PURPOSE: To reduce the dispersion of tube length after rolling by changing the gap and circumferential speed of roll on the basis of the actually measured diameter of mandrel bar and the actnally measured length of tube to be rolled when bored tube to be rolled is rolled by mandrel mill.
CONSTITUTION: To regulate the length of rough tube, the average diameter of each mandrel bar is acturally measrured and on the basis of the measured value, the roll gap is changed, and also the hole length of each tube to be rolled, bored by piercer, is actually measured and on the basis of the measured value, the circumferential speed of roll is changed. In short, rolling is made by changing the gap and circumferential speed of roll for every one tube and for every one mandrel bar on the basis of respective values measured in advance, so that uniform rough tube can be obtained regardless of the dispersion of mandrel bar and bored hole length.
UTAKOUJI MASARU
YAMADA TAKEO
SUMITOMO KAINAN KOKAN KK
| JPS5219152A | 1977-02-14 |