Abstract:
A method and apparatus for continuously hot rolling ferrous long products which employs a "post finishing" block of roll stands downstream from the finishing stands of the mill. Water boxes or other like cooling devices are preferably interposed between the last mill finishing stand and the postfinishing block. The post finishing block includes at least two reduction stands followed by at least two sizing stands. The reduction stands have an oval-round pass sequence, and the sizing stands have a round-round pass sequence. Clutches or other equivalent means are employed in the drive train to permit changes to be made between the interstand drive speed ratios of at least the reduction stands, and also between some or all of the remaining sizing stands. A fixed rolling schedule is provided for all roll stands in advance of the finishing stands. Thus, the finishing group is supplied with a first process section having a substantially constant cross sectional area and configuration. The first process section is passed through the finishing group and rolling occurs in either none, some, or all of the finishing roll stands, depending on the size of the desired end product. The product then continues through water cooling boxes to the post finishing block as a second process section. The interstand drive speed ratios of the roll stands in the post finishing block are appropriately adjusted to accommodate rolling of the second process section. The total reductions affected in the initial reduction stands of the post finishing block are well above 14%, thereby producing an increased energy level in the product sufficient to create a substantially uniform distribution of fine grains. Typically, such total initial reductions will be on the order of about 20-50%. Significantly lighter reductions on the order of 2-15% are taken in the final round-round pass sequences of the post finishing block to obtain the desired close sizing tolerances in the finished product. The time interval between the higher reduction affected in the oval-round pass sequence and the lighter reductions affected during sizing in the round-round pass sequence is such that the resulting grain size throughout the product cross section will not vary by more than 2, and in most cases by less than 1 ASTM grain size number.
Abstract:
A single strand rolling mill has successive pairs of work rolls arranged to roll rod and bar products in a twist-free manner. The work rolls are carried on roll shafts included as part of roll packages which are detachably mounted to gear housings, and the gear housings contain intermediate drive shafts and intermeshed gears connected via line shaft segments and intermeshed bevel gears to a primary mill drive. The gear housings are carried on a base which is made up of a flat vertically upstanding structural member standing on edge and joined to an underlying base plate. The structural member extends beneath and in parallel relationship to the rolling line. Rib members extend laterally away from and are spaced along opposite sides of the structural member. The rib members are joined on edge to both the structural member and the baseplate and have upper support edges on which the gear housings are secured.
Abstract:
A housingless roll stand (10) has a pair of work rolls (36,38) supported between bearing chocks (40,42) for rotation about parallel axes. The bearing chocks are mechanically engaged by nuts (32,34) which in turn are threadedly engaged by opposite hand screw segments on spindles (30). The spindles serve both to effect symmetrical roll parting adjustments, and to provide a short stress path loop for absorbing roll separating forces during rolling. The nuts (32,34) and associated adjusting spindles (30) are separable from the bearing chocks (40,42), thus enabling them to remain as permanent on line fixtures when making roll changes.
Abstract:
Apparatus for shearing elongated products such as rods, bars and the like moving longitudinally along a path of travel (Pt). The apparatus includes a pair of constant diameter helical blades (44) mounted for rotation about axes parallel to the path of travel. The rotational orientation of the blades and the spacing between their respective axes is such that segments of the blades coact along a cutting path (Pc) parallel to the path of travel. The blades are rotated in opposite directions to thereby cause coacting segments thereof to move repetitively along the cutting path in the direction of product movement. A switch (56) diverts the products from the path of travel across the cutting path for shearing by the coacting segments of the cutting blades.
Abstract:
A single strand block-type rolling mill has pairs of oppositely inclined work rolls (16) arranged successively along a mill pass line (18) to roll rod and bar products in a twist-free manner. A planar base structure extends in parallel relationship between the mill pass line. A plurality of housings (32) are arranged seriatim along the mill pass line. The housings are secured to the base structure and have mutually overlapping portions secured to one another. Each housing includes intermediate drive components for driving a pair of roll shafts (40) carrying one of the work roll pairs, with the intermediate drive components being mechanically coupled to each other and to a common mill drive.