1.45 to 1.85, Ti 0.005 to 0.020, Nb 0.005 to 0.050, O 0.0005 to 0.005, Si 0.15 or less, Al 0.015 or less, P 0.02 or less, S 0.005 or less, Mo 0.20 or less, Fe and inevitable impurities are the rest. The structure of metal of the parent material of the steel plate consists of ferrite with a fraction of the area of 30 to 95%, martensite, bainite and martensitic-austenitic component (MA) is the rest, and for the metal structure of the large-grained HAZ the fraction of the area of the grain boundary ferrite is 1.5% or more, the total fraction of the area of the grain boundary ferrite and intragranular ferrite is at least 11%, but not more than 90%, the fraction of the MA area is 10% or less, and bainite is the rest.

EFFECT: improvement of characteristics.

13 cl, 10 dwg, 4 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the field of metallurgy, namely to obtaining a highly strong steel sheet. The sheet is made from steel, containing, in wt %: C 0.02-0.07, Si 0.05-0.50, Mn 1.10-1.60, P maximum 0.015, S maximum 0.0030, Nb 0.005-0.030, Ti 0.005-0.020, Al 0.005-0.060, Ca 0.0005-0.0060, N 0.0015-0.0070, at least one of such elements as Cu, Ni, Cr and Mo, in the total amount from more than 0.1% to less than 1.5%, the remaining part - Fe and inevitable admixtures. The steel structure consists of at least 10%, by the area, of beinite, the remaining part - ferrite and perlite. A degree of segregation constitutes less than 1.6 for Nb and less than 1.4 for Mn in the central part of the steel sheet thickness.

EFFECT: sheets possess resistance to destruction and resistance to hydrogen-induced cracking.

3 cl, 1 dwg, 2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: after forming, due to exclusion of formation of linear structures, steel containing the following (wt %) is made: 0.0005-0.0050 C, not more than 0.30 Si, not more than 0.50 Mn, not more than 0.050 P, not more than 0.020 S, 0.010-0.100 Ti and not more than 0.080 sol. Al, not more than 0.007 N and Fe and inevitable impurities are the rest provided that content of C, N, S and Ti meets the following ratio (I): ([%Ti]/48-[%N]/14-[%S]/32)/([%C]/12)≥1.00…(I), where [%M] represents content in the steel of element M (wt %); it is subject to hot rolling, etching, cold rolling, continuous annealing and cooling at the rate not exceeding 30˚C/s at the temperature interval of 400-200°C.

EFFECT: improving steel plate surface quality.

5 cl, 2 tbl

FIELD: metallurgy.

SUBSTANCE: plate is made from steel containing the following, wt %: C 0.005 or less, Si 0.1-0.8, Mn 1.0-2.5, P 0.1 or less, S 0.02 or less, N 0.0035 or less, Al: 0.1 or less, at least one type of the element chosen from Ti 0.005-0.05 and Nb 0.01-0.08, and Fe and inevitable impurities are the rest. Ferrite grain diameter is at least 7 mcm. Ratio of ferrite grain length in rolling direction to ferrite grain length in plate thickness direction is 2.5 or less. A fraction of a high-angle boundary of the grain, at which disorientation of crystal between two adjacent crystals and a boundary between them is at least 15° is 50% and more throughout the ferrite grain boundary.

EFFECT: plates have high strength at high deep drawing.

16 cl, 3 tbl, 1 ex

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy, particularly, to production of metal strip with mechanical properties varying over strip width. The strip is heated, cooled and overaged at continuous annealing. Note here that at least one of the following parameters varies over the strip width: heating rate, maximum temperature, holding duration at maximum temperature and cooling trajectory after maximum temperature. Note here that at least one of the following parameters varies over the strip width at overaging: rate of heating to maximum temperature, duration of holding at maximum temperature, cooling trajectory after maximum temperature, overaging temperature, duration of holding at overaging temperature, minimum temperature before reaging and rate of heating to reaging temperature. Note here that at least one cooling trajectory follows the nonlinear temperature-time curve.

EFFECT: metal strip with mechanical properties varying over strip width.

15 cl, 8 tbl, 4 dwg

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