PASSES SYSTEM OF FIRST TWO SECTION ROLLING MILL STANDS OF ROLLS Russian patent published in 1996 - IPC

FIELD: rolling production, methods of first and second rolling mill stands of rolls grooving in particular during production of section rolling steel - mainly difficult to be deformed steel - by section rolling mills. SUBSTANCE: aim is to decrease probability of succeeded to rolling products backfins and cracks formation on surface of rolling due to decrease of metal surface temperature nonuniformity along rolling section perimeter. Blank of square or rectangular cross-section is heated in section rolling mill methodical furnace up to temperature of 1100 - 1170 C during rolling of usual metal and up to 1150 - 1230 C during rolling of difficult to be deformed marks of steel. Heated blank is delivered in first stand of rolls of rolling stand initial group, operational rolls of which have flat oval pass (see FIG. 1). Produced in second rolling mill stand of rolls rolling product is rolled in third rolling mill stand of rolls, operational rolls of which have usual oval pass (it is not shown on drawing). Following formation of shape is exercised in known systems of rolls passes with usage in process of intermediate formation of drawing systems of oval-square, oval-rib oval, oval-circle passes, etc (they are not shown on drawing). Flat oval pass formed by two rolls with grooves of trough-shaped form in their cross-section are made in following way (see FIG. 1). Space between lines of crossing of groove "b" flat surface with its side planes is made commensurable with side of initial blank "a". Groove taper of first rolling mill stand of rolls pass is made equal to 24 - 29 %. Radiuses of flat surface conjugation with side planes - r₁ are made equal to 2.0 - 3.5 of radius of rounding - r₂ between planes of initial blank. Grooving of rolls of second section rolling mill stand with semicircular form grooves in their cross-section is made with taper of grooves equal to 30 - 35 % ( see Fig.2). EFFECT: improved process of rolling mill stands rolls grooving. 2 dwg, 1 tbl