СПОСОБ ПРОШИВКИ ЗАГОТОВОК ИЗ СТАЛИ С СОДЕРЖАНИЕМ БОРА ДО 2%

摘要

FIELD: tube production, namely method for piercing billets in helical rolling mills, possibly manufacture of tubes of steels with boron content up to 2% in tube rolling aggregates, for example with automatic mills. ^ SUBSTANCE: method comprises steps of heating billet till temperature 1050 - 1100°C; biting billet between rolls; reducing continuous portion of billet till nose of mandrel; intensively deforming billet on mandrel till roll constriction and rolling it out on outlet cones of rolls. Piercing is performed at reduction degree of billet no more than 12% in roll constriction at oval degree in deformation zone 1.08 -1.12 and at relation of reduction value in roll constriction to reduction value in front of mandrel nose 2.0 - 2.7. Quantity of feed strokes from beginning of billet biting till mandrel nose is set by roll feed angle in range 3 - 5. ^ EFFECT: possibility for piercing sleeves of boron containing steels without breaking them.