Papers by Keyword: Composition Effect

Abstract: A reduction in trade barriers generally will affect the environment by expanding the scale of economic activity, by altering the composition of economic activity, and by bringing about a change in the techniques of production. This article presents empirical evidence to assess the relative magnitudes of these three effects as they apply to further trade liberalization in Zhongshan city. The author also puts forward some proposals on how to achieve coordinated development of trade and the environment in Zhongshan city.

Abstract: The effect of heat treatment conditions such as atmosphere, temperature, annealing time and alloying elements on the hydrogen content in Al-Mg based alloys was investigated. The hydrogen content after annealing depends on the annealing atmospheres and alloying elements. When annealed in a wet atmosphere, the release of the hydrogen in the Al-Mg alloys to outside and the absorption of hydrogen from atmosphere into Al-Mg alloys are presumed to occur at the same time. The oxide layer on the surface is revealed to prevent the hydrogen from being released to outside. The spheroidal MgO particles can be seen on the surface of Al-Mg alloys after annealing at 550°C. The number of the MgO particles increases with increasing impurity elements such as Si and Fe, reducing the shielding effect against hydrogen permeration. Therefore, the condensation of hydrogen near the surface after annealing occurs more easily in an Al-Mg alloy of a high-purity than that of an ordinary purity.

Abstract: A linear regression model consisting of the weighted sums of certain alloying elements has recently been developed to predict the activation energy (Qrex) and kinetics of static recrystallisation (SRX) for hot-deformed austenite based on stress relaxation test results for over 40 different carbon steels. The validity of the model has been further assessed here by determining the Qrex and the kinetics of SRX of certain high-Nb bearing steels, extra-low and low carbon Nb-Mo bainitic and high-Si dual phase and TRIP steels, and Nb-Ti grades with the varying N content. The validity of the model is shown to be fairly good for the Nb-Ti, Nb-Mo and Cr-Mo grades. The approach of maximum effective concentration of Nb and Si and the weight factor for Cr enable reasonable fit for DP, TRIP and Nb-Cr steels, as well. Possible influences of C and N on Qrex and the kinetics of SRX were checked, but none was observed in microalloyed steels.