scholarly journals Electrical Resistivity of Carbonaceous Bed Material at High Temperature

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 933 ◽  
Author(s):  
Gerrit Ralf Surup ◽  
Tommy Andre Pedersen ◽  
Annah Chaldien ◽  
Johan Paul Beukes ◽  
Merete Tangstad
Keyword(s):  
Heat Treatment ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Carbon Source ◽  
Heat Treatment Temperature ◽  
Electric Arc ◽  
Treatment Temperature ◽  
Electric Arc Furnaces ◽  
Arc Furnaces ◽  
Set Up

This study reports the effect of high-temperature treatment on the electrical properties of charcoal, coal, and coke. The electrical resistivity of industrial charcoal samples used as a reducing agent in electric arc furnaces was investigated as a renewable carbon source. A set-up to measure the electrical resistivity of bulk material at heat treatment temperatures up to 1700 ∘C was developed. Results were also evaluated at room temperature by a four-point probe set-up with adjustable load. It is shown that the electrical resistivity of charcoal decreases with increasing heat treatment temperature and approaches the resistivity of fossil carbon materials at temperatures greater than 1400 ∘C. The heat treatment temperature of carbon material is the main influencing parameter, whereas the measurement temperature and residence time showed only a minor effect on electrical resistivity. Bulk density of the carbon material and load on the burden have a large impact on the electrical resistivity of each material, while the effect of particle size can be neglected at high heat treatment temperature or compacting pressure. The mechanical durability of charcoal slightly increased after heat treatment and decreased for coal and semi-coke samples. The results indicate that charcoal can be used as an efficient carbon source for electric arc furnaces.

Effect of Pre-Weld Heat Treatment Temperatures on TIG Welded Microstructures on Nickel Base Superalloy, GTD-111

2015 ◽  
Vol 658 ◽  
pp. 14-18
Author(s):  
Tanaporn Rojhirunsakool ◽  
Duangkwan Thongpian ◽  
Nutthita Chuankrerkkul ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Tig Welding ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Base Superalloy ◽  
Weld Heat

Nickel-base superalloys have been used as high temperature materials in land-base gas turbine application. When subjected to long term, high temperature service, large crack propagation was observed. Typical refurbishment method of these turbines is carried out by using TIG welding followed by post-weld standard heat treatment. However, new crack initiation is found in the heat-affected zone after TIG welding. Pre-weld heat treatment has been discovered to improves final γ + γ’ microstructure. This study focuses on the effect of pre-weld heat treatment temperature on final γ + γ’ microstructure. Seven different conditions of pre-weld heat treatment temperature were investigated. Scanning electron microscopy studies were carried out after pre-weld and post-weld heat treatments to compare the γ + γ’ microstructure and capture microcracks. The best pre-weld heat treatment temperature produces uniform distribution of finely dispersed γ’ precipitates in the γ matrix without post-weld crack.

Phase Transformation of Coal at High Temperature

2014 ◽  
Vol 809-810 ◽  
pp. 815-821
Author(s):  
Xiao Hu Hua ◽  
Xiao Gang Wang ◽  
Jia Qing Yang ◽  
Shu He Lu ◽  
Li Rong Deng ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Phase Composition ◽  
High Temperature ◽  
Internal Migration ◽  
Heat Treatment Temperature ◽  
Functional Group ◽  
Treatment Temperature ◽  
Conductive Phase ◽  
Higher Temperature

Anthracite and bitumite were processed respectively at 1400°C,1700°C, 2000°C, 2200°C, 2400°C and 2600°C,and their chemical composition,resistivity,microstructure, phase composition,and the internal migration of molecular functional group were tested and characterized. The results indicate that moisture, ash and volatile in coal have gradually shifted and lost with the elevation of heat treatment temperature, while the higher temperature, the quicker and completer phase change. Heat treatment can make the coal transform from approximately insulative phase to conductive phase,. Furthermore, as the temperature increases, the conductive phase transformation effect is better. The higher the heat treatment temperature of coal, the more amorphous carbon transforming into crystalline carbon completely, but the less types of phases .

Effect of B4C and SiO2 on Bond Property for Phenolic Resin-Based Adhesive

2018 ◽  
Vol 281 ◽  
pp. 959-963
Author(s):  
Feng Zhang ◽  
Chuan Qi Hu ◽  
Shi Chao Zhang ◽  
Hao Ran Sun ◽  
Yuan Tian ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Bond Strength ◽  
Boron Carbide ◽  
Bonding Strength ◽  
Heat Treatment Temperature ◽  
Room Temperature ◽  
Phenolic Resin ◽  
Optical Microscope ◽  
Treatment Temperature

In this paper, the modified phenolic resin-based adhesive was prepared by dissolving different components. After low temperature curing, SiC samples were bonded by the binder. The samples were treated at different temperatures (400°C, 800°C, 1200°C, 1500°C) under an inert atmosphere. The bonding strength of samples was tested after heat treatment at room temperature. The results showed that the bonding strength of the B4C modified phenolic resin (PF) based adhesive is the highest. When the heat treatment temperature was above 1200°C, the bond strength increased with the additive amount of boron carbide at room temperature. The microstructures of the samples were observed by optical microscope and scanning electron microscope. The effects of the modified filler and heat treatment temperature on the bonding strength of the phenolic resin based adhesive were investigated. The bonding strength of boron carbide-modified phenolic resin-based binder was tested under high temperature. It was found that the bond strength at high temperature was lower than that at room temperature, and the bond strength decreased with the increase of temperature.

scholarly journals Research on the influence of heat treatment temperature on bearing capacity of high steel grade pipeline during in-service welding

2021 ◽  
Vol 353 ◽  
pp. 01020
Author(s):  
Yan Xu ◽  
Yinglai Liu ◽  
Xianghui Nie ◽  
Zhenjun Feng ◽  
Liang Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Bearing Capacity ◽  
Tensile Properties ◽  
Heat Treatment Temperature ◽  
Heating Temperature ◽  
Treatment Temperature ◽  
Steel Grade

During the welding of in-service pipeline, natural gas is continuously transported in the pipeline, which maintains a high gas pressure. Therefore, the welding process is completed under strong cooling conditions, and welding delay crack is easy to occur. Preheating before welding and heat treatment after welding can effectively control the hardened microstructure, reduce the residual stress and ensure the welding quality. In this study, the influence of heating temperature on the bearing capacity of high steel grade pipe during in-service welding repair was studied. The high temperature tensile test was used to simulate the bearing capacity of the pipe under heating and high temperature environment. It is found that when the heating temperature is below 400°C, the pipe strength remains at the original level. With the increase of heating temperature, when the test temperature is higher than 400°C, the yield strength and tensile strength of the pipe decrease significantly. When the test temperature is 450°C, the yield strength and tensile strength of the material decrease by 15.8% and 11.1%, respectively, compared with the normal temperature, which are lower than the pipe standard requirements. Therefore, it is suggested that when the heat treatment temperature is higher than 400°C during in-service welding repair, it is necessary to consider reducing the pipeline pressure. At the same time, the box furnace heat treatment method was adopted to heat treat the pipe, and the tensile properties of the pipe after heat treatment were tested to analyze the bearing capacity of the pipe after heat treatment. It is found that when the heating temperature is higher than 700°C, the tensile properties of high grade pipeline steel pipe decrease sharply. It is suggested that when the heat treatment temperature is higher than 700°C, the risk assessment of the service safety of the heat treated pipeline should be carried out.

scholarly journals An Experimental Study on the Slippage Effects of Sandstone under Confining Pressure and Low Pore Pressure Conditions

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Zhengdai Li ◽  
Jianping Zuo ◽  
Yue Shi ◽  
Fei Xu ◽  
Meilu Yu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Pore Pressure ◽  
Wave Velocity ◽  
Heat Treatment Temperature ◽  
Heat Treatments ◽  
Treatment Temperature ◽  
Slippage Effect ◽  
Temperature Heat ◽  
The Impact

Due to the influences of various factors, such as temperature, stress, and composition, the research regarding rock permeability has been complicated. This study examined the variation laws of sandstone specimens under changing rates of confining and pore pressures after high-temperature heat treatments. The results showed that the free water in the rock volatilized during the low-temperature heat treatments in the range of 100°C to 300°C, with the increase of the heat-treatment temperature above 500°C; the crystal water in the rock is gradually separated out; and the particles in the samples had undergone phase transformations resulting in increased permeability. According to ultrasonic wave velocity test results, the internal cracks of the samples expanded with the increases in the heat-treatment temperatures. In addition, the high-temperature heat treatments were found to improve the accuracy of the direction of the Earth’s stress when using circumferential wave velocity anisotropy methods. Under the influence of slippage effects, as the pore pressure increased, the measured permeability of the samples decreased and the slippage effect occurs in the rock samples with the permeability of 10-3 μm2~10-6 μm2. The experimental results showed that the contribution rate of the slippage effect decreases with the increase of the heat-treatment temperature of the specimen, and the contribution rates of the sandstone slippage effect were generally higher than 5%. Therefore, the impact effects on the permeability of sandstone slippage should be considered in practical engineering processes.

Heat-Treatment Temperature Influence on Structure and Magnetic Properties of SrFe11.85Sm0.15O19 Ferrite Nanofiber

2013 ◽  
Vol 575-576 ◽  
pp. 313-316
Author(s):  
Xian Feng Meng ◽  
Yin Bo Hong ◽  
Yong Kang Ji
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
High Temperature ◽  
Low Temperature ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Temperature Influence ◽  
One Dimensional ◽  
Structure And Morphology ◽  
Calcined Temperature

one-dimensional SrFe11.85Sm0.15O19nanofibers were synthesized by electrospinning combined with heating treatments. This paper involved an investigation of how heat treatment temperature and Sm3+influence structure and morphology of nanofibers. FTIR and XRD results demonstrated that SrFe11.85Sm0.15O19magnetoplumbite phase was formed with increasing of calcined temperature, and small amountα-Fe2O3and SmFeO3were detected at low temperature and high temperature, respectively. The calcined temperature had a great impact on the morphology of nanofibers, which changes from a continuous fibrous structure to large plate grain. The VSM results revealed that the Ms and Hc of nanofiber were both increased with calcined temperature.

Influence of ZrO2 on Oxidation Resistant Properties of Glass-Based Coating on Molybdenum Substrate

2010 ◽  
Vol 160-162 ◽  
pp. 1762-1766
Author(s):  
Qing Wei Wang ◽  
Hong Zhi Wang ◽  
Wei Ning
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Viscous Liquid ◽  
Oxidation Resistance ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Molybdenum Substrate ◽  
Oxidation Resistant ◽  
Glass Powders

the oxidation resistance of glass-based coating on molybdenum substrate was studied in the paper. The Mo substrates with glass based coating modified by the different concentration of ZrO2 in the coating were prepared and characterized; results showed the oxidation resistance of samples increased firstly and decreased subsequently with increase in ZrO2 concentrations. The influence of different heat treatment temperature was also discussed in the paper. After the sampes were pretreated at the high temperature for 20 minutes, the oxidation resistance properties were improved five times than un-pretreated ones. SEM showed the glass powders in the coating changed into viscous liquid which adhere to the substrate tightly after the samples had been pretreated. Resulting showed the sample exhibited the best oxidation resistance when pretreated at 1300°C.

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