To provide a method of piercing a round cast steel which can reduce thickness nonuniformity even by using roller shoes for multiple sizes when the round cast steel is pierced with a piercer rolling mill to make it into a hollow pipe for manufacturing a seamless steel pipe.
In the method of piercing a round cast steel to manufacture a hollow pipe by surrounding the round cast steel 2 with a pair each of inclined rolls 13 and roller shoes 14 of a piercing rolling mill, and by advancing and rolling the round cast steel 2 while pressing the plug against the center shaft of the round cast steel 2, the spacing in radial direction between the inclined roll 3 and the roller shoe 14 on the outer side from the gouge of the inclined rolls 13 in the cross-sectional view is set at 20 mm or less, so as to perform rolling.
MIYAZAWA TAKESHI
Next Patent: METHOD OF MANUFACTURING NON-TEMPERED HIGH-STRENGTH SEAMLESS STEEL PIPE