US2137008A - Die rolled article and method of producing same - Google Patents

Description

Nov. 15, 1938. T. 4N. SLOAN 2,137,008

DIE ROLLED ARTICLE AND METHOD OF PRODUCING SAME Filed Aug. 9, 1937 3 Sheets-Sheet lm V m *gx Q e I K 1 \r i f A '3 v U J Q J V INVENTOR.

I rHo/ws AQSLOAA/ ATTORNEYS Nov. 15, 1938. T, S OAN 2,137,008

DIE ROLLED ARTICLE AND METHOD OF PRODUCING SAME Filed Aug. 9, 19:57 a Sheets-Sheet 2 x H a I I I I v 7'fi0/fA /y i a lil I if .1 BY rm ATTORNEYS Nov. 15, 193s. N, SLO N 2,137,00

DIE ROLLED ARTICLE AND-METHOD OF PRODUCING SAME Filed Aug. 9, 1937 3 Sheets- -Sheei: 3

INVENTOR. 7770/7/15 /V- SZOA/V BY MM ATTORNEYS ends of railroad rails.

Patented Nov. 15 1938 UNITED STATES DIE ROLLED ARTICLE AND- METHOD OF PRODUCING SAME Thomas N. Sloan, Buffalo, N. Y., assignor to The Republic Steel Corp., poration of New Jersey Cleveland, Ohio, a cor- Application August 9, 1937, Serial No. 158,124

Claims.

This invention relates to the art of die rolling and more particularly to improved die rolled rail joint bars and new and improved methods of and apparatus for producing the same.

Rail joint barsare bars employed to secure together and maintain in alignment the adjacent The older types of rail joint bars were produced by rolling a billet into a bar having a uniform and proper cross-section and then severing this elongated bar into pieces of desired length. No control of the length was required in rolling this type of article. The severed joint bars were punched and straightened, either hot or cold, and were then ready for use. A later and improved type of rail joint bar which has been produced is illustrated in the Hedgcock et al. Patent No. 2,083,298 of June 8, 1937. This improved type of joint bar is solid and substantially rectangular in cross-section, has a relatively large middle portion and end portions which taper down from themiddle portion to the ends, and is unsymmetrical on opposite sides of every plane passing longitudinally-therethrough. By the expressionunsymmetrical on opposite sides of all planes passing longitudinally therethrough, as used in this specification and the appended claims, is meant that any longitudinal plane through the article will divide it into two parts which are dissimilar in transverse crosssectional shape. This distinguishes from previous die rolled articles which are divided into two identical parts by at least one longitudinally extending plane.

Heretofore these improved bars have been made as follows: Steel in the cross-sectional form of a round cornered square having a crosssectional area slightly greater than the largest cross-sectional area desired in the finished bar and having a length sufficient to afiford adequate tong holds is worked down to size and shape by being drop forged in dies. There is no gathering of metal during this forging but, on the contrary, the steel is reduced in thickness and increased in length and breadth so that flash is formed throughout the entire periphery of the forged article.

Sincethis improved bar depends for much of its success and value on the presence of accurate, closely maintained dimensions which cannot be changed in subsequent manufacturing operations, the forging operations must be performed with great accuracy. This prior procedure has certain well known disadvantages among which are relatively high scrap losses due to tong holds and flash. undesirable modification oi the flow line structure of the article during thed'rop forging operations, and slowness of production due to the numerous operations and handlings necessary to drop forge the joint bar.

' It is among the objects of the present invention to produce an improved form-of rail joint bar of the general type disclosed in said above mentioned patent and to provide an improved method and apparatus for manufacturing such an article whereby the waste dueto scrap metal is greatly reduced, the speed of production is increased, the labor cost is reduced, and at least as high a degree of accuracy in the finished article is obtained as in the drop forged bar. In order to accomplish these objects I have resorted to the die rolling process for the production of this type of rail joint bar.

Prior to this invention one general class of ferrous metal articles which have been die rolled has included complex, semi-finished blanks which were later to be drop forged in dies. These blanks were satisfactory if their dimensions were such that the blank could be forged. in a drop forge die by which the blank was brought to the dimensions required in the finished" forging. The tolerances for the-blanks were greater than those demanded in the finished drop forged articles. So far as I am aware, all ferrous metal blanks which have been die rolled heretofore have been identical on opposite sides of at least one plane passing longitudinally therethrough.

The present invention relates to articles of a newgeneral class. Articles of this new class may be briefly described as being complex, that is, having large and small sections definitely located with respect to one another along the length of r the article, substantially finished", i. e., having dimensions within the extremely small tolerance limits obtainable in drop forging dies; being ready for use except for shearing, trimming, straightening, punching, and/or heat treating; and being unsymmetrical on opposite sides of every plane passing longitudinally therethrough The rail joint bar of the above mentioned patent is an article of this new class and, in addition to the just described characteristics, has a solid medial portion which is substantially rectangular in cross-section and longer, smaller, solid, relatively flexible portions substantially rectangular in cross-section at the ends of the article with one edge being substantially straight.

I have discovered that the methods and apparatus used heretofore to die roll articles of the above described, old, general class are not en-- tirely suitable for producing articles of the new inclined fishing surfaces of the article. a location enables me to die roll the joint bar in improved method of and apparatus for making die rolled articles of this new class. As usual I provide a pair of driven rolls but modify the shape, dimensions and disposition of the grooves in the rolls. I use a generally rectangular leader bar which, preferably, is substantially the same in cross-sectional size and shape as the largest section of the finished article. This bar, contrary to prior practice, has a ratio of thickness to width of less than about 1 to 2, and has substantially the same width as the widest part of the largest portion of the article, and has a thickness slightly greater than the portion of the article of greatest thickness. Such a leader bar will slightly overfill the largest part of the grooves but does not overhang the sides of the roll grooves, except where the narrower portions of the article are to be formed. The extrusion of metal in the direction of rolling in the smaller portions is fairly large because of the reduction in width and the small amount of flash as compared with the amount ordinarily used to control extrusion or length, and is variable because of the varying amount of overhang and resultant flash forma tion. By correlating the factors of reduction and flash formation in, and groove lengths for, the various axially spaced portions of the article, I am able to compensate for the forward extrusion and control the length of the various portions of this article within the small finished dimension tolerances allowed. For example, I make the grooves for small portions shorter than the desired lengths of such portions and make such groove lengths even shorter when they follow a larger portion, and, in doing so, take into account the cross-sectional area of the portions on either side of the portion in question, the amount of flash to be formed and the direction of rolling. This procedure will be pointed out more fully hereinafter.

Ordinarily, heretofore, the flash formed on opposite sides of the die rolled blanks was located in the same horizontal plane. According to this invention I locate the flash in different horizontal planes and at edges of the opposite Such a horizontal plane and thereafter to shear the flash from both edges simultaneously, without damage to the fishing surfaces of the bar. It is important to shear the flash cleanly from those surfaces without mutilating or damaging them for they play an important part in the use of the article as a joint bar.

In order to so locate the flash in different horizontal planes on the opposite edges of the article I provide a pair of. die rolls the flash forming surfaces of which are of equal diameter on one side of the matrix grooves therein and of unequal diameters on the opposite side of the matrix grooves.

In the die rolled joint bar illustrated, as produced by my die rolling process, substantially all of. the flow lines of the metallic structure of the article extend longitudinally thereof and thus themost desirable grain structure is obtained for the uses to which the article is put. Further, by offsetting or staggering the flash on the opposite edges of the article the zones of severed flow lines, which necessarily exist after the flash is cut off, do not lie in the same plane and thus any tendency toward a plane of weakness due to alignment ofv the zones of severed flash lines is avoided.

class just described, and have devised a new and The foregoing general principles will be better understood by reference to the accompanying drawings and to the following description, including dimensions, of a rail joint bar of the type shown in the above mentioned patent which I have satisfactorily die rolled and held to dimensions within the small tolerances obtained heretofore in generally similar joint bars which were made in drop forging dies.

Figure 1 is a plan view, partly in section, of l a finished rail joint bar of the Evertite" type illustrated in said above mentioned patent.

Figure 2 is a side elevation of the joint bar of Figure 1.

Figures 3, 4, 5 and 6 are vertical cross-sections taken on lines 3--3, 44, 5-5 and 66 of Figure 2.

Figure 7 is an end view of the joint bar taken on line 1-4 of Figure 2.

Figure 8 is an end view of a pair of die rolls adapted to produce my improved article, a leader bar being illustrated entering the rolls and a string of substantially finished joint bars being shown emerging from the rolls.

Figure 9 is an enlarged fragmentary view of the top roll, dimensioned to illustrate the lengths of the different roll sections which roll a single bar.

Figures 10, 11, 12, 13 and 14 are enlarged fragmentary sectional views of the roll pass taken on the radial lines l0-|El, l|l I, |2-l2, l3l3 and |4-l4 respectively of Figures 8 and 9, it being understood that the views are taken when the portions of the rolls shown in crosssection lie on the common center line of the 3 rolls.

Figure 15 is a cross-sectional view of a leader bar ready to be rolled in the pass shown by Figures 8 to 14 to form the article shown in Figures 1 to '7. 4

An inspection of Figures 1 to 7, inclusive, will show that the substantially finished joint bar is not symmetrical on opposite sides of any longitudinal plane therethrough. It is not nec-' essary in this specification to discuss in detail the reasons for the particular contour of the article shown or the functions of the various surfaces, etc. However, it may be pointed out that the fishing surfaces I and 2 of the joint bar are adapted to engage the underside of the head of the rail and the top of the base of the rail respectively, and the three spaced portions 3:, y and z of the fishing surface 2 of the bar must lie in a single plane. The dimensions given on Figures 1 and 2 are those of a particular bar which has been produced and used in large quantities heretofore. These dimensions indicate the high degree of accuracy which must be maintained in die rolling these joint bars. For example, the radius ofv the surface indicated at 6 R is 26 feet in the illustrated bar while the radius shown in Figure 2 and indicated at R is 48 feet. Other surfaces of the article must be rolled with corresponding accuracy and I have found that my improved roll arrangement and method of rolling enables me to produce unsymmetrical articles, of the class described, by die rolling and to hold their dimensions well within the tolerance ranges obtainable with the old drop forging methods. -So far as I am aware 7 die rolling to this degree of. accuracy has not been practiced prior to my invention.

Referring particularly toFigures 9 to 14, in-

clusive, the top roll 5 and the bottom roll 6 are each mounted for rotation in any suitable man- 7 bar I which is of generally rectangular crosssection and has a ratio of cross-sectional- 'thick- -ness to width'of less than 1 to 2 (the bar being considered in the position in which it enters the rolls, the width being the horizontal dimension). The matrix groove in each roll consists'of three duplicate sets of impressions each set extending through substantially 120 of the roll circumference. As is seendn Figures 10 to 14, the matrix groovein the bottom roll 6 is entirely difierent in contour from "that in the top roll and the opposite peripheral surfaces 8 and 9 of the roll 6, and Ill and II of'the roll 5, are radially offset. The surfaces 8 and I2 of the rolls Sand 5 respectively have the same diameter while the surface ll of the roll 5 has a greater diameter than the surface llof the roll 6. It will be observed from Figures 10 to 14 that the diameter of the portion ll of the roll 5 is large enough substantially 'to encompass the entire body of the article and to locate the flash at the edge of the inclined fishing surface 2. Thus, when the rolls are adjusted to give the proper clearance I2 to permit thg desired flash to be formed in the clearance spaces, the flash extruded-thereinto will be staggered or radially offset when viewed as illustrated in Figures 10 1 section.

It will be seen from the dimensions on Figure 1 that the finished article is divided longitudinally into sections which are identical on each side of the transverse center line H. Thus, the sections M-IS are three inches long, sections I3-I2 three inches long, sections I2-il five inches long and sections ll-l0 two inches long. These length dimensions of the various sections of the finished article must be ri idly maintained. The arrows in Figures 8. and 9 indicate the direction of rolling and by referrin to Figure 9, which shows the lengths of the portions of the groove in the top roll which correspond to the sections of the article shown in Figure 1, it will be seen that to roll the 5" section ll--l2,, on the right hand end of. the article or the portion thereof which goes through the rolls first, the correspondir'ig'portion of the roll groove must be 4.8906" in length while, to roll the corresponding sections l2-H on the trailing end of the article, the roll groove section l2ll (Figure 9), should be only 4.5781" long. In each case the length of the roll groove is less than the-length of the corresponding part of the finished article due to the extrusion of the metal which takes place during rolling. The roll groove portion ll-l2 on the advance end of. the bar is longer than the roll grooveportion l2--l of the trailing end of the bar. because of the influence upon extrusion of rolling from a small to a large section or a large to a small In other words, in the unsymmetrical articles under consideration, the extrusion is less when rolling from a small section to a large section than it is when rolling from a large section to a small section.

It will be understood that the leader bar should bear a fairly close dimensional relation to the roll grooves. It should be slightly thicker than the greatest depth of the grooves and should closely approximate the greatest width of the grooves. For the specific article illustrated the leader bar used was about 1%" thick and about 4%" wide. to width of about 1 to 2 In Figure 15 is shown the cross-sectional size and shape of an elongated leader bar which was die rolled to make the rail joint bar above specifically described. This leader bar was formed from an elongated round cornered flat bar by passing such a bar through a leader pass in which the bar was changed into a leader bar of. the size and shape shown. This leader bar, still heated to rolling temperature in the neighborhood of about 1800 F., was then passed through the die rolling pass of Figures 8 to 14 to form a string of connected joint bars. will be noted that the leader bar is substantially the same as the largest portion of the finished joint bar in cross-sectional shape and size and that the leader bar will substantially fill the portions of the grooves of greatest width and height, and that the thickness of. the leader bar is less than half of its width.

After the" leader bar is formed into a string of connected joint bars by the rolling process described above the string is severed into bars of the proper length dimensions and having rounded corners at each end as seen at I of Figure 2, but still retaining the offset flash on the edges of. the fishing surfaces 6 and 2. As is seen in Figure 2, the ends of the bars are severed diagonally. By so severing the bars I am able to roll the string of articles with only approximately gate between adjacent articles of the string. Where a string of articles is severed with a square cut a, 2" gate-is required in order to provide metal enough to properly support the shear. By diagonally cutting the ends of the bars a substantial saving in the weight of the scrap which results from cutting out the gates between adjacent pieces is effected. The desired end shape is formed in a' single shearing operation and the diameter of the die rolls may be made substantially smaller than they would have to be were the usual square cuts and 2" gate provided. In other words, the spacing between the parts of the matrix grooves which form the three impressions of the die rolls 5 and 6 will be only instead of 2" and in the rolls illustrated this will effect a very substantial saving in roll metal as well as an appreciable saving in die sinking time.

This bar had a ratio of thickness By supporting the bars on a suitable shearing I die a vertical movement of. the top die member will sever the flash from each edge of the bar and the severed flash line or zone will not extend beyond the fishing surfaces l and 2 and thus willnot interfere with proper contact between these surfaces and the rails.

After removing the flash the bars. are placed in another die in which they are punched. After heat treating the bars are straightened in a gag press. This straightening operation cannot be utilized to change or correct the dimensions or r cross-sectional form of the article and therefore the accuracy of the die rolling steps must .be rigidly maintained.

In the production of my improved die rolled joint bars the scrap metal produced is approximately only one-half 'as much as the scrap metal produced when the same type of bar is made by the previous" drop forging process. This substantial saving is accomplished due to the fact that my process completely eliminates tong holds, end flash metal, etc. Production of my die rolled bars may be effected "at the rate of. approximately per minute as against a production of 160 per hour on a drop forging hammer.

It will be understood that the form of the joint bar or other article produced by my die rolling method may be varied from that illustrated and that other types and forms of articles unsymmetrical on opposite sides of. all longitudinal planes may be produced by my method. Although I have described in considerable detail the steps of producing an improved rail joint bar of the Evertite type, I do not Wish to be limited to the particular article and to the specific form of rolls and arrangement of matrix grooves thereinwhich Ihave described, but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. A die rolled, substantially finished rail joint bar unsymmetrical on opposite sides of all longitudinal planes therethru, substantially accurate as to size and shape within finishedrail joint bar tolerances and requirements and which has on one edge a severed fiow line area, and on the opposite edge, and disposed in a different plane, a severed flow line area of length different from that of said area on the other edge.

2. A die rolled, substantially finished rail joint bar having a relatively large, solid, generally rectangular medial section, and smaller, solid. tapering end sections, said sections being accurate as to size and shape within the usual die forging tolerance limits, inclined fishing surfaces on opposite edges of, the bar and severed flow line areas disposed at an edge of each of said fishing surfaces in onset relation to each other.-

3. As an article of manufacture, a rail joint bar unsymmetrical on opposite sides of all longitudinal planes therethru and characterized by having the metallurgical characteristics of die rolled metal and having substantially all fiow lines extending longitudinally of. the bar.

4. The method of die rolling which includes the steps of passing a heated leader bar having a small ratio of thickness to width between two die rolls, said leader bar being of a width substantially equal to the greatest Width of the roll grooves and of a thickness slightly greater thanthe greatest height of the roll pass, completely filling said grooves at all places and over-filling at least some of. the smaller parts of the grooves and forming a string of substantially finished articles having oppositely disposed flash fins of different width and disposed in different planes in offset relation to each other.

5. The method of producing rail joint bars of the type described, which includes the steps of,

forming an elongated bar into a leader bar having substantially the same cross-sectional shape as is desired in the largest portion of the desired article and having a small ratio of thickness to width, passing such heated leader bar between two die rolls, the bar being of a width substantially equal to the greatest width of the roll grooves and of a thickness slightly greater than the height of the roll pass, completely filling said grooves at all places and overfilling at least some of the smaller parts of the grooves, and forming a string of substantially finished articles, each being unsymmetrical on opposite sides of all longltudinal planes therethrough and having flash metal extending from portions of the opposite edges thereof in horizontal planes offset with respect to each other.

A method of producing rail joint bars of the type described which includes the steps of die rolling a heated leader bar between a pair of die rolls having dissimilar matrix grooves and having radiallyofiset clearance spaces between the rolls on opposite sides of said grooves to form a string of connected joint bars, diagonally severing said string of bars into individual units, each having a round corner at each end, trimming the offset flash simultaneously from both sides of the bar units and then punching and straightening the bars.

7 A method of producing rail joint bars of the type described which includes the steps of die rolling a heated leader bar, having a small'ratio of thickness to width and being of a width substantially equal to the greatest width of the roll grooves and of a thickness slightly greater than the greatest height of the roll pass, between a pair of die rolls, forming said leader bar into a string of connected joint bars, each being unsymmetrical on opposite sides of all longitudinal planes therethrough and having offset flash metal extending from the opposite edges thereof, diagonally severing said string of bars into individual units, re-heating said units, trimming the offset flash simultaneously from both sides of the bar units and then punching and straightening the bars.

8. A method of producing rail joint bars of the type described which includes the steps of die rolling a heated leader bar, having a small ratio of thickness to width and being of a width substantially equal to the greatest width of the roll grooves and of a thickness slightly greater than the greatest height of the roll pass, between a pair of die rolls, forming said leader bar into a string of connected joint bars, each being unsymmetrical on opposite sides of all longitudinal planes therethrough and having ofi'set flash metal extending from the opposite edges thereof, diagonally severing said string of bars into individual units, reheating said units, trimming the offset flash simultaneously from both sides of the bar units and then punching, quenching and straightening the bars.

9. As an article of manufacture a string of substantially finished, connected, die rolled rail joint bars, each of said joint bars being unsymmetrical on opposite sides of all longitudinal planes therethrough, and having flash metal extending from the opposite side edges thereof, said flash metal being disposed in different planes, each of said joint bars having its greatest thickness and width at the central portion and tapering both in thickness and width toward both ends, substantially all flow lines in said bars extending longitudinally of the string without abrupt changes in direction.

10. As an article of manufacture a string of connected, die rolled rail joint bars arranged end to end, said bars being substantially accurate as to size and shape within finished rail joint bar tolerances, having flash metal of varying width extending from their opposite edges in different planes and being connected by sections having substantially the same dimensions as the ends of the individual Joint bars which they connect.

THOMAS N. SLOAN.

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