Creep Of Steel Research Articles

Creep of mild steel at low temperatures

Creep data for mild steel at low temperatures (360–400°C) have been analysed and it has been found that the creep behaviour is similar to that at higher temperatures. The variation of secondary creep rate with stress and temperature, in the temperature range (360–538°C) may be described by two equations with a transition stress. This transition stress is 410 MPa at 360°C. For low stresses the creep equation is given by ε s = 250 σ 3.7 exp{−(2.17 × 10 5/ RT)} . Material response to stress is highly dependent on the amount of cold work; secondary creep rate decreases with increasing prior deformation.

建築構造用鋼材の第一期クリープにおける階段状温度変動の影響 (梗概)

建築構造用鋼材の第一期クリープにおける階段状温度変動の影響 (梗概)

Creep of structural steel in fire: Analytical expressions

AbstractTwo models of creep, one proposed by Harmathy1, the other empirical, have been fitted to published measurements of creep in seven steels. The data have been selected so as to cover the range needed for predicting the survival of protected steel or reinforced concrete buildings exposed to fire.

Creep of hardened steel in tempering

Creep of hardened steel in tempering

Radiation creep in 09Kh16N15M3B steel at stresses exceeding the elastic limit

Radiation creep in 09Kh16N15M3B steel at stresses exceeding the elastic limit

Creep of Te-implanted stainless steel

Creep of Te-implanted stainless steel

Effect of reactor irradiation on the long-term strength and creep of 0Kh16N15M3B steel in a plane stressed state. Part III. Experimental study of creep resistance

1. Reactor irradiation over the range of experimental parameters investigated does not have a substantial effect on the nature of the creep curves and long-term ductility of 0Kh16N15M3B steel but increases the intensity of the minimum rates of creep by almost two orders of magnitude. Here the extent of the radiation-induced increase in the rate of creep is reduced with an increase in stress intensity. 2. The ratio of the principal stresses in the experiments being discussed affects the form of the creep and long-term ductility curves appreciably in all the experiments conducted. Approximately, it can be considered that the\(\mathop {\varepsilon _i }\limits^ \bullet\) min (σi) relationship is invariant to the form of stressed state. An exception is the control experiments for σ1/σ3=−1.5. 3. The grain size of the initial structure of the steel investigated affects all the characteristics of the creep process substantially, both under normal and reactor test conditions. With an increase in the grain size the stage of accelerated creep preceding fracture is shortened, and the rate of steady-state creep and long-term ductility are lowered.

Influence of plasma spraying of molybdenum on the creep of 40Kh steel with preliminary application of a low-melting layer on its surface

Influence of plasma spraying of molybdenum on the creep of 40Kh steel with preliminary application of a low-melting layer on its surface

構造用鋼材 (SS41 および SM58Q) の第一期クリープにおける階段状応力変動の影響 (梗概)

構造用鋼材 (SS41 および SM58Q) の第一期クリープにおける階段状応力変動の影響 (梗概)

The formation of multipoles during high-temperature creep of austenitic stainless steels

It is shown that multipole dislocation configurations can arise during power-law creep of certain austenitic stainless steels. These multipoles have been analysed in some detail for two particular steels (Alloy 800 and a modified AISI 316L) and it is suggested that they arise either during instantaneous loading or during the primary creep stage. Trace analysis has shown that the multipoles are confined to {1 1 1} planes during primary creep but are not necessarily confined to these planes during steady-state creep unless they are pinned by interstitials.

Stress dependence of radiation-induced creep in 09Kh16N15M3B steel at 470�C

Stress dependence of radiation-induced creep in 09Kh16N15M3B steel at 470�C

Creep in 09Kh16N15M3B steel at 623?823� K in a reactor

Creep in 09Kh16N15M3B steel at 623?823� K in a reactor

Creep of heat-resistant steels under different temperature and force conditions

Creep of heat-resistant steels under different temperature and force conditions

Observations on the microstructure of 20Cr-25Ni-Nb stainless steel after exposure to iodine vapor during creep at 750�C

The microstructure of 20Cr-25Ni-Nb stainless steel creep specimens has been examined in detail using optical and electron microscopy, after exposure to iodine vapor, air, or vacuum for periods up to ∼1600 hr at 750°C. The overall corrosion-oxidation rate in iodine vapor was linear and the duplex product which formed was typical of enhanced oxidation of this steel in other environments. Three significant subsurface microstructural changes observed during long-term exposure to iodine vapor were the formation of subsurface intergranular voids, enhanced chromium depletion, and increased intragranular precipitation of chromium-rich particles; each of these effects is discussed in detail and interpreted in terms of the breakdown of the initial protective oxide by iodine vapor.

Sliding at twin boundaries during high-temperature creep

Abstract Offsets due to grain boundary sliding have been observed at previously coherent annealing twin boundaries after high-temperature power-law creep of an austenitic stainless steel (Alloy 800). On average the magnitude of these offsets was 0middot;2-0middot;3 of that measured at 'general' grain boundaries. Sliding at twin boundaries contributed approximately 1middot;6% of the total strain during steady-state creep, while sliding at 'general' grain boundaries contributed 12-22%. Observations of dislocation structures in twin boundaries after creep suggest that twin boundary sliding is a direct result of the mobility of extrinsic boundary dislocations collected at these interfaces through interactions with matrix dislocations.

構造用鋼材 (SM50A) の第一期クリープにおける階段状応力変動の影響 (梗概)

構造用鋼材 (SM50A) の第一期クリープにおける階段状応力変動の影響 (梗概)

LOW-CYCLE FATIGUE AND CYCLIC CREEP OF METALS

Abstract— This paper deals with the effect of accumulated (oriented) plastic deformation (cyclic creep) on the life of metals under conditions of cyclic loading typically in the range of low-cycle fatigue. Specific features of cyclic creep of aluminium, titanium alloys and structural steels were investigated for the lives ranging from 05 to 2 × 105 cycles to rupture as well as specific features of transition from quasistatic to fatigue fracture associated with the variation in the mode of deformation of metals. It is shown that under conditions of repeated stress-controlled loading in a wide range of low temperatures, the cyclic creep processes are the predominant ones determining life of metals over a wide range of cycles, and when calculating life under these conditions it is necessary to take into account the rate of these processes irrespective of the type of fracture: quasistatic or fatigue. An equation was obtained for calculating life under low-cycle loading conditions which takes into account the interrelationship between the life, the accumulated plastic strain, steady-state cyclic creep rate and the resistance of the material to cyclic creep.

Stress Drop Experiments During High Temperature Creep of an Austenitic 25Cr-20Ni Stainless Steel Between 1133 and 1193 K

Stress Drop Experiments During High Temperature Creep of an Austenitic 25Cr-20Ni Stainless Steel Between 1133 and 1193 K

The influence of second phase particles on the free dislocation density during creep of stainless steel

The free dislocation density was measured in a γ′-hardened stainless steel (A-286). The dislocation density is smaller in specimens which contain particles with a smaller interparticle distance provided the specimens were crept at equal stresses. The decrease of the dislocation density may be considered as supporting the view that particle hardened materials behave like pure materials subjected to a smaller stress.

The effects of temperature and dose-rate variations on the creep of austenitic stainless steels in the dounreay fast reactor

Loaded helices of cold-worked, austenitic stainless steels (En58B, E, J, FV548 and type 316) have been irradiated in DFR at damage rates ranging over an order of magnitude at temperatures between 513 and 633 K. Creep rates varied between steels but a common pattern emerged where strain per unit dose appeared to increase with decreasing dose-rate. Comparison with experiments at 773 K on three of the steels reveals creep rate increases by factors ranging from 1.2 to 5. The results are discussed in the context of other fast reactor data and possible explanations of the findings are considered.