| 摘要 |
FIELD: rolled tube production. ^ SUBSTANCE: method comprises steps of heating ingot-billets; piercing them in helical rolling mill to sleeves with different lengthwise elongation factors mupr and mupr1; rolling in pilger mill with elongation factor mupil . Ingot-billets are pierced to sleeves at different lengthwise elongation factors mupr, mupr1, mupr2 where maximum elongation value mupr2 corresponds to front end of sleeve forming guided end of tube in pilger mill. Elongation factor of front end of sleeve is decreased from mupr2 to mupr due to drawing roll apart along length (0.15 -0.20)LT forming guided end of tube in pilger mill and determined according to expression mupr2 = (1.4 -1.6)mupr where mupr -elongation factor in piercing mill at stable rolling process of central portion of sleeve equal to (0.65 -0.75)LT. Elongation factor of back end of sleeve is increased from mupr to mupr1 due to drawing rolls together along length of sleeve equal to (0.1 - 0.15)LT forming pilger head determined according to expression mupr1 = (1.3 -1.5)mupr. ^ EFFECT: lowered metal consumption, enhanced efficiency of pilger mills, prevention of crumbling back ends of sleeves. ^ 3 cl, 1 dwg, 1 tbl |
