SRZ technology is applied for Thermit© welding of tram-dented rails. The general sequence and structure of production steps of this process are identical to the SkV welding technology, except for the following specifics:
1. Rail ends pre-heating takes longer and is performed up to the temperature of 1,000 °С, it is visually controlled by color of the heated rail metal and takes, on average, 7-8 minutes;
2. The joint polishing is carried out not only on the roll surface but also in the flange way;
3. Part of equipment and production accessories are original and differ from those used for SkV process;
4. Casting fire-resistant molds for welding might compose of two parts (the option which is used more often) or three parts (to weld limited quantity of rails, for example at points, on the reinforced concrete foundation of the track, transition sections and other options). A special insert for the rail flange way is included in the set.
SRZ technology additional features:
- it is possible to perform welding with an increased space allowance of up to 75 mm when repairing rails or switches;
- in some cases, where necessary, the SRZ technology allows connecting the groove rails with the R65 and R50 type rails. At that, a special set of transitional fire-resistant molds is used, while the technology is complemented with cutting procedures and groove rail ends preparation (see fig.);