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2020, 30th April
Danieli Olivotto Ferrè multiline roller hearth furnace for alloyed-steel bar hardening and tempering
Excellent results achieved at ÇEMTAŞ – BURSA
The newly supplied plant in operation at ÇEMTAŞ – BURSA, Turkey, is an innovative concept for hardening and tempering of alloyed steel bars for automotive markets.
It processes alloyed steel bars in diameters from 15 to 100 mm, with an overall output up to 30,000 tons/year.
There, hardening (austenitizing and quench) and tempering, normalizing (in austenitizing furnace), soft annealing and stress relieving (in tempering furnace), are performed in continuous mode.
The key element used as common guideline to reach the performance targets is provided by the roll technology and design.
The equipment is designed with a new concept of multiline inclined and shaped rolls. Covered by Danieli patent, this specific solution is based on the concept of continuous rotation of selected bars during their handling inside the austenitizing furnace and the subsequent quenching system, in order to improve bar quality in terms of mechanical/metallurgical properties and excellent straightness.
Following, the excellent results already achieved:
- Hardness variation < +/- 1HRc along the surface of the bars
- Hardness variation < +/- 2 HRc from top-surface to core of the bars
- YTS = 850 ÷ 906 N/mm2
- UTS = 976 ÷ 1023 N/mm2
- Elongation = 15.6 ÷ 16.7 %
- Reduction Area = 60 ÷ 61 %
- Martensite percentage on the bar surface (by water quench) > 90%
- Martensite percentage on the bar core (by water quench) > 95%
- Decarburization < 0.003 * D (diameter of bar)
- Added bending on the bar < 1 mm/m
The plant is in industrial operation following a smooth commissioning period and final acceptance.
- Fabrizio Pere
- +39 345 029 6536