TH48130A - Heat extrusion of long, thin strips - Google Patents

Abstract

DC60 (27/06/44) A thin, long strip of steel (11) is passed through a clamping roller (12) consisting of clamping rollers (13) to a rolling mill (16) consisting of a pair of working rollers (17) and upper and lower support rollers (18). The strip (11) passes through the contact face between the working rollers (17), and compression force is applied to the strip between the working rollers to reduce its thickness. The clamping rollers (13) apply tension to the strip as it passes through the working rollers (17) in order to minimize defects caused by kinking in the strip. The tension applied by the clamping rollers (13) is kept at a high enough level to ensure that no part of the strip passing through the working rollers is subjected to longitudinal compression exceeding the stress caused by strip buckling. The applied tension is low enough to cause the strip to stretch no more than 1% through creep. The strip may be heated by working rollers (17) at temperatures in the range of 700°C to 1200°C. A thin strip of steel (11) is passed through a clamping roller platform (12) consisting of clamping rollers (13) to a rolling mill (16) consisting of a pair of working rollers (17) and upper and lower support rollers (18). The strip (11) passes through the contact face between the working rollers (17), and compression force is applied between the working rollers to reduce the thickness of the strip. The clamping rollers (13) apply tension to the strip as it passes through the working rollers (17) in order to minimize defects caused by kinking in the strip. The tension applied by the clamping rollers (13) is high enough to ensure that no part of the strip passing through the working rollers is subjected to longitudinal compression exceeding the stress caused by strip buckling. The applied tension is low enough to cause the strip to stretch no more than 1% through creep. The strip may be heated by working rollers (17) at temperatures in the range of 700°C to 1200°C.

Claims (22)

1. A method for continuously casting thin steel strips with a thickness not exceeding 3 mm, consisting of (a) casting a thin steel strip with a thickness not exceeding 3 mm in a double-roller casting machine; (b) feeding the cast strip with a thickness not exceeding 3 mm through roller impact between a pair of working rollers; (c) applying compression force to the strip between the working rollers to reduce the thickness of the cast strip; and (d) applying tension to the cast strip as it passes through the working rollers, sufficiently high to avoid buckling stress in the strip as it passes through the working rollers, and low enough to cause the strip to elongate by no more than 1% through creep. 2. The method as claimed in claim 1, where the strip thickness is in the range of 0.5 mm to 2 mm before being fed to the working roller. 3. The method as claimed in claim 2, where the long strips are hot-rolled at temperatures ranging from 700°C to 1200°C. 4. The method as described in claim 3, where the long strips are hot-rolled at temperatures ranging from 900°C to 1200°C. 5. The method described in Claim 1, where the long strips are hot-rolled at temperatures ranging from 700°C to 1200°C. 6. The method described in claim 5, where the long strips are hot-rolled at temperatures ranging from 900°C to 1200°C. 7. The method under claim 1, where the applied tension will limit the elongation of the strip by creep to no more than 0.5%. 8. The method under claim 1, where the variation in the thickness reduction of the longitudinal strip, as determined by the working rollers, is such that the deformation defect of the longitudinal strip at the ends of the working rollers does not exceed 400 I-units. 9. The method according to claim 8, where such variation in reducing the thickness of the long strip is such that the deformation defect of the long strip at the end of the working roller does not exceed 200 I-units. 10. Method according to claim 1, where tension is applied to the long bar by passing the said long bar through a pair of tensile clamping rollers before the working rollers. 11. Method according to Claim 1, where the long bar is a manganese/silicon neutralizing steel bar with a thickness ranging from 0.5 mm to 3 mm. The long bar is hot rolled at temperatures between 900 °C and 1200 °C, and the applied tension is within an operating range between maximum and minimum values determined by: Maximum tension = maximum allowable elongation at the rolling temperature, and Minimum tension = maximum allowable deflection stress of the long bar at the rolling temperature. 12. A method for continuously casting thin steel strips with a thickness not exceeding 3 mm, which are produced by direct casting in a double-roller casting machine, consisting of (a) casting a thin steel strip with a thickness not exceeding 3 mm in a double-roller casting machine; (b) feeding the cast strip through the impact of rollers between a pair of working rollers; (c) applying compression force to the strip between the working rollers to reduce the thickness of the cast strip; and (d) applying tension to the cast strip as it passes through the working rollers, high enough to avoid buckling stress in the strip as it passes through the working rollers, and low enough to cause the strip to elongate by no more than 1% through creep. 13. The method as claimed in claim 12, where the strip thickness is in the range of 0.5 mm to 2 mm before being fed to the working roller. 14. The method as claimed in claim 13, where the long strips are hot rolled at temperatures ranging from 700°C to 1200°C. 15. The method as claimed in claim 14, where the long strips are hot rolled at temperatures ranging from 900°C to 1200°C. 16. The method as claimed in claim 12, where the long strips are hot rolled at temperatures ranging from 700°C to 1200°C. 17. The method as claimed in claim 16, where the long strips are hot rolled at temperatures ranging from 900°C to 1200°C. 18. The method under claim 12, where the applied tension is able to limit the elongation of the strip through creep to no more than 0.5%. 19. The method under claim 12, where the variation in the reduction of the strip thickness along the length as determined by the working rollers is such that the deformation defect of the strip at the end of the working roller does not exceed 400-I-units. 20. Method pursuant to claim 19, where such variation in reducing the thickness of the long strip is such that the deformation defect of the long strip at the end of the working roller does not exceed 200 l-units. 21. Method according to claim 12, where the tension is applied to the long bar by passing the said long bar through a pair of tensile clamping rollers before the working rollers. 22. Method according to claim 12, where the long bar is a manganese/silicon neutralizing steel bar with a thickness ranging from 0.5 mm to 3 mm. The long bar is hot rolled at temperatures ranging from 900 °C to 1200 °C, and the applied tension is within an operating range between the maximum and minimum values determined by: Maximum tension = Maximum allowable elongation at the rolling temperature, and Minimum tension = Maximum allowable deflection stress of the long bar at the rolling temperature.