Method and system for the production of a seamless hot-rolled tube as well as a rolled centrifugally cast tube and use of a hollow block produced by means of centrifugal casting

Abstract

Sensitive hollow blocks or tubes are elongated in a hot-forming elongator while maintaining, if possible, the internal structure that is present or that forms immediately after casting, and thereby, in the case of suitable method management, even thin-walled tubes or tubes rolled from centrifugally cast hollow blocks can be made available to a sufficiently operationally reliable extent. As a result, for the first time, it is possible for rolled centrifugally cast composite material tubes to be made available and for composite material hollow. blocks produced using centrifugal casting to be utilized for the production of a seamless tube.

What is claimed is: 
     
         1 . A production method for producing a seamless hot-rolled tube comprising:
 elongating a cast hollow block in a hot-forming elongator with an elongation of 10 or less; including one of the following:
 (i) circumventing a cross-roll piercing step or interposing a cross-roll piercing step at an elongation below 1.5; 
 (ii) utilizing at least part of the casting heat; or 
 (iii) utilizing at least part of the casting heat and circumventing a cross-roll piercing step or interposing a cross-roll piercing step at an elongation below 1.5. 
   
     
     
         2 . The production method according to  claim 1 , wherein the hollow block is heated before elongation in the elongator, tempered in a furnace as a buffer, or heated before elongation in the elongator and tempered in a furnace as a buffer. 
     
     
         3 . The production method according to  claim 1 , wherein after elongation, the hollow block is calibrated in a calibration unit. 
     
     
         4 . The production method according to  claim 1 , wherein said cast hollow block is elongated in the hot-forming elongator with an elongation of 8 or less. 
     
     
         5 . The production method according to  claim 4 , wherein said cast hollow block is elongated in the hot-forming elongator with an elongation of 7 or less. 
     
     
         6 . The production method according to  claim 1 , wherein the elongator is a longitudinal rolling mill. 
     
     
         7 . The production method according to  claim 6 , wherein said longitudinal rolling mill is a push bench. 
     
     
         8 . A production system for producing a seamless hot-rolled tube comprising:
 (a) a hollow-block casting unit;   (b) an elongator disposed behind the hollow-block casting unit; and   (c) a conveying segment between the hollow-block casting unit and the elongator;   wherein said conveying segment is sufficiently short so that part of the casting heat can be utilized for elongation in the elongator; and   wherein said conveying segment is interrupted by a furnace, or runs without interruption and has a lock system to and from a furnace, or is interrupted at most by a severing unit.   
     
     
         9 . The production system according to  claim 8 , wherein the furnace serves as at least one of a buffer, a reheater, and a temperature equalizer. 
     
     
         10 . The production system according to  claim 8 , wherein the hollow-block casting unit is a centrifugal casting unit. 
     
     
         11 . The production system according to  claim 8 , wherein the elongator is followed by a calibration unit. 
     
     
         12 . The production system according to  claim 11 , wherein the calibration unit comprises at least one of a sizing mill and an elongation reduction unit. 
     
     
         13 . The production system according to  claim 8 , wherein the elongator is a longitudinal rolling mill. 
     
     
         14 . The production system according to  claim 13 , wherein the longitudinal rolling mill is a push bench. 
     
     
         15 . The production system according to  claim 13 , wherein the longitudinal rolling mill has an elongation of 2 or more and of 8 or less. 
     
     
         16 . A rolled centrifugally cast tube comprising a hot-rolled centrifugally cast composite material tube. 
     
     
         17 . A seamless hot-rolled centrifugally cast composite material tube produced using a composite material hollow block produced by centrifugal casting.