Saet (Italy)

Abstract The Ultra Large Bearing (ULB) industry can increase the production performances by using induction heating on a full range of thermal processes. The paper presents the technological, economical, and process optimizations that can be achieved using induction heating technology in both hardening and tempering. Two different solutions are available for (seamless) race hardening: a high-power induction single shot process for small to medium size rings and induction seamless scan hardening for large sized bearings. The ultra-low frequency induction tempering process is described and compared with a traditional furnace. These technologies are presented and compared to show application ranges, specific features, metallurgical results, and efficiencies in processing and cost.

Abstract Large slewing bearings are employed in wind turbines and other energy industry applications where they are subjected to harsh working conditions. In order to bear heavy dynamic loads, slewing ring tracks can be surface hardened by induction heating with a seamless process which allows for a uniform heat treatment without soft zones. In comparison with the traditional furnace carburizing, seamless induction hardening is faster, consumes less energy, and has been developed to achieve the same results utilizing medium carbon steel. The presence of a pre-heating coil, with an independent power source, allows for the adjustment of the heat input rate in order to tune the heating process according to the steel characteristics. The pre-heating operation allows for case depths up to 10 mm to be reached without a reduction in scanning speed or productivity. A mechanical tracking system adjusts the coils to compensate for ring deformation and thus assure a uniform heating pattern. Surface hardness tests and metallography have been performed in different process stages to verify the process consistency. A fine grain microstructure in the end zone has been obtained thanks to the pre-heating coil, which avoids surface overheating.

Abstract The inductors design process is the key point in the development of an induction heating machine to fulfil the customer specifications. Some special hardening profiles can be uniquely achieved using the induction heating technology. Different inductors shapes, flux concentrators, power supply frequencies and cooling media can be used to get the optimal thermal profile for the heat treatment. The possibility to study the design robustness of the process using virtual prototyping is the key to speed up the test-trials loop and to give a tool for a better understanding of the process. In the paper, a case study applied to a real industrial problem is presented. A batch of FEM (finite element method) simulations has been done to find the key parameters in the element positioning tolerances, the effect of the misalignment, and the influences of the part geometrical tolerances. Some additional simulation runs have been made to optimize the inductor shape, to stiffen the system and to achieve a more stable process. The method used is based on FEM taking into account the coupling between the electromagnetic and thermal fields, and the nonlinear behavior of the material properties.

Recently, nanoscale stimuli-responsive devices have received much attention thanks to their potential to limit the cytotoxic effect of the therapeutic treatment at the diseased tissue. Among different physical triggers, large alternating magnetic fields enable the conversion of magnetic energy into heat by using magnetic nanoparticles that generate localized hyperthermia, named Magneto Fluid Hyperthermia (MFH). This methodology can be exploited for cancer therapy or/and thermally activated drug release. The small size iron oxide nanoparticles (Fe-NPs), such as SPIO (small iron oxide particles) and USPIO (ultra-small iron oxide particles), currently used for this application have many limitations due to their 1) high intratumor concentration needed due to the low heating power 2) short particle blood-half-life, 3) non-specific distribution, 4) low internalization efficiency. For these reasons many efforts are necessary to make magneto fluid particle hyperthermia (MFH) a competitive tumor therapy for clinical applications. New iron oxide nanoparticles, coated with oleate, with a diameter of 5-18 nm, have been prepared by co-precipitation and incorporated into PLGA-NPs (PLGA=Poly(lactic-co-glycolic acid) in order to improve their biocompatibility and `` in vivo'' stability. Moreover, PLGA-NPs have been loaded with both NPs-Fe and antitumor drugs (Paclitaxel, PTX), an anticancer hydrophobic drug used in the treatment of ovarian and breast cancer, to perform MFH triggered drug release. The PTX and Fe-NPs loaded nanoparticles may be considered as an effective anticancer drug delivery system for Imaging-guided hyperthermic treatment of tumors.