Material Properties of Refractory Concrete under High Temperature

2015 ◽  
Vol 1126 ◽  
pp. 155-160
Author(s):  
Stanislav Šťastník ◽  
František Šot ◽  
Jiří Vala

The paper presents the validation of physical properties of refractory concrete with heavy filling, using the measurements under high temperature, assumed for the construction of a thermal storage. The whole system, consisting of the storage core and of the insulation container, is characterized by non-stationary thermal transfer, supplied from solar radiation into the core. The validation of behaviour of the system (including its sleeping state and the dynamics of charging and discharging) is needed for the optimization of its size parameters.

1970 ◽  
Vol 5 (2) ◽  
pp. 98-109 ◽  
Author(s):  
R Bertodo

Pearlitic flake-graphite grey cast irons have long been widely used for the manufacture of diesel-engine combustion-chamber components. Nonetheless, very few pertinent high-temperature data are to be found in published work. The investigation described attempts to enlarge current knowledge on the high-temperature behaviour of grey cast irons in view of requirements highlighted by high thermal ratings. A general consideration of the problem showed that the often quoted Eichelberg material-quality factor is largely irrelevant and an alternative assessment formula is proposed. This is broadly confirmed by a systematic examination of the mechanical and physical properties of 166 plain and alloyed cast irons and a limited number of engine components. Different engine components impose different demands upon the material properties but for economic reasons a single cast-iron melt capable of meeting most of the requirements of all components is needed. It is shown that this situation is best met with an alloyed iron containing 1.3 per cent of copper-nickel and 0.4 per cent of molybdenum. The scatter in properties obtained from production casts was found to be typical for such irons. For components having safety factors of 2 or less, a prerequisite of economic engineering design, the service reliability is crucially dependent upon the scatter of material properties. Thus, there are advantages in reducing this scatter and it is shown that this can be achieved by attention to the cleanliness of the matrix and tight control of the chemistry of the melt. In general, the absolute values of mechanical and physical properties of flake-graphite cast irons appear to be governed mainly by the form and size of the graphite flakes and the chemistry of the matrix (i.e. CEV and alloying additions). Regression analysis of the results permitted the derivation of empirical formulae for the prediction of the iron properties. The general findings are used to suggest possible ways of improving the thermal resistance.


2014 ◽  
Vol 508 ◽  
pp. 61-65 ◽  
Author(s):  
Han Bing He

EPMA was used to investigate the corrosion-evolution mechanism of a dense ceramic spinel layer on the surface of NiFe2O4-10NiO-based cermet inert anodes during electrolysis in a high-temperature molten salt electrolyte. The evolution behaviour of the grain boundary on the surface of a 22(20Ni-Cu)(NiFe2O4-10NiO) anode during the formation of a dense layer was also examined. The experimental results showed that the content of the Al element on the grain boundary at the bottom of both the NiFe2O4,NiAl2O4 and FeAl2O4 was higher than that in the core of the 22(20Ni-Cu)(NiFe2O4-10NiO) anode, and the content of the Al element between the Ni-Cu and the dense layer of NiFe2O4-NiAl2O4-FeAl2O4 was higher than that in both the NiFe2O4,NiAl2O4 and FeAl2O4. It was concluded that the production of the NiAl2O4 was due not only to the reaction of the NiO with the Al2O2F42-, but also to the oxidisation of the Ni, which then reacted with the Al2O2F42-.


Author(s):  
P.P.K. Smith

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.


Author(s):  
Assunta Andreozzi ◽  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Salvatore Tamburrino

Alloy Digest ◽  
1996 ◽  
Vol 45 (1) ◽  

Abstract Allegheny Ludlum AL276 is widely used in the most severe environments found in chemical plants and in power plant desulfurization systems. The high molybdenum level with tungsten gives excellent pitting and crevice corrosion resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, joining, and surface treatment. Filing Code: Ni-497. Producer or source: Allegheny Ludlum Corporation.


Alloy Digest ◽  
1995 ◽  
Vol 44 (3) ◽  

Abstract NICROFER 5520 Co is a nickel-chromium-cobalt-molybdenum alloy with excellent strength and creep properties up to high temperatures. Due to its balanced chemical composition the alloy shows outstanding resistance to high temperature corrosion in the form of oxidation and carburization. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-480. Producer or source: VDM Technologies Corporation.


Alloy Digest ◽  
1994 ◽  
Vol 43 (7) ◽  

Abstract Carlson Alloy C601 is characterized by high tensile, yield and creep-rupture strengths for high temperature service. The alloy is not embrittled by extended exposure to high temperatures and has excellent resistance to stress-corrosion cracking, to carburizing, nitriding and sulfur containing environments. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on forming, heat treating, machining, and joining. Filing Code: Ni-458. Producer or source: G.O. Carlson Inc.


Alloy Digest ◽  
1993 ◽  
Vol 42 (7) ◽  

Abstract DELORO 716 PM is a nickel-base alloy recommended for handling conditions of wear, erosion, heat and corrosion when impact is also a consideration. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance and wear resistance as well as machining and joining. Filing Code: Ni-435. Producer or source: Deloro Stellite Inc.


Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  

Abstract NILO alloy 36 is a binary iron-nickel alloy having a very low and essentially constant coefficient of thermal expansion at atmospheric temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-79. Producer or source: Inco Alloys International Inc..


Alloy Digest ◽  
1971 ◽  
Vol 20 (12) ◽  

Abstract UNITEMP N-155 is an iron-base austenitic alloy used over a wide temperature range from subzero to about 1800 or 1900 F. It has relatively good oxidation and corrosion resistance. It is used in such applications as turbine rotors, shafts and blades, afterburner parts, nozzles and combustion chambers. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance as well as forming, heat treating, joining, and surface treatment. Filing Code: Fe-48. Producer or source: Cyclops Corporation.


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