Effect of Tungsten on Creep Behavior of 9%Cr–3%Co Martensitic Steels

Abstract

Abstract:The effect of increasing tungsten content from 2 to 3 wt % on the creep rupture strength of a 3 wt % Co-modified P92-type steel was studied. Creep tests were carried out at a temperature of 650 • C under applied stresses ranging from 100 to 220 MPa with a step of 20 MPa. It was found that an increase in W content from 2 to 3 wt % resulted in a +15% and +14% increase in the creep rupture strength in the short-term region (up to 10 3 h) and long-term one (up to 10 4 h), respectively. On the other hand, in the long-term creep region, the effect of W on creep strength diminished with increasing rupture time, up to complete disappearance at 10 5 h, because of depletion of excess W from the solid solution in the form of precipitation of the Laves phase particles. An increase in W content led to the increased amount of Laves phase and rapid coarsening of these particles under long-term creep. The contribution of W to the enhancement of creep resistance has short-term character.

Effects of Tempering Temperature on the Microstructure and Mechanical Properties of T92 Heat-Resistant Steel

“…T92 heat-resistant steel has a microstructure of tempered lath martensite and precipitates, including M 23 C 6 carbides, MX V/N carbonitrides, and high density of dislocations in matrix [4][5][6], where all of them can contribute to the strength of the material. The main microstructural evolution of T92 steel during long-term thermal aging and service includes the coarsening of the lath martensite, decreasing of dislocation density, and the growth of precipitates (M 23 C 6 carbides and Laves phases) [6][7][8][9]. The microstructure evolution results in the deterioration of the mechanical properties of T92 steel.…”

Creep Buckling of 304 Stainless-Steel Tubes Subjected to External Pressure for Nuclear Power Plant Applications

“…Several parametric models have been proposed for predicting the long-term failure time based on short-term measurement data [19][20][21]. The LMP model and the Monkman-Grant model are widely used for the estimation of the creep-buckling failure time [12,[22][23][24]. These models are both based on experimental measurements, but the Monkman-Grant model needs the minimum strain rate of the specimen.…”

Microstructure and Mechanical Properties of Structural Metals and Alloys

“…The major portion of these papers is focused on the mechanisms of microstructure evolution and the mechanical properties of metallic materials subjected to various thermo-mechanical, deformation, or heat treatments [1][2][3][4][5][6][7][8][9][10][11][12]. Another large portion of the studies is aimed on the elaboration of alloying design of advanced steels and alloys [13][14][15][16]. The changes in phase content, transformation, and particle precipitation and their effect on the properties are also broadly presented in this collection [17][18][19][20][21].…”

“…Those readers interested in structural steels may learn much from comprehensive investigations of microstructural changes and their effect on mechanical properties caused by plastic working and heat treatment of diverse steel types [2,7,8,10,12,15,16,[19][20][21][22]. Two of these papers [7,12] present experimental/simulation results of mechanical behavior of high-Mn TWIP steels, which have recently aroused a great interest among material scientists and engineers because of outstanding strengthductility combination inherent in such steels.…”

“…Two of these papers [7,12] present experimental/simulation results of mechanical behavior of high-Mn TWIP steels, which have recently aroused a great interest among material scientists and engineers because of outstanding strengthductility combination inherent in such steels. Some crucial features of structure-property relations are detailed for advanced heat resistant [10,15,19,22] and stainless [8,21] steels. Materials scientists working with aluminum alloys may find many interesting results for dispersion strengthening, including processing, structural/precipitation analysis, and mechanical testing [13,17,18].…”