Cast-rolling plant
View Patent ↗A plant for the continuous casting of aluminum strip, according to current construction type, has two counterrotating continuous casting rolls ( 1, 2 ), between which a casting gap ( 4 ) is formed. According to the present invention, the 1. continuous casting roll ( 1 ) is made of a copper material at least in its circumferential edge region, and the other, 2. continuous casting roll ( 2 ) is made of a steel material at least in its circumferential edge region. The copper material should have a thermal conductivity λ K of 230 to 260 W/m·K, and the steel material should have a thermal conductivity λ S of 30 to 40 W/m·K. Rejecting the prevailing idea that casting can only be performed with two continuous casting roll materials of the same kind, so as to ensure uniform crystal growth, a continuous casting roll pairing of steel and copper is provided in the present invention. In order to ensure a qualitatively high value casting microstructure, the difference in the thermal conductivity of the continuous casting rolls should not exceed a factor from 5 to 9. A ratio of thermal conductivity λ K of the copper material to thermal conductivity λ S of the steel material of 6:1 to 8:1 has proven particularly favorable.
1. A cast-rolling plant for the continuous casting of metal strip, comprising: first and second counterrotating continuous casting rolls ( 1 , 2 ; 7 , 8 ; 14 , 15 ) which define a casting gap ( 4 , 11 ) therebetween wherein the first continuous casting roll ( 1 ; 7 ; 14 ) is made of a copper material at least in a circumferential edge region thereof, and the second continuous casting roll ( 2 ; 8 ; 15 ) is made of a steel material at least in a circumferential edge region thereof.
2. The cast-rolling plant according to claim 1 , wherein each continuous casting roll ( 7 , 8 ; 14 , 15 ) has a cylindrical core ( 9 , 10 ; 16 , 18 ) made of a steel material and has an edge region connected thereto in the form of a jacket ( 12 , 13 ; 17 , 19 ), the jacket ( 12 ; 17 ) of the first continuous casting roll ( 7 ; 14 ) being made of the copper material and the jacket ( 13 ; 19 ) of the second continuous casting roll being made of the steel material.
3. The cast-rolling plant according to claim 1 , wherein the copper material has a thermal conductivity of λ K of 200–370 W/m·K, and the steel material has a thermal conductivity λ S of 25–50 W/m·K.
4. The cast-rolling plant according to claim 1 , wherein the copper material has a thermal conductivity λ K of 230–260 W/m·K, and the steel material has a thermal conductivity of 30–40 W/m·K.
5. The cast-rolling plant according to claim 1 , wherein the thermal conductivity λ K of the copper material and the thermal conductivity λ S of the steel material are in a ratio to each other of 5:1 to 9:1.
6. The cast-rolling plant according to claim 1 , wherein the thermal conductivity λ K of the copper material and the thermal conductivity λ S of the steel material are in a ratio to each other of 6:1 to 8:1.
7. The cast-rolling plant according to claim 1 , wherein the first continuous casting roll ( 1 ; 7 ; 14 ) is situated below the second continuous casting roll ( 2 ; 8 ; 15 ).
8. The cast-rolling plant according to claim 1 , wherein the continuous casting rolls ( 1 , 2 ; 7 , 8 ; 14 , 15 ) have lateral surfaces ( 21 – 26 ) which have a surface roughness Ra of 0.2–0.8 μm.
9. The cast-rolling plant according to claim 1 , wherein the first continuous casting roll ( 14 ) has a coating ( 20 ) made of a material having a lower thermal conductivity λ B than that of the copper material.
10. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a thermal conductivity λ B of less than 100 W/m·K.
11. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a thermal conductivity λ B of 60–80 W/mK.
12. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a layer thickness of 0.5–2.0 mm.
13. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a layer thickness of 1.0 mm.
14. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a hardness of 180–420 HB.
15. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) has a hardness of 220–380 HB.
16. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) is made of nickel or a nickel alloy.
17. The cast-rolling plant according to claim 9 , wherein the coating ( 20 ) is made of a ceramic or a metallic spray layer.
18. The cast rolling plant according to claim 9 , wherein the coating ( 20 ) is made of MCrAlY.
19. The cast-rolling plant according to claim 1 , wherein the continuous casting rolls ( 1 , 2 ; 7 , 8 ; 14 , 15 ) have lateral surfaces ( 21 – 26 ) which are textured.
20. The cast-rolling plant according to claim 1 , wherein the metal strip is an aluminum strip.