Classifications

• • 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
  • B22D11/066—Side dams

Definitions

• the invention relates to an age-hardenable copper alloy as material for producing blocks for the side dams of continuous strip-casting installations.
• the side dams in, for example, the strip-casting installation known from U.S. Pat. No. 3,865,176 are made of metallic mold blocks or dam blocks having a T groove, which are lined up on a flexible continuous band such as one made of steel, and which move in the longitudinal direction, synchronously with the casting bands.
• the dam blocks bound the casting mold cavity formed by the casting bands.
• a testing method has proven itself for checking the tendency to crack, in which the mold blocks are submitted to heat treatment for two hours at 500° C. and are subsequently quenched in water at 20 to 25° C. Even if this thermal shock test is repeated several times, in the case of a suitable material no cracks may appear in the T groove surface.
• EP 0 346 645 B1 describes an age-hardenable copper-based alloy which is made of 1.6 to 2.4% nickel, 0.5 to 0.8% silicon, 0.01 to 0.2% zirconium, optionally up to 0.4% chromium and/or up to 0.2% iron, the remainder being copper including production-caused impurities.
• This known copper alloy basically satisfies the prerequisites for a long service life, if used as the material for producing standard mold blocks for the side dams of continuous strip-casting installations.
• a dam block made of the CuNiSiZr alloy described in EP 0 346 645 81 disadvantageously tends to premature wear of the side edges and casting surfaces, at very high mechanical and thermal stresses in the casting operation of a continuous strip-casting installation. As the results of investigations have shown, this wear may be attributed to a material softening of the casting edges and surfaces to a value below 160 HV. Furthermore, the thermal shock resistance of the known CuNiSiZr alloy is not always sufficient for effectively preventing the formation of cracks in the T groove during casting use, when the alloy is used for a dam block having a slot and key.
• an age-hardenable copper alloy made of 1.2 to 2.7% cobalt, 0.3 to 0.7% beryllium, 0.01 to 0.5% zirconium, optionally 0.005 to 0.2% magnesium and/or 0.005 to 0.2% iron and, in some instances, up to a maximum of 0.15% of at least one element from the group including niobium, tantalum, vanadium, hafnium, chromium, manganese, titanium and cerium, the remainder being copper including production-caused impurities and the usual processing additives.
• This alloy is used as the material for producing block for the side dams of strip-casting installations.
• a further improvement of the mechanical properties of the dam blocks, especially an increase in tensile strength, may advantageously be achieved by having the copper alloy contain 1.8 to 2.4 wt. % cobalt, 0.45 to 0.65 wt. % beryllium, 0.15 to 0.3 wt. % zirconium, up to 0.05 wt. % magnesium and/or up to 0.1% iron.
• the invention permits that, in the copper alloy up to 80% of the cobalt content may be replaced by nickel.
• the copper alloy contains up to a maximum of 0.15 wt. % of at least one elements of the group including niobium, tantalum, vanadium, hafnium, chromium, manganese, titanium and cerium.
• Usual deoxidants such as boron, lithium, potassium and phosphorus may also be added up to a maximum of 0.03 wt. %, without negatively influencing the mechanical properties of the copper alloy of the present invention.
• a part of the zirconium content may be replaced by up to 0.15 wt. % by at least one element of the group including cerium, hafnium, niobium, tantalum, vanadium, chromium, manganese and titanium.
• the blocks for the side dams of double strip-casting installations are produced using the age-hardenable copper alloy, by the method steps: casting, hot forming, cold forming up to 40%, solution treating at a temperature in the range of 850 to 970° C., as well as a 0.5 to 16-hour age-hardening treatment at 400 to 550° C.
• the copper alloy may be cold formed by 5 to 30% after hot forming.
• a cold forming degree of 10 to 15% lying within this range is particularly preferred in this context.
• the dam blocks in the age-hardened condition have a tensile strength of at least 650 Mpa, particularly 700 to 900 Mpa, a Vickers hardness of at least 210 HV, particularly 230 to 280 HV, an electrical conductivity of at least 40% IACS, particularly 45 to 50% IACS, a hot tensile strength at 500° C. of at least 400 Mpa, particularly of at least 450 Mpa, a minimum hardness of 160 HV after 500-hour ageing at 500° C., and a maximum grain size according to ASTM E 112 of 0.5 mm.
• dam blocks made of the copper alloy if, in the age-hardened condition they have a grain size, ascertained according to ASTM E 112, between 30 and 90 ⁇ m.
• the copper alloy after the hot forming of the cast blank, is cold formed up to 40%, is then solution treated at a temperature lying in the temperature range of 850 to 970° C., and is subsequently submitted to a 0.5 to 16-hour age-hardening treatment at 400 to 550° C.
• a surprisingly simple way one may succeed in getting rid of the bad recrystallization behavior observed in the known CuCoBe alloys during the hot forming and solution treatment.
• the bad recrystallization behavior in the production of mold blocks made of CuCoBe alloys, in the hot formed, solution treated and age-hardened condition leads to a coarse microstructure, that is not acceptable for the application purpose, having grain sizes up to more than 1 mm.
• composition of alloy D a known CuNiSi-based alloy is involved, whereas E and F are normalized CuCo2Be or CuCoNiBe materials.
• All the copper alloys were smelted in an induction crucible oven and were cast by the continuous strip-casting method to round billets having a diameter of 280 mm.
• the round billets of exemplary alloy A, B and C were extruded on an extrusion press at a temperature above 900° C. to flat bar of a dimension 79 ⁇ 59 mm, and subsequently were drawn, at a loss in cross section of 12%, to a dimension of 75 ⁇ 55 mm.
• the blocks of the reference alloys D, E and F were extruded at the same temperature, directly to the dimension 75 ⁇ 55 mm, and were not submitted to additional cold forming.
• the CuCoBe and CuCoNiBe materials were subsequently solution-treated at 900 to 950° C. and were age-hardened at a temperature range between 450 and 550° C. for 0.5 to 16 hours.
• the CuNiSi-based alloy was solution-treated at 800 to 850° C. and age-hardened under the same conditions.
• the tensile strength Rm, the Vickers hardness HV10, the electrical conductivity (as substitute quantity for the heat conductivity), the grain size according to ASTM E112, the heat resistance Rm at 500° C. and the resistance to softening via Vickers hardness measurement (HV10) after ageing at 500° C. after 500 hours were ascertained.
• mold blocks (1) of dimensions 70 ⁇ 50 ⁇ 40 mm and mold blocks (2), having slot and key, of dimensions 70 ⁇ 50 ⁇ 47 mm were first annealed for two hours at 500° C. and then quenched in water at 20 to 25° C. The T groove of the blocks were then searched for cracks with the naked eye and a microscope at 10-fold magnification.
• the extension of determined cracks in the groove was 2 to 5 mm, and in individual cases, the length of the crack was up to 10 mm.
• materials E and F only copper alloys A, B and C, and produced using slight cold working, at optimum properties, have a surprisingly uniform and fine-grained microstructure, and have the necessary resistance to the formation of cracks when used as mold block having slot and key.
• the copper alloys in accordance with the invention have a clearly better resistance to softening compared to the known CuNiSi alloys D, and a somewhat better resistance to softening when compared to alloys E and F.
• the copper alloy in accordance with the invention is eminently suitable as the material for producing all mold blocks, that are submitted to typically changing temperature stress during the casting process, for the side dams of strip-casting installations.
• mold blocks used up to the present and the mold blocks embodied with slot and key as in EP 0 974 413 A1.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Continuous Casting (AREA)
• Chemically Coating (AREA)
• Dental Preparations (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Conductive Materials (AREA)
• Breeding Of Plants And Reproduction By Means Of Culturing (AREA)

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• 2002
  • 2002-02-15 DE DE10206597A patent/DE10206597A1/de not_active Withdrawn
• 2003
  • 2003-01-08 MX MXPA03000218A patent/MXPA03000218A/es active IP Right Grant
  • 2003-01-18 EP EP03001084A patent/EP1340564B1/de not_active Expired - Lifetime
  • 2003-01-18 DK DK03001084T patent/DK1340564T3/da active
  • 2003-01-18 ES ES03001084T patent/ES2288572T3/es not_active Expired - Lifetime
  • 2003-01-18 AT AT03001084T patent/ATE367229T1/de active
  • 2003-01-18 PT PT03001084T patent/PT1340564E/pt unknown
  • 2003-01-18 DE DE50307676T patent/DE50307676D1/de not_active Expired - Lifetime
  • 2003-01-22 CN CNB031033067A patent/CN1271228C/zh not_active Expired - Fee Related
  • 2003-01-28 CA CA2417546A patent/CA2417546C/en not_active Expired - Fee Related
  • 2003-02-10 US US10/361,660 patent/US20030159763A1/en not_active Abandoned
  • 2003-02-11 PL PL358681A patent/PL198565B1/pl unknown
  • 2003-02-12 JP JP2003033937A patent/JP4472933B2/ja not_active Expired - Fee Related
  • 2003-02-13 KR KR1020030008977A patent/KR100967864B1/ko not_active Expired - Fee Related
  • 2003-02-13 BR BRPI0300445-7A patent/BR0300445B1/pt not_active IP Right Cessation
  • 2003-02-14 RU RU2003104534/02A patent/RU2301844C2/ru not_active IP Right Cessation
• 2008
  • 2008-06-02 US US12/156,604 patent/US20080240974A1/en not_active Abandoned

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