Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/50—Pouring-nozzles

Definitions

• the present invention relates to a continuous casting ladle tube.
• these tubes are made of high performance refractory materials.
• the flow of molten steel through such a tube is both very specific and of variable geometry. By this is meant in particular that this flow, which occurs in a non-uniform manner, often gives rise to delamination of the boundary layer, or even to zones of negative speed, and this at an overall average speed of the order of a meter per second. . All this depends on many parameters, including the hardware configuration at the head of the tube (presence of a pocket drawer in particular), and the detailed geometry of the tube.
• the dynamics of the jet on the bottom of the distributor has the effect of generating vibrations, stronger if the tube is convergent. These vibrations produce stresses which, adding to the aggressiveness of the environment, can result in the rupture of the tube, in particular if the latter is rigidly fixed (without degrees of freedom in rotation) on the pocket drawer.
• the invention aims to provide an improved continuous casting ladle tube, avoiding these difficulties as much as possible.
• the tube when each ladle is in place, the tube must be able to be placed on the ladle drawer, which closes the outlet passage from the ladle to the tube.
• Each pocket filled with steel contains a plugging mass, made of refractory sand, which is interposed between the molten steel and the shutter, obstructing the tap hole located at the bottom of the pocket.
• this blocking mass must be able to be completely evacuated, passing through the shutter and the pocket tube, and this, without the tube becoming blocked, to avoid any rebound of the pressure wave linked to the nascent flow of steel ("blow back").
• the invention also aims to allow the drawer to be opened while the end of the tube is already immersed in the steel of the distributor and without risk of clogging.
• the invention also aims to ensure a reduction in the speed of injection of steel between the pocket and the distributor, while maintaining a given flow rate.
• the Applicant has observed that it is thus possible to eliminate the unsteady dynamic effects due to the impact of the jet on the bottom of the distributor, and thus limit or even eliminate the vibrations of the tube itself, and thereby the risk of it breaking. .
• it also promotes decantation (beneficial) in the distributor, by modifying the structure of the flow within it.
• the shape of the tube also makes it possible to avoid blocking the sand constituting the blocking mass.
• the subject of the invention is a continuous casting ladle tube, characterized in that it comprises, in a downstream zone, a first part of section which is substantially constant and, upstream of said first part, a second part of relatively divergent section.
• the first part may however be slightly divergent or convergent.
• An example will be given below.
• the second part its section is relatively divergent, which means that it is more divergent than the first part. Its downstream internal cross section is identical to the upstream internal cross section of the first part, so as to form a regular passage.
• FIG. 1 is a view in longitudinal section of a particular embodiment of a tube according to the invention.
• FIG. 1 is an end view, along arrow A, of the tube of Figure 1.
• Figure 1 is an axial sectional view of a continuous ladle pocket tube comprising, in known manner, a flange 1 for connection to the ladle and a tubular conduit 2, here of variable circular section.
• the tubular conduit 2 itself consists of a first downstream part 3, of substantially constant section, on the side of the distributor, and a second upstream part 4, divergent, of the side of the ladle. Parts 3 and 4 are connected in a plane 5 where their sections are identical, inside at least.
• the part 3, defined as having a substantially constant section, is here very slightly divergent by an angle at the top of 2 °.
• the upstream part 4 diverges from an apex angle of 10 °.
• both part 3 and part 4 have a substantially constant divergence and therefore correspond to shapes in trunks of cones.
• the wall thickness of the tube in zone 3 is preferably substantially constant. Preferably, it is the same for part 4.
• the external shape of the tube can be modified according to needs, or considerations other than those related to the flow.
• the illustrated ladle tube includes another part 6, bordering the flange 1, and which, like part 3, has a substantially constant section, also in fact very slightly divergent.
• the parts 4 and 6 are connected in a plane 7 where the downstream section of the part 6 is identical to the upstream section of the part 4, inside at least.
• Part 3 of the tube has a length preferably equal to approximately 3 times its downstream diameter.
• the part 4 has a length which is in particular a function of its angle of divergence, and of the desired outlet diameter.
• the tube can be produced in particular from graphite alumina, or from other refractory materials which can be used in steelworks.
• the Applicant has observed that the liquid steel entering the tube leaves it uniformly with a speed lower than its entry speed.
• the ratio of the average flow velocities is equal to the ratio of the sections and, therefore, equal to the square of the ratio of the diameters since the tube is here of circular section.
• no pulverulent or granulated solid mass in particular plugging mass
• the present invention is particularly advantageous where a pocket drawer is used.
• the shape of the tube is advantageously arranged according to the characteristics of the flow leaving this drawer.
• the Applicant currently prefers to manufacture the tube in two or more parts, then assembled in a known manner. At least some of these parts can be produced by isostatic pressing.
• said first part is divergent by an angle at the top of the order of 2 °.
• another angle preferably small, in particular zero, or convergent, is possible, provided that we stay with an average angle below a threshold of the order of 2 °.
• said second part diverges from an apex angle of between approximately 1 ° and approximately 20 °, preferably between approximately 3 ° and approximately 14 °, and advantageously between approximately 6 ° and approximately 10 °.
• the invention can be applied when the shutter is other than a pocket drawer.
• said first part has a length of between approximately once and approximately five times its largest transverse dimension, preferably between approximately twice and five times, and advantageously between approximately twice and approximately four times its largest. transverse dimension.
• the shape of the cross sections of the first and second parts of the tube, perpendicular to its axis, could be arbitrary, provided there is sufficient continuity. However, it is preferably substantially oval, for example substantially elliptical, or more precisely substantially circular.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Continuous Casting (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Domestic Plumbing Installations (AREA)
• Washing And Drying Of Tableware (AREA)
• Metal Rolling (AREA)

Priority Applications (11)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9512427

Family Applications (1)

Country Status (17)

Cited By (1)

Families Citing this family (2)

Citations (8)

Family Cites Families (1)

• 1997
  • 1997-10-20 FR FR9713116A patent/FR2769861A1/fr active Pending
• 1998
  • 1998-10-14 CA CA002305495A patent/CA2305495A1/fr not_active Abandoned
  • 1998-10-14 CN CN98810391A patent/CN1121919C/zh not_active Expired - Fee Related
  • 1998-10-14 SK SK547-2000A patent/SK5472000A3/sk unknown
  • 1998-10-14 EP EP98945509A patent/EP1028822B1/fr not_active Expired - Lifetime
  • 1998-10-14 PL PL98340260A patent/PL187078B1/pl not_active IP Right Cessation
  • 1998-10-14 TR TR2000/01045T patent/TR200001045T2/xx unknown
  • 1998-10-14 BR BR9812942-2A patent/BR9812942A/pt not_active IP Right Cessation
  • 1998-10-14 JP JP2000516796A patent/JP2001520123A/ja active Pending
  • 1998-10-14 RU RU2000112404/02A patent/RU2208498C2/ru not_active IP Right Cessation
  • 1998-10-14 ES ES98945509T patent/ES2172919T3/es not_active Expired - Lifetime
  • 1998-10-14 NZ NZ503979A patent/NZ503979A/en not_active IP Right Cessation
  • 1998-10-14 KR KR1020007004138A patent/KR100585245B1/ko not_active IP Right Cessation
  • 1998-10-14 AT AT98945509T patent/ATE213677T1/de not_active IP Right Cessation
  • 1998-10-14 DE DE69804003T patent/DE69804003T2/de not_active Expired - Fee Related
  • 1998-10-14 WO PCT/IB1998/001621 patent/WO1999020420A1/fr active IP Right Grant
  • 1998-10-14 AU AU92787/98A patent/AU753291B2/en not_active Ceased

Patent Citations (8)

Non-Patent Citations (3)

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