US3225580A - Reduction of edge taper in strip rolling - Google Patents

Description

Dec. 28, 1965 A. H. EL-WAZIRI Filed April 24, 1963 2 Sheets-Sheet 1 I, A: t i g 30 H a l 30 3 l W 3/ 2a 28 I l I 2.9

29 28 L9 2 Lg 34 Z Attorney Dec. 28, 1965 A. H. EL-WAZIRI 3,225,580

REDUCTION OF EDGE TAPER IN STRIP ROLLING Filed April 24, 1963 2 Sheets-Sheet 2 IIVVEIVTOI? ABDEL H. [L WAZl/P/ By M QMZV Af/omey United States Patent 3,225,580 REDUCTION OF EDGE TAPER IN STRIP ROLLING Abdel H. El-Waziri, Pittsburgh, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed Apr. 24, 1963, Ser. No. 275,282 6 Claims. (Cl. 72236) This invention relates to the reduction of metal strip and the like by cold-rolling, and is more particularly concerned with the control of transverse uniformity in gauge of the product, especially reduction in edge taper, by means of selective limitation of lubricants conventionally applied to the metal being rolled, prior to roll entry.

Variation of thickness across the strip is known to be responsible for a number of difliculties encountered in rolling, such as locked-up stresses, buckling and waviness, edge cracking and other defects.

During rolling, the resistance of the lateral spread of the material at the center of the strip is greater than that at the edges thereof. This causes a comparatively larger amount of lateral flow of the material to take place locally at the edges of the strip. Therefore, the resulting product is not of uniform thickness. This condition is referred to as edge taper.

In an endeavor to eliminate edge taper and thereby obtain a product of uniform thickness, it has been proposed that roll surfaces be ground to a shape which would compensate for this effect.

The use of specially shaped rolls present many disadvantages. For example, in multiple-stand mills the width of the strip progressively increases as the strip passes through the stands of the mill. Therefore, the rolls of the various stands must be ground to a shape suitable to compensate for this condition. Since the dimensions of the rolls used at each stand differ from those of the other stands of the mill, the rolls are not interchangeable. Furthermore, the use of specially shaped rolls to correct edge taper limits the use of a particular set of rolls to only one strip width and, therefore, requires a complete change of rolls each time a strip of different width is to be rolled. Also, for this method to be effective the strip must be fed with its centerline strictly in the plane of symmetry of the mill stand. This is a requirement that is not easily met in practice.

The present invention provides a method for correcting edge taper that circumvents the problems encountered in the proposed roll shaping practice. This is accomplished by limitation of amounts of conventionally applied cold rolling lubricants, in areas adjacent to the strip edges, preferably by totally or partially removing the lubricant over adjustable widths along the edges of the strip and the corresponding area on the workrolls. This increases the friction between the strip and the workrolls at the area of lubricant removal and thereby constrains the lateral flow of the material at said area. The degree and area of lubricant removal are regulated to achieve a uniform reduction across the width of the strip.

An understanding of the details of the method of lubricant removal may be obtained by reference to the specialized equipment employed, as depicted in the drawings, where:

FIGURE 1 is an elevational view of a rolling mill stand with the lubricant removal devices installed to remove lubricant from strip edges;

FIGURE 2 is a partial perspective view of the roll mill stand of FIGURE 1; and

FIGURE 3 is an enlarged elevational view of the rolls and strip, with the housings of the lubricant removal devices shown in section to permit presentation of their internal mechanism.

3,225,580 Patented Dec. 28, I965 In the interest of clarity of presentation, the drawings are somewhat schematic in detail, and while essential functions are depicted, mechanical details related to their incorporation in the apparatus may be altered without departure from the inventive concept.

With further reference to the drawings, particularly FIGURES 1 and 2, each stand of the mill is preferably supplied with two pairs of lubricant removal devices 1, each pair being composed of an upper element 1a and a lower element 1b, each pair of devices being mounted astride the strip 2, adjacent to each edge, and adjacent to the entry side of rolls 3, to permit selective removal of lubricant from areas adjacent to the strip edges and from the corresponding areas of the rolls which will contact the strip edge areas. The rolls are mounted in pillar like supports 4, to which the lubricant removal devices are conveniently afiixed as shown in the drawings.

The construction and operation of the lubricant removal devices 1 will become apparent by reference to FIGURE 3.

An apparatus suitable for this purpose is shown in FIF- URE 3. A continuous belt 10, of absorbent material, driven by a motor 11' attached to drum 11, is moistened with any suitable detergent or solvent by applicator roll 12. The moistened portion of the belt then passes over drum 11 and moves toward drum 13. As the belt passes over drum 13, it contacts the surface of the workroll 3. The positioning of drums 13 and 14 causes the belt when passing therebetween to contact the surface of the strip for an appropriate distance along the length thereof. Since the belt is moistened with detergent, the lubricant is removed from the workroll and the strip over an area equal to the contact area of said belt. The belt is now guided in a horizontal path by rolls 16 and 17, and the sprayer 18 applies a detergent or solvent to that portion of the belt horizontally positioned between said rolls, to dilute the mixture of removed lubricant and detergent or solvent. The belt then passes between wringer rolls 17 and 19, which have their surface covered with a pliable elastic material, such as rubber, and the contaminated detergent or solvent is removed from the belt. Any excess solvent from sprayers 18 and the solvent removed from the belt by wringer rolls 17 and 19 fall into a collecting basin 20 for subsequent disposal. The belt, having been thoroughly cleaned by the combined action of the sprayers and the wringer rolls, again contacts the applicator roll and is moistened with the detergent.

As shown in FIGURE 3, the applicator roll 12 is immersed in a detergent contained in a shallow trough 21. Pump 22 maintains the detergent in the inner cylinder 23 constantly overflowing. The overflow passes into the outer cylinder 24 and from there into the sump 25. Therefore, if the top of the inner cylinder is positioned on the same horizontal plane as the desired level of detergent in trough 21, the amount and level of detergent in said trough will remain constant.

FIGURES 1 and 2 illustrate essential mounting structure. The two units positioned above the strip are hinged to screw spindles 26 that extend along the length of the roll. A handle 27 is attached to the ends of the spindles, and the position of the units may be changed by merely turning the handles in the proper direction. This enables the area of lubricant removal to be increased or decreased according to changes in operating conditions. It also enables the position of the units to be changed to accommodate various widths of the strip. The maximum area of lubricant removal is determined by width of the belt.

A member 28 extends horizontally from each unit. Holes are provided in the ends of the top members, and threaded rods 29 are passed therethrough. The end of each rod is attached to the bottom member. A nut 39 with a coil spring 31 therebelow is screwed onto the top of the threaded rod. By turning the nut in the proper direction, the operator may adjust the pressure at the contact area of the belt. The magnitude of pressure and the relative velocity of the belt, as it contacts the strip and the workrolls, determine the degree of lubricant removal and hence the magnitude of the coefiicient of friction between the strip and the workrolls. The speed of the motor may be regulated to achieve the desired relative velocity.

The lower elements In may receive additional support from horizontal bars 32. These have slots 33 which are coordinately positioned with respect to flange 34 of element In to receive spring loaded attaching bolts 35.

The detergent or solvent chosen is appropriate to the lubricant employed. Various trade-named detergents and solvents may be employed. As indicative of the types of detergents and solvents contemplated, sodium lauryl sulphate is an example of a detergent generally applicable and examples of solvents are butyl acetate, ethylene glycol, and carbon tetrachloride.

While certain specific examples have been given of the application of the invention, these are to be considered as illustrative for ready application of the invention, rather than as limiting thereof, as modifications therein will be apparent to those skilled in the art to which this invention pertains.

I claim:

1. The process of reduction of metal strip and the like by cold rolling, comprising removal of normally present lubricants from selected areas adjacent to the strip edges, prior to roll entry, and from the corresponding areas of the roll surfaces about to contact said strip areas, to reduce edge taper of the strip material upon cold rolling, and cold rolling said strip.

2. Apparatus for the reduction of metal strip and the like by cold rolling comprising means for reducing an amount of normally present lubricants from selected areas adjacent to the strip edges, prior to roll entry, and from the corresponding areas of the roll surfaces about to contact said strip areas, to reduce edge taper of the strip material upon cold rolling.

3. The apparatus of claim 2 in which said means for selective reduction in amount of lubricants includes lubricant removal means comprising pairs of lubricant removal devices adapted to be selectively positioned, in operative contact, astride strip and the like undergoing cold rolling, and in operative contact with corresponding roll areas,

each of said pairs of devices comprising an upper and lower element, each of which comprises a continuous belt of absorbent material for contacting strip and roll surfaces; drums for carrying said belt into contact with the strip and roll areas; motor drive means for said belt; means for moistening said belt with detergent, solvent, and the like; and means for cleaning the belt.

4. The apparatus of claim 2 in which said means for selective reduction in amount of lubricants includes lubricant removal means comprising pairs of lubricant removal devices adapted to be selectively positioned, in operative contact, astride strip and the like, undergoing cold rolling, and in operative contact with corresponding roll areas, each of said pairs of devices comprising an upper and lower element, each of which comprises a continuous belt of absorbent material for contacting strip and roll surfaces; drums for carrying said belt into contact with the said strip and roll areas; motor drive means tor said belt; means for moistening said belt with detergent, solvent, and the like comprising an applicator roll and a constant liquid level trough for said roll; and. means for removal of contaminated detergent, solvent, and the like from the belt comprising means for spraying the belt with detergent, solvent, and the like, wringer rolls, and a collecting basin.

5. The process of reduction of metal strip and the like by cold rolling, comprising selective limitation of nor mally present lubricants in areas adjacent to the strip edges, prior to roll entry, and in the corresponding areas of the roll surfaces about to contact said strip areas, to reduce edge taper of the strip material upon cold rolling, and cold rolling said strip.

6. The process of reduction of metal strip and the like by cold rolling, comprising removal of normally present lubricants from selected areas adjacent to the strip edges, prior to roll entry, to reduce edge taper of the strip material upon cold rolling, and cold rolling said strip.

References Cited by the Examiner UNITED STATES PATENTS 1,487,375 3/1924 Fuchs 15l00 2,234,153 3/1941 Herbert l.2 2,318,320 5/ 1943 McFadden -80--l.2 2,555,021 5/1951 Backus 80l.2 3,002,210 10/1961 Gawne 15102 CHARLES W. LANHAM, Primary Examiner,

Claims (1)

1. THE PROCESS OF REDUCTION OF METAL STRIP AND THE LIKE BY COLD ROLLING, COMPRISING REMOVAL OF NORMALLY PRESENT LUBRICANTS FROM SELECTED AREAS ADJACENT TO THE STRIP EDGES, PRIOR TO ROLL ENTRY, AND FROM THE CORRESPONDING AREAS OF THE ROLL SURFACES ABOUT TO CONTACT SAID STRIP AREAS, TO REDUCE EDGE TAPER OF THE STRIP MATERIAL UPON COLD ROLLING, AND COLD ROLLING SAID STRIP.

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