MANUFACTURING METHOD OF SEAMLESS HOT-ROLLED CASING PIPES WITH DIMENSIONS OF 508×11,1, 508×12,7 AND 508×16,1 mm ON TPU 8-16" PIPE ROLLING UNIT WITH PILGER MILLS IN STANDARD AND COLD-RESISTANT CONFIGURATIONS Russian patent published in 2015 - IPC B21B21/00 

FIELD: metallurgy.

SUBSTANCE: in cone-shaped crop-end ingots with dimensions of 600/615×100×1500 with the head removed by a flame method or by electromachining, a through central hole with diameter of 100±5 mm is drilled. Ingots are heated to ductility temperature and pierced in a mill for transverse screw rolling on a mandrel with a diameter of 500 mm into shells with diameter of 670xin515×2850 mm with an average rise as to diameter of up to 10.3%, and throughout length of the cone-shaped ingot of 8.9 to 11.7%. Shells are rolled on the pilger mill into pipes with the size of 508×11.1×20500±250, 508×12.7×18500±250 and 506×16.1×13500±250 mm. Pipes with the size of 508×11.1×20500±250 and 508×12.7×18500±250 mm are cut with a hot cutting saw into two equal parts. Rolling of casing pipes on the pilger mill is performed at rotation speed of working rolls of 32-36 revolutions per minute.

EFFECT: increasing capacity of a unit; excluding double heating and reducing metal consumption coefficient.