Applied Mechanics and Materials Vols. 217-219

Abstract: Two S-type thermocouples connected to paperless recorder are used to record the temperature change during solidification of the wedge spheroidal-graphite casing. The cool-down time and eutectic temperature are obtained from the cooling curves which are calculated by Pro CAST software. Aided by the image-pro plus software, graphite nodules’ mean diameter and amount can be obtained. Carbon diffusion coefficient of graphite nodule is calculated according to the spherulite growth model. The result is in good agreement with the reference date which shows the validity of parameters. It could provide the parameters for simulation of casting solidification.

Abstract: Effects of Sintering atmosphere and temperature on properties of warm compacted 410L stainless steel powder were studied. Sintered density, hardness, tensile strength and elongation were measured. Results showed that in order to achieve high comprehensive properties, the optimal sintering temperature was 1230°C for 410L stainless steel powder. At the same sintering temperature, density and hardness sintered in vacuum were much higher than that sintered in cracked ammonia while tensile strength sintered in cracked ammonia were much higher than that in vacuum. When sintered in vacuum at 1230°C, sintered density was 7.45 g•cm-3, hardness was 65 HRB, tensile strength was 410 MPa and elongation was 29.5%. When sintered in cracked ammonia atmosphere at 1230°C, sintered density was 7.26 g•cm-3, hardness was 97 HRB, tensile strength was 515 MPa and elongation was 3.8%.

Abstract: The aim of this study is to simulate the micromechanics of dual phase (DP) 600 steel during tension-compression deformation and apply the calculated stress-strain curves to identify material parameters of phenomenological constitutive models with focus on Bauschinger effects. Image-based and statistical representative volume element (RVE) models were built to perform virtual tension-compression tests. The effects of mesh size, dimension, martensite volume fraction and martensitic particle size on stress-strain response were also studied. The results showed that the RVE models gave good overall prediction compared with experiment data. Material parameters of Chaboche nonlinear kinematic model were identified by fitting the resulted cyclic strain-stress curve from virtual tests using optimization software LS-OPT.

Abstract: A mathematical model on activities of CaO-based slag system has been established on the bases of ion-molecule coexistence theory of melted slag structure. The activities of CaO-SiO2-B2O3 (Al2O3, Fe2O3) systems are calculated. The effects of the content of B2O3, Al2O3 and Fe2O3 on activities are analyzed. The results indicate that the activities of CaO and 2CaO•SiO2 are decreased with the increases of B2O3, Al2O3 and Fe2O3. The effect of B2O3 is most remarkable. Moreover, the activity of CaO•SiO2 can be enhanced with increasing the contents of B2O3, Al2O3 and Fe2O3 respectively. These effects of Al2O3 and Fe2O3 are very similar, whereas the effect of B2O3 is most significant. As a conclusion, B2O3 is most effective to inhibit the formation of 2CaO•SiO2 as well as to promote the dissolution of lime.

Abstract: In the acetic acid solution containing bromine ions, Br- has strong penetration ability, which cause PTA production device serious pitting corrosion, and even perforation failure. This paper use the immersion method and the electrochemical experiment, to study the corrosion behaviors of austenitic stainless steel which is commonly used in equipment 316L and 1Cr18Ni9Ti in the acetic acid solution containing bromide ions. The results show that: In a certain temperature range, as the temperature rising, 316L and 1Cr18Ni9Ti's annual average corrosion depth shows the changing law of type curve. At the start, the annual average corrosion depth increases rapidly, and after the passivation film formation, the rate of increase slows. With the increase of the Br- concentration, 316L and 1Cr18Ni9Ti's corrosion rate increases, but apparently the 316L than 1Cr18Ni9Ti slow growth of many.

Abstract: The nucleus orientations and the nucleation sites at the early stage of recrystallization were studied by EBSD analysis in Ti-IF steel during direct annealing after warm rolling. It is concluded that the formation of the recrystallization texture is dominated by oriented nucleation mechanism. The recrystallized nuclei with γ-orientation emerge preferentially at the beginning of recrystallization and prefer to form inside the γ-oriented deformation bands and on the boundaries between γ and α-oriented bands.

Abstract: Gas is a key byproduct of the iron and steel process, and the scheduling of gas is the most valuable one in Energy Management System. The production and consumption of the byproduct gas will be related to many sub-processes and tends to encounter imbalance problems. One GAP-like optimization model of gas scheduling is setup, where there are 3 key objectives, minimization of emission, external energy purchasing and instability of the byproduct gas system. The model is NP-Hard and can be find the solution by using intelligent optimization algorithm to realize the static and dynamic scheduling.

Abstract: B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3 steelmaking slags to substitute for CaF2. The influences of B2O3 and CaF2 on the melting properties of this system slags were investigated and compared. The results indicate that the fluxing effect of B2O3 is more remarkable than that of CaF2. Therefore, B2O3 promotes the dissolution of CaO, SiO2 and 2CaO•SiO2, etc, then the slagging speed can be improved greatly. The melting temperatures of slags increase with the increasing of basicity, especially, when CaF2 is used as fluxing agent as well as the basicity is up to 5.0, the melting temperature is increased higher than 1420°C. These characteristics of boron-containing slgas are more suitable for steelmaking process than those of fluoride-containing slags.

Abstract: In this paper the closed-cell sponge of chloroprene rubber(CR) were produced by foaming agent Azodicarbonamide (AC) and Oxybis (benzene sulfonyl) hydrazide (OBSH). The blend blowing agent AC/OBSH was more effective than the pure AC as it could produce chloroprene foam with greater cell porosity, more uniform and better cell distributions. The CR foam prepared with AC/OBSH had better tensile strength and tear strength than pure AC, but higher Shore C hardness. The Polyethyene glycol (PEG) modified Zinc Oxide (ZnO) could accelerate curing and foam process simultaneously. Increase the content of PEG, CR foam has bigger swell ratio, smaller cell size, and better softness.

Abstract: Some novel composites were prepared with polyamide 6(PA6) filled with wollastonite particles and wollastonite inorganic modified by aluminium silicate composite materials (WIMS) as fibrous fillers. Subsequently, these composites were investigated for tensile, charpy notched impact, bending strength, bending modulus and heat distortion temperature, and the mechanism of PA6 reinforced by WIMS was discussed through SEM photos of wollastonite and WIMS and the current two most popular equations: Pukanszky equation and Nielsen equation.The results show that the PA6 products filled with WIMS have superior mechanical properties(tensile strength 71.65Mpa, bending strength 106.61Mpa, bending modulus 3258.22Mpa) than that of uncoated wollastonite and pure PA6, and the heat distortion temperature increases by 88.6°C than pure PA6 and 17.2°C than wollastonite. Inorganic modification of wollastonite can improve the joint interface between wollastonite and PA6, thus improving their mechanical properties.