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Pre-hardened Manganese Crossing

The complete central part of the crossing is cast in one block from high-manganese steel - it`s called common monoblock crossing "EHZ Centro MN13" pre-hardened.

This part corresponds to a monoblock crossing, with the only exception of the length of the fishing table. Closure rails are flash-butt welded to the four ends of the central block using a special flash-butt welding technique (intermediate piece welding). The bearing surfaces (seat of the plates) as well as the complete area of the running and head surfaces are milled and/or planed. The thus achieved manufacturing accuracy facilitates optimal wheel overrun and interchangeability of crossings on existing sets of plates.

Materials and quality inspection:

  • Rail in line with rails steel within turnout
  • Crossing: High-manganese steel (13% Mn) according to EN 15689
  • Visual and geometric check
  • Penetration test: Flash-butt weld
  • Radiography test: Prototypes
  • Mn13 casting according to EN 156

Benefits:

  • Can be thermit welded into the track
  • Requires low maintenance (no bolting)
  • Excellent wear resistance through work-hardening process of the high-manganese steel during operation
  • Optimised wheel overrun
  • Guaranteed interchangeability
  • Can be used for curved turnouts
  • Repair and built-up welding possible without preheating
  • Suitable for all types of rail fastenings
  • Reduced maintenance expenditure, due to prehardened running surfaces

Explosive pre-hardening of running surfaces

Process for increasing the surface hardness of manganese crossings. The hardness of the entire running surface of the crossing is raised through a targeted explosion hardening. In the area of the running surfaces and running head, blasting mats are placed and detonated. Through this procedure, the high-manganese steel is subjected to work-hardening, which corresponds in principle to the work-hardening process during train operation. This explosive hardening provides in advance some of the work-hardening which occurs during train operation and increases the hardness in the wheel contact area to 321 - 350 HB, depending on the requirement. As this procedure is applied not only in the overrunning area but the whole length of the crossing, a constant hardness curve is guaranteed.

Quality inspection:

  • Visual and geometric check
  • Penetration test - crack test: Complete running surface

Benefits:

  • Particularly in case of heavier loads, workhardening of high-manganese steel can lead to premature deformations in the overrunning area, which can be prevented by this procedure.
  • Significant improvement of wear resistance