Improving a technology for treating pig iron outside the furnace with magnesium

Institute of Ferrous Metallurgy. Translated from Metallurg, No. 4, p. 24, April, 1989.     

Effects of sulfur content in tube steel welds on sulfide cracking

Materials Science - Results are presented on the tendency to stress corrosion cracking in NACE solution for welded joints in tube steel with sulfur contents from 0.002 to 0.028%. Threshold stresses...     

Dependence of dielectric properties of manganese-doped strontium titanate ceramics on sintering atmosphere

It is shown in this paper that the microscopic mechanism of the dielectric relaxation in Mn-doped strontium titanate (SrTiO₃–ST) ceramics is associated with the off-center displacement of ions. This was accomplished by studying the dielectric properties and electron spin resonance spectroscopy in combination with X-ray powder diffractometry and scanning electron microscopy techniques in Sr_1−xMn_xTiO₃ ceramic samples sintered in different atmospheres (air, oxygen and nitrogen) at 1500 °C. First, it is shown that manganese is incorporated into the perovskite lattice of ST, preferably as Mn²⁺ at Sr sites. However, a small amount of Mn⁴⁺ at Ti sites is also observed when fired in air or oxygen flow. The concentration of is the highest for sintering in oxygen, but firing in a reducing atmosphere (nitrogen) results solely in the incorporation of Mn²⁺ at Sr sites. Correspondingly, the dielectric relaxation observed in Sr_1−xMn_xTiO₃ markedly increases in intensity and slightly shifts towards a higher temperature for ceramics sintered in nitrogen compared with those fired in air or oxygen. All these facts are consistent with a suggestion that the off-center displacement of Mn²⁺ ions at the Sr sites of the highly polarizable ST lattice is the source of the observed relaxation behavior.     

Corrosion cracking of welded joints in a pipe steel in a hydrogen-sulfide medium

Conclusions 1. The maximum long-term corrosion strength in the NACE solution was recorded for the specimens welded under the conditions of specimens 2 (3.0 kJ/mm); their threshold stress was equal to 250 MPa (0.7_0.2); for other types of specimens welded with a heat input of 6.0 kJ/mm and 1.25 kJ/mm the threshold stress was equal to 180 and 160 MPa, respectively.2. In the experiments with a low strain rate of the metal the highest relative resistance was recorded for the specimens 2 and the resistance decreased in the sequence 213.E. O. Paton Electric Welding Institute, Academy of Sciences of the Ukraine, Kiev. G.V. Karpenko Physico-mechanical Institute, Academy of Sciences of the Ukraine, L'vov. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 2, pp. 52–56, March–April, 1993.     

Calculation,planning, and production technology of the radiation shielding means of nuclear power plants in spacecraft

"Krasnaya Zvezda." Scientific Planning Department Physics Power Institute of New Materials. Translated from Atomnaya Énergiya, Vol. 74, No. 3, pp. 237–243, March, 1993.     

Influence of Heat Treatment on the Mechanical Characteristics of Diamond Powders

Powder Metallurgy and Metal Ceramics - Improvement in the efficiency of diamond tools is inextricably linked with the use of high-strength heat-resistant diamond grains for tooling. Hence, study of...