Like the bainitic rails themselves, the Thermit® welds in between must withstand the same high traffic loads without causing surface degradation to achieve better track performance – in other words: The welds must perform just as well as the bainitic rails.
Challenges of the perlitic rail
Today, in high-loaded track sections head-hardened perlitic rail steels are commonly used to minimise wear and maintenance efforts and to keep life cycle costs reasonable. However, as traffic densities increase, these steels are reaching their limits in terms of durability. Perlitic rails are heavily affected by rolling contact fatigue (RCF) and its removal. As a result, track availability is suffering and costs are spiralling out of control. Both are driving the need for new materials.
Bainitic rail – an alternative for high-load tracks
For these demanding, high-load tracks bainitic rails are increasingly being introduced to minimise maintenance and life-cycle costs, thus achieving higher track availability.
For Thermit® welds, this means they must perform just as well as bainitic rails: Same wear and stability, especially against rail surface degradation, to finally achieve the benefits of the new rail steel grade. Durable Thermit® welds in bainitic rails therefore require almost identical material properties. In steels, this is achieved with a very similar bainitic microstructure – preventing the formation of head checks due to RCF.
At Goldschmidt, metallurgists and welding experts have developed Thermit® welding portions, such as B340 E that generate such a bainitic microstructure themselves after aluminothermic reaction, casting, solidification and standard cooling.
The challenge of high reproducibility and stability – not only in the laboratory or in the factory – could be ensured in multiple tests. B340 E portions are available for SkV, SkV-Elite and SoW-5 processes and are ready for track testing.
Hall 25/Stand 485
Outdoor Display O/177