A method for manufacturing a seamless pipe, capable of preventing the
carburization phenomenon that occurs in a manufacturing process of pipe
and simplifying an elongation rolling process, is provided. In this
method, after piercing in the piercing rolling process, rolling is
performed without using an inside regulating tool in the elongation
rolling process, or without performing the elongation rolling followed by
reducing rolling in a reducing rolling process, and thickening is then
performed by use of a cold mill or cold draw bench in a cold rolling
process. According to this method, the trap of graphite fine particles in
the inner and outer surfaces of the pipe that took place in the
conventional elongation rolling process can be minimized to prevent the
carburization of the pipe. The method of the present invention is
effective, particularly as a measure for preventing the carburization of
an ultra-low carbon stainless steel or high alloy steel.