فهرست مطالب

International Journal of iron and steel society of Iran
Volume:2 Issue: 1, Winter and Spring 2005

  • تاریخ انتشار: 1384/10/12
  • تعداد عناوین: 7
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  • T. Saeid, S. Yazdani, N. Parvini Ahmadi Page 1
    The effect of an electroless Ni-Cu-P coating on the fatigue behavior of quenched and tempered CK45 steel has been investigated. The fatigue tests under rotating bending conditions have been conducted in three different conditions of uncoated, as-deposited and shot peened prior to the coating deposition. The results indicate that plating of the base steel leads to a fatigue life reduction. The decrease in the fatigue strength was observed to be less marked for the shot peened specimens. The microscopic observations indicate that in the as-deposited condition, the reduction in fatigue life is associated with the nucleation of fatigue cracks on the lateral side of coating. On the contrary, when the samples were shot peened prior to the coating deposition, the crack initiation sites were displaced to the coating-substrate interface which led to an improvement of fatigue behaviour.
  • High Temperature Behavior of Dual Phase Steels
    Page 5
  • A. R. Azimian, A. R. Kazemi Page 7
    In this paper the heating process in a box annealing unit is simulated and the effect of various parameters involved in the process is examined. For this purpose, the full Naiver-Stokes equations along with the standard k- turbulence model are solved in the fluid region using the finite volume approach. In the solid area the conduction heat transfer equation is employed using approporate surface conductance models. The program used for these calculations was the well known fluent code. The effect of various parameters such as inlet temperature, type of gas used, fan power and coil size and weight are examined. Using the simulation results, it is possible to examine the time variation of the temperature at the critical points, i.e. the temperature at the cold and hot spots. Comparisons of the predicted results with the existing field measurement results were promising.
  • Setsuo Takaki Page 21
    It is well-known that severe deformation to metals causes a direct grain refinement of the matrix without special heat-treatments due to the mechanism of dynamic continuous recrystallization (DCR). However, the microstructural revolution during severe deformation is seemed to be different depending on the deformation mode, namely the direction of deformation. In general, multi-directional deformation is thought to be effective for the grain refinement caused through DCR. For instance, ultra-grain-refinement to 10nm has already achieved by mechanical milling treatment in a steel powder and hardness of mechanically milled steel powder is increased to around HV12GPa by such a marked grain refinement. On the other hand, hardness of iron never exceeds HV4GPa by the mode of uni-directional deformation such a conventional cold rolling. In this paper, a limit of dislocation density is discussed for iron which is severely strained by the mode of uni-directional deformation, and also the importance of multi-directional deformation on DCR will be mentioned in association with a significant work hardening behavior in mechanically milled iron powder.
  • M. Karaminezhaad, E. Kordzadeh, S. Ebrahimi Page 31
    The openings of Copper converter in Sarcheshmeh Copper Complex in Iran is made of a heat resisting austenitic steel (Fe-25Cr-12Ni) and many failures have been reported. Understanding the failure mechanism of the alloy helps to develop better alloys for similar complex environments. Samples of as-cast alloy and those taken from failed ones were examined. Optical Microscopy (OM), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) have been applied to examine the alloy and oxide scales. Investigations show that microscopic structure and operational conditions are parameters which affect the fracture of the alloy. The existence of SO2 in the environment increases the reaction rate and formation of sulphides comes near the surface and around the grain boundaries. The sulphides decrease the oxidation resistance of the alloy.
  • H. Aliakbarzadeh, Sh. Mirdamadi, M. Tamizifar, M. R.Saleh Page 34
    Microalloyed cast steels are a group of microalloyed steels in which reliable mechanical properties could be achieved by heat treatment.In this work, the heat treatment processes were carried out on the cast specimens as the step samples by different thicknesses and Zr content. The results show that after homogenization, variations in thickness have no effect on the hardness. Also, after heat treatment, Zr has more effects on properties. The optimum austenitization time was determined 2 hours in 950C. Aging has no effect on hardness on Zr- microalloyed cast steels.
  • K. Mehrabi, M. R. Rahimipou, A. Shokuhfa Page 37
    In this research, the influence of chemical composition of slags and the melting rate on the impurity of commercial grade iron in ESR processing has been investigated.The chemical composition and microstructure studies were evaluated, using spectrophotometer, OM and EDX analyses attached to SEM.The results show that ESR process has successfully reduced the amount and size of inclusions. In some cases, sulfide inclusions were not observed and the size of other inclusions was reduced down to 10, whereas in primary electrodes the size of inclusion was up to 100. An increase in the slag basicity up to a critical point and a decrease in the melting rate caused better desulfurization ability of the slags. However, the increase in the time of process was governed by the melt temperature and fluidity.