US1987324A - Method of rolling hexagon bars - Google Patents

Description

Patented Jan. 8, 1935 PATENT OFFICE 1,987,324 METHOD or ROLLING HEXAGON BARS William .11". Catterall and William I. am, manon,-Pa., assignors to Bethlehem Steel Company, a corporation of Pennsylvania Application December 6, 1932, Serial No. 845,890.

70lalms.- (01. 80-6 3) This invention relates to improvements in the method of rolling symmetrical polygonal bars and particularly to hexagon bars.

The objects sought to be attained are: first,

.5 such accuracy in size and shape of the finished bar as to permit the making of hexagon nuts from the bar without the usual additional operation of cold rolling or drawing the barto obtain this accuracy in size and shape; second, to provide suitable form of bars for automatically repeating from one pass to the next on continuous or mechanically-fed mills.

In the manufacture of certain kinds of nuts it is the usual practice to take an ordinary hot rolled hexagon bar and cold roll or draw the bar to obtain the size and shape as required by trade specifications. This necessarily adds to the cost of the finished article, not only from the extra labor and time consumed but also from the additional equipment necessary for these operations.

By our improved method of rolling we eliminate the cold rolling or drawing operation by producing a bar having shape and size characteristics equivalent to a cold rolled or drawn bar of the same size which is acceptable to the trade.

In the previous method of rolling hexagons, the finished bar was usually rolled from an oval in five to seven passes. The shapes following the oval were preferably squares, diamonds and other configurations which resulted in accumulating inaccuracies and distortions to the extent that the finished product had to be cold rolled or drawn to bring the rolled bar to accurate size and shape for the manufacture of certain kinds of nuts which are extensively used.

The novel features will be more fully understood from the following description and claims taken with the drawing.

' Fig. 1 represents a round billet bar.

Fig. 2 represents a roll pass and a section of the leader formed from the round bar of Fig. 1.

Fig. 3 represents the finishing roll pass and the section of the hexagon bar formed from the leader of Fig. 2.

In rolling symmetrical polygonal sections it is advantageous to get a section as near to the finishing pass as practicable, over which the roller has as much control of the exact shape and sectional area as possible. This is the round, which has but one sectional dimension. The roller can get this round. as accurate to size as a finished round, and in the two remaining passes, the billet being turned 90 for the last pass, any slight inaccuracy of the round is diminished so that it is possible to work to even closer accuracy in making hexagons this way than the accuracy of rounds rolled in the usual manner.

1 In Patent 706,994 to Nighman there is disclosed a method of rolling polygonal sections using an .oval from which the leader is formed. However, 5

no great accuracy can be obtained by this method, as the oval to start with has two dimensions against one for the round, and the oval is more difiicult to roll true to shape than. a round. Again-an oval must be turned for the succeeding 10 pass, whereas a round does not need to be turned with the resulting inaccuracies on entering the second pass. Therefore in forming the leader we start from a round, which produces a leader of greater uniformity than that produced by an oval or any other shape known to us. The novelty of this invention comprises the rolling of the finished hexagon bar from the shape of Fig. 1 with but one intermediate pass.

In the first pass, the round is reduced to the shape as shown in 2. This shape has two pairs of fiat sides 10 which converge to points 11 and 12, the bases of the fiat sides being connected by concave surfaces 13. This shape is called the leader. .The leader before entering the finishing 25 pass Fig. 3 is turned at right angle so that the finishing pass tends to compress and spread the pointed ends of the leader which increases the angularity of said ends so as to fill out the concave portions of the leader without forming fins 30 at the parting of the rolls. The width of the fiats of the leader being substantially the same width of the finished faces 14 of the hexagon. By this method, having started with an accurately formed round, we are able to roll .a leader partly of the 3 final shape which has consistent accuracy of shape and section and with this accurately formed leader we are able to produce a hexagon having greater accuracy of shape and section than any hot rolled bar heretofore produced. In the final shape the faces will all be the same length and have the same angular relation one to the other.

The tolerance practice as specified by the Association of American Steel Manufacturers is .020" for to 1" hexagons, and .046" for 1" to 2" hexagons. By our method of rolling we roll bars to a tolerance as low'as .006" on all sizes.

Although we have particularly described the rolling of a hexagon, it is to be understood that our method is also applicable to other polygonal shapes. The only difierence being in selecting a suitably shaped leader for the final shape. The round still being used to form the leader in order to obtain accuracy. Any suitable type of.

continuous, mechanically-fed mill or hand-fed mill may be employed for carrying out our improved method of rolling.

' By this our improved method of rolling we 5 are enabled to roll a bar having tolerances and shape equivalent to a cold rolled or drawn bar which we believe has not heretofore been accomplished, thereby making a very substantial saving in cost of productionnotonly in time and labor but in the elimination of cost and of cold rolling or drawing apparatus.

Having thus described our invention, what we claim as new and desire to secure by Letters Pat-j ent, is:

1. In the manufacture of hot rolling hexagon bars having shape and tolerance characteristics equivalent to a similar cold rolled or drawn bar, the steps comprising forming a leader having a major axis and a minor axis from a substantially circular cross section bar, supplying the leader to a rolling mill in such a manner that the direction of compression of the leader in the mill is along the long cross sectional dimension of the leader, and rolling the leader to a finished hexagon.

2. In the manufacture of hot rolling hexagon bars having shape and tolerance characteristics equivalent to a similar cold rolled or drawn bar, the steps forming a bar having but one cross sectional dimension, rolling said bar to form a leader of elongated section having pointed ends and concave side portions, and finish rolling said leader in a hexagon pass to compress and spread said pointed ends and fill out the concave side portion of the leader so as to form a substantially perfect hexagon having said characteristics.

3. A method of rolling hexagons including the producing of a round of larger section than the 40 finished hexagon, rolling in one pass said round to a leader having fiat pointed ends and two oppositely disposed concave sides forming major and minor axes respectively, the width of the leader across its major axis being greater than 4 the diameter of said round and the depth through its minor axis being less than said diameter, and reducing said leader to a hexagon in another pass.

4. A method of hot rolling hexagon bars of ac- 50 curate section, including the continuous feeding of a heated round bar of greater diameter than the finished section to a rolling mill leader pass adapted to reduce the top and bottom convex surfaces of said round to oppositely disposed 55 concave surfaces and to spread the side portions of the round to form oppositely disposed pointed upkeep portions, turning the section thus formed 90, and in another pass continuously reducing said section to a hexagon.

5. A method of rolling accurately shaped hexaand in a single hexagon pass compressing said:

leader in the direction of its major axis to reduce its major dimension and simultaneously a increase the angularity between the flattened ends and widen the section in the direction of its minor axis thus transforming said concaved faces to straight parallel faces of equal length of the finished angular end portions, whereby to produce a true hexagon having corners equally spaced circumferentially and radially.

6. A method of rolling accurately formed hexagon bars including the production of a substantially round bar of larger section than the finished hexagon, compressing said round inarollpasspartlyofthefinalshapesoasto effect a reduction of the round in one direction and uniformly spread the same ina direction opposite to that of the compressive force of the rolls to form an undistorted leader having opposed angular ends and opposed concaved sides all correspondingly equal in length and symmetrically disposed relative to its axes, and reducing said leader to a hexagon having faces of equal length forming corners equally spaced circumferentially in another roll pass.

7. A method of rolling accurately shaped hexagons, including the producing of a round of larger section than the finished hexagon, deforming said round in a roll pass to a symmetrically shaped leader having pointed ends forming fiat faces of lengths substantially equal to the finished hexagon and concaved side faces of greater length than the faces of said hexagon, feeding said leader to a true hexagon roll pass so as to compress said leader section in the direction of its pointed ends to spread said pointed ends and simultaneously laterally spread said concaved faces in one direction while shortening their length in an opposite direction, whereby to completely fill out the pass without finning at the parting of the rolls.

WILLIAM H. CA'I'IERALL. WlILIAM J. BARRY.

CERTIFICATE oE' CoRRECTIoNL' Patent No. 1,987,324. January s, 1935.

WILLIAM H. CATTERALL, ET AL.

It is hereby certified that error appears'in the printed specification of the;

aiiovenumbered patent requiring'correction as follows: Page 2, first column,

line 29, claim 2, after "steps" insert the word comprising; and that the said Letters Patent should'be read with this correction therein that, the same may conform to the record of the case in thePatent Office.

Signed and sealed this 11th day of June, A. D. 1935.

Les] ie Frazer (Seal) Acting Commissioner oi Patents

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