scholarly journals Development of a Novel Resistance Heating System for Microforming Using Surface-Modified Dies and Evaluation of Its Heating Property

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 440
Author(s):  
Ming Yang ◽  
Tetsuhide Shimizu
Keyword(s):  
Electrical Properties ◽  
Compression Test ◽  
Stress Reduction ◽  
Electrical Resistance ◽  
Heating System ◽  
Resistance Heating ◽  
Heating Efficiency ◽  
Coated Tools ◽  
Modified Surfaces ◽  
Surface Modified

For this study, a novel resistance heating system for microforming was developed using surfaces of forming dies as heating resources. The electrical resistance of the die surfaces was designed and the hard-coating material AlCrSiN was selected to coat the die surfaces for heating. To clarify the effects of the thickness and modified surfaces on heating efficiency, the temperature and stress reduction were evaluated in a micro-compression test using dies coated with 0.5 and 1 μm AlCrSiN films. Furthermore, the formability was also demonstrated using 1 μm thick AlCrSiN-coated tools in a microforging test. By applying surface-modified dies to the forming processes, we found that not only was the heating efficiency improved, but also the dependence of heating on the product’s shape and the material’s electrical properties was reduced.

Direct Heating Billet within Die during Hot Forging Process

2013 ◽  
Vol 479-480 ◽  
pp. 25-29 ◽  
Author(s):  
Fang Sung Cheng ◽  
Yu Shun Cheng
Keyword(s):  
Hot Forging ◽  
High Strength ◽  
Heating System ◽  
Heating Time ◽  
Resistance Heating ◽  
Heating Efficiency ◽  
Forging Process ◽  
Direct Heating ◽  
Forging Die ◽  
Hot Forging Process

This paper reports a simple and effective method to increase heating efficiency and decrease heating time that renders direct heating billet within die using resistance heating system during hot forging process. The apparatus employs resistance equipment set into the forging die, and the billet was directly resistance heating by the forging die. Base on the approach, the die as a forming condition on direct heating and forging was also researched. The result of experiments shows that the billet could be heated quickly to 1000°C in about 5 seconds and the high strength material (AISI4140) was successfully formed to the shape of bolt head. With this mechanism, the rapidly heating and isothermal deformation during the hot forging process can be achieved.

scholarly journals Research on Electromagnetic Sensitivity Properties of Sodium Chloride during Microwave Heating

2020 ◽  
Vol 39 (1) ◽  
pp. 54-62
Author(s):  
Hua Chen ◽  
Junjiang Chen ◽  
Weijun Wang ◽  
Huan Lin
Keyword(s):  
Sodium Chloride ◽  
Electric Field ◽  
Water Content ◽  
Heating Rate ◽  
Microwave Heating ◽  
Resonant Cavity ◽  
Relative Dielectric Constant ◽  
Heating System ◽  
Heating Process ◽  
Heating Efficiency

AbstractThe multimode resonant cavity is the most common cavity. The material often shows on selective heating performance during the heating process due to the effect of microwave heating having a closely relationship with the electromagnetism parameters. This paper is based on finite difference time domain method (FDTD) to establish the electromagnetic-thermal model. The electromagnetic sensitivity property parameters of sodium chloride including relative dielectric constant, loss angle tangent and water content of sodium chloride is studied during the heating and drying process. The heating rate and the electric field distribution of sodium chloride, at the different water content, were simulated with the electromagnetic characteristic parameters changing. The results show that with the electromagnetic sensitivity property parameters varying, the electric field strength, heating rate and steady-state temperature of the heating material will all have a variety in the cavity. Some measures are proposed to improve the heating efficiency and ensure the stability of the microwave heating system in the industrial application.

scholarly journals Вплив параметрів адитивного формування на електричні властивості графітонаповненого композиту на основі полілактиду

2021 ◽  
Vol 150 (5) ◽  
pp. 93-102
Author(s):  
Н. В. Сова ◽  
О. О. Слепцов ◽  
Т. Р. Федорів ◽  
А. О. Мартиненко ◽  
М. Р. Кудлай ◽  
...  
Keyword(s):  
Electrical Properties ◽  
3D Printing ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Polymer Melt ◽  
Electrical Characteristics ◽  
Additive Production ◽  
Filled Composite ◽  
Printing Parameters ◽  
Bulk Electrical Resistance

Purpose. Investigate the effect of additive formation parameters on the properties of an antistatic composition based on polylactide (PLA). Methodology. Surface and bulk electrical resistance were determined by ASTM D257. Findings. The influence of additive formation parameters on the electrical properties of graphite-filled composite based on polylactide has been studied. It was found that the value of resistivity significantly depends on the printing conditions, namely the temperature, speed, thickness of the layer. Increasing the printing temperature helps to reduce the resistivity of the sample. Reducing the thickness of the polymer layer also reduces the resistivity at a print speed within 3000 mm / min It was found that the specific electrical characteristics are significantly different in the plane of the sample in contact with the printing platform. Concentric method of laying layers of polymer melt is less effective in terms of resistivity than mutually perpendicular. It was found that the electrical resistivity of samples made of material for 3D printing, which was previously subjected to drying below the resistance of the sample made of undried material. The programmed change of 3D printing parameters allows to control the specific resistance of graphite-filled composite based on polylactide in the range of three orders and to obtain products with properties from antistatic to statically dissipative materials. Additive production allows to obtain products of the desired configuration with adjustable electrical properties. Originality. The peculiarities of the change of antistatic properties of the polymer composite depending on the conditions of additive formation of experimental samples are investigated. Depending on the applied parameters of additive molding, it is possible to obtain products with properties from antistatic to statically dissipative materials. Practical value. Technological modes of additive molding of composite products based on polylactide and graphite have been developed. Energy consumption for additive formation of products of different mass is estimated.

scholarly journals The influence of multifunctional microalloyed ceramics microstructure on its capacity properties

2018 ◽  
Vol 15 (2) ◽  
pp. 187-199
Author(s):  
Jelena Purenovic ◽  
Nedeljko Ducic ◽  
Branko Matovic ◽  
Milovan Purenovic
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Electrical Resistance ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Electrophysical Properties ◽  
Microstructural Properties ◽  
Structure Morphology ◽  
Composition Structure

Modified porous alumo-silicate ceramics, alloyed with magnesium and microalloyed with aluminum, belongs to modern multifunctional ceramic materials. Microalloying has led to important changes in dielectric and electrical properties of ceramics, such as dielectric constant and electrical resistance. These changes are conditioned by the microstructural properties of modified porous ceramics. The obtained results have shown the unity of the influence of composition, structure, morphology and application of microalloyed multifunctional alumosilicate ceramics on electrophysical properties. Microstructural investigations have shown that this type of ceramics has an amorphous-crystal structure, which causes important changes in its electrical properties and affects its activity. Therefore the ceramics can be considered as an active dielectric. A correlation between microstructural properties and structurally sensitive, i.e. electrophysical properties of microalloyed multifunctional alumo-silicate ceramics, was confirmed.

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