Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D7/00—Modifying the physical properties of iron or steel by deformation
  • C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B9/00—Measures for carrying out rolling operations under special conditions, e.g. in vacuum or inert atmosphere to prevent oxidation of work; Special measures for removing fumes from rolling mills
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C23/00—Extruding metal; Impact extrusion
  • B21C23/009—Gas treatment of work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C43/00—Devices for cleaning metal products combined with or specially adapted for use with machines or apparatus provided for in this subclass
  • B21C43/02—Devices for cleaning metal products combined with or specially adapted for use with machines or apparatus provided for in this subclass combined with or specially adapted for use in connection with drawing or winding machines or apparatus
  • B21C43/04—Devices for de-scaling wire or like flexible work
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material

Definitions

• the invention relates to a method and a device for reducing scale formation during hot forming of metal, in particular steel, in which the heated metal is briefly elastically deformed under high pressure and can then relax.
• Nitrogen is preferably used as the inert gas, with which the material leaving the roll gap is blown over a certain distance during the hot rolling of steel.
• the blowing direction of the inert gas is preferably set obliquely against the feed direction of the steel.
• the inert gas is also blown into the free spaces of the roll gap lying to the side of the rolling stock.
• a device for carrying out the method according to the invention is that a device for supplying inert gas is connected to a plant for hot forming of metal, which device has a plurality of nozzles directed against the material to be formed and means which prevent the supply of inert gas after the forming the relaxation limit the phase of the application.
• the device has elements which at least enclose the material to be deformed during the relaxation phase, and on the inside of which the inert gas, which is at a higher than atmospheric pressure, can be supported. It has been shown that a certain inert gas pressure is required in order to bring it sufficiently close and intensively to its surface despite its spontaneous heating when the material to be formed is approached. However, such pressure of the inert gas cannot be built up without at least largely enclosing the material to be formed during the expansion phase.
• the enclosing elements can be parts on the output side of the roll stand of a roll stand.
• Figure 3 shows the lower roller table in plan view.
• Figure 4 is an illustration of the U-shape process in the roll gap.
• FIG. 5 shows a vertical central section through the rolls and the rolling stock in FIG. 4.
• These elements include, below the hot strip 7, a roller table consisting of the two parts 8a and 8b with a stripper 9 resting on the work roll 3, and a cooling water distributor 10 below the roll table 8a.
• the cooling water delivered by these to the work roll 3 is at 11 indicated.
• a water tank 12 can be seen in FIG. 1, the underside 16 of which is provided with a stripper 13 in the area of the work roll 2.
• Distributors 14 for the cooling water 15, which is sprayed onto the work roll 2 are arranged in the water box 12.
• the scraper 13 prevents the cooling water from draining onto the hot strip 7; the cooling water runs off to the side in the region of the cheeks of the stand 1 and is discharged below the roll stand.
• Hot strip 7 is provided immediately after leaving the roll gap 6 through the space.
• a pipe 20 running transversely to the rolling direction leads through a hose line 21 to a double pipe transverse distributor 22, which distributes it to a plurality of relatively thin nozzle pipes 23, which have their openings 24 push through the underside 16 of the water tank 12 in a sealed manner and direct an inert gas jet 25 at an angle against the direction of advance of the hot strip 7 against the hot strip 7.
• Another hose connection 26 leads from the inert gas tube 20 to a transverse distributor 27 arranged in the feed direction of the hot strip behind the water tank 12, which is provided with various nozzle openings 28 distributed over the width of the hot strip 7 and in turn is positioned at an angle to the inert gas jets against the feed direction of the hot strip 7 29 issues. The same applies at an even greater distance from the roll gap 6 for the transverse distributor 30, which is fed from the pipe 20 through a distributor pipe 31.
• the underside of the hot strip 7 is covered with inert gas.
• a double tube transverse distributor 42 receives the inert gas via a tube 41 and distributes it to a plurality of nozzle tubes 43 distributed over the width of the roll stand on nozzles 44 which pass through the lower roller table 8a and are inertly inclined against the feed direction of the hot strip 7 ⁇ direct gas jets 45 against it.
• hoses 46, 47, cross distributors 48, 49 are connected to the pipe 40 and direct inert gas jets 50, 51 (again at an angle to the feed direction) (through the spaced-apart individual elements of the roller table 8b; see FIG. 3) against the Bottom of the hot strip 7.
• the passage of the hot strip 7 through the work rolls 2, 3 is illustrated schematically in FIG. 4.
• the warm band 7 comes from the left with the initial thickness s and is plastically deformed in the roll gap 6 to a smaller thickness, which has the size s ⁇ at some distance from the roll gap 6.
• the scale layer 7a which surrounds the hot strip 7 on all sides before entering the roll gap 6, can be seen in FIG. 4 to the left of the roll gap. This scale layer is torn open and blown off in the course of the wedge-shaped deformation; in Fig. 4 this is indicated greatly enlarged.
• the zone E of the relaxation phase extends over a certain distance which adjoins the roll gap 6 in the feed direction and which is identified by “E” in FIG. 4 on the top and bottom of the hot strip 7.
• the hot strip 7 is covered according to the invention with inert gas, preferably nitrogen, so that no new scale can form there on the strip.
• inert gas preferably nitrogen
• the inert gas is also blown into the free spaces 52 of the roll gap 6 located next to the hot strip 7.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Metal Rolling (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6454076

Family Applications (1)

Country Status (9)

Cited By (2)

Families Citing this family (7)

Citations (2)

Family Cites Families (1)

• 1992
  • 1992-03-14 DE DE4208208A patent/DE4208208C2/de not_active Expired - Lifetime
• 1993
  • 1993-03-10 PL PL93301315A patent/PL170068B1/pl unknown
  • 1993-03-10 ES ES93905334T patent/ES2088276T3/es not_active Expired - Lifetime
  • 1993-03-10 AU AU36322/93A patent/AU3632293A/en not_active Abandoned
  • 1993-03-10 EP EP93905334A patent/EP0630295B1/de not_active Expired - Lifetime
  • 1993-03-10 DE DE59302830T patent/DE59302830D1/de not_active Expired - Fee Related
  • 1993-03-10 WO PCT/EP1993/000545 patent/WO1993018869A1/de active IP Right Grant
  • 1993-03-12 ZA ZA931765A patent/ZA931765B/xx unknown
  • 1993-03-15 CN CN93103128A patent/CN1078179A/zh active Pending
  • 1993-03-24 TW TW082102212A patent/TW227019B/zh active

Patent Citations (2)

Non-Patent Citations (4)

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