DK147499B - PROCEDURE FOR THE MANUFACTURING OF Wear-resistant rails - Google Patents

Description

147499

The invention relates to a method of the kind specified in the preamble of the claim.

From United States Patent No. 1,127,177 it is known to reinforce the particularly stressed places on rails by welding resistant metal alloys. In addition, the manganese welding material used herein is preferably welded to the head or side surfaces of the rails. In addition, US Patent No. 1,501,092 discloses a groove rail which is secured against premature wear by inserting a hard metal. The metal insert is placed here by rolling, casting or forging. From German patent specification No. 829 029 it is known that by automatic welding, worn tram rails can be manufactured. US Patent 147499 2 No. 2 186 967 relates to the repair of old rails, whereby a hard metal, namely ferritic-perlitic welding material, is welded to the running surfaces. This removes the worn parts of the rails.

It is known to wear welded rails and then grind them to re-fabricate the profile at the respective parts of the rail head. This work can be done both in the mounted and in the dismounted state of the rails.

In the past, it was the rule to weld worn rails in the assembled condition, where preferably, additives were used which, with respect to the rail material, had an increased wear resistance. However, it has been found that the previous working method is no longer sufficient for the requirements of the running and guiding surface of the reinforced driving. Furthermore, the elevated driving speeds require the most accurate profiling of the welded surfaces, which accuracy cannot be achieved in the assembled condition.

In addition, it has been found that an increased wear of the track rim of the wheels is obtained by using the known durable additives for this application welding. In this way, the driving characteristics of the vehicle are degraded and the expediency and economy of the remanufacturing of worn rails by application welding is questioned.

The object of the invention is to provide rails with particularly durable driving edges and lateral guide surface and / or running surface, respectively, where the rail is suitably already provided before mounting, ie a new rail, with particularly durable driving edges and lateral guide rails or / or running surface, or already laid , workshop-fitted with durable driving edges and finally mounted again. In this way, it is sought that the driving edges respectively the side guide surface and / or the running surface exhibit extremely high abrasion resistance, and thus the rail thus treated achieves a long life, and that the accurate and uniform rail profile required for good driving characteristics is again produced by accurate grinding.

In this way, it is appropriate that the necessary work is carried out in the most workshop and automatic way.

This object is achieved according to the invention by the fact that the method stated in the introduction is characterized by the characterizing part of the claim.

Preparation of the driving edge or the side guide surface and / or the running surface and the formation of the weld joint is conveniently done by grinding, planing, milling or according to the so-called ARCAIR method. This ensures that the rail is only slightly heated.

Of particular advantage is that when the square cut in the case of elaboration of the driving edge or side guide surface has a height b of 25 mm and a width a of 6 mm, respectively, the cut in case of preparation of the running surface has a height b of 5 mm and a width a of 20 mm.

These indications for the height and width of the cut-outs have been obtained through long practical experiments where the application of welding has been limited due to crack and fracture tendency at the rail. An excessive amount of welding material requires the application of too much heat, which creates tension in the rail which can cause cracks or breakage. An insufficient amount of welding material can lead to weld seam cracks and thus later cause crumbling or cracks.

The welding wire used for the invention or the welding band of the specified composition can be welded to the cold rail. The strengthening or hardening of the welded alloy is achieved by the wheel pressure at the run. A special rail heating may lapse.

4 147499

Preferably, the welding wire or welding band is welded according to the electric arc method, especially by powder welding.

Within the composition limits of the inventive alloy, an alloy is preferred whose carbon content is 0.55 to 0.60, silicon content 0.35 to 0.40, nickel content 3.60 to 3.70, manganese content 14.00 to 15.00 and the rest iron and manufacturing contaminants. A thread of this composition achieves an optimum of wear resistance, workability, ductility, deformation hardenability and guide properties.

To minimize the throw of the rail to the minimum, the rail is preferably either counter-heated during the bag welding or directed after the bag welding by counter-heating.

The finishing grinding after welding must give profile-rich goals.

It is clear from this requirement that a hand grinding is only conditionally suitable. Preferably, therefore, during grinding, a grinding means is used which slides back and forth over the overall length of the rail. By properly clamping the rail it is possible to grind the required rail profile by adjusting the grindstone in small steps.

Practical experiments have shown that a rail constructed according to the invention satisfies all the necessary requirements. Smooth and reproducible work has been achieved in the workshop execution of the individual workflows.

The drawing is intended to illustrate in detail the objects of the invention. Thus, in FIG. 1, at which the lateral edge and the running edge of the rail according to the invention are worked, with a denoted the width and with b the height of the profile machined weld seam; FIG. 2 shows a rail in which the method according to the invention has been carried out only at the side driving edge of the rail. a and b again have the same meaning,