Electron Microscope Studies of the 01Cr17Ni13Mo3 Austenitic Steel Structure after Cold Rolling Combined with Hydrogen Alloying with Varying Degrees of Deformation

In this paper, we consider the effect of cold rolling and hydrogen alloying on the formation of twin boundaries of the corrosion resistance of austenitic steel 01Cr17Ni13Mo3. Using the method of transmission electronic microscopy, microdiffraction patterns were obtained. The analysis of microdiffraction patterns indicates the formation of a developed grain-subgrain structure with small-angle and large-angle misorientation. The structure has a high dislocation density, deformation twins and localized shift bands. It was established that plastic deformation by flat rolling to ε = 90 % at room temperature does not contribute to the appearance of a noticeable amount of α' and ε-martensite. At the temperature of liquid nitrogen, the samples were found to form a small fraction of the α'-martensite phase. Such a small amount of martensite can contribute to steel strengthening, and a decrease in the rolling temperature will lead to an increase in the strength properties of steel. It was detected that the density of twin boundaries under the decrease in the rolling temperature but with the same intensity of hydrogen saturation is significantly higher. A noticeable reduction in the width of the twin lamellas was revealed.

Minimization of Ultra-High Temperature Filtration Loss for Water-Based Drilling Fluid with ß-Cyclodextrin Polymer Microspheres

Due to the rapid degradation of conventional biopolymer or synthetic polymeric additives at high temperature (HT) or ultra-high temperatures (ultra-HT), effective control of water-based drilling fluid filtration in HT or Ultra-HT environment is still a great challenge in drilling operation. β-cyclodextrin polymer microspheres (β-CPMs), generally using for drug release and waste water treatment, are evaluated as environmentally friendly ultra-HT filtration reducer. The impact of the microspheres on water-based drilling fluids’ properties including rheology and filtration prior to and after hot rolling at different temperatures ranging from 120 to 240°C was investigated. The high temperature and high pressure (HTHP) filtration properties of the microspheres compared to several commercial high temperature filtration reducers were conducted according to the API recommended procedures. The filtration controlling mechanism was analyzed from zeta potential measurement, particle size distribution measurement, and scanning electron microscope observation of filter cake. The results indicated that the β-CPMs exhibited peculiar filtration behavior differently from conventional additives. When the hot rolling temperature was below 160℃, β-CPMs performed a 30% filtration reduction at 1 w/v% content in comparison with control sample. Once the hot rolling temperature was above 160℃, the capacity of filtration control was further improved with increasing temperatures. This is contrast with conventional filtration reducers that the filtration control capacity deteriorate with increasing temperatures. The microspheres still exhibited superior filtration control after exposure to 240℃. Furthermore, β-CPMs showed little effect on the drilling fluid's rheology. When the temperature was below 160℃, the filtration reduction was obtained by water absorption and swelling of β-CPMs. When the temperature was above 160℃, hydrothermal reaction occurred for β-CPMs. Numerous micro- and nano-sized carbon spheres formed, which bridge across micro and nanopores within filter cake and reduce the filter cake permeability effectively. When the temperature was higher than 160℃, hydrothermal reaction occurs. Carbon spheres generated by the hydrothermal degradation of the β-CPMs, which are responsible for the effective filtration control. The hydrothermal reaction changes the adverse effect of high temperature into favorable improvement of filtration control, which provides a novel avenue for HT and ultra-HT filtration control. The β-CPMs show potential application in deep well drilling as environmental friendly and high temperature filtration reducers.

Effect of Process Parameters on the Microstructure and Mechanical Properties of Bars from Al-Cu-Mg Alloy Processed by Multipass Radial-Shear Rolling

The study of microstructure and mechanical properties formation of A2024 alloy obtained by the multipass radial-shear rolling (RSR) method is discussed in this article. FEM simulation was carried out that made it possible to evaluate the influence degree of rolling temperature-velocity parameters on the strain state of material. It has been found the increase in rotary velocity of rolls significantly influences on the deformation heating of bar after RSR (predominantly in its surface layer). The combination of rolling temperature-velocity conditions at selection of deformation regime has complex effect on structure and properties formation. The analysis of sizes and distribution of phase particles has shown that the rolling at lower temperatures allowed to increase the mechanical strength due to the more intensive refinement of undissolved Fe-containing phase. The gradual decrease in the rolling temperature in each pass makes possible to achieve the high strength (UTS~430 MPa and YS~255 MPa) while maintaining the ductility level ~15%, that are comparable to ones obtained at some severe plastic deformation (SPD) methods.