Advanced Materials Research Vols. 415-417

Abstract: Aiming to solve the plate-cutting difficulties on new phenolic insulation board production line, this study designed a synchronous fixed-length system. On the basis of analyzing system workflow, this system took PLC as the main control unit, used photoelectric encoder to measure the plate traveling motion and velocity, got PLC to control servo system to achieve the target of the synchronous tracking and fixed-length cutting on insulation board by synchronous cutting car, so as to increase cutting accuracy and production efficiency. This design includes the software and hardware designs of the control system and takes the PID control algorithm in accurate positioning. This system properly realizes the synchronous fixed-length cutting of new insulation board, has high cutting accuracy, operates steady, meets the control needs of new phenolic insulation board on production line, and largely improve production efficiency.

Abstract: A novel microalloy Q&P steel with Nb and Mo is designed. The dilatometric curves of low-carton microalloyed Q&P steel with and without Nb and Mo are detected at different cooling rates on DIL-805 thermal dilatometer．The CCT curves are determined using thermal dilation measurement, microstructure observation and hardness measurement. In the Q&P process, the niobium carbide precipitate plays a precipitation strengthening effect, so the tensile strength of Q&P steel is enhanced. The results show that: The element Nb decreases the phase-transformation temperatures of ferrite and pearlite, which leads the proeutectoid ferrite and pearlite phase transformation finish lines to move to lower-right. For the low-carton Q&P steel microalloyed with Nb and Mo, when cooling rate is higher than 5°C•s^－1, the microstructures is only martensite. Its excellent hardenability is propitious to improve the strength of the Q&P steel. While, for the traditional C-Si-Mn Q&P steel, the martensite can be only obtained until the cooling rate higher than 20°C•s^－1.

Abstract: 0.04C-16Cr and 0.04C-16Cr containing 26ppm B ferritic stainless steels were smelted by using a vacuum induction furnace. Then 65% boiling nitric acid method and the electrochemical potentiokinetic reactivation method (EPR) were used to research their intergranular corrosion sensitivity. Meanwhile, electrochemical test method (Tafel polarization curve method, the anode circular polarization curve method) and chemical immersion method were used to research their pitting corrosion resistance. The results showed that the corrosion rate of 0.04 C-16Cr stainless steel containing 26ppm B in 65% boiling nitric acid is lower than that of 0.04 C-16Cr stainless steel. The reactivation rate of 0.04C-16Cr containing 26ppm B in dilute sulphuric acid medium significantly reduced compared with that of 0.04C-16Cr. The pitting corrosion potential, self-corrosion potential and the value of (Eb-Ep) of the stainless steel containing with 26ppm B in chlorideions medium reduced, while the corrosion rate increased compared with the stainless steel without B addition. It indicates that trace boron addition improves the intergranular corrosion resistance and repair ability of the passive film of the 0.04C-16Cr ferritic stainless steel after pitting corrosion process in chloride ions medium, but it also promotes the pitting corrosion tendency of the steel. Besides, introduction B to 0.04C-16Cr ferritic stainless steel reduces the steel’s corrosion resistance in active dissolved zone and promotes its intergranular corrosion tendency in chloride ions medium. The electrochemical characteristics of local corrosion are consistent with the results of chemical immersion test.

Abstract: This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The variation rules of strength, load, and reliability of mechanical components are studied with a change in time, and a model is established for dynamic reliability of mechanical components under the random load acting. By combining the theory of reliability design with the method of sensitivity analysis, the computational method of dynamic reliability sensitivity design with arbitrary distribution parameter is proposed based on the methods Edgeworth and perturbation, and the problem of dynamic reliability sensitivity design of mechanical components distributed arbitrary distribution is solved as well as the variation rules of dynamic reliability sensitivity are given. The variation of reliability is studied as design parameters change a little, which provides theoretical data for dynamic reliability design of mechanical components.

Abstract: Along with increasing W and Mo contents in Cr-W-Mo-V high alloy medium-upper carbon steels, the maximal hardness of secondary hardening during tempering is increasing gradually and arrives to 66.8HRC, and the congruent quenching temperature and the tempering temperature corresponding to maximal hardness are ascending. The quenching microstructure of experimental steels is matrix and a small quantity of undissolved carbides when the hardness is maximal, wich is corresponding to tempering temperature of remnant austenitic decomposing acutely. The precipitation of M₆C and MC carbides was detected, and M₇C₃ and M₃C carbides was detected too. But M₂₃C₆ carbide did not appear and M₂C carbide was detected undistinguishably. The temperature range of tempering maximal hardness is 500°C-550°C, and an exact temperature is opposite to the mass fraction ratio of equilibrium carbide phases at the temperature. The tempering hardness value can be obtained from H_S= a(1+b)/(0.0127a+0.00297), in which a is square root of saturation level of the carbon in the matrix and b is correction factor having something to do with alloy elements of carbide precipitation.

Abstract: Soft reduction has been proved to be the best way to minimize center segregation and eliminate center porosity. Aiming at determining optimum soft reduction parameter for variation steel grades and different process conditions, a thermal-mechanical coupled FEM(Finite Element Method) model was developed to analyze the deformation behavior of the given bloom under the operation of soft reduction technology. The mechanical strain / stress of the bloom cross-section, especially the stain /stress around the solidification front, under the application of soft reduction are obtained. Considering the high temperature mechanical properties of the given steel grade GCr15 (with chromium content of 1.40~1.65 percent and carbon content of 0.95~1.05 percent) and strain/stress distribution in the section thoroughly, the proper soft reduction parameter are determined.

Abstract: Abstract. This paper had an improvement research on the annealing process of AISI4145H steel by changing the processing parameters of heat treatment in laboratory. An experimental physical simulation was conducted between 650 °C and 740 °C. The effect upon the hardness of AISI4145H steel under different temperature and holding time investigated. And the condition of Φ 150 mm AISI4145H steel that was heated and warmed up in an annealing furnace was tested by adopting a black box. Results showed that the Ac1 of AISI4145H steel was 757.2 °C and the Ac3 was 787.7 °C. By the annealed conditions that sample was heated at 710 °C for 1h, cooled to 500 °C in furnace and cooled in air in turn, we found its hardness was HRC 21.4 and meet the needs of industrial production. New process of the present work shortened holding time of workpiece, increased cooling rate of annealed, shortened the annealed time about 24 h, effectively increased production efficiency, and reduced production costs.

Abstract: The problem occurs in producing thin wall ductile iron (TWDI) is high cooling rate due to its thickness. Cooling rate must be strictly maintained to prevent carbide formation. There are many ways to control cooling rate. Casting design is one of these, especially gating system design. This parameter is often chosen because of its independence. Major changes in equipment and raw material used in the foundry are not needed when a casting design is chosen to deal with cooling rate. This paper discusses the effect of gating system design on microstructure and mechanical properties of 3 mm TWDI plate. A casting design based on gating system design is made to produce 1, 2, 3, 4, and 5 mm TWDI plates. There are three designs coded as T1, T2, and T3. These three designs were also used in making 1 mm TWDI plates of which the result has been published. The plate with thickness of 3 mm will be used for automotive component like the crankshaft made by Martinez. The moulds used were furan sand. Beside the experiment, casting design simulation with Z-Cast was also conducted to see the behaviour of solidification in 3 mm TWDI plate. Simulation result showed every design has its own solidification behaviour for 3 mm TWDI plate, especially for T2. Experiment result showed that all the designs have microstructure consisting of nodule graphite in ferrite matrix, no trace of carbide and skin effect are formed. Skin effect length is various for all designs. Nodularity exceeded 75% and nodule count exceeded 900 nodules/mm². Brinell hardness number for all design is beyond standard given by JIG G5502. As for UTS and elongation none of the designs exceed the minimal standard. Experiment results confirmed simulation result. Compared to the previous result nodularity and nodule count decrease and curve trends for every result are not the same.

Abstract: Laser tailor-welded blanks is one of the widely used in automotive industries as it reduces manufacturing cost and weight and also improves the quality of the components. The effects of difference in material properties, welding properties on blank formability become important in various forming processes. In this study the welding property of different gauge laser tailor-welded blanks was observed in microhardness and microstructure aspect. The property effects on the formality of the tailor-welded blanks were discussed. That the laser welded joint is qualified to satisfy the demand of sheet forming.

Abstract: Optically induced dielectrophoresis (ODEP) has been proved experimentally as a powerful method for efficiently manipulating some micro-scale, or even nano-scale objects. However, few ODEP platforms have been demonstrated towards the fully automatic wafer-scale manipulation and rapid fabrication of micro and nano sensors and devices. That would be of great significance to the application and industrialization of micro and nano materials. In this paper, an innovative ODEP platform for reconfigurable and automatic micro/nano-scale material manipulation is presented by combining microactuation and microvision analysis with ODEP technology. The ODEP chip consists of a typical photoconductive layer of amorphous silicon, which generates a nonuniform electric field at the light-illuminated region to induce dielectrophoretic (DEP) force for manipulating particles within the chip. A high resolution 3D motorized stage enables an accurate and rapid movement of the chip in wafer-scale. The microvision analysis program automatically recognizes the positions and sizes of randomly distributed particles and creates direct image patterns to manipulate the selected particles to form a predetermined pattern in predesired position. The programmed dynamic reconfigurable optical patterns provide increased functionality and versatility in particle manipulation. The patterning of polystyrene beads with different sizes is accomplished. This platform may be promising for rapid and wafer-scale fabrication of micro and nano sensors and devices, high-throughput bio-sample pretreatment and other applications requiring massively parallel manipulation.