Advanced Materials Research Vols. 311-313

Abstract: Corroded behavior of 310S stainless steel by molten Al-Si eutectic alloy in high temperature thermal cycles of 495～620°C was investigated. SEM/EDX, XRD and metallographic technique were used for observing and analyzing the morphology, composition and internal microstructure of the corrosion specimens. Results showed: on the surface of 310S stainless steel, after corroded through 300 melting-solidification thermal cycles, a corrosion layer of about 3μm thick, composed mainly of Fe2Al5 phase and FeAl3 phase was formed. Besides, upon observation of internal microstructure of 310S stainless steel after corrosion, plenty intercrystalline precipitation was present, which resulted in relatively severe intercrystalline corrosion. This was considered the principal factor that compromised mechanical property of the specimen of 310S stainless steel.

Abstract: To avoid slag sticking onto the ladle snorkel during the CAS-OB refining and alloying process, CaO-B₂O₃ and CaO-CaF₂ were respectively employed as modifiers added into the ladle slag. The desulfurization capability of modified slag was investigated. The results of experiments on sulphur partition equilibrium between metal and slag indicate that the sulphur content of metal can be further decreased by the modified slag. When CaO-B₂O₃ is used as additive and the mass ratio of CaO to B₂O₃ is 1:1, the desulfurization ratio of slag to liquid steel is 50%, the final sulphur content can be controlled at 0.002%. The efficiency of desulfurization is fine. When CaO- CaF₂ is employed as additive and the mass ratio of CaF₂ to CaO is 2:8, the final sulphur content of metal can be controlled lower than 0.004%, the efficiency of desulfurization is also acceptable.

Abstract: B₂O₃ is employed as fluxing agent of high basicity CaO-based flux to substitute for CaF₂. The effects of B₂O₃ and CaF₂ on the metallurgy properties of CaO-based flux were investigated. The results indicate that the fluxing action of B₂O₃ is better than that of CaF₂. For the high basicity CaO-based flux, when CaF₂ is substituted with B₂O₃, the melting temperature can be decreased remarkably. Especially, when the mass ratios of CaO/SiO₂ are in range of 5.25~8.0, the flux melting temperature is lower than 1300 °C. The inflection point temperature of flux viscosity-temperature curve is lowered remarkably when B2O3 is employed to substitute for CaF₂. Meanwhile, the desulfurization capacity of flux can be improved markedly when CaF₂ is substituted with equal mass of B₂O₃.

Abstract: Fracture images automatic classification and recognition is an important one of fracture failure intelligent diagnosis, and in which feature extraction is a key issue. In this paper, fractional cosine transform, which is a useful time-frequency analysis method, is used in feature extraction of fracture images, and then the classification of fatigue, dimples, intergranular and cleavage is performed by Hidden markov model (HMM). For metal fracture images classification, experiment shows that fractional cosine transform is better than the cosine transform in fracture images feature description, and the correct recognition rate can be achieved 98.8% based on HMM classification mode

Abstract: Three different quenching media (water, oil and air) were used to compare the effect of cooling rate on the microstructure and mechanical properties of SA508-3 steel. The result has demonstrated that the microstructure for water-quenched specimen is the mixture of martensite and lower bainite, for oil-quenched specimen is the mixture of upper bainite，lower bainite and a little martensite, while for air-cooled specimen is mostly granular bainite. The product of water and oil Q&T was tempered martensite with qualified mechanical properties. The air-cooled granular bainite was translated to massive and allotriomorphic ferrite during tempering, which had poor mechanical properties. To avoid the formation of granular bainite, it is necessary to increase the cooling rate to above 5°C/s.

Abstract: Removed due to authors request.

Abstract: Consistency maintenance is a key problem in collaborative product design. Firstly, based on product design theory, the semantics relationships described by XML among components in collaborative product design system are made. Secondly, the associated components are determined through backward and forward semantics reasoning. Finally, the data is updated by constraints solving, and the consistency maintenance is achieved.

Abstract: Abstract: To Huanggang River watershed protection, for example, to carry out the exploration of environmental education on campus. River basin water pollution on the East China survey, indicating that the industry, and agriculture are the three sources of life; of the East China River Basin water quality trends and the causes of water pollution in Huanggang River Basin; described Huanggang the importance of water resource protection, and Defining the student's role in the protection of the environment.

Abstract: The corrosion behavior of X70 pipeline steel in 0.5% NaC1 solution in different temperature of 25°C、35°C and 55°C was studied by dynamic potential polarization curve and electrochemical impedance spectroscopy（EIS）method. The corrosion topography of X70 pipeline steel in normal temperature and 30°C was also compared in immersion corrosion test after 25 days. The results show that when the temperature rises, the corrosion current density Icorr increases, the linear polarization resistance reduces, cathode polarization curve right shift, caused corrosion rate increases which primarily by the increasing the transmission of reactant in the cathode reaction. Pitting corrosion developed after 25 days immersion corrosion in 30°C solution which proved the promoter action of temperature to pit corrosion, and which is agreed with the electrochemical corrosion test results.

Abstract: In the process of customizing of CAD system for parametric product design, the modeling technology of product knowledge, the KBE (Knowledge Based Engineering) application architecture and technologies was studied. This paper proposed the classification standard for product knowledge base upon the methods of defining and representing ontological knowledge and procedural knowledge. Depending on the logic of product knowledge model, the function architecture of KBE software package embedded in CAD system has been constructed. Some practical technologies have been illustrated, like the visual interactive 3D annotation user interface base upon engineering semantic symbol, which can actualize the acquisition, representation, and ratiocination of knowledge. Using NXTM Open C and KF (Knowledge Fusion) as program language, all the methods for knowledge manipulation can be carried into execution in CAD system.