The absorption of oxygen and hydrogen by titanium during heat treatment with high frequency currents

2019 ◽  
Author(s):  
Marina Fomina ◽  
Andrey Zakharevich ◽  
Aleksandr Skaptsov ◽  
Alexey Serdobintsev ◽  
Viktor Galushka ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Frequency

scholarly journals Failure Analysis of Rheocast Cylinder Head Covers of Hypereutectic Al–Si Alloys

2020 ◽  
Author(s):  
Jian Feng
Keyword(s):  
Heat Treatment ◽  
Surface Morphology ◽  
Service Time ◽  
Shot Peening ◽  
High Frequency ◽  
Cylinder Head ◽  
Die Casting ◽  
Fatigue Properties ◽  
Homogeneous Distribution ◽  
Engine Components

AbstractThe purpose of the present study is to determine the cause of failures of semisolid rheocast cylinder head covers of hypereutectic modified LM30 alloys. The covers, manufactured by rheocasting, a process that consists of the incorporation and homogeneous distribution of the reinforcements in semisolid metal (SSM) before die casting, were shot-peened after heat treatment to increase the fatigue resistance. However, these engine components failed during operation after a short service time. The major flaws were located by radiography. The microstructure was controlled by metallography. Significant interactions between shot peening and surface/subsurface contaminants were identified by surface morphology and fractography. The fatigue properties of hypereutectic alloys were investigated by a high-frequency vibrophore. It was identified that the failure was related to the cleanliness of SSM as well as the rheocasting process. Recommendations were given to prevent the recurrence of similar failures.

scholarly journals Factors affecting the temperature increasing rate in arc-shaped bamboo pieces during high-frequency heating

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2656-2667
Author(s):  
Feihu Chang ◽  
Yanhe Liu ◽  
Bin Zhang ◽  
Wansi Fu ◽  
Pengfei Jiang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Electric Field ◽  
Heating Rate ◽  
High Frequency ◽  
Great Influence ◽  
Chord Length ◽  
High Frequency Electric Field ◽  
Frequency Electric Field ◽  
Frequency Heating

In the process of applying the high-frequency heating technology to bamboo heat treatment, controlling the material temperature has a great influence on the quality of bamboo forming. Therefore, research on the heat transfer mechanism of high-frequency heating of arc-shaped bamboo pieces is of great importance. In this paper, the influence of different moisture content, chord length, and plate voltage on the heating rate of arc-shaped bamboo pieces under high-frequency electric field were studied. The moisture content of bamboo had the most remarkable effect on the heating rate. With increased moisture content, the temperature rose faster. The selection of the plate voltage had an obvious influence on the heating. If the voltage was low, the heating rate was too slow, the heating time was long, or the voltage was high, it was easy to cause electric field breakdown and damage the bamboo pieces. As the chord length decreased, the heating rate gradually increased. When the radian of the arc-shaped bamboo pieces could be ignored, the heating rate was the fastest. The results showed that under certain conditions, the arc-shaped bamboo pieces showed a good heat treatment effect in a high-frequency electric field.

Vulcanization or Other Heat Treatment by Electrical Conduction

1944 ◽  
Vol 17 (1) ◽  
pp. 188-191
Author(s):  
Felix L. Yerzley
Keyword(s):  
Heat Treatment ◽  
Electric Current ◽  
High Frequency ◽  
Direct Consequence ◽  
Electrical Energy ◽  
Internal Resistance ◽  
Appreciable Amount ◽  
Rubber Belt ◽  
High Dielectric ◽  
Electrical Conductors

Abstract This communication relates to the heating of plastic materials of. a semiconducting nature by passing electricity through them. In particular, it relates to the vulcanization of rubber and rubberlike materials, including Neoprene, with heat generated by the conduction of an electric current and, similarly, it relates to the heat treatment of thermosetting plastics by conduction of an electric current. It is well known that all electrical conductors are heated to some extent by the passage of an electric current. This heating is a direct consequence of internal resistance. The effect so obtained is proportional to the electrical energy absorbed, and is expressed by the equation: power=I2R, in which I is the current in amperes between two points and R is the corresponding resistance in ohms. The unit of power is the watt. Others have used electrical means of heating unvulcanized rubber, but the disclosures differ fundamentally from this proposal. For example, Neerlye coils a steel ribbon and an uncured rubber belt in a spiral and heats the coil by passing electricity through the steel. Newton claims vulcanization by abeam of electrons from a cathode ray tube. The most significant disclosure is by Dufour. This claims the “process for the vulcanization of rubber characterized by the feature that the rubber to be heat-treated is arranged as a dielectric between the electrodes of an electric condenser to which there is applied a high frequency alternating current of a periodicity of several million cycles per second”. This patent is characterized by utilization of high-frequency fields of the order of several megacycles per second. Further, it is not required in induction curing with high-frequency current that the electrodes be in actual mechanical contact with the rubber. Induction curing is facilitated when the material to be heated has both a high power factor and a high dielectric constant, but high electrical conductivity of appreciable amount is not essential to the application of the method.

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