Hennigsdorfer Stahl Engineering (HSE) is a company with a long tradition and vast experience in the field of quenching processes for rolling mills. We started in this field round 1969. In 1971 the first small producing line was taken in function. Years of intensive research work carried out by our company in this field has resulted in the successful development of different quenching procedures and associated hardware. Special importance was accorded to the development of a rapid water quenching system for the production of thermoprocessed rebars to meet the exacting demands from civil designers in terms of low costs and increased strength without additionally processes such as twisting resp. additional alloying elements in steelmaking. The THERMEX cooling technology specially developed by HSE to meet this demand has gained wide acceptance from both - producers and users in all parts of the world. Apart from the efforts made to perfect the cooling technology required, HSE also paid special attention to the relevant hardware essential for easy implementation of the process. The THERMEX cooling system – as it is populary known worldwide – and the specially designed THERMEX cooling pipes have been patented in a lot of countries. Today about 100 steelplants in different parts of the world employ the THERMEX-system for manufacture of rebars in strands and coils. We are sure from economic considerations, there is no alternative process. All international grades of high strength rebars are made from practically the same ordinary steel quality – that is mild steel. The different mechanical properties required by various standards are easily achieved by only adjusting the water quenching parameters. In the last years the THERMEX-technique has been used more and more for different in line heat treatments, for ball bearing steels, for austenitic CrNi steels, or normalizing process for low alloyed carburizing steels.