US3480072A - Core portion of a railroad frog and method of making the same - Google Patents

Description

Nov. 25, 1969 A. HEIM r-:T AL. 3,480,072

CORE PORTION 0F' A RAILROAD FROG AND METHOD OF MAKING THE SAME Filed may 14, 196e Fig. 2

Inventors United States Patent C) 3,480,072 CORE PORTION OF A RAILROAD FROG AND METHOD OF MAKING THE SAME Armin Heim and Friedhelm Hillebrand, Osnabruck, Germany, assignors to Kloeckner-Werke AG, Duisburg,

Germany Filed May 4, 1966, Ser. No. 547,563 Int. Cl. E01b 7/12; B22d 19/02 U.S. Cl. 164-93 5 Claims ABSTRACT F THE DISCLOSURE In a railroad frog, in combination, a core portion having spaced end portions and having intermediate said end portions and spaced therefrom a center portion, said center portion consisting essentially of manganese steel and said end portions consisting essentially of a weldable steel; and intermediate portions interposed between said center portion and each of said end portions, said intermediate portions consisting predominantly of a mixture of said manganese steel and said weldable steel and said intermediate portions being fused to said center portion and said end portions. The railroad frog of the invention permits easy welding to adjacent rail portions.

The present invention relates to a core portion of a railroad frog and to a method of making the same and, more particularly, the present invention is concerned with a railroad frog core portion of great resistance to wear and tear which, nevertheless, can be easily welded to adjacent rail portions.

With respect to resistance to Wear and tear, core portions of railroad frogs which consist of hard manganese steel lwill give the best results. These core portions are preferably made of steel containing between 12 and 14% of manganese and will have an elongation of about 40%. Due to the high degree of elongation there will be a high degree of cold deformability so that with core portions of hard manganese steel as the load supporting surface a strength of between 140 and 150 kg./mm.2 can be obtained.

'Core `portions of railroad frogs consisting of hard manganese steel thus satisfy all requirements which practically may be made on the material and can be operated under all practical loads and, from this point of View, core portions of hard manganese steel would be most desirable. However, such core portions of hard manganese steel are used only to a very limited extent, due to the fact that it is not possible to yform a satisfactory butt-weld between such core portion of hard manganese steel and adjacent rail portions. This is at least partly due to the fact that during the -water treatment of manganese steel hardening cracks are formed. Such water treatment, as is well known to those skilled in the art, is generally required in order to obtain a hard manganese steel with the desired high resistance against wear and tear, and is usually carried out, for instance in the case of Hadeld steel, by quenching the steel having a temperature of more than 900 C. with water. Many attempts have been made to so modify the treatment of the steel and the welding .process so that satisfactory welding of hard manganese steel to rail steel could be achieved, however, up to now, apparently these attempts did not give any satisfactory results.

It is therefore an object of the present invention to overcome the above-discussed difficulties and disadvantages.

It is a further object of the present invention to provide a core portion of a railroad frog which includes a center portion consisting essentially of hard manganese steel,

which core portion, nevertheless, can be welded to rails of conventional weldable rail steel.

It is another object of the present invention to provide a method for producing the above-described core portion of a railroad frog in a simple and economical manner.

Other objects and advantages of the present invention will become apparent from a further reading of the description and the appended claims.

With the above and other objects in view, the present invention contemplates in a railroad frog, in combination, a core portion having spaced end portions and having intermediate the end lportions and spaced therefrom a center portion, the center portion consisting essentially of manganese steel and the end portions consisting essentially of a `weldable steel and intermediate portions interposed between and integral with the center portion and the respective end portion, the intermediate portion consisting predominantly of a mixture of the manganese steel and the weldable steel.

Preferably, the manganese and carbon content of the intermediate portions of the railroad frog core portion will be lower than that of a mixture formed of equal proportions of the manganese steel of the Center portion and the weldable steel of the end portions.

The present in-vention is also concerned with a method of producing a railroad frog, which method comprises the steps of casting in a center chamber of a mold, the latter corresponding to the shape of the center portion of a railroad frog, a manganese steel material, casting into opposite end portions of the mold spaced from the center portion thereof a wel-dable steel material, establishing communication between the chambers permitting the cast materials prior to solidication thereof to form intermediate zones between the center portion and the end portions and permitting the cast materials in the mold to solidify.

Preferably, the composition of the manganese steel material and of the weldable steel material, as well as of the ferrous separators in the mold will be so chosen, in conjunction with the casting temperatures of the manganese steel material and the weldable steel material, that in the intermediate zones interposed between the center portion and the respective end portions of the core of the railroad frog a steel material will be formed having a manganese and carbon content which is lower than that which would be obtained by mixing equal proportions of the manganese steel material and the weldable steel material.

In other words, the abovediscussed problems are solved according to the present invention in a simple, technically and economically satisfactory manner by providing that the center portion of the core of the railroad frog is to consist of hard manganese steel, whereas the lateral end portions consist of an easily weldable steel, and by having interposed between the end portions and the center portion a mixing zone formed of a mixture of the steel materials of the center portion and of the end portions, plus the material of the ferrous separators of the compound mold in which the compound casting of the entire core portion of the railroad frog is carried out.

According to the present invention, the hard maganese steel is cast in the center portion of the compound mold and weldable steel is cast in the two lateral end portions of the mold, and the hard manganese steel and the weldable steel ow into interposed mixing zones which are separated from the center portion and the respective end portion by at least two perforated or corrugated ferrous separating walls or sheets which initially dene between themselves the respective mixing zones.

`Compound casting, per se and including ferrous separator walls, is well known to those skilled in the art and described for instance in U.S. Patent 1,710,931.

The composition of the hard manganese steel preferably is as follows: Y

Carbon Between 0.9 and 1.3 Silicon Between 0.2 and 0.6% Manganese Between 12 and 14%. Nickel Between 4 and 6%. Iron Between 82.9 and 78.1%.

Ihe iweldable rail steel preferably will be within the range of the following compositions:

Carbon Between 0.4 and 0.7%. Manganese Between 0.8 and 2% Silicon -Between 0.4 and 0.70%. Iron Between 98.4 and 96.6%.

The ferrous separating walls which, between themselves on each side of the core portion, define the mixing or intermediate zone in which a steel com-position will -be formed of a mixture of the maganese steel and of the weldable rail steel, preferably have a composition within the following ranges:

Carbon Between 0.05 and 0.03%. Manganese Between 0.20 and 0.6%. Silicon Between and 0.5%

Iron Between 99.75 and 99.86%

The novel features which 4are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and `advantages thereof, will be best understood lfrom the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a schematic, longitudinal, cross sectional view of a core portion of a Irailroad frog in kaccordance with the present invention; and

FIG. 2 is a plan View of the lcore portion of the railroad frog illustrated in FIG. l.

Referring now to the drawing, it will be seen that in its center portion 1 the core portion is formed of hard manganese steel. Adjacent to the center portion will be found intermediate zones 2 and 2 which schematically are indicated as limited by broken lines 3 and 3'. Outwardly of intermediate zones 2 and 2' will be found end portions 4 and 4' which preferably consist of a butt weldable rail steel having a minimum strength of 90 kg./-mrn.2. The composition of the intermediate zones 2 and 2', as described above, is formed by the mixture of the hard manganese steel and the weldable steel which flows during casting of the core portion into the mixing zone formed by the separating walls described further above, and includes the material of the separating walls.

The length of the individual portions of the core portion of the railroad frog, particularly the length of the center portion of hard manganese steel will depend primarily on the inclination of the core portion of the railroad frog. Generally, the length of the center portion formed of hard manganese steel will be between `about 1800 and 3500 mm. Preferably, the length of the mixing zones which are interposed between the center portion and the end portion will be between and 200 mm. The thickness of the individual separating sheet or walls which between themselves define the mixing zones in the compound mold, generally will be between 2 `and 20 mm., :and the perforations of the separating sheet generally will amount to about 40% of the area thereof. The weldable or butt weldable end portions should be as short as possible and will serve, as described `above to be connected by butt welding to ladjacent rail portions.

It is preferred, -according to the present invention and as described above, to cast the core portion of the railroad frog in a compound mold including 2 ferrous Separating sheets on each side of the center portion into which the hard manganese steel is to be cast so that between the two separating sheets on each side of the center portion a mixing chamber or zone is defined. In this manner, it is possible to obtain a well-defined and relatively wide zone of transition between the hard manganese steel of the center portion and the weldable steel of the two end portions. A similar result can also be obtained with a corrugated single separating wall or -a zigzag shaped separating wall on each side of the center portion, whereby the amplitude of the corrugated sheet should not -be greater than the distance between the two perforated separating sheets defining a mixing zone as described further above.

By utilizing a system of separating walls or sheets in the compound mold so as to form one or several mixing zones, the advantage is obtained that the composition of the steel in the mixing zone, i.e. intermediate 'the hard manganese steel portion and the weldable steel portion can be easily controlled. It is Adesirable to obtain in the mixing zone a steel material containing a relatively small proportion of manganese and carbon, in order to irnprove the tenacity of the steel in the intermediate or mixing zone. The composition of the steel in the intermediate or mixing zone can be controlled by the composition of the separating sheets and adjustment of the same to the casting temperature of the hard manganese steel on the one hand and the weldable steel on the other hand. Generally it is preferred to have smaller or less perforations in the perforated separating sheet adjacent the hard manganese steel casting center zone than in the perforated sheet adjacent the outer or end zone in which the weldable steel will be cast, so that a larger proportion of the weldable steel will enter the mixing zone.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of railroad frogs differing from the types described above.

While the invention has been illustrated and described as embodied in la core portion of a railroad frog, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the f standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a method of producing a railroad frog, the steps of casting in a center chamber of a mold, the latter corresponding to the shape of the center portion of a railroad frog, Ia manganese steel material, casting into chambers corresponding to the shape of the end portions of the railroad frog and at opposite end portions of said mold and spaced from the center port/ion thereof a weldable steel material; establishing communication between said chambers permitting said cast materials prior to solidification thereof to form intermediate zones between said center portion and said end portions consisting essentially of a mixture of said manganese steel material and of said weldable steel material; Iand permitting the cast materials in said mold to solidify.

Z. A method as defined in claim 1, wherein said end portions are separated from said center portion by pairs of ferrous separators defining between themselves respective intermediate zones, said separators consisting of a material adapted upon casting of said manganese steel and weldable steel materials to form integral steel bodies therewith, and wherein the composition of said materials and the casting temperatures are so chosen as to form in said intermediate zones a steel material the manganese and carbon content of which is lower than that of a mixture of equal proportions of said manganese steel and weldable steel materials.

3. In a railroad frog, in combination, a core portion having spaced end portions and having intermediate said end portions and spaced therefrom a center portion, said center portion consisting essentially of manganese steel and said end portions consisting essentially of a weldable steel; and intermediate portions interposed between said l0 center portion and each of said end portions, said intermediate portions consisting predominantly of a mixture of said manganese steel and said weldable steel and each of said intermediate portions being fused together with said center portion and said end portions in the form of one overall compound casting by the method of claim 1.

4. A railroad frog as defined in claim 3, wherein the manganese and carbon content of said intermediate portions is lower than that of a mixture of equal proportions of said manganese steel and said weldable steel.

5. The railroad rog of claim 3, wherein the manganese steel has the following composition:

Carbon Between 0.9 and 1.3%. Silicon Between 0.2 and 0.6% Manganese Between 12 and 14%. Nickel Between 4 and 6% Iron Between 82.9 and 78.1%.

Vand the weldable steel has the composition:

Carbon Between 0.4 and 0.7%.

Manganese Between 0.8 and 2%.

6 Silicon Between 0.4 and 0.70% Iron Between 98.4 and 96.6%

References Cited UNITED STATES PATENTS 728,217 5/1903 Falk 164-80 X 694,731 3/1902 Cosgrove 164-93 415,173 11/1889 McCarty 164-93 473,466 4/1892 Kennedy et al 164-93 1,031,506 7/1912 Angerer 246-460 1,765,856 6/1930 Werthmann 246-460 1,241,899 10/1917 Armstrong et al. 246-460 FOREIGN PATENTS 1,317,493 1/1963 France.

946,606 1/ 1964 Great Britain.

OTHER REFERENCES ASM Metals Handbook, 8th ed., vol. 1, copyright 1961 by the American Society for Metals, pp. 841-842 relied on.

AIRCO Catalog 1313, printed in U.S.A. by Air Reduction Co., Inc., pp. 47, 48, 53 and 68 relied on, October 1959.

I. SPENCER OVERHOLSER, Primary Examiner V. RISING, Assistant Examiner U.S. Cl. X.R. 246-461, 468

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