Bitte wählen Sie ihr Lieferland und ihre Kundengruppe
The induction heating is widely used for surface hardening the steel rolling rolls. An algorithm was developed to describe the conversion of the electromagnetic energy into the thermal one and to calculate the depth of the hardened surface layer taking the electric power, temperature fields, heat convection, thermal insulation of the treated surface and physical properties of the roll materials into consideration. The effect of the displacement rate of the induction heating zone as well as of the induction heating section size and location on the hardening course and surface properties of the treated rolls was estimated by computer simulation on under industrial conditions. According to the simulation, the supporting roll (9Ch2 steel, 1000 mm in diameter) was heated up to 850 deg C to 900 deg C with a three-section inductor (section width 350 mm, step distance 375 mm, displacement rate 1 m/h to 7.5 m/h), then cooled by water spraying (cooling section width 2000 mm) down to the room temperature and tempered at 130 deg C to 245 deg C for 1.8 h to 4 h. The original perlite structure of the steel was transformed to the austenite one during the heating and to the martensite, bainite and perlite ones during the cooling period. The temperature fields in longitudianal section of the roll were determined and the thermokinetic diagrams of the austenite-to-martensite transformation were constructed. The distribution of particular structures the surface layer depth along was also shown. The content of martensite increased up to 30% with increasing zone displacement rate. The distribution of axial temperature stress along the roll diameter was also calculated.