US3558367A

US3558367A - Wheel cooling

Info

Publication number: US3558367A
Application number: US676274A
Authority: US
Inventors: Bernard John Eck
Original assignee: Amsted Industries Inc
Current assignee: Amsted Industries Inc
Priority date: 1967-10-18
Filing date: 1967-10-18
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26
Also published as: FR1586315A; GB1186149A; NO128207B; SE331292B; ES359013A1; DE1802188A1; CH480441A; BE722291A; DE1802188B2

Abstract

IN THE COOLING OF A STEEL RAILWAY WHEEL HAVING RELATIVELY THICK HUB AND TREAD PORTIONS AND A RELATIVELY THIN PLATE PORTION, IT IS IMPORTANT THAT UNDUE STRESSES ARE NOT SET UP IN THE PLATE PORTION, AND SIMULTANEOUSLY, THAT THE TREAD HARDNESS FOR GOOD WEAR QUALITIES WHILE THE HUB REMAINS SOFT FOR EASY MACHINABILITY. THIS PROBLEM IS SOLVED BY AIR COOLING THE WHEELS, THE HUBS OF WHICH HAVE BEEN COVERED BY AN INSULATING MATERIAL, UNITL THE HUBS ARE AT A TEMPERATURE BELOW THE CRITICAL TRANSFORMATION TEMPERATURES WHICH IS APPROXIMATELY 123*F.

Description

Jan. 26, 1971 B. J, ECK 3,558,367

WHEEL COOLING Filed vom. 18 19s? INVENTOR,

BERNARD J.ECL,

WWW

ATT'YS United States Patent 3,558,367 WHEEL COOLING Bernard John Eck, Elmhurst, Ill., assignor to AMSTED Industries Incorporated, Chicago, III., a corporation of Delaware Filed Oct. 18, 1967, Ser. No. 676,274 Int. Cl. C21d 1 70, 9/34 US. Cl. 148-3 3 Claims ABSTRACT OF THE DISCLOSURE In the cooling of a steel railway wheel having relatively thick hub and tread portions and a relatively thin plate portion, it is important that undue stresses are not set up in the plate portion, and simultaneously, that the tread hardens for good wear qualities while the hub remains soft for easy machinability. This problem is solved by air cooling the wheels, the hubs of which have been covered by an insulating material, until the hubs are at a temperature below the critical transformation temperature which is approximately 1230 F.

It has been customary in prior art wheel cooling arrangements to remove the cast steel whels from the molds, cool them slowly in a cooling oven to a range of about 1150-1200 F., torch cut the axle hole, heat the wheels in a normalizing furnace to approximately 1700 F., and then cool the wheels to approximately 1150 F., after which the hubs were force cooled by water sprays or air jets in order to obtain proper stress patterns in the plate portion of the wheels. The disadvantage of this procedure is that, while satisfactory stress patterns are obtained, the hub is of such hardness that it has very poor machinability.

If the entire wheels are air cooled other problems arise because the hub and tread are at approxiamtely the same hardness. If, for example, the rate of air cooling is such as to produce a tread with good wear qualities, the hub is difficult to machine. If, on the other hand, the rate of air cooling is such as to produce a machinable hub, the tread is too soft to provide wear qualities.

In the present arrangement a cast steel railway car Wheel is produced which has a tread sufliciently hard so as to have good wear properties while the hub is soft enough to be easily machined.

The proposed method of cooling wheels will be better understood 'with reference to the single figure of the drawing which is a cross-sectional view of a railway car wheel positioned on a cooling conveyor.

Referring to the drawing, the wheel 10 has a central relatively thick hub 12 and a relatively thick tread 14 interconnected by a relatively thin plate 16. The wheel is illustrated at that portion of the manufacturing cycle wherein an axle hole 17 has been torch cut and the wheel is being transported on a conveyor indicated schematically at 18.

In the preferred method of treating a cast steel railway car wheel, the wheels are moved from the mold and cooled to a temperature in the range of ll00 F. to 1200 F., after which an axle hole is torch cut through the wheel hub. The wheel is then heated in a normalizing furance to a temperature of approximately 1700 F. As each wheel emerges from the normalizing furnace, it is placed upon an insulating disk 20 which is positioned on slat conveyor 18. The insulating disk is preferably of refractory fiber glass construction but may be any ceramic insulating material which will withstand temperatures of up to 1700 F., or a fibrous insulating material such as asbestos. A second insulating disk 22 is placed on the upper face of the wheel hub. To provide ease of handling and to lend support to the fibrous insulating material, the

individual disks

20 and 22 may be supported by metallic plates 2.4 though this is not essential. The wheels are permitted to cool in air, with the wheel treads completely exposed but with the wheel hubs insulated so that the loss of heat from the hubs is retarded. Cooling in this manner is continued until the hub temperature is below the transformation temperature of the steel of which the wheel is cast. This transformation temperature will generally be approximately 1230 F. and, in practice, the wheels are cooled to a temperature within the range of approximately 0 F. to 1200 F. The foregoing method results in wheels having a preferred tread hardness in the range of approximately 265-300 B.H.N., and the hub hardness less than about 340 B.H.N.

An alternate method, not quite as effective as the preferred method described above, is to provide a conveyor having a continuous strip of insulating material suspended thereabove and having a width approximately equal to the hub diameter. The wheels are then slowly carried on the conveyor so that the hubs are always positioned immediately below the strip of insulating material. In this arrangement the wheel hubs are once again cooled at a slower rate than the wheel rims and the desired hardness characteristics are obtained. If desired, heating means in the form of a heating element, an induction coil or gas flames may be utilized in the strip to aid in retarding loss of heat from the Wheel hubs.

I claim:

1. A method of making a steel railway wheel, comprising the steps of forming steel while molten to the shape of a wheel, then cooling the wheel to a temperature value within the range of about 1200 F. to room temperature, then heating the wheel in a furnace to a normalizing temperature of about 1700" F., and as the wheel emerges from the furance placing a non-metallic insulating disk upon each face of the wheel hub, then cooling the wheel in air until the hub portion has cooled to a temperature of at least about 1200 F.

2. The method of claim 1 wherein the insulating disk comprises refractory glass fibers.

3. The method of claim 1 and including the step of first providing each insulating disk with a metallic support.

References Cited UNITED STATES PATENTS 1,071,012 8/1913 Unger 14-146 1,859,623 5/1932 Gregg l48l49 2,029,819 2/19'36 Gregg et a1. 148l49X 3,043,317 7/1962 Hursen 266-6 3,370,993 2/1968 Carpenter et al. 14813.1

CHARLES N. LOVEDL, Primary Examiner US. Cl. X.R. 148-146, 149

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3558367 Dated January 26, 1971 Inventor(s) Bernard John Eek It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 22 change "340B.H .N. to --240 B.H.N.

Signed and sealed this 29th day of February 1972.

(SEAL) Attest ROBERT GOTTSCHALK ELWARD ILFLETCHER, JR.

Commissioner of Patents Attesting Officer