Pipe with rib and method for manufacturing pipe with rib

Abstract

A pipe with a rib includes a pipe portion, and a rib portion formed inside the pipe portion. The rib portion includes a plurality of bent portions in accordance with bending of the pipe portion.

What is claimed is: 
     
         1 . A pipe with a rib, comprising:
 a pipe portion; and   a rib portion formed inside the pipe portion,   wherein the rib portion includes a plurality of bent portions in accordance with bending of the pipe portion.   
     
     
         2 . The pipe with the rib according to  claim 1 , wherein the pipe with the rib is a continuous casting. 
     
     
         3 . The pipe with the rib according to  claim 1 , wherein the plurality of bent portions are formed continuously. 
     
     
         4 . The pipe with the rib according to  claim 3 , wherein the plurality of bent portions are structured so that the adjacent bent portions are bent in opposite directions to each other. 
     
     
         5 . The pipe with the rib according to  claim 1 , wherein the rib portion further includes a twisted portion that is formed in accordance with twisting of the pipe portion. 
     
     
         6 . A pipe with a rib, comprising:
 a pipe portion; and   a rib portion formed inside the pipe portion,   wherein the rib portion includes a twisted portion in accordance with twisting of the pipe portion.   
     
     
         7 . The pipe with the rib according to  claim 6 , wherein the pipe with the rib is a continuous casting. 
     
     
         8 . A method for manufacturing a pipe with a rib, in which a rib portion formed inside a pipe portion includes a plurality of bent portions in accordance with bending of the pipe portion, comprising:
 drawing out molten metal held in a molten metal holding furnace by using a starter, from a surface of the molten metal, and drawing up the molten metal through a shape defining member that defines a sectional shape of the pipe with the rib to be cast; and   cooling and solidifying the molten metal that has passed through the shape defining member and been drawn up,   wherein the plurality of bent portions are formed by moving at least either one of the starter and the shape defining member in a horizontal direction.   
     
     
         9 . The method for manufacturing a pipe with a rib according to  claim 8 , wherein cooling gas is introduced to an inner side of the pipe with the rib to be cast, and an opening is provided in the starter. 
     
     
         10 . A method for manufacturing a pipe with a rib, in which a rib portion formed inside a pipe portion includes a twisted portion in accordance with twisting of the pipe portion, comprising:
 drawing out molten metal held in a molten metal holding furnace by using a starter, from a surface of the molten metal, and drawing up the molten metal through a shape defining member that defines a sectional shape of the pipe with the rib to be cast; and   cooling and solidifying the molten metal that has passed through the shape defining member and been drawn up,   wherein the twisted portion is formed by rotating at least either one of the starter and the shape defining member about an axis that extends along a vertical direction.   
     
     
         11 . The method for manufacturing a pipe with a rib according to  claim 10 , wherein cooling gas is introduced to an inner side of the pipe with the rib to be cast, and an opening is provided in the starter.