The invention provides a method for the on line controlled cooling process of a hot rolling seamless steel
pipe, the method is realized by a controlled cooling
system, and the method comprises the steps that a blower fan and a water pump are started up; the controlled cooling device starts working; the rolled temperature of the seamless steel
pipe which is rolled by a three-roller slight tension
sizing mill is between 950 DEG C and 980 DEG C, when the
tail of the seamless steel
pipe is not completely rolled out from the end of the mill housing of the
sizing mill, the rotation of the seamless steel pipe can not happen; when the
tail of the seamless steel pipe completely breaks away from the end of the mill housing, and is detected by a thermometal
detector, meanwhile a changeable angle roller way declines on the horizontal plane according to a set angle, to lead the seamless steel pipe to go forward in spiral way along the rolling direction by the own axis till the whole seamless steel pipe passes through completely; the
cooling speed of the process requirement can be achieved finally; subsequently the seamless steel pipe enters into a chain-type cooling
bed to implement the
air cooling to the
room temperature. The invention has the advantages that the controlled cooling process controls the
cooling speed of the hot rolling seamless steel pipe after the rolling through the air-mist cooling, to meet the purpose of improving the metallographic structure and the comprehensive
mechanical property of the seamless steel pipe.