PURPOSE: To reform an existing mandrel mill line at low cost and to produce product pipes of larger outside diameters by composing rolling equipment for seamless pipes of a Mannesmann inclined piercer, a mandrel mill, a incline type expansion rolling mill and a pipe finishing mill.
CONSTITUTION: A blank billet 2 heated in a rotary hearth type heating furnace 1 is pierced by a Mannesmann piercer 3 which is the inclined piercer and is made to a hollow pipe stock 4a. A mandrel bar 5 is then inserted into this hollow pipe stock 4a and the hollow pipe stock 4a is stretched to a smaller thickness by the mandrel mill 6, by which the hollow pipe stock 4b is obtd. The mandrel bar 5 is drawn out of the inside of the hollow pipe stock 4b and the stick is immediately expansion rolled by the inclined expansion rolling mill 8 and is made to the pipe stock 4d for finish rolling having the outside diameter larger than the outside diameter of the hollow pipe stock 4c. The pipe stock 4d for finish rolling is finished to a product 10 of a prescribed outside diameter by the pipe finishing mill 9.
| JP3452039 | METHOD FOR ROLLING SEAMLESS STEEL TUBE |
| JPS5717318 | ROLLING METHOD FOR METALLIC PIPE |
YORIFUJI AKIRA
TOYOOKA TAKAAKI
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