US2167485A - Rail cooling - Google Patents

Description

July 25 1939.'v P. w. LEISNER El AL 2,1%?,435

RAIL COOLING Filed April 20, 1937 3 Sheets-Sheet 1 Egg. 1,25

.V/fjz/s figa] f .201 20 wenn? ,y ai

o di

L-fi if?. \`I`y 95 Base 0&0

RAIL COOLING Filed April 2o, 1937 n :5 sheets-sheet 2 RAIL COOLING Filed April 2o, 1937 s sheets-sheet s Patented July 25, 1939 UNITI-:o STATES PATENT GFFICE RAIL CGOLING Paul W. Leisner, Evanston, and Bernard M. Lockard, Oak Park, Ill. Y

Application April zo, 1931, serial No. 131,973

l 7 Claims. This invention relates to rails for railroad and like uses, and particularly to a new and improved rail construction, whichwill c ool substantially uniformly without substantialV bending or distortion and without undue damage or stress to the metal fibers.

Railroad rails are commonly cooled', as they leave the last `set of rolls at the `rolling mill in hot plastic condition, by placing them in the l0 air or atmosphere and subjecting them to the cooling action'thereoi.. Due tothe symmetry of the rail cross section about its vertical axis, the..

rail` may be depended upon to cool without lateral bending or distortion. However, because of a lack .of symmetry of the rail crosssection about Vits horizontal axis,'the head and base of the rail do not cool at the-same rate'. This leads .to vertical bending and distortion-of the rail I during the cooling process.y AMore particularly,

A" with :thepresent and conventional. form of rail,v

v:so tended that' the rail will substantially straighten itself out during the cooling operation. This willA be best understood byfreference to Fig. lof the accompanying drawings wherein the rail is shown Y in solid lines in the general curved shape which is given to it by this set of special rolls. Initially the entirerail structure is in hot relatively plas tic condition. As'cooling commenceajthe basev cools more rapidly* than the head, .and vconsequently, throughout the cooling, thebase is more 40 elastic and stronger Athan-the head. The base4 will contractwith its vfull elastic force'av'ailable to combat the efforts of 'thefhead `which Vareto enforce less contraction. Thefhead, `having less elastic strength, may emerge'inerely deformed,

-45 and this probably explainswhy -most ofY the cooled rails are stralghtas well as shorter (see,z

(Cl. 23S-125) quired to a ,far greater extent in the manufacture of rails than in the manufacture of symmetrically shaped rolled steel products, and itY can hardly be denied that gagging is harmful since it obviously requires stressing the bers be- Y yond their elastic in order to permanently strain the fibers.

Conicting internal stress and strain of the rail bers lead to these shatter cracks in the rail structures, which in turn result in transverse s- 1 y sures which frequently develop ln conventional rails as they are used in railroad tracks. These transverse ilssures were formerly the cause of many railroad disasters and now cause muchfexfpense for the detection and replacement of ns- 15 sured rails.

Itis a primary object of the present invention v y ltoproduce a vrail which will have improved cool#l ing characteristics. v It is a further object of the invention to prom duce a rail structure which will cool uniformly Vwithout bending or distortion and` without damage or stress to the metal fibers during the cooling operation.

vIt is a further object of the invention to pro" u duce a rail which will cool without bending or distortion, as aforesaid, but which does not sacriiice any of .the esentlal'characteristics of the A further object isl to produce a rail which, 30

Vduring and after cooling, will retain the shape vwhich it .is initially given as it leaves the shaping rolls, whereby to preserve the rail fibers and to limit gagging operations.

' Another object of the invention is to produce 35 a rail having the same depth of heat center in head-and base, though the head and base may be of different shape, and to demonstrate how the depth of heat center in the head andv base may be relatively proportioned to' produce any desired 40 cooling characteristic. d .A

Still another object of the invention-is to elimi-V nate the Ydilliculties heretofore discussed in connection with conventional rail. cooling.. v

Other objects' and advantages of the inven- 45 tion will be apparent from the following speciication,when taken'in connection` with the ac- "companyln'g drawings, wherein certain principles and preferred embodiments of the invention are illustrated.

` In the drawings, lwherein like reference numerals refer to like parts throughout:

Fig. 1 is a diagrammatic view, heretofore referred to, illustrating rail cooling according to conventional methods. L

Fig. 2 is an end view of a rail of conventional form.

Fig. 3 is an end view illustrating a rail to which certain features of' the invention have been applied.

Fig. 4 is an end view of a rail further improved in accordance with the principles of the invention.

Fig. 5 is an end view of a preferred embodiment.

Figs. 6 and 6A are partial end views of iurther preferred embodiments of rail heads.

Fig. 7 is a diagrammatic view illustrating the analysis of the invention applied to a rail head.

Fig. 8 is a similar view illustrating the analysis applied to the rail base.

Fig. 9 is 'a graphical illustration illustrating a comparison of heat center depths.

Fig. 10 is a detail view illustrating the manner in which the rail of Fig. 3 is changed to that illustrated in Fig. 4, and

Fig. l1 is a similar view illustrating the manner in which the rail of Fig. 4 is changed to that illustrated in Fig. 5.

Referring to Flg.- 2 of the drawings, there is illustrated 'a standard 131 pound A. R. E. A. (American Railroad Engineering Association) rail which has been selected for the purpose of analysis. However, it is to be understood that the principles of the present invention are applicable to rails of various shapes and constructions, and is not to be limited to the speciiic embodiments illustrated.

Reference -is now made to the diagrammatic views, Figs. 7 and 8, wherein the head and base respectively of the A. R. E. A. rail are illustrated. One of the manifestations or laws of heat confined withina body placed within a cooling atmosphere, is that the Yeiitexiox'heat.radiates to the atmosphere from the body surface, and the interior heat is conducted from the interior of the bodyto the surface to be radiated in its turn. Another manifestation of heat Js that in its conduction through the body it follows the path of least resistance, which, in s. homogeneous metal body, is'a straight line.` In Figs. 7 and 8 the heat center for the head and the bulky portion 'of the base are indicated by the letter C. Theseheat centers are the points furthest removed from the exterior surfaces of the rail, in point of heat escape, and their depths determine the ultimate cooling rates of the rail head and base. It will be seen that heat will escape from each heat-center through three paths of least resistance. Representing a quantity of ,heat in any given transverse plane at the heat center, by the length oi line T, this heat quantity in the case of the base will escape through two trapezoidal areas Il) and Il and a. rectangular area |2,and` in the case of the hea'd through three trapezoidai areas I 3, I4 and l5. 'I'he area I5 is slightly trapezoidal rather than rectangular due to the curvature of the Atop of the head. While'a rail has length as weil as height and width, the conditions of heat escape volumetrically within the rail will be proportional to the conditions of heat escape within any given transverse plane. Hence, for purposes of analysis it is necessary merely to consider the conditions within the given transverse plane. as in Figs. 'I and 8. Also, while the aforementioned trapezoidal and rectangular areas may not define all the possible channels of escape of heat from the heat center, they do represent the relative resistance against the facilities for escape of heat in the three principal directions and thus do accurately define the relative conditions of heat escape from the heat center. The length T is intended to be a derivative length, but has been magnified in the drawings for purposes of illustration.

The heat center will be that point from which heat may escape in the three principal directions of escape at the same rate. Inasmuch as the derivative quantity of heatv represented by the length of the line T escapes through the aforesaid rectangular and trapezoidal areas, and inasmuch as the escape from these areas is limited by their exposed or radiating surfaces, it follows that in the case of the rail base the location of the heat center C will be found by formulating the condition for the rectangular area I2 of heat radiating from its exposed surface I6 in the same space of time in which the trapezoidal area I0 of heat radiates from its exposed surface l1. Expressing this in mathematical relation, T divided by the rectangular area I2 is equal to S divided by the trapezoidal area. Il. A solution of this mathematical equation results in the following radiation equation, reference being made to Fig. 8 of the drawings:

Radiation equation:

S T Trapezodal area Rectangular area Rectangular area=D T; and Trapezoidal area:

In the foregoing equation R, which is the radius of curvature of the iillet connecting the rail web and rail base, is the only variable, inasmuch as the va'lues for A and B for any given rail design (for example, the 131 pound A. R. E. A rail) are dependent only upon the value of R and may be determined when R is known. Accordingly the depth of heat center D. which is the measure of the rate of escape of heat from the heat center, isA determined by the value of R.

For the head. referring to Fig. 7, substantially the same radiation equation may be made, except that the equation will be changed slightly due to the slight convexity of the top surface I 8 of the head. 'Ihe rail under consideration has a twentyfour inch tread radius which renders the area i5 of slightly trapezoidai shape. In the case of the head the radiation equation is as follows: Radiation equation:

30 Again it will be seen that the depth ofheai center D for the head, for any given rail design, is dependent solely upon the value of R,the radius of curvature of the fillet between thehead and the web, inasmuch as the values. oi A and B for such given rail design are dependent solely upon the value of R and are determined thereby.

A rail will cool without substantial bending if the head and thebase cool at the same rate. The rate at which the web cools is negligible. Inasmuch as the rate at which the rail head and base will cool is deter'm'ned primarilybythe depths of heat centers of these parts, it follows that the rail will cool substantially uniformly'and without sub.. stantial bending or distortion if the depths'gof heat centers are the same in' the head and base.

'f lrfthe standard ll paundAMhA-rail. selected for purposes of analysis, and shown iiFlg-"n the drawings, the'radius 20 between the web and base of the rail is three-quarters of an inch. The radius 2|. between the rail web and head is one' half inch.

By determining the depth of heat center D for the rail base, for different values of the illlet ra'- dius R. in accordance with the aforementioned equation, it will be found that the depth of heat center materially increases as the fillet radius between the web and base of the rail is decreased. This will best be understood by the graphical illustrations in Fig. 9,' For the standard 131 pound A. R. E. A. rail, the depth of heat center for thebase, using the standard three-quarter inch llet is 0.957 inch. whereas for a. radius of three-eighths of aninch the depth of heat center is increased to 1.017 inches. The heat depth would be further increased by a yfurther reduction-f of iillet radius, but a radius of three-eighths of an inch is probably the smallest practical and usable radius and hence will be here assumed for the purpose of this analysis as a limiting factor to heat center depth increase by llet change. By solving the depths of heat center for theirail head, for diierent values of the llet radius R,` it will be seen, also referring to Fig. 9, that whereas the depth of heat center for the standard 131 pound A. R. E. A. rail with its present one-half inch llet radius is 1.218 inches, this heat center depth may be decreased to 1.197 inches by increasing the fillet radius tothree-quarters of an inch. As will be seen from the graphical illustration, further increase in the fillet radius of the head results in no further decrease in heat center depth, and increase of the fillet radius beyond seven-eighths of an inch actually results in an increase of heat center depth. The improved rail having a three-eighths inch fillet radius 22 at the base and a three-quarter inch fillet radius 23 at the head is illustrated in Fig, 3. Y i' In the improved rail of Fig. 3 the cooling of the base has'been materially retarded and the cooling of the head materially increased. However, a further equalization of cooling rates is 'desirable to produce a rail` which .will cool uniformly and without bending or distortion. A `further reduction of the depth of heat center of the rail head may be effected by changing its shapein the manner illustrated in'Fig. 10.4 This change in design modies the A and B values of the head to facilitate cooling, but does notjsacriflce any of the desirable physical characteristics of the standard rail headdesign. In Fig. l'the rail head illustrated in Fig..3 is shown 'in'the'dotted outline 25. The solid outlinel '26 illustrates "a modified shape of head wherein an area. of metal 21 .ls 4'remmoved fromthe underneath'I part vof the he'adand arrangedat the side ofthe head in' an 'equalarea 28. The thus improvedrail he'adfis'illustr'ated in l Fig. 4. The head fillet radius l'23*'lias beenfpreiserved at three-quarters of an inch'..-However, this rail head, while retaining the most'desirable fillet radius, dueto its different shaping, will have diife'rent A and B values, though the. value :of the fillet .radius R remains unchanged. "Itfwill be found, by solving the radiationequationthatthe improved-rail head of'Fig. 4 hasawdepth of fheat center of'- 1.111 inches, la further'substantial reduction and equalization, 'towardif'lthe' 1.017' inch -1 depth of heat center of`the base. "I'his relation is illustrated -in the graphical view, Fig-9. The improved rail head of Fig. 4 has ilatsurfaces 30 (.729 inch wide) on Vthe underneath portions `of 'thehead substantially as great as those found in 11 of the drawings wherein the rail `head of Fig; 4 is shown inthe dotted outline 35 and the Vfurtherv improved rail vhead 'of Fig. 5 is indicated by the solid outline 36. The rail head 36 differs from the head 35 in that its widthhas beenincreasedon'ehalf inch, the vsame area of metal inthe headl being preserved. This widenedv h ead, Fig'. 5,'retains the surfaces of curvature 3l which correspond with the shaping of the wheel vflanges, but provides even wider flat surfaces 38 (.881 inch wide) for the seating of splice bars. The curvature of the llet 23 between the head and the rail web remains the most favorable three-quarter inch radius, but due to the changes in the A and B values in this shape of head, the depth of heat center will be found to be 1.031 inches, Fig, 9, substantially the same as the 1.017 inch depth of 'loy heat center of the base, for all practical cooling head being wider and thinner than a standard purposes. This rail may be depended upon to cool substantially uniformly without substantial bending or distortion or without undue stress to the metal ilbers during the cooling process, the

rate of cooling in the rail head and rail base being-` substantially the same. The wide rail head is fully as rugged and strong as conventional rail heads, and provides a. greater seating surface for the wheels. The essential characteristics of the rail design are all preserved.

In Fig. 6 there is illustrated a rail head substantially the same as that illustrated in Fig. 5. except that the tread or top surface 4I of the head is fiat rather than convex as in Fig. 5, no other changes being made. Such a rail head is well adapted for use with wheels having a cylindrical tread rather than the conventional conical tread. The depth of heat center of this rail head will be found 4to.l:e 0.9l1 inch, Fig. 9, or actually less than the depthV of heat center of the base, assuming the base fillet to be three-eighths of an inch as in the previously described embodiments. The cooling rates of the head and base are, however, substantially equal for all practical purposes and the' rail will cool uniformly and without distortion or stress to the metal fibers. In order to make the cooling rate of the base the same as that of the head, if desired, it will be seen, by reference to Fig. 9, that it is merely necessary to increase the base illiet slightly to substantially seven-sixteenths of an inch.

In Fig. 6A there is illustrated a rail head. which is the same as that illustrated in Fig, 6 except that the nllet radius 24 is so proportioned that the depth of heat center will be 1.017 inches, or the same as that of a rail base with a fillet or threeeighths of an inch. By reference to the cooling curve for the head, Pig. 9, it will be found ithi; fillet 24 will be substantially one-,half of an Ih accordance with the principles of the present invention, the rail may be so proportioned and shaped as to control or equalize the cooling rates oi the head and base. By retarding the cooling rail of like weight, the radius of the fillet connecting the rail web and head being increased above that of said standard rail, and the radius of the fillet connecting the rail web and base being decreased below that of said standard rail, whereby to provide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same general shape as that of said standard rail.

2. A rail for railroad and like uses, said rail having a head, a base and a connecting web, said head being wider and thinner than a standard rail of like weight, and the radius of the fillet connecting the rail web and base being decreased below that of said standard rail, whereby to pro vide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same general shape as that of said standard rail.

3. A rail for railroad and like uses, said rail having a head, a base and a connecting web, said head being reshaped as compared with the head of a standard rail of like weight to facilitate cooling, the radius of the fillet connecting the rail web and head being increased above that of said standard rail, and the radius of the fillet connecting the rail-web and base being decreased below that of said standard rail, whereby to provide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise oi substantially the same general shape as that of said standard rail. I,

4. A rail for railroad and like uses, said rail having a head, a base and a connecting web.

ksaid head being reshaped as compared with the head of a standard rail oi like weight to facilitate cooling, and the radius of the fillet connecting the rail web and base being decreased below that of 'said standard rail,` whereby to provide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same 'general shape as that of said standard rail.

f the base and accelerating the 60011.11*lr nf *he-having af lad, a base and a connecting web,

liet'.Tswrthattile'zoJoliiTtes'v are substantially equal, uniform cooling will be eii'ected so that the rail will not be bent or distorted during the cooling process and the metal iibers will not be strained'or injured. Gagging is limited. 'Ihe improved rail, moreover, does not sacrifice any of the essential physical characteristics of the railand in fact improves them. It retains the desirable characteristics of the head and base shaping.

While the foregoing analysis has referred specifically to a 131 pound A. R. E. A. rail, it is to be understood that the principles of the invention are applicable to rails in general having a wide variation in size and design. It is also to be distinctly understood that the foregoing theory and analysis has been set forth for the purpose of facilitating a better understanding of the principl'es of the invention, and that the invention, in its broader aspects, is in no sense'to be limited thereto or to the accuracy thereof.

Various changes may be made in the invention without departing from the principles thereof. The invention is accordingly not to be limited to the precise embodiments shown and discussed, but only as indicated in the following claims.

The invention is hereby claimed as follows:

l.. rail i'or railroad and like uses, said rail raving a head, a base and e. commenting web, said said head being wider and thinner than a standard rail of like weight. the radius of the llet connecting the rail web and head being increased above that of said standard rail to a size imparting a maximum cooling rate to the head, and the radius of the iillet connecting the rail web and base being decreased below that of said standard rail to a minimum practicably producible size, whereby to provide' a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same general shape as that of said standard rail.

6. A rail for railroad and like uses, said rail having a head, a base and a connecting web, said head being provided with a dat tread and being wider and thinner than a standard rail of like weight, the radius of the fillet connecting the rail web and head being increased above that of said standard rail, and the radius of the fillet connecting the rail web and base being de creased below that of said standard rail, whereby to provide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same general shape as that of said standard rail.

7. A rail for railroad and like uses, said rail having a head, a base anda connecting web, said head being wider and thinner than a standard rail of like weight, the fillet between the tread and the side of the head being shaped to conform to the ange illet of the Wheel With which the rail is designed to cooperate, the radius of the iiet connecting the rail web and head being increased above that of said standard rail, and the radius of the liet connecting the rail web and base being decreased below that of said standard rail, whereby to provide a rail having equalized cooling rates in the head and base thereof, and said rail being otherwise of substantially the same general shape as that of said standard rail.

PAUL W. LEISNER. BERNARD M. LOCKARD.

Images