Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
  • B21B45/08—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing hydraulically
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
  • B21B1/466—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a non-continuous process, i.e. the cast being cut before rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/004—Heating the product

Definitions

• the invention relates to a device for removing loose scale from the surface of a slab, in particular a thin slab of a mini mill, comprising at least one slab casting machine, a slab separating device, a temperature compensation furnace and one or more roll stands with a coiler.
• the invention also relates to an operating method of the device mentioned.
• the slab supplied by the casting machine is naturally tainted with scale.
• a slab is fed unpurified to the roller hearth furnace of a mini mill system.
• scale carried along in the roller hearth furnace builds up on the furnace rollers to irregular scale accumulations (pick-up formation) in the course of the operating time.
• This can lead to impressions on the underside of the slab and thus to impairment of the surface quality of the slab or of the finished rolled strip.
• the loosely placed scale acts as an insulation layer, which leads to deteriorated heat transfer when the slab is heated in the roller hearth furnace.
• document JP 11 04 78 20 describes a process for descaling stubborn scale from the surface of a slab by spraying large amounts of water with low pressure and then spraying it with small amounts of water at high pressure onto the slab surface for the purpose of shock-cooling the surface to 300 to 400 ° C and Rinsing of the dissolved scale by mechanical force.
• the high-pressure water is sprayed on at approx. 200 to 300 bar in order to mechanically clean the scale.
• Document JP 10 12 84 25 describes a device for descaling a heated slab on the outlet side of a heating furnace. Approximately 10 seconds after the slab is discharged from the furnace with a pre-descaling device, low-pressure water is first applied to the surface of the slab for 30 seconds to generate a thermal stress, the pressure of the low-pressure water being approximately 20 bar. The high-pressure water is sprayed onto the surface of the slab at approx. 120 bar, 30 seconds after cooling with the low-pressure water, in order to carry out a complete descaling.
• the invention is based on the object of specifying improved scale cleaning technology and a corresponding spraying device, in particular for mini-mills, in order to carry out a slab cleaning with as little heat loss as possible of the slab, the scale entry into the roller hearth furnace reduce and improve the surface quality of the rolled hot strip.
• a spray device comprises at least one spray tube installed at the bottom and top relative to the slab, each spray tube being equipped with a number of spray nozzles that the spray device is arranged in front of the temperature compensation furnace, in particular a roller hearth furnace, and that the spray device is connected to a supply for water with technologically required pressure and with a volume flow dimensioned according to the number of spray nozzles.
• the spray device is designed in such a way that scale and reflecting water are fed to a sintering pit with a separating device for water / solids installed in the drain.
• a method for spraying loose scale from the surfaces of a slab is advantageously characterized in that the supply pressure of the water to the spray pipes of the spraying device is between 5 and 15 bar, preferably ⁇ 10 bar.
• the method expediently works according to the thermal shock principle.
• the spray-off method according to the invention is particularly advantageous if it is carried out before the slabs are placed in the roller hearth furnace.
• FIG. 1 shows a family tree of the device according to the invention.
• a slab 1 which is cast as a thin slab in a casting machine (not shown)
• a roller table 10 is initially conveyed to a directional driver 8, which conveys the thin slab 1 to a spraying device 11 for the slab surface.
• This spray device 11 forms the actual invention, and comprises at least one lower spray pipe 2 and at least one upper spray pipe 3.
• the spray pipes 2, 3 are permanently installed and each of the spray pipes is equipped with a number of spray nozzles 4 in the direction of the surface of the slab 1.
• Each spray tube 2, 3 is connected to a supply 6 for water with technologically required pressure and with a volume flow dimensioned according to the number of nozzles 4.
• the spray device 11 is arranged in front of the roller hearth furnace 5 but behind the directional driver 8. Between the spraying device 11 and the rolling hearth furnace 5 there is a slab separating device 9 designed as scissors, which cuts the slab into commercially available weights.
• the scale sprayed off from the scale surface in the spraying device and the reflecting water are fed to a sintering pit 7 with a separating device for water / solids installed in the outlet.
• the operating parameters of the spray device are set so that the supply pressure of the water to the spray pipes 2, 3 is between 5 and 15 bar, preferably ⁇ 10 bar.
• the scale that is loosely on the slab surface is detached from the surface and removed using the thermal shock principle.
• the loosened scale and the spray water are - as mentioned before - directed into the sintering pit 7 and separated there in part.
• the spraying device 11 is not limited to the arrangement shown in FIG. 1 between the directional driver 8 and the roller hearth furnace 5, but it is possible, without departing from the inventive concept, to arrange the spraying device 11 in the direction of slab passage between the scissors 9 and the roller hearth furnace 5. In the case of a slab installation with a roughing stand which may additionally reduce the slab thickness, the spraying device 11 can be arranged between the roughing stand and the roller hearth furnace 5. Also at In other systems lay-out, the spray device 11 should in any case be used in front of the roller hearth furnace.
• the slab can be cleaned with little heat loss from the slab. Furthermore, the scale input in the roller hearth furnace and thus the scale build-up on the furnace rollers is reduced. The reduced scale on the slab surfaces improves the heat transfer into the slab in the roller hearth furnace and enables an improvement in the surface quality of the hot strip produced in the subsequent rolling stands.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Rolling (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Cleaning By Liquid Or Steam (AREA)
• Cleaning In General (AREA)
• Continuous Casting (AREA)
• Rollers For Roller Conveyors For Transfer (AREA)
• Vehicle Cleaning, Maintenance, Repair, Refitting, And Outriggers (AREA)
• Nozzles For Electric Vacuum Cleaners (AREA)
• Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7698032

Family Applications (1)

Country Status (16)

Families Citing this family (6)

Family Cites Families (11)

• 2001
  • 2001-09-07 DE DE10143868A patent/DE10143868A1/de not_active Withdrawn
• 2002
  • 2002-08-28 US US10/489,004 patent/US20040261206A1/en not_active Abandoned
  • 2002-08-28 EP EP02776944A patent/EP1423216B1/fr not_active Expired - Lifetime
  • 2002-08-28 JP JP2003526592A patent/JP2005501729A/ja active Pending
  • 2002-08-28 CA CA2459881A patent/CA2459881C/fr not_active Expired - Fee Related
  • 2002-08-28 AU AU2002339453A patent/AU2002339453B2/en not_active Ceased
  • 2002-08-28 CN CNA028175581A patent/CN1553833A/zh active Pending
  • 2002-08-28 WO PCT/EP2002/009572 patent/WO2003022475A1/fr active IP Right Grant
  • 2002-08-28 DE DE50202292T patent/DE50202292D1/de not_active Expired - Lifetime
  • 2002-08-28 BR BRPI0212218-9A patent/BR0212218B1/pt not_active IP Right Cessation
  • 2002-08-28 AT AT02776944T patent/ATE289233T1/de active
  • 2002-08-28 KR KR10-2004-7003336A patent/KR100880148B1/ko not_active IP Right Cessation
  • 2002-08-28 RU RU2004110403/02A patent/RU2296021C2/ru not_active IP Right Cessation
  • 2002-08-28 MX MXPA04002153A patent/MXPA04002153A/es unknown
  • 2002-08-28 ES ES02776944T patent/ES2236593T3/es not_active Expired - Lifetime
  • 2002-08-28 UA UA2004042616A patent/UA78237C2/uk unknown
  • 2002-09-04 EG EG2002090994A patent/EG23334A/xx active

Non-Patent Citations (1)

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