AU600316B2

AU600316B2 - Process for producing frogs of railway switches

Info

Publication number: AU600316B2
Application number: AU79787/87A
Authority: AU
Inventors: Robert Pirker; Franz Rotter; Ernst Schrotter
Original assignee: Voestalpine AG
Current assignee: Voestalpine Railway Systems GmbH
Priority date: 1986-10-29
Filing date: 1987-10-15
Publication date: 1990-08-09
Anticipated expiration: 2007-10-15
Also published as: AT387049B; ZA877690B; PT85959A; NO167714C; AU7978787A; PL268345A1; PT85959B; EP0269603A2; FI874752A0; FI88518B; KR880005328A; BR8705751A; DK565687A; FI88518C; DE3767982D1; DD263482A5; CA1313610C; FI874752A; ES2021396B3; TNSN87119A1

Abstract

To manufacture frogs or rail sections in the wheel-running region of points with a highly wear-resistant wheel-running surface of a hardenable steel of composition C 0.01 to 0.05 % Si 0.01 to 0.2 % Mn 0.01 to 0.2 % Co 0 to 15 % Mo 1.5 to 6 % Ni 7 to 20 % Ti 0.1 to 1 % Cr O to 13 % Al 0 to 0.2 % B 0 to 0.1 % Zr 0 to 0.1 % the wheel-running surface is applied by explosive plating or electron beam welding or compound-rolling to a base body of readily weldable steel, especially a steel having not more than 0.24 % of C, not more than 0.04 % of P and S, not more than 0.65 % of Si and not more than 1.7 % of Mn.

Description

Australia 60 0 3 16 Form PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: ,Related Art:

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un t. t 0 iur 9 4 1i" Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: TO BE COMPLETED BY APPLICANT VOEST-ALPINE Aktiengesellschaft A-4020 Linz, Turmstrasse 44, Austria.

FRANZ ROTTER, ROBERT PIRKER and ERNST SCHROTTER.

CALLINAN AND ASSOCIATES, Patent Attorneys, of j4 U 48-50 Bridge Road, Richmond, State of Victoria, Australia.

Complete Specification for the invention entitled: "PROCESS FOR PRODUCINGFROGS OF RAILWAY SWITCHES".

The following statement is a full description of this invention, including the best method of performing it known to me:-* Note: The description is to be typed in double spacing, pica type face, in an area not exceeding 250 mm in depth and 160 mm in width, on tough white paper of good quality and it is to be inserted inside this form.

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:i 1A The invention refers to a process for producing frogs of railway switches or rail pieces located in the area of switches which is hit by the wheels, in which process a highly wear-resistant surface layer, which is travelled upon by the wheels, of an age-hardening steel of the composition: C, from 0.01 to 0.05%; Al, from 0 to 0.2%; Si, from 0.01 to 0.2%; B, from 0 to 0.01%; Mn, from 0.01 to 0.2%; Zr, from 0 to 0.1%; Co, from 0 to Mo, from 1.5 to 6%; fit SNi, from 7 to 15 Ti, from 0.1 to 1%; Cr, from 0 to 13%, with the balance being Fe, is applied onto a base body of well weldable steel.

From EP-A-105 864 there have already become known frogs, in particular frog tips of a steel for railway crossings or railway switches, the tip of 204 which or, respectively, their surface layer to be travelled upon by the wheels consists of the above-mentioned age-hardening steel. The stress exerted It I

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C CC on frog tips is particularly high when the wheel travels from the wing rail onto the frog tip and increases to an uncomparatively high degree with increasing axle load and, above all, with increasing travelling speeds, so that considerable deformations may occur at the frog tip, which deformations considerably reduce the life-time of the frog.

The material proposed in said EP-A was, according to this EP-Aapplied by building-up welding onto a base body of a standardized rail steel. The production of the whole frog 10 from such a highly wear-Ye steel is relatively expensive and the use of composite materials in combination res isi-o'a with such a wear-"esistent layer within the area of the gap over which pass the wheels, or, respectively, in the frog tip provides the possibility to connect without problems by welding at the connecting areas the base materials and, respectively, the standardized rail steel. Connecting the base materials by welding can be performed without special precautions by means of electrical flash butt welding machines. On account of the material of the wear-, 20 layer having, according to this known process for producing such frogs, been produced by building-up welding onto the base body of standardized rail steel, there resulted still the difficulty that no 1 "e-agnR3 thermal connection could be obtained without simultaneously reducing the ,re 0,r Vk quality. Application of wear -k materials by building- -up weldinghas always as a consequence intermingling with the base material and thus the formation of a.-more or. less 'p 3- *9 0 9*9 9 99 99 00 0 9 009 0*9* 0 09 00 9 9 *9 9 00* 0 90 9 0 0* 900 0 9 9909 0000* 9 9 99 0 9 00* 0 9 0*0009 0 distinct zone of ;4hoMoGcncG;iiz formed on account of the process. The advantages of the materials used for the wearri -gQn layer can thus not fully be utilized when working according to the known process for build-up welding.

SUMMARY OF THE INVENTION The invention now aims at providing a process of the iitially mentioned type, which allows to connect the material for the running surface with the base body homogeneously according to a thermal process, for thus increasing the 10 quality of the frog. In particular, the formation of an inhomogenous boundary layer between the different materials of the frog piece or rail piece shall be avoided. For solving this task, the process according to the invention essentially consists in that the surface layer travelled 15 upon by the wheels is applied by explosion plating or electron beam welding or mill plating onto the base body of well weldable steel, in pa~rt1'il-r base body containing 0.24 C, KO-O4 P Sd 0.65 Si and <1.7 Mn. The explosion plating is a principally 20 known technology for connecting equal or different materials along a metal surface. In the explosion plating process,, the connection results by a high pressure acting during a short time interval, whereby the metal surfaces are brought one relative to the other into distances of atomic dimensions by plastic deformation. As a rule, the melting temperature is not attained within the binding zone and therefor it is also spoken of a pressure welding process. The explosion

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v 1 ~u~ii 4 plating process provides the possibility to connect also metals,which would give rise to the formation of brittle phases in case of fusion welding. When selecting the material, proposed according to the invention, for the ces-,+0 ntwear -resi~tant layer, an intermingling zone is avoided when applying the explosion plating process and the advantages with respect to the wear-resistance of the running surface being travelled upon by wheels are reliably obtained.

A no\ oo 00 s Ana!L nu oe considerations apply for the mill plating.

The material selected for the wear -Qie nt layer Si_ the premises required for electron beam welding proposed as an alternative. Only materials of relatively low carbon content may be applied as a layer by electron beam welding and the use of the initially mentioned material for r\s Vcn the wear-Ca-is-..n layer provides the premises required for this purpose. Also when applying electron beam welding there results an only very thin connecting layer, so that n on- homoyenert iS

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r nmpngi1e 1 Ya are substantially avoided. In both cases, there remains a base body of well weldable steel, so that S 20 frogs can be welded to connecting rails without difficulties.

S Such frogs are, in contrast to known materials for frogs of particularly high wear resistance such as austenitic manganese steel as well as highly upgraded low-alloy steels, easily weldable with connecting rails and can thus be used 25 without difficulties in the consistently welded track of the modern railroad track. In comparison thereto, welding Sof the austenitic manganese steel and also of the frog tips of quenched and annealed low alloy steels with rail steels requires on account of the limited welding properties of such steels special precautions,which are relatively expensive.

A further improvement of the homogeneity of the thermal connection between the material used for the layer being travelled upon by the wheels and the base member can be obtained if, after having applied the layers to be travelled upon by the wheels and in particular after having applied 10 said layer by electron beam welding, an aging is effected at t 0 temperatures from 350 to 450 C, in particular 400 C. At Stemperatures of 400 there results the additional Sadvantage that simultaneously the gap filling welding bead is stress-annealed, noting that the base material itself is included within the group of well weldable materials.

By means of the mentioned processeslthere can be applied tin a preferred manner running surfaces having a thickness of 12 to 25 mm, in particular 15 to 20 mm.

As a whole, there is thus provided a frog and, 20 respectively, a wing rail, in which a well weldable base material of a favourable price is combined with a layer consisting of an extremely wear- Psistnt material and having a small volume and thus also a low weight to a composite material which can be used within the area to be 25 travelled upon by the wheels and being subjected to the highest stress. Thus it becomes possible to produce at favourable costs high-quality frogs which can without further r -I

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In particular when using for applying the wear- czistent layers and, respectively, the surfaces to be travelled upon by the wheels the explosion plating process one can do with a relatively low layer thickness of 15 mm, whereas the thicknesses applied in the electron beam welding process are approximately 20 mm for providing to a certain degree for a fire loss. When using the electron beam welding process, there has primarily to be considered the upper 10 limit of 0.03 carbon. This upper limit is of no importance when using the explosion plating process.

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Claims

1. A process for producing frogs of railway switches or rail pieces located in the area of switches which is hit by the wheels, in which process a highly wear-resistant surface layer, which is travelled upon by the wheels, of an age-hardening steel of the composition: C, from 0.01 to 0.05%; Al, from 0 to 0.2%; Si, from 0.01 to 0.2%; B, from 0 to 0.01%; Mn, from 0.01 to 0.2%; Zr, from 0 to 0.1%; Co, from 0 to it Mo, from 1.5 to 6%; Ni, from 7 to Ti, from 0.1 to 1%; Cr, from 0 to 13%, with the balance being Fe, is applied onto a base body of well weldable steel, wherein the surface layer I S travelled upon by the wheels is applied by explosion plating or electron beam 120' welding or roll plating onto the base body of well-weldable steel.

2. The process as claimed in claim 1, wherein said base body contains 4 0.24%C, <0.04%P, <0.0 4 ,0.65%Si and <1.7%Mn.

3. The process as claimed in claim 1 or claim 2 wherein, after having applied the surface layer to be travelled upon by the wheels and in particular after having applied said layer by electron beam welding, aging is effected at temperatures of 350* to 450 C.

4. The process as claimed in claim 3, wherein aging is effected at 400 C. -i I, C, -8- The process as claimed in any one of the preceding claims, wherein the surface layer to be travelled upon by the wheels is applied in a thickness of from 12 to 25 mm.

6. The process as claimed in claim 5, wherein said surface layer is from to 20 mm thick.

7. A process as claimed in claim 1, substantially as described herein.

8. Frogs of rail switches or rail pieces located in the area of switches which is hit by wheels, when produced by the process as claimed in claim 1. ft. ft f ft., ft ft *r ft ft. ft ft ft ft. I e. ft ft ft9 f DATED the 22nd day of May, 1990 VOEST-ALPINE AKTIENGESELLSCHAFT by their Patent Attorneys CALLINAN LAWRIE H. r 11 I ft ft f ft t ft t f f ft. ft ft 4 ft ft. f a a ft ft