scholarly journals Experimental Research on the Influence of Temperature on the Static Properties of Skarn

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lei Liu ◽  
Xiang Meng ◽  
Hao Qin ◽  
Zhaozhao Chang

Studying the high-temperature mechanical properties of rocks is of great significance to engineering disasters caused by deep rock mining and underground protection projects. In view of insufficient research on the high-temperature mechanical properties of deep rocks in southwestern China, we used high-temperature heating devices and statics equipment to conduct static tests on Skarn. XW7L-12 box-type resistance furnace was adopted to heat Skarn (25°C, 200°C, 400°C, 600°C, and 800°C), and the temperature effect of its basic physical parameters (density and wave velocity) was measured and analyzed. Uniaxial compression experiments were performed on two cooling methods of Skarn (natural cooling and water cooling) by a constant stress pressure testing machine to obtain a stress-strain curve and analyze its statics index (peak strength, tensile strength, elastic modulus, and peak strain) and the change rule of failure mode with temperature rise and different cooling methods. With the temperature increasing, various static mechanical indexes of Skarn will be greatly affected. Meanwhile, the different cooling methods are not related to the change trend of the mechanical properties of Skarn under high temperature.

2014 ◽  
Vol 1014 ◽  
pp. 49-52
Author(s):  
Xiao Ping Su

With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.


2017 ◽  
Vol 898 ◽  
pp. 711-718 ◽  
Author(s):  
Cheng He ◽  
Bao Liang Shi ◽  
Wen Sheng Li ◽  
Jian Ping Zhao ◽  
Kai Xu ◽  
...  

The influence of long time service on the microstructure and high temperature mechanical properties of T23 steel was studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile testing machine. Results showed that lathy bainite ferrite disappears with the increasing service time, both the size and number of the carbides increases, and M23C6 carbides transform into M6C carbides rich in W element. The service process also has a significant influence on the recovery. Sub-grains were found at the grain boundaries with little dislocations in the matrix after 27448 h service time. After running for 27448 h the microstructure degradation of T23 steel is serious. High temperature tensile properties of T23 are closely related to the alloy aging degree. The reasons for the decrease of high temperature mechanical properties after long time service included microstructure degradations such as the increase of both the size and quantity of M23C6 carbides, the transformation of M23C6 to M6C, the desolution of Cr,W,and Mo elements, the decrease of the dislocation density and the occurrence of the sub-grains.


2008 ◽  
Vol 575-578 ◽  
pp. 1101-1105 ◽  
Author(s):  
Li Guang Zhu ◽  
Wen Gang Lu ◽  
Yi Hua Han

Using Gleeble-3500 thermal simulation testing machine, the high-temperature mechanical properties of GCr15 Bearing steel was tested. The zero plastic temperature (ZPT) and zero strength temperature (ZST) were measured, so the optimum plastic temperature range and brittle temperature range were fond. The appearances of fracture at different temperature were analyzed by using scanning electronic microscope, and the fracture mechanism at different temperature area of the steel was discussed. which was thought as the theoretical basis for establishing the secondary cooling zone system of continuous casting.


2012 ◽  
Vol 446-449 ◽  
pp. 23-28
Author(s):  
Gang Wu ◽  
De Yong Wang

The mechanical properties and acoustic emission evolution process of limestone under the action of high temperature load were investigated by combining methods of uniaxial compression test and acoustic emission (AE) technique. The temperature varies in the range of 100, 200, 400, 600 and 800°C. By analysis of AE parameters and the mechanical parameter, the relations of stress-time (strain)-accumulative counts of AE, stress-time (strain)-AE rates under different temperatures are analyzed. The results show that the temperature does not obviously affect the mechanical properties of limestone at the temperature ranging from 100 to 400°C, the accumulative ring-down counts and accumulative energy increase with the rise of temperature. However, when the temperature is above 400°C, the mechanical properties of limestone deteriorate rapidly with the increase of temperature, and also the peak stress of limestone decrease in different extents. In the meantime, the accumulative ring-down counts decrease coupled with the change of mechanical parameter. The brittle fracture is main failure mode of limestone when the temperature is below 800°C and the change of peak strain of limestone is unobvious. The stress-strain curve conforms to the acoustic emission curve which shows that changes of minerals formation and microstructure due to high temperature result in the changes of mechanical and acoustic emission characteristic of limestone.


Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.


Alloy Digest ◽  
1975 ◽  
Vol 24 (9) ◽  

Abstract BERYLCO NICKEL ALLOY 440 is an age-hardenable nickel-beryllium-titanium alloy that offers high strength, excellent spring properties outstanding formability, good high-temperature mechanical properties, and resistance to corrosion and fatigue. Complex shapes can be produced in the solution-treated (soft) condition and then aged to a minimum tensile strength of 215,500 psi. It is used for mechanical and electrical/electronic components in the temperature range -320 to 800 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-94. Producer or source: Kawecki Berylco Industries Inc.. Originally published September 1964, revised September 1975.


Alloy Digest ◽  
1973 ◽  
Vol 22 (1) ◽  

Abstract HASTELLOY alloy S is a nickel-base high-temperature alloy having excellent thermal stability, good high-temperature mechanical properties and excellent resistance to oxidation up to 2000 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-184. Producer or source: Stellite Division, Cabot Corporation.


2006 ◽  
Vol 23 (1) ◽  
pp. 29-37 ◽  
Author(s):  
G.D. Janaki Ram ◽  
A. Venugopal Reddy ◽  
K. Prasad Rao ◽  
G. Madhusudhan Reddy

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