| 1. |
- Akujärvi, Ville, et al.
(författare)
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Evolution of magnetic properties during tempering
- 2021
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Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015.
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Tidskriftsartikel (refereegranskat)abstract
- Quality control in heat treatment of steel is often conducted after the treatment. Failure to confine within the specified range of mechanical properties may lead to wasted energy and production resources. Performing quality control in-line in the heat treatment process allows for early detection and possibility to react to changes in the process. The prospects of utilizing the change in the electromagnetic (EM) properties of steel, as means for quality control, are investigated in this paper. The focus is on the tempering process of hardened SS2244 (42CrMoS4) steel. The tempering takes the hardness of the steel from approximately 600 HV down to around 400 HV. The EM signature of the steel is recorded during the tempering process. This is later compared with results from more traditional means of material characterization, such as laser scanning microscopy, X-ray diffractometry and Vickers microhardness measurement. This initial study shows clear indications of precise detection of the hardness through EM properties during the tempering process of selected material.
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| 2. |
- Akujärvi, Ville, et al.
(författare)
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Mapping of magnetic properties for simulations of high-Temperature electromagnetic applications
- 2017
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Ingår i: COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering. - 0332-1649. ; 36:2, s. 546-554
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Tidskriftsartikel (refereegranskat)abstract
- Purpose -The purpose of this paper is to investigate the added value of using temperature-dependent electric and magnetic properties in high-Temperature electromagnetic simulations. Design/methodology/approach - In this work, the electromagnetic properties of Domex 420, SSAB, have been characterized as a function of the temperature, from room temperature to 900°C. The measurement of the electric and magnetic properties was performed inside a vacuum furnace at a number of discrete temperature steps, with particularly small intervals around the Curie temperature. A simple transient multi-physics model was used to investigate the impact of the measured properties in three different representations. Findings - In certain intervals, a simplified approximation of the properties produces accurate results, while fully parametric representation is beneficial when heating above the Curie temperature. Originality/value -Temperature-dependent electromagnetic properties are rarely found, especially in an easy-To-use form. Using parameterized temperature-dependent approximation of key properties shows noteworthy differences in the outcome of high-Temperature electromagnetic modeling.
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| 3. |
- Areitioaurtena, Maialen, et al.
(författare)
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A semi-analytical coupled simulation approach for induction heating
- 2021
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Ingår i: Advanced Modeling and Simulation in Engineering Sciences. - : Springer Science and Business Media LLC. - 2213-7467. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- The numerical simulation of the induction heating process can be computationally expensive, especially if ferromagnetic materials are studied. There are several analytical models that describe the electromagnetic phenomena. However, these are very limited by the geometry of the coil and the workpiece. Thus, the usual method for computing more complex systems is to use the finite element method to solve the set of equations in the multiphysical system, but this easily becomes very time consuming. This paper deals with the problem of solving a coupled electromagnetic - thermal problem with higher computational efficiency. For this purpose, a semi-analytical modeling strategy is proposed, that is based on an initial finite element computation, followed by the use of analytical electromagnetic equations to solve the coupled electromagnetic-thermal problem. The usage of the simplified model is restricted to simple geometrical features such as flat or curved surfaces with great curvature to skin depth ratio. Numerical and experimental validation of the model show an average error between 0.9% and 4.1% in the prediction of the temperature evolution, reaching a greater accuracy than other analyzed commercial softwares. A 3D case of a double-row large size ball bearing is also presented, fully validating the proposed approach in terms of computational time and accuracy for complex industrial cases.
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| 4. |
- Frogner, Kenneth, et al.
(författare)
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Induction heating of carbon fiber structures - properties and challenges
- 2014
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- Carbon fiber reinforced plastic is constantly gaining market shares due to its unique properties. By heating this kind of materials using induction, many new applications occur. The high resistivity and anisotropic properties of carbon fiber composites means there are a number of challenges to overcome. This work emphasizes the key components related to induction heating of complex materials and present ways to characterize the important properties using non-contact methods. Successful experimental results are presented and the work also shows very good agreement between measurements and simulations.
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| 5. |
- Johansson, Daniel, et al.
(författare)
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Selecting Cutting Data Tests for Cutting Data Modeling Using the Colding Tool Life Model
- 2018
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 72, s. 197-201
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Konferensbidrag (refereegranskat)abstract
- An analysis on selecting cutting speed, cutting feed and depth of cut when collecting data for the Colding Tool Life Model based on Woxen's Equivalent Chip Thickness was performed to achieve the lowest possible model error. All possible combinations of a large data set were evaluated with regard to model error. This work shows that an increase of ratio between the highest and lowest cutting speed, feed, depth of cut and tool life within the five included tool life tests increases the likelihood of an accurate model. Further, to ensure an accurate model, it is not enough to have a large ratio of one single parameter, but a large ratio in all parameters is needed. The paper also presents a suggestion on how to select the cutting data points, derived from the best performing tool life models. It is concluded that one should aim to have one pair of cutting data points with equal equivalent chip thickness while varying cutting speed and three more test points with different equivalent chip thickness.
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| 6. |
- Lundström, Fredrik, et al.
(författare)
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Cooling of Litz Wires in Industrial Induction Heating Applications
- 2016
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Konferensbidrag (refereegranskat)abstract
- Induction heating has the potential to be a very efficient heating method and by using litz wires instead of copper tubes the losses can be significantly reduced. The drawback with litz is the fact that it comprises insulation materials with low temperature resistance, typically in the range 150 – 200 °C. In order to solve this problem a solution is to create channels in the litz structure in which a cooling medium can flow. In order to investigate the possibility with cooled litz wires a number of litz wires were manufactured with different types of internal cooling channels and infiltration materials. The experiments showed that it was possible to maintain a steady state temperature of the litz wire below 25 °C at a current density of 10 A/mm2 and frequency of around 20 kHz. A thermal FEM model was developed in order to calculate the equivalent thermal conductivity of the litz structure based on the measurements. The induced losses in the cooling tube was also investigated with an electromagnetic FEM model showing that the choice of dimensions and material for the cooling tube might be crucial for the heating efficiency.
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| 7. |
- Olsson, Mike, et al.
(författare)
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Cryogenic and hybrid induction-assisted machining strategies as alternatives for conventional machining of refractory tungsten and niobium
- 2021
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Ingår i: International Journal of Refractory Metals and Hard Materials. - : Elsevier BV. - 0263-4368. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Tungsten (W) and niobium (Nb) belong to the refractory metal group and are used as alloying elements in steels and superalloys for high demand products. These metals are also used in a high purity single-phase state for products within nuclear, space, military and research facilities.In the current study, tool wear development and surface quality at different cutting conditions have been evaluated when machining high purity W 99.95% and Nb 99.7% in longitudinal turning. Cryogenic LN2 cooling and hybrid induction-assisted machining strategies were applied in order to alter W and Nb material state with respect to the ductile-to-brittle transformation temperature, and thus to attempt controlling their machinability. These advanced machining strategies were benchmarked against the more conventional machining solutions of dry, flood and high pressure cooling.It was found that the use of LN2 cooling demonstrated the best result in terms of tool life when machining W followed by induction-assisted heating, dry and flood. All machining strategies provided similar surface quality which is related to strong build-up edge formation and respective surface alteration. When machining Nb, high pressure coolant results in best performance in terms of tool life and surface quality, then followed by flood and cryogenic strategies. Overall, substantial improvement of surface quality (Ra = 0.4–0.6 μm) was observed for high cutting speeds vc ≥ 225 m/min.
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| 8. |
- Reinap, Avo, et al.
(författare)
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Design and development of a roller with embedded heating for uniform temperature generation
- 2014
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- This paper provides design experience based on 2D FE electromagnetic and heat transfer analysis that are used to support product development. An induction in-roll heater is analyzed, tested and verified. The scientific challenge is to develop fast and fair models to provide design guidelines for layout specification, material selection and performance estimation. The transferred energy capability and efficiency are the essential performance figures focused on the first hand in prior to temperature distribution and profiles.
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