US3818744A

US3818744A - Method of, and entry-guide for, feeding stock to a rod-rolling reduction mill

Info

Publication number: US3818744A
Application number: US00306409A
Authority: US
Inventors: R Sayer
Original assignee: Copper Refineries Pty Ltd
Current assignee: Copper Refineries Pty Ltd
Priority date: 1971-11-18
Filing date: 1972-11-14
Publication date: 1974-06-25
Anticipated expiration: 1991-06-25
Also published as: AU4865272A; FR2160579A1; JPS4862654A; CA961675A; GB1364156A; FR2160579B1; BE791558A; AU459717B2

Abstract

A roll stand for a rolling mill for changing the shape of an ingot or wirebar into a rod or wire which has rollers to guide the stock at its point of entry. Each roller preferably has two circumferential grooves in it so that a first stock piece moving through one groove will set the correct speed of the roller for a second piece of stock moving through the other groove. A method of practicing the invention is also disclosed.

Description

United States Patent [191 [111 3,818,744 Sayer June 25, 1974 [54] ETHOD OF, AND ENTRY-GUIDE FOR, 3,640,109 2/1972 Ashton 12/250 FEEDING STOCK TO A ROD-ROLLING REDUCTION MILL Inventor: Raymond Oliver Sayer, Townsville,

Queensland, Australia Assignee: Copper Refineries Pty. Limited,

Townsville, Queensland, Australia Filed: Nov. 14, 1972 Appl. No.: 306,409

Foreign Application Priority Data Nov. 18, 1971 Australia 7077/71 US. Cl. 72/250 Int. Cl B2lb 39/14 Field of Search 72/250, 227

References Cited UNITED STATES PATENTS 10/1935 Geer 72/231 Primary Examiner-Milton S. Mehr Attorney, Agent, or Firm-Stevens, Davis, Miller &

Mosher [5 7] ABSTRACT A roll stand for a rolling mill for changing the shape of an ingot or wirebar into a rod or wire which has rollers to guide the stock at its point of entry. Each roller preferably has two circumferential grooves in it so that a first stock piece moving through one groove will set the correct speed of the roller for a second piece of stock moving through the other groove. A method of practicing the invention is also disclosed.

- 6 Claims, 5 Drawing Figures p rgmgnJumlsn I I 3.81 8.744

SHEET 3 OF 3 F IG. 4.

FIG. 5.

This invention relates to the rolling of ingots, wirebars or the like, of copper or other metals, into rod or wire form, and to reduction mills for performing the rolling operation.

The stock fed to a rolling mill is usually furnace heated and then sent through a break-down mill, a roughing mill, an intermediate mill and a finishing mill. The stock emerging from the finishing mill is of the required rod cross-sectional shape and dimensions and is then suitable for use as rod either as a finished product, or as starting material for further fabrication.

Each of the mills or roll-stands comprises a pair of grooved rolls; and each pass (while it may change the cross-sectional shape of the stock to encourage plastic flow of the metal) is essentially one causing length extension and transverse area reduction of the stock. The number of reduction passes is variable depending upon the rod size to be made; a typical installation may perform nine reductions in the roughing mill, four reductions in the intermediate mill and five reductions in the finishing mill.

It will be seen that in the overall attenuation and lateral reduction of a stock length, the leading end of the stock is called upon, at each roll-stand, to enter between a complementary pair of roll grooves defining a rolling space which is smaller than one which would freely accept the oncoming leading end; and that the critical nature of the process of effecting the entry will become progressively greater as the leading end approaches the final or finishing stages of the reduction run. This will be obvious from the fact that as the stock is presented to the last finishing roll-stand it is then moving at its maximum linear entry speed, and at the same time the length over which it is able stiffly to support itselfis at a minimum.

To facilitate stock entry between the rolls of the rollstands it is usual to provide the entry points with entry guides. In the earlier days of the art these guides were no more than contoured and tapered tubes (called trumpets) having their smaller ends as close as possible to the rod entry point, and their opposite ends bellmouthed or flared so to provide an easy target for the leading end of the oncoming stock. Because of the friction involved it was subsequently proposed to provide the guide interiors with rollers which lightly engaged the stock. Some of these were power rotated, with the intention that their peripheral speed be as close as possible to the linear speed of the stock to be handled by them.

While the entry guides, with power rotated rollers, had many desirable features over the previously existing entry guides, they have not been entirely satisfactory because of the difficulty of equating the rotational speed of the rollers to the linear speed of the stock leading end to be received by those rollers.

This situation is particularly critical during the rolling processes in the finishing mill stands, and although the invention subject hereof may be usefully applied at any stage in the series of reductions, including the roughing mill, its importance increases in its application progressively towards the final roll-stand from which the finished rod emerges.

Further shortcomings of the prior entry guide practices are best discussed in terms of the two different types of mill with which such entry guides may be used. In one common form of rolling mill the rolls in the rollstands are furnished with journals at each end so that the rolls are doubly supported. Any such rolling mill is referred to herein as being of standard type. In a second type of mill (referred to herein as the cantilever type) the rolls are supported at one end only, with alternate roll-stands being horizontal and vertical," thus avoiding the necessity to turn the stock through between passes.

The cantilever type of rolling mill has such advantages as: roll changing time is reduced to a minimum as a change can usually be carried out without the necessity to disturb and upset entry and exit guides, and because of the unobstructed accessibility of the cantilevered rolls at one end. The main disadvantage of the cantilever in-line rolling mill is that only one length of stock can be rolled through the mill at any one time and this has necessitated a great deal of costly mill stand duplication. Thus, the standard types have an advantage over the cantilevered type of mill in that they are able to handle more than one reduction operation at the same time by the simple expedient of providing the doubly supported rolls with extra stock reception grooves thus permitting multi-strand operation which as they are presently constituted, cannot be applied to cantilever type rolling mills.

Thus a further disadvantage of the cantilever type has been the necessity hitherto to provide each single roll stand with its own entry guide which, of course, causes costly duplication in large scale production. But notwithstanding the shortcomings attributable to the types of mill discussed above, the major shortcoming is that initially referred to namely the difficulty of arranging for the peripheral speed of the stock engaging rollers in the entry guide to be exactly the same as the linear speed of an oncoming stock length to be directed into a roll-stand thereby.

The main object of the present invention is to overcome the disabilities referred to above in a very simple way, by the provision of a roller type entry guide and method of using it which ensures that roller speed of rotation is precisely equivalent to that required to accommodate an oncoming stock leading end. This in turn, by virtue of its compactness, enables the cantilever type roll stands to operate in a double or multistrand capacity.

Another aspect of the prior art is that, so far as we are aware, it has invariably been considered essential for the axes of the entry guide rollers to be disposed at right angles to the axes of the reduction rolls associated therewith. In this connection, it will be clear that it is desirable for the guide rollers to contact the through-going stock only or primarily by way of the circumferential (and usually cylindrical) floors of the guide roller grooves, so that side scruffing of the stock, due to the variable radii of the groove side-walls, will be avoided or kept to a minimum. Still further in this connection (and as is wellknown) in most rod reduction passes, the stock is most efficiently reduced if it is rolled to an elliptical or non-circular shape, particularly one giving it major and minor cross-sectional axes as in an ellipse.

It follows, that where the rotational axes of the entry guide rollers and the associated reduction rolls are disposed at right angles, each to the other, the guide rollers make their main contact with the through-going stock along the arcuate sides of the stock, (that is, at the ends of the minor cross-sectional axis of the stock) and this contact is virtually a point contact.

We have found that if the mentioned main contact, between the stock and the guide rollers, takes place at the ends of the major cross-sectional axis of the stock (as distinct from the minor axis as before) the stock proceeds through the guide rollers with greatly enhanced smoothness and stability; that is, with less vibrational or whip movement of the stock and less likelihood of stock wandering out of coincidence or phase with the angular orientation required of it relative to the guide roller grooves. Moreover, this effect of greater stability may be considerably enhanced if the stock arriving at an entry guide has been slightly longitudinally flattened (during the immediately previous reduction) at the ends of its cross-sectional major axis, thus to transform what was previously virtual pointcontact at the ends of the minor cross-sectional axis, into a line-contact at the ends of the major crosssectional axis.

The present invention provides a method of feeding stock to be rolled, to and through an entry guide having at least one pair of opposed double-grooved guide rollers freely-revolvably mounted therein, and leading to a plural-stranding pair of grooved reduction rolls; said method consisting in advancing the leading end of a length of stock towards said guide rollers and entering said leading end therebetween, while drive-rotating said guide rollers by frictional contact therewith of another length of throughgoing stock already partly fed through said guide rollers prior to the arrival of the said leading end at said guide rollers.

It will be seen that by using a length of throughgoing stock for frictionally driving a plural-stranding pair of entry guide rollers, a newly arriving leading end will first engage the rollers while they are turning at exactly the right speed to receive the new leading end, and that immediately the new leading end has started its run through the entry guide it then becomes able to constitute the means for driving the entry guide rollers at the required speed of reception for the next oncoming length of stock.

Because of the elimination of conventional driving mechanism for the entry guide rollers, the entry guides may be sufficiently reduced in size, and structurally simplified, to permit overall space saving whereby a twin or other multi passage entry guide may be applied to a cantilever type roll stand thus pennitting it to handle two or more strands simultaneously; provided its reducing rolls are appropriately double-grooved.

A typical twin entry guide for use with a doublestranding standard type roll-stand, or a doublestranding cantilever type roll-stand is illustrated to some extent schematically, in the drawings herewith:

FIG. 1 is a partly sectioned perspective view of an entry guide;

FIG. 2 is a side elevation of the same guide;

FIGS. 3 and 4 are sectional end elevations respectively taken on lines 3 3 and 4 4 in FIG. 2; and

FIG. 5 is an end elevation looking in the direction indicated by line 5 5 in FIG. 2.

The illustrated entry guide is furnished with conventional means for supporting it in relation to the rollstand with which, in use, it is associated. it comprises a block-like body formed in two

parts

6 and 7 having mutually confronting

faces

8 and 9.

Faces

8 and 9 are appropriately spaced apart by spacer studs, indicated at 10 and 13, the necessary adjustment to effect appropriate spacing being achieved by rotating the countersunk screw heads 13. The parts are located, each in relation to the other, by such means as dowells 11 fixed on one part, able to enter holes 12 in the companion part. The two parts are held fixedly together by machine bolts or the like within a guide box (not shown).

One end of the two-part body is tapered, at 14, to protrude in nose form adapted to be positioned closely to and in axial alignment with the reduction grooves in the rolls of the related roll-stand. The mutually confronting

faces

8 and 9 have registering runway grooves 15 therein which at the nose end of the body are so sized as to ensure correct presentation of the leading ends of stock lengths to the roll-stand rolls. Along their length the mentioned grooves are preferably tapered and at the reverse or stock-entering end of the block body (shown in FIG. 5) the grooves are bell-mouthed or flared 16) so that they are an easy target for oncoming stock leading ends. Towards the centre of the entry guide body, the sides are machined to support axles 17 upon which twin or multi-groove entry guide rollers 18 are freely rotatably mounted with their longitudinal axes about which they are rotatable, parallel to the similar axes of the roll-stand reduction rolls.

As previously indicated the guide rollers preferably each have two stock accommodating grooves 19 (as shown) but they may be arranged to accommodate more than two stock lengths at any one time. The preferred arrangement is for double grooves and that is sufficient to ensure that one through-going stock length, being hauled through the entry guide by the related reduction rolls, will act as an entry guide roller drive means for a next oncoming stock length, which in turn, becomes a roller driver element relative to still another following length of stock.

it will be appreciated that for effective operation of the entry guide rollers it is essential to arrange for infeed of the stock into the reduction mills in such a manner as will avoid simultaneous arrival of two or more stock leading ends in any one entry guide.

The rollers 18 are freely-rotatably mounted on axles 17 by way of bearings 20. The axles are supported in bushes 21 mounted in the sides of the

body parts

6 and 7. Through-pins 22 obstruct axial movement of the axles in one direction (to the left in FIG. 3) and keeper plates 23 restrain axial movement of the axles in the opposite direction; and also restrain rotation of the axles, by engaging in stepped end portions (24) of the axles.

I claim:

1. A method of feeding stock to be rolled, to and through an entry guide having at least one pair of opposed double-grooved guide rollers free-revolvably mounted therein, and leading to a plural-stranding pair of grooved reduction rolls forming a reduction mill; said method consisting in advancing the leading end of a length of stock towards said guide rollers and entering said leading end therebetween, while drive-rotating said guide rollers by frictional contact therewith of another length of throughgoing stock already partly fed through said guide rollers and the reduction mill prior to the arrival of the said leading end at said guide rollers.

2. A method according to claim 1 which includes the steps of forming stock arriving at said entry guide with a noncircular cross-sectional shape having crosssectional major and minor axes, and causing said stock to enter between said guide rollers with the ends of its said major axis in contact with the floors of the grooves in said guide rollers.

3. The combination with a rod-reduction roll-stand incorporating a pair of plural-stranding circumferentially-grooved reduction rolls; of an entry guide, comprising:

a. a two part body juxtaposed the rod receiving side of said reduction rolls said parts being fixedly joined together with spaced apart mutually confronting faces; a

b. at least one pair of opposed circumferentiallygrooved guide rollers freely-revolvably mounted in said body; and

c. rod runways formed as grooves in both of the faces in said body and longitudinally aligned with the grooves in said rollers, said runways having bellmouthed stock-entering ends.

4. The combination according to claim 3 wherein the longitudinal, rotational axes of said guide rollers and said reduction rolls are parallel.

5. The combination according to claim 3 wherein said roll-stand is of the cantilever type in which the reduction rolls are supported at one end only, and in which each of the reduction rolls has at least two circumferential grooves formed in it.

6. The combination according to claim 3 which incorporates four pairs of guide rollers, and wherein each of said four pairs has its rollers respectively mounted in said two body parts.

Claims

2. A method according to claim 1 which includes the steps of forming stock arriving at said entry guide with a noncircular cross-sectional shape having cross-sectional major and minor axes, and causing said stock to enter between said guide rollers with the ends of its said major axis in contact with the floors of the grooves in said guide rollers.

3. The combination with a rod-reduction roll-stand incorporating a pair of plural-stranding circumferentially-grooved reduction rolls; of an entry guide, comprising: a. a two part body juxtaposed the rod receiving side of said reduction rolls said parts being fixedly joined together with spaced apart mutually confronting faces; b. at least one pair of opposed circumferentially-grooved guide rollers freely-revolvably mounted in said body; and c. rod runways formed as grooves in both of the faces in said body and longitudinally aligned with the grooves in said rollers, said runways having bell-mouthed stock-entering ends.