METHOD FOR WELDING COLD-ROLLED NARROW STRIPS IN THE FORM OF FLAT WIRE OR PROFILES OF A TWIP STEEL AND A WELDED COLD-ROLLED NARROW STRIP OF A TWIP STEEL
The invention relates to a method for welding cold-rolled narrow strips (5) in the form of flat wire or profiles of a TWIP steel, in particular for use in flexible pipes (1), in particular in flexible pipes (1) for offshore applications, in which the ends (7) of the portions of the narrow strip (5) that are to be welded are formed as bevelled in relation to the main direction of loading (8) of the narrow strip (5) and are arranged so as to match one another, and the weld seam (9) is created by a fusion welding method with a relatively small melting zone and/or a relatively low welding temperature. Likewise proposed is a cold-rolled narrow strip (5) in the form of flat wire or profiles of a TWIP steel, in particular for use in flexible pipes (1), in particular in flexible pipes (1) for offshore applications, in which the narrow strips (5) to be welded have ends (7) that are respectively made to match one another and are formed as bevelled in relation to the main direction of loading (8) of the narrow strip (5).
C21D 9/52 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for wiresHeat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for strips
C22C 38/58 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
C22C 38/48 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
C22C 38/46 - Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
C22C 38/06 - Ferrous alloys, e.g. steel alloys containing aluminium
C22C 38/02 - Ferrous alloys, e.g. steel alloys containing silicon
B21B 1/22 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling bands or sheets of indefinite length
B21B 1/16 - Metal rolling methods or mills for making semi-finished products of solid or profiled cross-sectionSequence of operations in milling trainsLayout of rolling-mill plant, e.g. grouping of standsSuccession of passes or of sectional pass alternations for rolling wire or material of like small cross-section
F16L 11/10 - Hoses, i.e. flexible pipes made of rubber or flexible plastics with reinforcements not embedded in the wall
C22C 38/22 - Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
C22C 38/20 - Ferrous alloys, e.g. steel alloys containing chromium with copper
C22C 38/18 - Ferrous alloys, e.g. steel alloys containing chromium
C22C 38/28 - Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
C22C 38/24 - Ferrous alloys, e.g. steel alloys containing chromium with vanadium
C22C 38/26 - Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
C22C 38/32 - Ferrous alloys, e.g. steel alloys containing chromium with boron
C22C 38/40 - Ferrous alloys, e.g. steel alloys containing chromium with nickel
B21C 1/00 - Manufacture of metal sheets, wire, rods, tubes or like semi-manufactured products by drawing
C21D 9/08 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for tubular bodies or pipes
C21D 9/14 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
C21D 1/25 - Hardening, combined with annealing between 300 °C and 600 °C, i.e. heat refining ("Vergüten")
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C22C 38/08 - Ferrous alloys, e.g. steel alloys containing nickel
C22C 38/12 - Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium or niobium
F16L 11/08 - Hoses, i.e. flexible pipes made of rubber or flexible plastics with reinforcements embedded in the wall
3.
COLD-ROLLED NARROW STRIP IN THE FORM OF FLAT WIRE OR PROFILED ELEMENTS MADE OF A HIGH-STRENGTH STEEL FOR USE IN FLEXIBLE PIPES, IN PARTICULAR IN FLEXIBLE PIPES FOR OFFSHORE APPLICATIONS, AND METHOD FOR PRODUCING SUCH COLD-ROLLED NARROW STRIPS
The invention relates to a flat wire or a narrow strip having a profiled cross-section made of a high-strength steel having the following composition (in weight percent): C 0.2 - 0.9%, Mn 12 - 25%, Si up to 0.5%, Al 0.5 - 2.0%, Cr 1.80 - 3.5%, S max. 0.005%, P max. 0.06%, N max. 0.1%, Mo max. 1.5%, B max. 0.01%, Ni max. 2.0%, Cu max. 2.0%, Ca max. 0.015%, Nb 0.02 - 0.35%, and/or V 0.02 - 0.35%, and optionally Ti 0.01 - 0.35%, and, as the remainder, iron and unavoidable, production-related impurities, cold-rolled and/or cold-profiled from wire-shaped starting material having optional intermediate annealing and/or optional final annealing treatment in order to achieve the following mechanical values: Rp0.2 500 - 1650 MPa, Rm 750 - 1800 MPa, A80 3 - 50%, for the production of reinforcing layers in flexible pipes for petroleum and natural gas extraction and for the transport of liquefied gas (FLNG) with acid-gas conditions (acidic corroding media). The invention further relates to a method for producing corresponding flat wires or narrow strips.
B21C 37/04 - Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided forManufacture of tubes of special shape of rods or wire
B21C 1/02 - Drawing metal wire or like flexible metallic material by drawing machines or apparatus in which the drawing action is effected by drums
B22D 11/124 - Accessories for subsequent treating or working cast stock in situ for cooling
The invention relates to a cold-rolled carbon steel comprising (in % by weight) C 0.63-0.85%, max. 0.40% Si, 0.20-0.90% Mn, max. 0.035% P, max. 0.035% S, max. 0.060% Al, max. 0.40% Cr, 0.003-0.010% N, preferably 0.005-0.008%, and a maximum of 0.12% of at least one micro-alloying element, the remainder being iron and steel production-related pollutants. Possible micro-alloying elements are Ti, Nb, V and optionally Zr. A carbon steel of the type is cold-rolled into texture-rolled strip steel with a high cold reduction degree and can be used in particular as a material for coiling springs or other components having spring properties.
C22C 38/04 - Ferrous alloys, e.g. steel alloys containing manganese
C22C 38/14 - Ferrous alloys, e.g. steel alloys containing titanium or zirconium
C22C 38/12 - Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium or niobium
C21D 7/02 - Modifying the physical properties of iron or steel by deformation by cold working
C21D 9/02 - Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articlesFurnaces therefor for springs
F16F 1/02 - Springs made of steel or other material having low internal frictionWound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant
5.
Method and device for the continuous creation of a bainite structure in a carbon steel, particularly in a strip steel
A method continuously creates a bainite structure in a carbon steel, especially a strip steel by austenitizing the carbon steel; introducing the austenitized carbon steel into a bath containing a quenching agent; adjusting the carbon steel to the transformation temperature for bainite and maintaining the transformation temperature for a certain period of time; and then cooling the carbon steel. The carbon steel stays in the bath until a defined percentage of the bainite structure relative to the total structure of the carbon steel has formed. Residues of the quenching agent are removed from the surface of the carbon steel by blowing the same off when the carbon steel is discharged from the bath, and the remaining structure components of the carbon steel are then transformed into bainite in an isothermal tempering station without deflecting the carbon steel at all.
The invention relates to a cold-rolled carbon steel comprising (in % by weight) C 0.63 - 0.85 %, max. 0.40 % Si, 0.20 – 0.90 % Mn, max. 0.035 % P, max. 0.035 % S, max. 0.060 % Al, max. 0.40 % Cr, 0.003 – 0.010 % N, preferably 0.005 – 0.008 %, and a maximum of 0.12 % of at least one micro-alloying element, the remainder being iron and steel production-related pollutants. Possible micro-alloying elements are Ti, Nb, V and optionally Zr. A carbon steel of said type is cold-rolled into texture-rolled strip steel with a high cold reduction degree and can be used in particular as a material for coiling springs or other components having spring properties.
A method continuously creates a bainite structure in a carbon steel, especially a strip steel by austenitizing the carbon steel; introducing the austenitized carbon steel into a bath containing a quenching agent; adjusting the carbon steel to the transformation temperature for bainite and maintaining the transformation temperature for a certain period of time; and then cooling the carbon steel. The carbon steel stays in the bath until a defined percentage of the bainite structure relative to the total structure of the carbon steel has formed. Residues of the quenching agent are removed from the surface of the carbon steel by blowing the same off when the carbon steel is discharged from the bath, and the remaining structure components of the carbon steel are then transformed into bainite in an isothermal tempering station without deflecting the carbon steel at all.
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