Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
  • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0637—Accessories therefor
  • B22D11/0648—Casting surfaces
  • B22D11/0651—Casting wheels
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon

Definitions

• the invention relates to a casting roll for a two-roll continuous casting installation.
• the service life between reworking is, among other things, substantially dependent on the effectiveness of the lubrication/release agents at the casting surface, the constructive and process-conditioned cooling as well as the casting speed.
• the casting installation has to be stopped and the casting process has to be interrupted.
• a further disadvantage of the proven mold material CuCrZr for this particular application is the relatively low hardness of approximately 110 HBW to 130 HBW.
• the solidified steel particles are then pressed into the relatively soft surfaces of the continuous casting rolls, whereby the surface quality of the poured strips of about 1.5 mm to 4 mm thickness are considerably impaired.
• the lower electrical conductivity of a known CuNiBe alloy having an addition of up to 1% niobium, also leads to a higher surface temperature. Since the electrical conductivity behaves approximately proportionally to the heat conductivity, the surface temperature in the sleeve, of a continuous casting roll, made of the CuNiBe alloy as compared to a continuous casting roll having a sleeve made of CuCrZr, at a maximum temperature of 400° C. at the surface and 30° C. on the rear side will be increased to about 540° C.
• Ternary CuNiBe and CuCoBe alloys do indeed basically demonstrate a Brinell hardness of more than 200 HBW, however, the electrical conductivity of the standard semifinished products made of these materials, such as rod for manufacturing resistance welding electrodes or sheet or strip for manufacturing springs or leadframes, reach values of at most in the range of 26 Sm/mm 2 to about 32 Sm/mm 2 . Under optimum conditions, with the use of these standard materials, a surface temperature of only about 585° C. could be reached at the sleeve of a continuous casting roll.
• an age-hardening copper alloy is also related art, which has 1.0% to 2.6% nickel that may be fully or partially replaced by cobalt, 0.1% to 0.45% beryllium, optionally 0.05% to 0.25% zirconium and possibly up to a maximum of 0.15% of at least one of the group of elements including niobium, tantalum, vanadium, titanium, chromium, cerium and hafnium, the rest being copper inclusive of production-conditioned contaminations and usual processing additives, having a Brinell hardness of at least 200 HBW and an electrical conductivity greater than 38 Sm/mm 2 as the material for producing continuous casting rolls and wheels.
• Alloys having these compositions have disadvantages in their hot forming capability, because of their relatively high alloying element content.
• high heat deformation strains are required to attain a fine grained product having a grain size ⁇ 1.5 mm (as per ASTM E 112), starting from a coarse-grained cast structure having a grain size of several millimeters.
• sufficiently large continuous casting rolls have been producible only at very high expenditure; however, technical shaping devices are hardly available for realizing, at a justifiable cost, a sufficiently high hot kneading for recrystallization of the cast structure into a fine grain structure.
• a casting roll for a two-roll continuous casting installation which has a sleeve made of an age-hardening copper alloy made of—as expressed in each case as weight %—0.4% through 2% cobalt, which is partially exchangeable for nickel, 0.1% through 0.5% beryllium, optionally 0.03% through 0.5% zirconium, 0.005% through 0.1% magnesium and possibly a maximum of 0.15% of at least one element of the group including niobium, manganese, tantalum, vanadium, titanium, chromium, cerium and hafnium, the remainder being copper inclusive of manufacturing-conditioned impurities and usual processing additives.
• the casting roll may undergo changing temperature stress and high roll pressures.
• This continuous casting roll may be developed as a hollow cylinder, i.e. inherently rigid without a core.
• the surface coming into contact with the strips to be cast may also be a component of a sleeve having a core, especially a steel core.
• the sleeve may then be shrink fitted onto such a core as the carrier, hot isostatically pressed on or slipped on and then locked mechanically.
• the enveloping surface of the surface of the casting roll may be designed cylindrically or having a camber, so as possibly to compensate for the sagging of a roll.
• a further improvement in the sleeve's mechanical properties, particularly an increase in tensile strength, may be advantageously achieved, if the copper alloy contains 0.03% to 0.35% zirconium, and 0.005% to 0.05% magnesium.
• the copper alloy contains a proportion ⁇ 1.0% of cobalt, 0.15% to 0.3% of beryllium and 0.15% to 0.3% of zirconium.
• the ratio of cobalt to beryllium in the copper alloy of the sleeve is between 2 and 15. Most preferably, this ratio of cobalt to beryllium is 2.2 to 5.
• the invention permits having the copper alloy contain, in addition to cobalt, up to 0.6% nickel.
• the copper alloy of the sleeve contains up to a maximum of 0.15% of at least one element of the group including niobium, manganese, tantalum, vanadium, titanium, chromium, cerium and hafnium.
• the sleeve is advantageously produced by the processing steps casting, hot working, solution treatment at 850° C. to 980° C., cold working up to 30% as well as age-hardening at 400° C. to 550° C. within a period of 4 to 32 hours, the sleeve having a maximum average grain size of 1.5 mm as per ASTM E 112, a hardness of at least 170 HBW, and an electrical conductivity of at least 26 Sm/mm 2 .
• the sleeve in the age-hardened state has an average grain size of 30 ⁇ m to 500 ⁇ m as per ASTM E 112, a hardness of at least 185 HBW, a conductivity between 30 and 36 Sm/mm 2 , a 0.2% yield strength of at least 450 MPa and an elongation at break of at least 12%.
• the sleeve is provided with a coating which reduces the permeability to heat, or evens out the flow of heat, the product quality of the cast strip made of a non-ferrous metal, but particularly of aluminum or an aluminum alloy, is further enhanced.
• this coating is made effective, especially in the case of an aluminum strip, due to the fact that, at the beginning of a casting or rolling process, an adhesion layer forms from the acting together of copper and aluminum on the surface of the sleeve, from which, then, during the further course of the casting process aluminum penetrates the copper surface and there forms a stable, resistive diffusion layer, whose thickness and properties are essentially determined by the casting speed and cooling conditions. That clearly improves the surface quality of the aluminum strip and consequently the product quality.
• the service life of the sleeve can be prolonged even further by using a coating having a great surface hardness.
• the surface of the casting roll may be made smooth. This design is achievable particularly by rolling. In this manner, pressure stresses are induced in the edge zone, and these make possible additional resistance to the formation of cracks and the progression of cracks, so as to raise the life duration of the casting roll.
• the surface of the casting roll may be textured. Texturing can be applied, for example, by cutting, roller-burnishing, eroding or blasting. With the use of such measures, the heat transfer coefficient may specifically be influenced.
• a substance may be embedded having a low heat conductivity compared to the heat conductivity of copper.
• such a substance may also be a ceramic material.
• a filling up of the depressions formed by the texturing on the surface of the casting roll is used to create good surface quality and to ensure a lasting influence on the heat conductivity.
• Table 2 TABLE 2 Rm Rp 0.2 A HBW 2.5 El. Cond.
• the alloys according to the present invention for producing a sleeve of a casting roll, attain the aimed-for recrystallized fine grained structure while having an appropriately good elongation at break.
• the alloys according to the present invention there is a grain size of more than 1.5 mm, which reduces the ductility of the material.
• Alloys A to G according to the present invention demonstrate good elongations at break and a grain size less than 0.5 mm, while comparison alloys H to J have a coarse grain, having a grain size greater than 1.5 mm and lower values of elongation at break.
• these copper alloys have clear processing advantages during the production of sleeves, particularly for larger continuous casting rolls of two-roll casting installations, whereby it is made possible to produce a fine grained end product having optimum basic properties for their field of application.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Continuous Casting (AREA)
• Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
• Extrusion Of Metal (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Mold Materials And Core Materials (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26010619

Family Applications (1)

Country Status (10)

Cited By (3)

Families Citing this family (2)

Citations (6)

Family Cites Families (9)

• 2002
  • 2002-10-25 TW TW091124995A patent/TW590822B/zh not_active IP Right Cessation
  • 2002-10-28 CA CA2410245A patent/CA2410245C/en not_active Expired - Lifetime
  • 2002-11-05 MX MXPA02010879A patent/MXPA02010879A/es not_active Application Discontinuation
  • 2002-11-14 EP EP02025371.2A patent/EP1314495B1/de not_active Expired - Lifetime
  • 2002-11-14 US US10/294,357 patent/US20030094219A1/en not_active Abandoned
  • 2002-11-19 CN CN02151419A patent/CN1419982A/zh active Pending
  • 2002-11-19 BR BR0204713-6A patent/BR0204713A/pt not_active Application Discontinuation
  • 2002-11-20 KR KR1020020072434A patent/KR100961239B1/ko not_active Expired - Fee Related
  • 2002-11-20 NO NO20025563A patent/NO340437B1/no not_active IP Right Cessation
  • 2002-11-20 JP JP2002336609A patent/JP4295492B2/ja not_active Expired - Lifetime

Patent Citations (6)

Also Published As

Similar Documents

Legal Events