DE2635454A1 - USE OF A COPPER ALLOY - Google Patents

Description

Gutehoffnungshütte Aktiengesellschaft

2-176 O4.08.76

Use of a copper alloy

The invention relates to the use of a copper alloy consisting of 0.3 to 1.5 % chromium, 0.10 to 0.5 % zirconium, up to 0.04 % deoxidizer, the remainder copper and common impurities.

As a material for the production of continuous casting molds for continuous casting Of refractory metals like steel, copper has long been used, which because of its high thermal Conductivity to dissipate the heat from the melt very quickly able. The wall thickness of the molds was chosen so large that they adequately meet the expected mechanical Stresses are sufficient.

To increase the heat resistance, it has been proposed to produce continuous casting molds from an alloy with at least 85% copper and at least one further alloy element which brings about precipitation hardening. Up to 3 % chromium, silicon, silver and beryllium are suggested as alloying elements. The continuous casting molds made from this material have not yet been completely satisfactory either, since the alloy components silicon and beryllium in particular reduce the thermal conductivity sia ~ k. (OE-PS 234 93O)

To improve the thermal conductivity, a copper material for continuous casting molds has therefore become known which consists of 0.05 to 0.08 % chromium and 0.005 to 0.04 % phosphorus, the remainder being copper. A Brinell hardness of 120 kp / mtn with a thermal conductivity of at least 80 % of that of pure copper can be achieved through cold deformation. The Entfesti-

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supply temperature is above 350 ° C (DT-AS 2 318 662)

All of these solutions have not yet been fully satisfactory as materials for continuous casting molds.

Accordingly, the invention consists in the use of a copper alloy consisting of 0.3 to 1.5 % chromium, 10 to 0.50% zirconium, up to 0.04 % deoxidizer, the remainder copper and usual impurities, in the hardened state as Material for continuous casting molds, in particular for continuous casting of refractory metals.

Commonly used as a deoxidizer for copper alloys Phosphorus, lithium, calcium, magnesium, silicon, etc.

The material preferably contains 0.5 to 0.8 % chromium, 0.15 to 0.25 % zirconium and 0.005 to 0.02 % boron. The boron can be supplied to the melt as calcium boride, for example.

The material is characterized by particularly favorable mechanical and physical properties. It has a thermal conductivity that is over 85 % that of pure copper. The values for the heat resistance, creep resistance and hot plasticity are also in an extremely favorable range for continuous casting molds. The Brinell hardness as a measure of the abrasion resistance reaches values of over 140. Another essential benefit of continuous casting molds is a high level of corrosion resistance, which is achieved through the copper-chroin-zirconium alloy.

A copper alloy consisting of 0.3 to 1.5 % chromium and 0.03 to 0.5 % zirconium is known from DT-AS 1 165 876, but this material is only intended to be used for objects that have high heat resistance and must have high electrical conductivity. Therefore, this material is preferred as a material for manufacturing

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of electrodes for electrical resistance welding used. From the known use, no conclusions could be drawn on the behavior of the copper alloy in the for the Invention relevant area can be drawn.

The invention is explained in more detail on the basis of an exemplary embodiment explained.

A copper alloy with 0.7 % chromium and 0.18 % zirconium, 0.015 % boron, the remainder copper and the usual impurities was first cast into a rolling ingot and hot-rolled at 95O ° C. in several passes with a total degree of deformation of 65%. The rolled plate was then solution-annealed at 1030 ° C. and quenched in water. The plate was then heat-cured at 475 ° C. for 4 1/2 hours. The plate was then machined into the desired mold plate, which had the following values:

Thermal conductivity 87 %

Softening temperature 525 C (10 % drop in strength at room temperature after 1 h annealing time)

Hardness HB 2.5 / 62.5 145

Tensile strength 442 / mm ²

Elongation at break 26 %

Hot strength at 200 ⁰ C 38O ^N / mm ²

Reduction of fracture at 200 ° C 58 %

Thermal strength at 350 ° C 3l8 ^N / mm2

Constriction of fracture at 350 C 6l %

The continuous casting mold produced by the above-mentioned process was still after a casting trip of 450 batches true to size and showed only minor signs of wear. The good results are due in particular to the high heat resistance and the high necking of the copper alloy at break.

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The invention is of course not limited to the exemplary embodiment, but can also be used for Molds of all kinds with which metallic shaped strands can be produced in a semi-continuous or fully continuous manner, for example tubular molds, block molds of all kinds, casting wheels, Casting roll shells, etc.

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Claims (2)

Cable and metal works Gutehoffnungshütte Aktiengesellschaft 2-176 0 ^ .08.76 Pat enta η proverbs (T. / Use of a copper alloy, consisting of 0.3 to 1.5 % chromium, 0.10 to 0.5 % zirconium, up to 0.04 % of a deoxidizer, the remainder copper and usual impurities in the hardened state as a material for Continuous casting molds, in particular for the continuous casting of refractory metals. 2. Use of a copper alloy according to claim 1 with 0.5 to 0.8% chromium, 0.15 to 0.25% zirconium and 0.05 to 0.02 % boron for the purpose specified in claim 1. 709886 / 040S