The “Tempcore ™” process, a quench and self-tempering process initiated in the seventies, is designed for the manufacturing of high quality concrete reinforced bars. A specifically adapted cooling box is located near to exit of the finishing stand to quench the bar surface with a high cooling rate during a limited time. The thickness of the external layer is transformed in a hard martensitic phase, later reheated and tempered by the core of the product during the final slow cooling.

It consists in subjecting the hot rolled steel to an in-line heat treatment in 3 successive stages:

  • When leaving the final mill stand, the product is rapidly and energetically cooled through a short cooling installation, where it undergoes surface hardening (martensite layer)
  • As soon as this quenching operation is stopped, the surface layer is TEMPERED by using the residual heat left in theCORE of the bar (self-tempering of the martensite layer) ; hence the name TEMPCORE™.The process ensures uniform formation of the wall-thickness of each layer all throughout the Re-bar ( as shown in the ring-test image )
  • The third stage takes place while the product lies on the cooling bed where the bar is subjected to normal cooling down to ambient temperature (transformation of the residual austenite in the core)

TEMPCORE™ is the best process for the production of high quality rebars.  Costly alloying elements (Vanadium, Niobium) are replaced by low-cost

It allows obtaining from low C-Mn steel concrete reinforcing bars with high mechanical properties, excellent weldability and superior ductility and bend-ability.

The TEMPCORE™ technology

Each TEMPCORE™ equipment is designed by CRM Group on the basis of precise calculations complemented with a very large experience. Such design guarantees excellent process controllability (giving consistent product properties) and high flexibility (allowing to produce several grades with the same chemistry).  Equipment manufacturing is then often carried-out locally at low cost.