| 摘要 |
FIELD: processes for making seamless tubes, namely with use of screw rolling equipment. ^ SUBSTANCE: method comprises steps of reducing heated blank in three-roll pass formed by rolls turned by feed angle and having reduction portion; piercing blank in pass formed by mandrel, guiding tool and two rolls turned by feed angle and having piercing portions; reducing blank in three-roll pass at feed angle of rolls consisting 1.4 - 4.0, at inclination angle of generatrix of reduction portion relative to rolling axis consisting 1.3 - 5.6, and at percentage reduction value consisting 1.6 - 6.2 respectively of feed angle, inclination angle of generatrix of roll piercing portion to rolling axis and percentage reduction value before nose of mandrel during piercing process. ^ EFFECT: lowered quantity of technological waste caused by occurring of inner and outer films, improved accuracy of sleeves made by screw rolling, mainly of continuously cast billets. ^ 1 tbl, 3 ex |
