Effect of tungsten on the temper brittleness in steels with 9%

The impact toughness and the structure of high-chromium martensitic steels with different tungsten contents are studied after tempering at 300 – 800°C. It is shown that when the tungsten content is increased from 2 to 3%, the temperature range of the irreversible temper embrittlement is widened and the impact toughness is decreased by a factor of

Effect of tantalum on the tensile properties of 12%Cr martensitic steels for steam blades

Co-modified 12%Cr martensitic steels are perspective materials for steam blades for fossil power plants which are able to work at ultra-supercritical parameters of steam (T=620-650°C, P=2530 MPa

Effect of alloying on interfacial energy of precipitation/matrix in high-chromium martensitic steels

The effect of cobalt, tungsten, and boron on interfacial energy of precipitate/ferritic matrix in the 9% Cr martensitic steels on the base of creep tests at 650 °C under different applied stresses ranging from 80 to 220 MPa was investigate

Effect of alloying on the nucleation and growth of laves phase in the 9-10% CR-3% CO martensitic steels during creep

Five Co-modified P92-type steels with different contents of Cr,W, Mo, B, N, and Re have been examined to evaluate the effect of the chemical composition on the evolution of Laves phase during creep at 650 C. The creep tests have been carried out at 650 C under various applied initial stresses ranging from 80 to 200 MPa until rupture. An increase in the B and Cr contents leads to a decrease in the size and volume fraction of M₂₃C₆ carbides precipitated during tempering and an increase in their number particle density along the boundaries. In turns, this affects the amount of the nucleation sites for Laves phase during cree

THE EVOLUTION OF M(C,N) CARBONITRIDES IN 9 % Cr STEELS UNDER CREEP

Высокохромистые стали мартенситного класса с различным содержанием вольфрама (2 и 3 вес.%) были испытаны на длительную прочность при Т = 650 °С и приложенных напряжениях от 100 до 220 МПа. Обе стали демонстрируют перелом на кривой Приложенное напряжение – время до разрушения при времени испытания ~ 2 000 ч. Двухфазное разделение карбонитридов М(C,N) на Nb- и V-обогащенные частицы происходит в процессе отпуска. Было обнаружено, что перелом на кривой Приложенное напряжение – время до разрушения для исследуемых сталей не связан с укрупнением этих частиц или их трансформацией в Z-фазу.Two 9Cr-3Co-0.5Mo-VNb steels with 2 and 3 wt.%W were crept at 650°C under applied stresses ranging from 100 to 220 MPa. Both steels exhibit the creep strength breakdown at a rupture time of ~2 000 h. The two-phase separation of M(C,N) carbonitrides to Nb- and V-rich particles occurs during tempering. The creep strength breakdown was not related to the coarsening of these particles or their transformation into Z-phase.Исследование выполнено за счет гранта Российского научного фонда (проект №14-29-00173)

Analysis of mechanical properties for the heat resistant CO-modified 12 and 9% CR steels

An analysis of mechanical properties has been performed for 12% Cr and 9% Cr steels by means of tension tests at 20 and 650°C and yield tests at 650°C and applied stresses of 200-100 MPa with a step of 20 MPa. The yield strength and ultimate tensile strength of the 12% Cr steel are, correspondingly, 614 and 710 MPa at 20°С and 365 and 390 MPa at 650°

The effect of creep and long annealing conditions on the formation of the Z-phase particles

The influence of the temperature, applied stress, degree of creep deformation, and aging time on the formation of Z-phase (CrVN) particles in 9% Cr 10Kh9K3V2MFBR martensitic steel at temperatures of 650 and 675°С upon long aging is studied in this wor

Renin-angiotensin-aldosterone system in ISIAH rats with stressinduced arterial hypertension

Because the renin-angiotensin system (RAS) has a wide range of opportunities in the regulation of fluid and electrolyte balance and arterial pressure, it is currently hypothesized that alterations in systemic circulating or local tissue RAS are some of the most important pathogenetic factors in the development of essential hypertension. The aim of the study was to investigate circulating and local tissue RAS activities in ISIAH rats with stress-induced arterial hypertension. We estimated the serum levels of renin, the angiotensin-converting enzyme, angiotensin II and aldosterone by an enzymelinked immunosorbent assay, and mRNA expression of RAS genes in kidney, adrenals and brain tissues was measured by the real-time polymerase chain reaction. The mRNA expression of the renin gene (Ren) in the ISIAH rats was significantly decreased as compared to the normotensive WAG rats, but plasma renin concentrations had no difference. At the same time, the serum levels of angiotensin II and aldosterone in the ISIAH rats were enhanced, which suggests the existence of an ectopic site of angiotensin synthesis. Expression of RAS genes in the adrenals of hypertensive rats was unchanged. By contrast, a significant increase of RAS genes expression was found in the brain tissues. The mRNA of the Ren gene was increased in the hypothalamus, and the mRNA of Ace gene was increased in the brain stem of the ISIAH rats. This may be indicative of a local increase of RAS activity in the brain tissues of ISIAH rats. Nevertheless, the results of the study define ISIAH rat strain as a model of human low-renin hypertension

Fluctuation-induced phase in CsCuCl3 in transverse magnetic field: Theory

CsCuCl3 is a quantum triangular antiferromagnet, ferromagnetically stacked, with an incommensurate (IC) structure due to a Dzyaloshinskii-Moriya interaction. Because of the classical degeneracy caused by the frustration, fluctuations in CsCuCl3 have extraordinarily large effects, such as the phase transition in longitudinal magnetic field (normal to the planes, parallel to the IC wavenumber q) and the plateau in q in transverse field (perpendicular to q). We argue that fluctuations are responsible also for the new IC phase discovered in transverse field near the Neel temperature T_N, by T. Werner et al. [Solid State Commun. 102, p.609 (1997)]. We develop and analyse the corresponding minimal Landau theory; the effects of fluctuations on the frustration are included phenomenologically, by means of a biquadratic term. The Landau theory gives two IC phases, one familiar from previous studies; properties of the new IC phase, which occupies a pocket of the temperature-field phase diagram near T_N, agree qualitatively with those of the new phase found experimentally.Comment: 12 pages, revtex, 4 postscript figures, submitted to J. Phys: Condens. Matte