Method of quenching large-diameter thin-wall metal pipe

Abstract

A method of quenching a large-diameter thin-walled metal pipe includes the steps of moving the metal pipe through a heating zone and passing the pipe through a cooling zone following passage of the pipe through the heating zone. The cooling zone includes a plurality of nozzles for spraying a cooling liquid onto the pipe from the nozzles, so as to quench the pipe. The process steps further include detecting the amount of strain on the outer periphery of the quenched pipe at the rear end of the cooling zone, as seen in the direction of movement of the pipe, so as to obtain a deviation of a detected value from a preset value, and adjusting the amount of cooling liquid sprayed onto the pipe from the nozzles in accordance with the amount of deviation from the preset value, so that the adjusted cooling water spray controls the deviation of pipe emerging from the cooling zone, for example, reduces the eccentricity of a circular pipe.

Dependencies are inferred from the claim text.