GB2174320A

GB2174320A - Mould for continuous casting

Info

Publication number: GB2174320A
Application number: GB08609057A
Authority: GB
Inventors: Horst Gravemann
Original assignee: KM Kabelmetal AG
Current assignee: KM Kabelmetal AG
Priority date: 1985-04-19
Filing date: 1986-04-14
Publication date: 1986-11-05
Also published as: SE8601774D0; KR870009780A; FI861625A; ES8707436A1; BR8601736A; CH674719A5; BE904616A; MX173251B; AT401628B; ATA100586A; DE3514123C2; DE3514123A1; GB2174320B; GB8609057D0; FI861625A0; IT8620134A1; ZA862948B; KR920004452B1; CA1274755A; SE8601774L

Description

1 GB 2 174 320 A 1

SPECIFICATION a mandrel may be performed in various ways.

Moulds for continuous casting For-instance, mandrel and preform may be moved together thro6gh a die. In this The present invention relates to a process for conjunction, a bent mandrel which has the final the production of open-ended moulds for 70 internal dimensions and inside shape of the continuous casting machines from tubular mould to be produced and the external preforms of hardenable copper alloys produced dimensions of which are only slightly smaller or by continuous casting and/or drawing and/or slightly greater than the internal dimensions of forging, in which these preforms are initially the preform, has already (German Patent solution-annealed and then quenched, and the 75 Specification 1,809,633) been introduced into a copper material is subsequently artificially aged. straight preform (pipe section), the preform It is already known (German correspondingly being preformed to the mandrel Offenlegu ngssch rift 2,635,454) to use hardenable dimensions. Subsequently, preform and mandrel copper alloys as material for continuous casting are pressed together through a die to press the moulds, achieving high values for the thermal 80 inside areas of the pipe section tight onto the conductivity, the high-temperature strength and mandrel. Finally, the mandrel is pressed out of creep strength and thermo-plasticity by suitable the then work-hardened preform.

selection of the alloy constituents, such as Another advantageous possibility is to perform chromium and zirconium. Mould plates produced the cold working and calibration by the effect of from such hardenable alloys are subsequently 85 force on the outside walls of the preform by a solution-annealed at 10300C, then quenched in forging or rolling operation. Further suitable water and finally artificially aged at 475'C, processes for the working are explosion machining of the plate to final dimensions being processes, as well as hydrostatic and performed subsequently. electrodynamic processes. For special application These known process steps can also be 90 purposes, it has proven expedient to combine applied in a similar way to the production of two or more of the stated possibilities. For thick-walled, tubular, one-piece open-ended example, after passing mandrel and preform moulds when, after production of the pipe form together through a die, and after cold working by pressing, drawing or other processes, the by forging or rolling, a subsequent force effect hardening treatment is carried out and 95 by detonation of explosive may be provided.

subsequently a final machining is performed. The solution annealing of the preform before However, the process steps proposed above cold working and calibration may be performed are not applicable as such in the case of a in air, after which the surfaces of the preform known process in which, for the production of must be subjected to a cleaning or smoothing straight, but in particular of bent, conical or 100 process, for instance by grinding. One more partially conical open-ended moulds, a mandrel advantageous alternative may therefore be to with the final internal dimensions and the inside perform the solution annealing of the entire shape of the moulds to be produced is tubular preform or just of the inside in a introduced into a pipe section of copper reducing atmosphere. The latter is performed, for materials and the pipe section is subsequently 105 example, with advantage by filling dry charcoal pressed onto the mandrel by cold forming on inside the preform, which is closed at both ends the mandrel (German Patent Specification with partially perforated sheet metal caps.

1,809,633). In implementation of the invention, virtually all The invention is therefore based on the object hardenable copper materials can be used with of finding a possibility of also producing tubular 110 which the process steps of solution annealing, open-ended moulds from hardenable copper cold forming and hardening produce properties materials such that they meet today's which make it possible for them to be used as requirements with regard to their quality. mould materials. These are, for example, alloys This object is achieved according to the based on CuCr, CuCrZr, CuCoBe, CuCoNiBe, invention by a cold working of the preform with 115 CuCoNiBeZr, CuNiSi and others. Hardenable simultaneous calibration of the shaping walls by copper materials which'have an advantageous means of a mandrel introduced into the preform application in implementation of the invention being performed before the artificial ageing. A are, for example, alloys of 0.2 to 1.2% surprising effect which has emerged from this is chromium, 0.05 to 0.4% zirconium, up to 0.04% that, owing to the cold working and calibration 120 lithium, calcium, magnesium, silicon or boron as by a mandrel having the final internal deoxidant, the remainder copper and usual dimensions and inside shape, there is no impurities.

distortion of the mould produced when it is The invention is explained in more detail with subsequently subjected to a heat treatment for reference to Figures 1 to 7, in the example of a the purpose of artificial ageing of the copper 125 bent pipe mould, taking first a sequence shown material. Continuously cast moulds produced in in Figures 1 to 5.

this way therefore have even higher dimensional Here, 1 denotes a pipe section, of any desired stability with low wear even after a lengthy cross-sectional shape, produced by continuous casting cycle. casting and/or drawing and/or forging, which The cold working and calibration by means of 130 pipe section consists of a hardenable copper 2 GB 2 174 320 A 2 alloy, for example with the composition 0.5% chromium, 0.12% zirconium, 0.015% boron, the Compared with this, the values with a non remainder copper and usual impurities. This pipe calibrated and cold- worked mould of the same section 1 is first solution-annealed, preferably in a alloy composition are reducing atmosphere, at 1000-10200C for about 11 70 2 an hour and subsequently quenched in water.

Then the, for example, hard chromium-plated Thermal conductivity 315 M1m. K) mandrel 2 is pressed into the straight, in some cases also pre-bent, pipe section 1 and Recrystallization temperature 700 (OC) subsequently external force effect is used, for 75 instance by pushing them together through a die or Softening temperature 500 (OC) by one or more forging or rolling operations, to form the pipe section onto the mandrel 2. The cold Hardness HB 2.5162.5 115 forming of the copper pipe section is chosen, for example, such that the original hardness of about 80 Tensile strength 375 (N/mm') HB is raised to a value of 80-100 HB.

The mandrel 2 may already be bent for 0.2 permanent elongation adaptation of the mould to be fabricated to the stress 282 (N1m m') circular shape of the continuous casting installations; in some cases it may also be shaped 85 Elongation atfracture 19M conically or partially conically.

When such a mandrel is pressed into the straight High-temperature strength pipe section, a corresponding preforming of the at 200'C 345 (Nlmm') mould pipe then already takes place. It goes without saying that the pipe section 1 may also 90 Elongation at fracture at already be brought into the bent shape by an 2000C 16(%) additional working step before a bent mandrel is likewise introduced. High-temperature strength As a rule, after removal of the mandrel 2 from the at 350'C 285 (Nlmm') pipe section 1, the mould pipe, which is already 95 accurate in size, is artificially aged for about 3-4 Elongation at fracture at hours in a temperature range from 460'C-480'C. 3500C 14(%) This heat treatment is expediently likewise performed under protective gas. The exemplary embodiment leaves open the In the case of the specified copper alloy, the 100 question as to the cross-section of the mould. As following values could be established for a pipe well as round, square, rectangular and polygonal mould with the process according to the invention. cross-sections of known type, it goes without saying that any other cross-sections, for instance T or double-T-shaped cross-sections may be chosen, Thermal conductivity 324 (W1m.K) 105 provided that the mandrel 2 has the corresponding cross-sectional shape. Figures 6 and 7 show two Recrystallization temperature 700 (OC) such configurations.

Claims

Softening temperature 500 (OC) CLAIMS

110 1. A process for the production of an open-ended Hardness HB
2.5162.5 142 mould for a continuous casting machine from a tubular preform of a hardenable copper alloy Tensile strength 445 (Nlmm') produced by continuous casting andlor drawing and/or forging, the preform being initially solution 0.2 permanent elongation 115 annealed and then quenched, and the copper alloy stress 360 (Nlmm') subsequently being artificially aged, wherein, before the artificial ageing, a cold working of the Elongation after fracture 18(%) preform is performed with simultaneous calibration of the shaping walls by means of a mandrel High-temperature strength 120 introduced into the preform.

at 200'C 416 (Nlmm') 2. A process according to claim 1, wherein the cold working and calibration step is performed by Elongation at fracture at pushing mandrel and preform together through a 2000C 17(%) die.

125
3. A process according to claim 1, wherein the High-temperature strength cold working and calibration step is performed by at 350'C 352 (Nlmm') applying force to the outside walls of the preform by a forging or rolling operation.

Elongation at fracture at
4. A process according to claim 1, wherein the 3500C 15M 130cold working and calibration step is performed by 3 GB 2 174 320 A 3 applying force to the outside walls of the preform by 20 the elements phosphorus, lithium, calcium, detonation of explosive or electrodynamic process. magnesium, silicon and boron as a deoxidant, the
5. A process according to claim 1, wherein the remainder being copper and normal impurities.

cold working and calibration step is performed by 9. A pipe mould for a continuous casting means of hydrostatic pressure, or by a hydrostatic installation, produced by a process according to any process. 25 of claims 1 to 8, which mould has a rectangular,
6. A process according to claim 2 andlor 3 and polygonal or round cross- section.

also according to claim 4, which combines a step of 10. A pipe mould fora continuous casting pushing through a die, andlor forging or rolling, installation produced by a process according to any with a subsequent step of calibration by detonation of claims 1 to 8, which mould has a T, double-T, U or of explosive. 30 L-shaped cross-sectional configuration.
7. A process according to any of claims 1 to 6, 11. A pipe mould according to claim 9 or 10, wherein the solution annealing at least of the wherein the inside areas bounding the mould cavity shaping inside region of the tubular preform is run conically or partially conically.

performed in a reducing atmosphere. 12. A process according to claim 1, substantially
8. A process according to any of claims 1 to 7, 35 as described with reference to Figures 1 to 5 of the wherein the hardenable copper alloy used is an accompanying drawings.

alloy comprising 0.2 to 1.2% chromium, 0.05 to 13. A mould produced by a process as claimed in 0.4% zirconium, and up to 0.04% of one or more of any of claims 1 to 8, or claim 12.

Printed for Her Majesty's Stationery Office by Courier Press, Leamington Spa, 1111986. Demand No. 8817356. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.