Advanced Materials Research Vols. 476-478

Abstract: The effect of Mo and Ni content on the mechanical properties of low carbon and alloy casting steel by using Vacuum Arc Melting Furnace had been studied in this paper. The results indicated that increasing Mo or Ni content would enhance the hardness and strength of the steel separately, with some of elongation loss. It showed that ferrite refined with the increasing alloy content. The combinations of Mo and Ni content were of importance for comprehensive mechanical properties and wear resistance. The appropriate content in low carbon casting steel with 0.02%Nb was 0.5%-0.6%Mo and 0.2%-0.4%Ni.

Abstract: To improve the service performance of Cr-series steel for cold roller, the combined effects of chromium and silicon on hardness and wear resistance of cold roll steel had been studied in this paper on the basis of MC5 cold roll steel. The results showed that, with increasing Si content the hardness tended to decrease when Cr content was about the same. The hardness was the highest and the wear resistance was the best when Cr content was about 6.7% and Si content about 0.6%. The reason for this found by microscopic analysis was that the carbide size was the finest and carbides were the most dispersively distributed. Meanwhile, the amount of carbides was also the largest.

Abstract: With an increasing demand for high grade electric magnetic steels, SSRF(Single Snorkel Refining Furance) has got much attention due to its high efficiency of both decarburization and desulphurization. However the desulphurization mechanism of this kind SSRF is remarkably different from that of other steel refining processes such as LF,RH etc. , so it is necessary to understand the behaviour of desulphurization clearly. A mathmatical model has been established in this paper to investigate the degree of desulpurization with time on the basis of the influencing factors such as sulphur capacity of flux ,stirring energy of molten steel. It is shown that the desulpurization rate constant is about 1.0E-8 in accordance with the data from the practical test of a steel plant with SSRF.

Abstract: Creep-rupture properties of modified 9Cr-1Mo steel with 140~150HB low hardness were studied. Results showed that the creep-rupture properties of the experimental steel deteriorate badly and decreased with experimental temperature increasing. The life evaluation was carried out based on the experimental results, that provides guidance for material evaluation and operation supervision.

Abstract: Three groups of GCr15 steel were heat-treated respectively by conventional spheroidizing annealing, circulation spheroidizing annealing, 1050°C for 30min oil cooling quenching + 700°C tempering. The final heat treatment of these GCr15 steel was 840°C oil cooling quenching + 150°C tempering. The microstructure of the heat-treated GCr15 were observed and the mechanism of three spheroidizing treatment were discussed in this paper. The results showed that: There is obvious difference among the three groups carbide of GCr15 for the mechanism of three spheroidizing treatments is different. The GCr15 has 1050°C for 30min oil cooling quenching + 700°C tempering showed the best result of carbide spheroidizing. The microstructure of GCr15 after 840°C oil cooling quenching + 150 °C tempering was tempered martensite and carbide which is fine, round and widely distributed.

Abstract: The acid leaching of spent aerospace material with pollution-free oxidation is discussed. Effect of parameters including initial concentration of hydrochloric acid solution, leaching temperature, reaction time, agitation speed, liquid to solid ratio and concentration of oxidant on valuable element extractions are determined, the optimized conditions are 6 M, 60 °C, 30 min, 250 r/min, 6:1 and 0.0378 mol•L-1•min-1, respectively. The comprehensive results of experiments show that the extracting efficiency of Co and Cu are over 83% and 98% respectively when optimized conditions were adopted.

Abstract: Sealing processing technique, a major measure to join parts or components together in machinery or electronic industry, is adopted in this research to seal the fabricated composite material and protect the composite from the potentially harmful influence of the outside environment, particularly the environment with corrosive media like ozone gas (O3), etc. The manufactured composite material mainly consists of organic polymeric materials like polyester fabric and PET thin film. Mechanical tests are performed to measure the mechanical strength of the fabricated composite which has been submerged in corrosive environment for some time period, and to study possibly different failure behavior or mechanism of the composite when the sealing methods are different.

Abstract: Blends of Poly(L-lactide) (PLLA) and nano-SiO2 powder were prepared via solution mixing. Effect of nano-SiO2 particles on the crystallinity of PLLA in composite was investigated by X-ray diffraction, the result indicated that the incorporation of nano-SiO2 did not influence the crystallinity of PLLA in composite. The bending strength and modulus of the PLLA/nano-SiO2 composites with varying nano-SiO2 content were tested, showing that the bending strength reduced with the increase of nano-SiO2 content and the bending modulus increased. The SEM graphs of PLLA/nano-SiO2 composites were illustrated that the cross-section of composites varied from brittle to ductile fracture with the content of nano-SiO2 increasing up to 10 %, and changed from ductile to brittle fracture with further increasing of nano-SiO2 content.

Abstract: With the development of wireless sensor network (WSN), Internet of Things (IOT) has been widely adopted by different fields. Cultural heritages preservation is one of the typical application scenes in these fields. The cultural heritages are always in the special environments, such as open land or damp tomb cave, which is very suitable for IOT. In this paper, some current preservation technologies and solutions are analyzed, and existing problems are described. Finally, a novel cultural heritage preservation solution based on IOT is proposed, and a corresponding prototype system is introduced and verified.

Abstract: In electrochemical machining (ECM) machining accuracy of workpieces is greatly influenced by many machining parameters. In this paper the BP neural network model is employed to optimize machining parameters in ECM. Taking a three dimensional complicated surface as the research object the experimental results have shown that the optimization process can be easily operated and the result is of high precision.