For a better understanding of the reasons why choosing the DUBUIS rail bond system is a shrewd choice, it is worth comparing it with the existing systems presently in use today.
1. Alluminothermy Welding
A) Direct welding
This welding can only be performed on soft rails where the steel is of grade 700 MPa or less. The abrupt rise in temperature beyond the critical threshold (700 deg C for steel of grade900MPa), coupled with a lack of cooling of this zone can cause molecular imbalance with the formation of Martensite-Bainite.
This hardening structure leads to the formation of micro-cracks which, through the various mechanical stresses associated with the passage of trains and with climatic conditions, can cause the rails to break. If this type of welding is inadvertently performed on a hard or extra hard rail, the rail is at risk.
B) Braze welding
This type of welding may be performed on all types of rail since the temperature reached at the rail is less than 500 deg C. However, the operating procedure involves rail preparation operations which it is essential to carry out with the greatest care, since they determine the quality of the braze weld. The operator must therefore be qualified for performing braze welding in order that each stage of the operation is done properly.
It is difficult to perform braze welding without interrupting traffic. Indeed, if traffic passes during the following lighting up, the operation is considered faulty. It is not advisable to undertake braze welding if it is raining.