SkV Premium: The new optimized welding process featuring rapid preheating

The standard, and highly reliable, SkV process for railroad aluminothermic welding, which has been in use for decades, has been substantially improved.

Thanks to the use of larger portions and more efficient preheating, the time needed to carry out aluminothermic welds has been reduced to a minimum.

Thanks to an optimized analysis method for SkV Premium portions (e.g. lower silicon content) and improved internal form geometry and robustness, we have significantly improved the process in terms of melting, shearing performance and mechanical/technological properties. In the interest of improving welding ergonomics, our crucibles are now around 1.5 kilograms lighter, but are still extremely safe to use.

SP variant

Apart from the SkV Premium solution, we also offer the SP variant for this process. By virtue of their external geometry, these forms are slimmer and lighter and can be sealed with either sand or paste.

Metallurgical properties

Identical metallurgical micro-structure

  • Only a small heat affected zone (HAZ)
  • Homogeneous fusion zone
  • Low internal stress thanks to homogeneous elimination of heat centers
  • Rated for all steel qualities

Process characteristics

  • Preheating time only 90-120 seconds.
  • For the same track profile, all SkV-P and SP welding parameters such as orientation,  preheating and shearing time are identical.
  • Rectangular riser geometry with adequate width makes it easier to center the forms; plus it’s possible to verify at any time that the forms are in the correct position.
  • Thanks to the use of special binders and additives, the high-quality form sand eases the task of working on contours, and ensures high stability for robust worksite use.

Overview of our processes:

  • SkV-P & SP
  • LP
  • LP groove
  • SKS

SP variant

Paste or sand?

Paste allows for avoidance of the following welding anomalies:

  • Gas bubbles owing to unduly damp sand
  • Sand inclusions
  • Bubbles from sand inclusions
  • Pores on weld collar
  • Leakage owing to unduly dry sand

Rectangular riser section