Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/16—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section
  • B21B1/18—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section in a continuous process

Definitions

• ABSTRACT A method of rolling small sections is provided in which [30] Fol-mg Apphcatlon Pnomy Data the metal to be rolled is passed through a plurality of July 1970 Germany P 20 35 successive roll stands having grooved rolls, while tension is applied to the metal in successive stands and is [52] US. Cl 72/205, 72/235, 72/366 varied between the Stands depending upon the relative [51] Int.
• This invention relates to methods of rolling and particularly to a method of rolling light sections, chiefly wire, under tension in a multi-stand rolling mill, e.g. one having non-adjustable rollers, the finished cross section of the work-material or strands being adjustable within limits.
• roller grooving constitutes a predetermined, constant factor (when considering a short period of time)
• the cross section of the first pass and the tension may be varied, the tension being a function of the cross section of the first pass.
• the range of variation of the cross section of the first pass is dependent upon the roughing stands connected in front of the block.
• the upper limit of the tension is particularly dependent upon the tensile strength of the work-material and upon the rollers which, in the case of great tension, are subjected to considerable wear.
• the lower limit can be fixed at zero, which would correspond to tension-free rolling, although, for reason of safety, the lower limit is fixed somewhat higher in dependence upon the rolling conditions in order still to obtain a perceptible tension between the stands under all operating conditions.
• the roller grooving determined by the configuration of the freshly fitted rollers is not constant and varies by virtue of the unavoidable wear of the rollers, the amount of wear increasing towards the delivery end of the block owing to the greater rotational speed of the rollers or the greater throughput length of the work-material.
• this variation in the grooving, occasioned by wear results in an increase in the tension throughout the entire block, so that there is an increase in the reduction of the cross section occasioned by tension.
• the optimum extent to which the sizing passes are filled, particularly the finishing sizing pass, necessarily falls below the optimum extent by virtue of the increase in the diameter of the sizing passes conditioned by wear and by virtue of the associated increase in the reduction of the cross section occasioned by tension, so that a non-circular cross section of the wire is produced, which is disadvantageous during further reduction of the wire by drawing for example.
• a circular cross section of the wire is always desired and can be obtained only by maintaining a specific optimum extent to which the finishing sizing pass is filled.
• the cross section of the first pass is increased to effect a corresponding increase in the final cross section.
• this possibility of adjustment is limited, since the optimum extent to which the sizing passes can be filled cannot be attained by increasing the cross section of the first pass after a specific amount of wear has occurred, although the wire, which would be obtained with optimum filling of the sizing passes widened by wear, would still be within the admissible range of to]- erance.
• the sets of rollers, particularly at the finishing sizing passes frequently have to be removed before the actual limit of wear has been reached and have to be replaced by fresh or reconditioned rollers.
• a feature of the invention is to provide a method of rolling light sections, chiefly wire, in which an optimum extent to which the sizing passes are filled, particularly the finishing sizing pass, can be maintained even when the sizing passes have been subjected to a considerable amount of wear.
• the under-filling of the sizing passes caused by variation in the roller grooving conditioned by wear, particularly the under-filling of the final sizing passes subjected to greatest wear, is at least partially compensated for by reducing the tension between the stands.
• the extent to which the sizing passes are filled can be controlled by reducing the tensioneven when the possibilities of control by increasing the cross section of the first pass have not yet been fully utilized.
• the amount of wear on the rollers with respect to time, which increases with increasing tension, can be reduced by keeping the tension to a minimum from the outset.
• one set of rollers can beused to roll circular wire for a longer period of time than hitherto, the range of tolerance of the cross section of the wire being fully utilized on the one hand and, on the other hand, the absolute service life of the rollers can be increased.
• a block comprising a plurality of stands is used as the rolling mill, one group of stands or, if required, all the stands, being driven by two motors.
• One motor in the form of a group drive then drives the stands over a primary range of speed, while the second motor superimposes on each stand an additional and variable range of speed by way of a differential drive.
• the block operates at an average tension with an average cross section of the first pass for example.
• the rolling mill has to be adjusted before the operating state is reached in which the rolling mill produces non-circular, unserviceable wire or in which the tension would exceed the upper admissible limit.
• the difference in the rolling conditions may readily be compensated for by varying the cross section of the first pass, since, by appropriately increasing the cross section of the first pass, the tension is reduced on the one hand and, on the other hand, the final cross section or the filling of the finishing sizing pass is increased.
• the extent to which the sizing passes are filled can be varied only slightly even by large variations in the cross section of the first pass, until it is finally impossible to increase the extent to which the sizing passes are filled by further increasing the cross sections of the first pass.
• the sizing passes are normally not worn to an extent where wire could not be produced by optimum adjustment of the extent to which the sizing passes are filled and which is within the range of tolerance.
• the tension which has increased owing to the variation in the sizing passes is now reduced by appropriate adjustment of the motor supplying the additional speed, so that the reduction in cross section occasioned by tension is reduced, thus increasing the final cross section without varying the cross section of the first pass, i.e., the extent to which the finishing sizing pass is filled is increased and, of course, that of the preceding sizing passes.
• adjustment of the tension may also be used in the opposite case when the finishing sizing pass is over-filled, this being effected by increasing the tension by supplying a corresponding addi tional speed. This increases the reduction in cross section occasioned by tension, so that the final cross section decreases together with the extent to which the finishing sizing pass is filled.
• the extent to which the sizing passes are filled, or the cross-sectional area of the finished product, are adjustable over a substantially greater range than hitherto by virtue of combining variation in the entry crosssectional area'and variation in the tension. Furthermore, the variation in tension effected by regulating the additional motor is very flexible, so that it is possible very rapidly to compensate for flaws in the finished product caused by not maintaining the optimum extent to which the sizing passes are filled.
• a method of rolling small sections under tension in a multi-stand rolling mill comprising the steps of a. passing the metal to be rolled through a plurality of successive roll stands having grooved rolls,

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Metal Rolling (AREA)
• Control Of Metal Rolling (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=5777046

Family Applications (1)

Country Status (4)

Cited By (8)

Citations (3)

• 1970
  • 1970-07-17 DE DE19702035481 patent/DE2035481A1/de active Pending
• 1971
  • 1971-07-14 US US00162627A patent/US3756060A/en not_active Expired - Lifetime
  • 1971-07-15 JP JP5217271A patent/JPS5415544B1/ja active Pending
  • 1971-07-16 GB GB3341671A patent/GB1330927A/en not_active Expired

Patent Citations (3)

Also Published As

Similar Documents