US2648750A

US2648750A - Method of making a brake beam

Info

Publication number: US2648750A
Application number: US73629A
Authority: US
Inventors: Loren L Whitney
Original assignee: American Steel Foundries
Current assignee: American Steel Foundries
Priority date: 1949-01-29
Filing date: 1949-01-29
Publication date: 1953-08-11
Anticipated expiration: 1970-08-11

Description

1953 L. L. WHITNEY 2,648,750

METHOD OF MAKING A BRAKE BEAM Filed Jan. 29, 1949 @MHMW 4/ j INVENTOR.

' A Joye/z l. Z/fizizzg Patented Aug. 11, 1953 METHOD OF MAKING A BRAKE BEAM Loren L. Whitney, Hammond, Ind., assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application January 29, 1949, Serial No. 73,629

3 Claims. 1

This invention relates to the welding of truss structures, such as truss type brake beams, which are subjected in service to severe stresses, primarily compressive, along the inboard edges of the weld metal connecting the tension and compression members at the ends of the beam.

A primary object of the present invention is to devise a novel brake beam and welding method for reducing stress concentrations of the abovedescribed type.

A more specific object of the invention is to Weld the tension and compression members of the beam in such a manner as to deposit the weld metal in the form of a fillet to prevent stress concentrations therealong.

A further object of the invention is to supply molten weld metal to feed the cooling weld and prevent formation of shrinkage cracks and sinkholes therein.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

Figure 1 is a fragmentary plan view, partly in central horizontal section, of a welded brake beam fabricated according to the invention;

Figure 2 is a rear elevational view of the structure shown in Figure 1 Figure 3 is an end elevational view, partly in section, on the line 3-3 of Figure 1; and

Figure 4 is a welding diagram illustrating the steps by which the novel beam is welded.

V Describing the invention in detail and referring first to the brake beam structure shown in Figures 1 to 3, the beam comprises a compression member, generally designated 2, having a rear web 4 and top and

bottom webs

6 and 8 respectively, the rear web being slotted as at IU from the outboard extremity thereof. A brake head is fragmentarily indicated at [2 and comprises top and bottom ribs [4 and I6 and a portion l8 inboardly thereof sleeved or telescoped within the compression member 2 between the top and bottom webs 5 and 8 thereof. The brake head portion l8 comprises top and bottom walls and 22 respectively, defining a slot 24 (Figure 3) therebetween aligned with the slot l0 of the compression member web 4. The brake head portion 1 8 also comprises a wall 26 connected between I the top and

bottom walls

20 and 22 and having a diagonal substantially flat surface 28 adapted to snugly engage a tension member 30 which, as best seen in Figures 2 and 3, is confined within the slot 24 between the top and bottom walls 20 and '22 and is also confined between the surface cated at 50 in Figure l.

2 28 and a parallel surface 32 of a brake head wall 34 connecting the top and

bottom walls

20 and 22, as best seen in Figure 3.

The brake head I2 also comprises a portion 36 outboardly of the vertical ribs l4 and l t, the portion 36, as best seen in Figure 2, having approximately the same depth as that of the compression member and being provided with a socket 38 receiving the outboard end of the tension member 30, as best seen in Figures 1 and 2. The socket 38 comprises a diagonal surface 40 approximately coplanar with the surface 32 and, as best seen in Figure 2, comprises top and bottom surfaces 42 and 44 respectively, confining the top and bottom margins of the tension member 30.

The outboard end of the tension member is sheared as at 46 to afford a rear edge arranged diagonally with respect to the compression member wall 4 and thereby defining the inner extremity of a pocket or cavity defined by the slots l0 and 24 and the tension member at, said pocket being adapted to contain weld metal indicated at 48 in Figure 1 fusing the tension and compression members and the brake into an integral truss structure.

As best seen in Figure 1, the weld metal at 48 is formed with a fillet 50 between the compression member web 4 and the tension member 30. This construction prevents the concentration of stresses primarily compressive in character, as the brake head I2 is applied in service to an associated railway wheel and axle assembly (not shown) in a manner well known to those skilled in the art. A primary feature of the present invention resides in the discovery that welded truss type beams, such as those heretofore known in the art, have inadequate resistance to fatigue, due to concentration of compressive stresses in the inboard edge of the weld metal connecting the compression and tension members. This difficulty has been remedied by providing a fillet in the inboard edge of the weld metal, as indi- Beams of this type have disclosed remarkable resistance to fatigue such as that encountered in repeated applications of the beam in railway service to decelerate an associated wheel and axle assembly (not shown).

Referring now to Figure 4 which is a Welding diagram illustrating the novel method by which the brake beam shown in Figures 1 to 3 is fabricated, it may be noted that the weld 48 may be of any conventional arc type but is preferably of the type disclosed in United States Letters Patent No. 2,043,960, issued June 9, 1936, to Union Carbide and Carbon Corporation. The welding 3 technique disclosed in the above-identified patent as applied to a brake beam such as that shown in Figures 1 to 3, comprises connecting the beam parts, which are steel, to one terminal and a weld electrode to another terminal of a conventional voltage supply. The electrode is positioned within the slots Ill and 2s and a readily fusible conductor, such as a piece ofsteel wool, may be placed between the electrode and the tension member an to establish an arc. conductor may be eliminated by momentary use of a high frequency current to establish l}h Q' arc. The slots Iii and 24 are filled with a prefused powdered welding composition of'the characteristics described in the patent, the composition being electrically conductive when molten and being readily fusible at the temperature. deyjeloped upon closing of the electrical circuit through the.

brake beam and electrode.

The novel welding process of the present invention. 'is. initiated, as will be understood reference to Figure 4, by closing the welding circuit with the electrode extending into the slots it and 24' at the point indicated by" the numeral 52 approximately midway between theinboard and t,

outboard ends of the. slots and the electrode is passed in the direction of the arrows irom'point 52 to 'the inboard end of the slot at a rate 'of speed accommodating a layer of weld metal from the'point 52 to the point 55 which is at the inboard end oii'th e slots. The electrode is then held stationary without breaking the welding circuit to establish a plug weld at s for a brief period of time'preferably of the order of; three to six seconds. The welding" circuit is then broken for a brief pause 'of-the order of threeto six seconds While the electrode is moved outboardly to a point indicated'at 56 in Figure 4, which point is substantially outboard the inboard ends of the slotsfAfter: the pause, the welding; circuit is again established with'the electrode at point 56 from'whichthe electrode is moved in the direction" of the arrows to the outboard end of the slots at a 'rate of speed accommodating a second layer of weld metal on top cf-fthe first'andfiising therewith. Th'enthe welding circuit'i's' again broken for. a brief pause of the order or three to siirsecond w-hile the electrode dwells at 'th eoutboar-d" ends (if-the slots, and after this second pause, thethird passer the electrode is initiated by establishing the'welding circuit, with "the electrode at the'outboard end of the slots, and moving the electrode in the direction of; the arrows 58. to the'inboard end of the slots at a rate of speedaccoinmodating a third layer of weld metal depo'sited on' top of the second layer.

After the electrode, at the end of its third pass, hasreached the inboard ends of the slots, the; welding circuit is again broken for a brief pause of the order of three to six seconds and thereafter the circuit is again closed, with the elcctrodeat the inboard end of the slotsfrom which it is moved infthe direction of the arrows 60 on the fourthor last pass at a'rate of speed accommodating a fourth layer of weld metal d epo'sited 'ori top of thejthirdlayer. The last pass of tl'ie"electrodeisjprererably terminatedapproximately midwayf intermediate the inboard and outboard ends er the slots, and the circuit is again broken Jforapause ofjthe order of three to 'six seconds whereupon the circuit is L again closed for a period of about three tosix -seconds with the electrode stationary intermediate the However, the,

ends ofthe slots t o provide a Weld puddle indi cated at $2. The circuit is then broken and preferably after a pause of the order of three to six seconds, the circuit is again closed for a period of about three to six seconds with the electrode stationary to provide another Weld puddle intermediate the ends of the slots, as indicated at 64 (Figure 4) It may be noted that the, plugv welds. following the fourth pass or the electrode, which is in effect a half "pass from the inboard ends of the slots to a point approximately intermediate the ends thereof, afiords a pool of molten weld metal constitutingareservoir adapted to feed the cooling weld to prevent formation of shrinkage cracksthe rein. It may be noted that the structure s'hown in Figures 1 to 3 is normally welded with the slots [0 and 24 facing upwardly and thetension member surface 46 at the bottom of the, slots so that the reservoir of molten metal provided by the plug welds at 62 and 64 feeds downwardly by force of gravity to the cooling weld metal.

Thepause at the-end of each passpermits the weld metal to partially cool, and the-succeeding passfills in any cracks which may develop in the cooling weld metal. The plug weldsat the end of the last pass provide a reservoirof molten metal which as above described prevents forma- 'tion or cracks in the -cooling weld-metal.

The above-describedvv process. results in a weld which shows no layers under microscopic-examination. but is a homogeneous solidaweldgwithout the slightest-trace of'shrinkage cavities -onsink holes. formed: during: cooling of:- theweld metal. Furthermore, this process provides-afil-let, indicated at 583 in Figures. lands,- preventing concentration of compressive stresses in the-inboard edge of. theweld metal. during application of the beam in service.

It may be noted that the engagement of the tension member. with. thediagonal" surf aoes2'8', 32, and ie. and with the. surfaces 42 and-'44 and the complementary. flat surfacesof the brake-head walls 26 and 2.2 ..prevents escapeiof the-molten weld metal during the. welding operation.

I clainif. w

l. -#"einethod .ofwelding a brake-beam -tension member .within. relativelytelescoped brake-head and compression membersdefining an elongated cavitywith the rearsurfaceof said tension member, said methodcomprisingpositioning an=electrode in. said Cavity at. appoint. between its-eends, then closing. an electrical welding circuit through said: electrode .andndepo'siting a layer; of-weld metal. in the cavity. by passingtheelectrode lengthwise of :the. cavity to approximately the-in-- board. end thereof, thenwholding the electrode stationaryv at saidzinboardend of saidcavityfor a period. of time. of; the order of at least; three secondsto form a. puddle-Hot weld me-talat the inboard end ofl said cavity, then breaking said circuit: and: moving the. electrode outboardlyg-in said..cay;ity to apoint bctWeen-thefirst mentioned point.v and the. inboards. end of the slot, :themestablishing another. electricali Welding circuit through. the electrodes and depositing another layer. of weld metal on thetop of; the first mentioned. layer by. passing. the. electrodebutboardly of said cavity. lengthwisethereof-to .a point outboardly of; the first mentioned point,-thenbreaking thelast mentioned"circuit for a time interval of 1 the order of rat rleast three-seconds; then-closing another electrical .weldingcireuit*throu-gh the ele ctrode...and. depositing another layers-of weld m tal. on. t p, of. the ,first ,;two layers by massin he. cle trp ez e etbwiselaf .1.5 .a Yi Y;-1ZQ anoint inboardly of the second mentioned point, then breaking the last mentioned circuit for a time interval of the order of at least three seconds without substantially moving said electrode, then closing another electrical welding circuit through said electrode and depositing a top layer of weld metal in said cavity by moving the electrode lengthwise of the cavity to a point between the inboard and outboard ends of the cavity, then breaking the last mentioned circuit for a time interval of the order of at least three seconds, and then, before the layers have solidified, establishing another electrical welding circuit through said electrode while holding the electrode substantially stationary at approximately the last mentioned point until a weld puddle has formed at said last mentioned point to feed shrinkage in the layers of weld metal.

2. A method of welding a brake beam tension member to brake head and compression members, at least one of which defines an elongated cavity with said tension member, said method comprising positioning an electrode in said cavity, then closing an electrical welding circuit through said electrode and depositing a layer of weld metal in the cavity by passing the electrode lengthwise of the cavity to approximately the inboard end thereof, then holding the electrode stationary at at said inboard end of said cavity for a period of time of the order of at least three seconds to form a puddle of weld metal at the inboard end of the cavity, then breaking said circuit and moving the electrode outboardly in said cavity lengthwise thereof to a point outwardly of the inboard end of said cavity, then establishing another electrical welding circuit through the electrode and depositing another layer of weld metal on top of the first mentioned layer by passing the electrode outboardly in said cavity lengthwise thereof, then depositing another layer of weld metal on top of the first two layers by passing the electrode lengthwise of said cavity to a point inboardly of said first mentioned point, then depositing another layer of Weld metal in said cavity on top of the first three layers by moving the electrode lengthwise of the cavity outboardly thereof, and then, before the layers have solidified, holding the electrode between the inboard and outboard ends of the cavity until a weld puddle has formed to feed shrinkage in the layers of weld metal.

3. A method of welding a brake beam tension member to brake head and compression members, at least one of which defines an elongated cavity with an edge of said tension member, said method comprising positioning an electrode in said cavity, then closing an electrical welding circuit through said electrode and depositing a layer of weld metal in the cavity on top of said edge by passing the electrode lengthwise of the cavity to approximately the inboard end thereof, then holding the electrode approximately stationary at said inboard end of said cavity for a period of time of the order of at least three seconds to form a puddle of weld metal at said inboard end of said cavity, then breaking said circuit and moving the electrode outboardly in said cavity lengthwise thereof to a point outboardly of the inboard end of said cavity, then establishing another electrical welding circuit through the electrode and depositing another layer of weld metal on top of the first mentioned layer by passing the electrode outwardly in said cavity lengthwise thereof, and then depositing another layer of weld metal on top of the first two layers by passing the electrode inboardly lengthwise of said cavity to a point inboardly of said first mentioned point.

LOREN L. WHITNEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 461,776 Alley Oct. 20, 1891 1,290,091 Cole Jan. 7, 1919 1,290,093 Cole Jan. 7, 1919 1,293,871 Murry Feb. 11, 1919 1,634,995 I-Iuntoon July 5, 1927 1,810,005 Burnish June 16, 1931. 1,939,732 Stresau Dec. 19, 1933 2,141,021 Rooke Dec. 20, 1938 2,177,927 Hodge Oct. 31, 1939 2,239,186 Anderson Apr. 22, 1941 2,262,212 Stone Nov. 11, 1941 2,356,720 Aurien Aug. 22, 1944 2,371,823 Jackson Mar. 20, 1945 2,416,379 Cohn Feb. 25, 1947 2,473,002 Baselt June 14, 1949 2,500,232 Baselt Mar. 4, 1950 2,517,747 Whitney Sept. 18, 1950 FOREIGN PATENTS Number Country Date 618,890 France Dec. 21, 1926 OTHER REFERENCES The Welding Engineer, Aug. 1944, page 37. Procedure Handbook of Arc Welding Design and Practice, 8th ed., 1945, pages 34 and 166,