Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
  • D21G1/0246—Hard rolls
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/021—Construction of the cylinders
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
  • D21G1/0253—Heating or cooling the rolls; Regulating the temperature

Definitions

• the invention relates to a heatable roller with a smooth, hard surface for the production and / or treatment of a fibrous web, in particular paper, board or tissue web. It further relates to a process for producing such a roll.
• KSTV chrome casting
• the invention has for its object to provide an improved roller and an improved method of the type mentioned, in which the aforementioned problems are eliminated.
• the roller comprises a base tube made of weldable steel, to which at least one welding layer is applied, which has a greater hardness than the base tube.
• the base tube of the roller can thus be made of a relatively simple weldable steel, while over one or more hard welding layers are applied.
• the welding layer consists of a metal alloy which can be welded to the base tube.
• all metal alloys come into question, which are welded to the base tube.
• the welding layer is spirally applied to the base tube.
• the layer can be welded in a spiral manner when the base tube rotates.
• the roll preferably has a surface hardness of Vickers ⁇ 450 HV.
• surface hardnesses are above a value of about 450 HV without problems reachable.
• Conventional chill rolls have hardnesses of about 530 HV.
• curing up to, for example, about 800 HV is conceivable without further ado.
• this has a surface hardness according to Vickers> 530 HV.
• it has a surface hardness of Vickers ⁇ 600, in particular ⁇ 700, in particular ⁇ 750 and preferably of about 800 HV.
• the surface hardness according to Vickers can therefore in particular be in a range of about 450 to about 800 HV and preferably in a range of about 530 to about 800 HV.
• the welding layer may be formed by one or by a plurality of welding layers.
• the thickness of a respective welding layer is preferably about 3 mm.
• the total thickness of the welding layer after the finishing of the surface is advantageously in a range from about 1 to about 20 mm, preferably in a range from about 3 to about 10 mm.
• the layer or metal alloy to be welded has relatively freely determinable constituents, the physical and chemical properties of the layer or the various layers of this layer can be variably adjusted.
• the hardness of the welding layer, starting from the base tube increases radially outward, as a result of which internal stresses are correspondingly reduced.
• the heatable roll may in particular be a rotating hollow roll with flanged mounted journals.
• the roller is provided with peripheral, preferably parallel to the roll axis extending heating channels or holes.
• a preferred wall thickness of the heatable roll is in a range of about 100 to about 200 mm.
• the base tube of the heatable roller may in particular consist of a forged tube, a seamlessly drawn tube or a turned round steel.
• a base tube made of simple steel, which can be drilled very easily, can be used for the heatable rolls of generally relatively thick wall thickness in question here.
• the residual stresses can be significantly reduced.
• the roller is heated to temperatures in the range of 100 ° to 250 ° C, the sum of residual stresses and external stresses is reduced to a manageable level.
• a constant hardness layer thickness can be achieved according to the invention, which brings about a significantly better dimensional stability and a better dynamic running behavior of the roll.
• Another decisive advantage of the heatable roller according to the invention is that it offers improved repair options.
• the respective repair can be carried out by renewed build-up welding.
• the object stated above according to the invention is achieved accordingly by applying to a base tube made of weldable steel at least one welding layer which has a greater hardness than the base tube.
• the welding of the welding layer is expediently carried out under powder or under protective gas and by a material addition in the form of at least one band or wire.
• the welding layer can advantageously be applied spirally when the base body rotates.
• the invention moreover relates generally to a process for producing a roll for use in papermaking, which is thus applicable not only for the production of heating rolls but also for the production of other rolls serving for the papermaking or treatment.
• this method is characterized in that at least one welding layer is applied to a base tube made of weldable steel and that the final material properties of the coating after the welding application are set by a corresponding heat treatment.
• the heat treatment may in particular comprise an annealing treatment.
• the material properties which can be set via the subsequent heat treatment include the toughness, the microstructure, the dimensional stability, the residual stress, the hardness and / or the like.
• a heatable roller made of a steel base tube with a hard hardfacing layer can also be produced again.
• the desired material properties, here, for example, the hardness, can be adjusted by the subsequent heat treatment in the desired manner.
• At least one welding layer is applied to the base tube made of weldable steel, which has a greater hardness than the base tube.
• the welding layer is preferably provided in conjunction with a tungsten carbide layer.
• this is preferably defined by a roughness value Ra in a range from about 0.01 to about 0.2 ⁇ m.

Landscapes

• Rolls And Other Rotary Bodies (AREA)
• Paper (AREA)
• Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Related Child Applications (2)

Publications (3)

Family

ID=37461538

Family Applications (2)

Family Applications After (1)

Country Status (4)

Cited By (2)

Family Cites Families (20)

• 2005
  • 2005-08-29 DE DE102005040869A patent/DE102005040869A1/de not_active Withdrawn
• 2006
  • 2006-03-30 EP EP06111988A patent/EP1760193B1/fr not_active Expired - Lifetime
  • 2006-03-30 EP EP07013737A patent/EP1840261B1/fr not_active Expired - Lifetime
  • 2006-03-30 AT AT07013737T patent/ATE532900T1/de active
  • 2006-03-30 AT AT06111988T patent/ATE534766T1/de active
  • 2006-08-22 US US11/466,334 patent/US20070057019A1/en not_active Abandoned

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