HAVLÍČEK Petr DT - Výhybkárna a strojírna, a.s.

Spoluautoři ZBOŘIL Josef

The procedure and application of explosive hardening technology of the railway turnout frogs made of high alloyed austenitic manganese steel - Hadfield steel - is the subject of the article. As far as this steel with its chemical composition carbon (1,2%), manganese (12%), silicium (0,45%) comprise the ability of the strain hardening, they are the operational (running) areas explosive hardened by means of plastic explosive prior to installation in the track. The strain hardening induced by the impact wave pressure resulted into increase of the frog surface and the subsurface hardness. A such way explosive hardened frogs installed into SŽDC, s.o. railway tracks in the Czech Republic are regularly monitored in terms of changes of their surface hardness and extent of wear and of the plastic deformation caused by the pressure and impact loads coming from the railway vehicles wheels running across the frog surface. The surface hardness is checked along the whole frog length by means of portable hardness tester Equotip and the wear amount together with inception of plastic deformation by means of 3D scanner is monitored. The values checked are compared with the frog wear, which is made of Hadfield steel as well and installed in the Czech Republic railway track, but its running surface was not explosive hardened at all. The outcomes analysis makes possible to assess the explosive hardened frogs technology assets under condition that a longer time period with higher running loads will be applied to enable the full-valuable assessment.

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