Papers by Keyword: Heat Resistant

Abstract: The main objective of this experimental work is to study the effect of Hydro Fluoric acid in ultrasonic machining of polycarbonate bullet proof UL-752 and Acrylic Heat resistant BS 476 Glass. In which, mixture of abrasive particle are also used as the input machining parameter. Three types of abrasive; Alumina, Silicon Carbide and Boron Carbide are used for machining. Experiment has been performed with 8mm of high carbon high chromium tool steel (D2), high carbon steel (HCS) and high speed tool steel (HSS) tools. The material removal rate was father enhanced by HF acid. The experimentation date represent the main effect plots for tool wear rate and material removal rate. After analysis, results reveals that Al₂O₃+SiC+B₂C mixed slurry (1:1:1), Hydro Fluoric acid with 1% concentration and High Speed tool Steel material produce the higher material removal affect.

Abstract: Water-soluble phenolic resin was synthesized via two-step alkaline catalytic reaction. The influences of synthesis process conditions on hydroxymethyl content of water-soluble phenolic resin molecular chain were also studied. The results show that the increase of formaldehyde dosage, as well as the increase of reaction temperature and reaction time, the content of hydromethyl in resin increased first, and then decreased. Without the addition of stabilizer, polymer weak gel for flooding was synthesized with HPAM crosslinked water-soluble phenolic resin. The performance analysis of the weak gel shows that the change of viscosity of weak gel corresponds to the change of the content of hydromethyl in resin. Phenolic resin with good water-solubility and strong reaction ability to HPAM was polymerized and the reaction conditions are as following: phenol and formaldehyde in mol ratio 1:2~1:3, in solution with pH= 9~10, under final condensed polymerization temperature 85°C and in condensed polymerization time 30 minutes.

Abstract: The phase composition of the AlNiMnFeSiZr system was analyzed with respect to new-generation heat resistant casting aluminum alloys based on a Ni-containing eutectic, which are strengthened by the Al₃Zr (L12) nanoparticles. It is shown that the presence of iron and silicon considerably complicates the phase analysis compared with the AlNiMnFe base alloy. Alloys with low silicon content have a sufficiently good casting property, which enables fabrication of thin-walled castings, not inferior to AA356 alloy types widely used to cast complex shapes. Addition of silicon to the AlNiMnFe base alloy sharply deteriorates hot cracks. Silicon greatly decreases the solubility of Zr at (Al), which is reflected on hot brittleness of Al2%Ni1%Mn0,5%Fe-0,2%Zr system alloys.

Abstract: The Mg-12Gd-3Y-1Sm-0.5Zr (wt.%) alloy was prepared. After solution and aging treatment, the microstructure and mechanical properties of alloy was investigated. The results show that the experimental alloy is mainly composed by α-Mg matrix and Mg₅Gd, Mg₂₄Y₅, Mg₄₁Sm₅ phase. The experimental alloy has excellent creep properties at 200-300°C/50-70MPa.

Abstract: In this paper, we choose heat resistant material wollastonite and corundum to get the concrete which has heat resistance up to 600 centigrade. SEM reveals that at the temperature of 400 centigrade and 600 centigrade, the material is very dense. But when the temperature gets 800 centigrade and 1000 centigrade, the SEM reveals cracks. The refractory concrete made by magnesium potassium phosphate as the binder and wollastonite and corundum as aggregate has short setting time, early strength and rapid hardening. And it is suitable for emergency repair materials for the kiln.

Abstract: The phase composition of the AlNiMnFeSiZr system is analyzed as applied to heat resistant nikalines (aluminum alloys of a new generation based on Ni containing eutectic), which are strengthened by the Al₃Zr (L12) nanoparticles. It is shown that the presence of iron and silicon considerably complicates the phase analysis when compared with the AN4Mts2 base alloy. Silicon strongly widens the crystallization range, which increases the tendency of the alloy to form hot cracks during casting. It is shown that economically doped nikaline AN2ZhMts substantially exceeds the most heat resistant cast aluminum alloys of the AM5 grade in the totality of its main characteristics (heat resistance and mechanical and production properties).

Abstract: By way of alloying, a sort of low-chromium heat-resistant ductile iron material was developed. Through the observation of microstructure, testing of mechanical properties and process performance, heat-resistant test, the microstructure and properties of heat resistant ductile iron of low chromium was studied. The results show that microstructure of the developed heat-resistant ductile iron is spherical graphite distributed regularly on matrix of pearlite and a small amount of ferrite; mechanical properties, processing performance and high-temperature heat resistance of samples of different chrome composition are preferable, but 1.6% of chromium component possess the best performance.

Abstract: Through the addition of nano-silicon dioxide in the pure polyphenylene sulfide, the masterbatches were obtained, then using melt spinning technology to prepare SiO₂/PPS fiber. The structure and heat-resistant properties of samples were characterized by transmission election microscopy (TEM), infrared spectrum (IR), differential scanning calorimeter (DSC) and other measurements. The experiment results indicate that the mechanical and heat resistance properties of PPS fiber were improved after adding the content of 1%wt nano-silicon dioxide. When the fiber was heated at 230°C for 24 hours, the breaking strength and elongation increased by 2.412cN/dtex and 11.90% compared to the pure PPS fiber. Moreover, the working temperature raised by 50°C.

Abstract: Mg-4Al-6RE-0.3Mn (RE=La, Ce, Pr, Nd, wt.%) magnesium alloys were prepared successfully by the high-pressure die-casting technique. The microstructures and tensile properties in the temperature range from room temperature to 200 °C were investigated. It was confirmed that the Mg-Al-RE-based alloys exhibited an outstanding die-cast character. The cross-section of test bar could be divided into the fine skin region and the relatively coarse interior region by a narrow band with fine structure. Two binary Al-RE (RE=La, Ce, Pr, Nd) phases with the former being the dominant one, Al₁₁RE₃ and Al₂RE, occupied large grain boundary area. All the four alloys exhibited excellent tensile properties until 200 °C, which were mainly attributed to the fine grain size and the strengthening phase Al₁₁RE₃ with high volume fraction, fine acicular/lamellar morphology, "orderly stack” distribution and good thermal stability. The results of this work provided a basis for further investigation of the new heat-resistant high-pressure die-cast magnesium alloys designed to serve at temperature up to 200 °C.

Abstract: The state of the microstructure of ferritic heat resistant steels during creep was evaluate by the system free energy, which composes mainly chemical free energy, surface energy and elastic strain energy, and its stress dependence was expressed quantitatively by using a relaxation time. The steels used in this study were P91 (9Cr-1Mo-C-N-V-Nb) steel and P92 (9Cr-Mo-W-C-N-V-Nb-B) steel. The obtained results are as follows: (1) the relaxation time of elastic strain energy was expressed as a function of stress and temperature, (2) surface energy of P92 scarcely decreased during creep due to the formation of the Laves phase, and (3) the relaxation time of the chemical free energy in P92 was larger than that in P91.