scholarly journals High-Temperature Tensile and Creep Behavior in a CrMoV Steel and Weld Metal

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 109
Author(s):  
Yan Song ◽  
Mengyu Chai ◽  
Zelin Han ◽  
Pan Liu
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Creep Damage ◽  
Uniaxial Tensile ◽  
Second Phase ◽  
Creep Tests ◽  
Damage Mechanisms ◽  
Integrity Assessment ◽  
Steel Weldment ◽  
High Temperature Tensile

The 2.25Cr1Mo0.25V steel is a vanadium-modified 2.25Cr1Mo steel and is being widely used in the manufacture of heavy-wall hydrogenation reactors in petrochemical plants. However, the harsh service environment requires a thorough understanding of high-temperature tensile and creep behaviors of 2.25Cr1Mo0.25V steel and its weld for ensuring the safety and reliability of hydrogenation reactors. In this work, the high-temperature tensile and creep behaviors of base metal (BM) and weld metal (WM) in a 2.25Cr1Mo0.25V steel weldment used for a hydrogenation reactor were studied experimentally, paying special attention to its service temperature range of 350–500 °C. The uniaxial tensile tests under different temperatures show that the WM has higher strength and lower ductility than those of BM, due to the finer grain size in the WM. At the same time, the short-term creep tests at 550 °C reveal that the WM has a higher creep resistance than that of BM. Moreover, the creep damage mechanisms were clarified by observing the fracture surface and microstructures of crept specimens with the aid of scanning electron microscopy (SEM). The results showed that the creep damage mechanisms of both BM and WM are the initiation and growth of creep cavities at the second phase particles. Results from this work indicate that the mismatch in the high-temperature tensile strength, ductility, and creep deformation rate in 2.25Cr1Mo0.25V steel weldment needs to be considered for the design and integrity assessment of hydrogenation reactors.

scholarly journals Creep damage behavior of red sandstone after high temperature

2021 ◽  
Author(s):  
Xiaokang Pan ◽  
Filippo Berto ◽  
Xiaoping Zhou
Keyword(s):  
High Temperature ◽  
Uniaxial Compression ◽  
Deformation Modulus ◽  
Creep Damage ◽  
Viscosity Coefficient ◽  
Creep Tests ◽  
Red Sandstone ◽  
Instantaneous Strain ◽  
Treated Sample ◽  
Instantaneous Deformation

This work discusses the results from tests conducted to investigate the uniaxial compression and creep behavior of red sandstone. The original untreated sample and the 800 ℃ treated sample have been selected to carry out the experiments. It has been found that high temperature has obvious influence on the mechanical properties of red sandstone. The relationship between creep strain and instantaneous strain, as well as instantaneous deformation modulus and creep viscosity coefficient have been analyzed. It has been found that high temperature reduces the ability of red sandstone to resist instantaneous deformation and creep deformation. Acoustic emission (AE) technology has been also used in the loading process of uniaxial compression and creep tests, providing a powerful means for damage evolution analysis of red sandstone.

High Temperature Creep Damage Mechanisms in a Directionally Solidified Alloy: Impact of Crystallography and Environment

2016 ◽  
pp. 745-756 ◽  
Author(s):  
L. Mataveli Suave ◽  
L. Mataveli Suave ◽  
J. Cormier ◽  
P. Villechaise ◽  
D. Bertheau ◽  
...  
Keyword(s):  
High Temperature ◽  
Creep Damage ◽  
High Temperature Creep ◽  
Directionally Solidified ◽  
Damage Mechanisms ◽  
Temperature Creep

Evaluation of Microstructures and Creep Damages in HAZ of P91 Steel Weldment

2007 ◽  
Author(s):  
Masaaki Tabuchi ◽  
Hiromichi Hongo ◽  
Yongkui Li ◽  
Takashi Watanabe ◽  
Yukio Takahashi
Keyword(s):  
Damage Mechanics ◽  
Early Stage ◽  
Rupture Life ◽  
Creep Damage ◽  
Specimen Thickness ◽  
Creep Tests ◽  
Steel Weldment ◽  
Type Iv ◽  
Damage Process ◽  
Term Creep

The present paper aims to clarify the Type IV creep damage process of Mod.9Cr-1Mo (Gr.91) steel weldment. Long-term creep tests for base metal and simulated fine-grained HAZ and welded joints were conducted at 550, 600 and 650 °C. Furthermore, creep tests of thick welded joint specimens were interrupted at 0.2, 0.5, 0.7, 0.8, 0.9 of rupture life, and damage distributions were measured quantitatively. It was found that creep voids initiated at the early stage of life inside the specimen thickness, and grew into cracks at the later stage of life. Experimental creep damage distributions were compared with computed ones using FEM and damage mechanics analysis. The effect of multiaxial stress condition on creep damage evolution is discussed.

Ambient-Temperature and High-Temperature Tensile Properties of Investment Casted Titanium Matrix Composites with B4C Additions

2016 ◽  
Vol 849 ◽  
pp. 443-451
Author(s):  
Ji Heng Wang ◽  
Guang Fa Huang ◽  
Jiu Xiao Li ◽  
Jian Wei Mao ◽  
Xiang Long Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
Second Phase ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Strength Enhancement ◽  
Solution Strengthening ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

Titanium matrix composites (TMCs) were prepared by investment casting in a consumable arc skull casting furnace. The effects of B4C additions on ambient-temperature and high-temperature tensile properties of TMCs were investigated. It has been found that with the addition of B4C, the microstructure of TMCs was refined and the strength improved. The strength enhancement of the TMCs is ascribed to the combined effects of the second-phase strengthening, grain refinement strengthening and the solution strengthening. The grain refinement and solution strengthening effects play a main role in the yield strength enhancement of TMCs at ambient temperature, and the second-phase strengthening of TiB whiskers and TiC particles plays a more important role at high temperature.

scholarly journals Experimental Investigation and Modeling of Damage Accumulation of EN-AW 2024 Aluminum Alloy under Creep Condition at Elevated Temperature

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 404
Author(s):  
Adam Tomczyk ◽  
Andrzej Seweryn
Keyword(s):  
Damage Accumulation ◽  
Axial Stress ◽  
Axial Strain ◽  
Creep Condition ◽  
Creep Damage ◽  
Creep Rupture ◽  
Uniaxial Tensile ◽  
Creep Tests ◽  
Damage State ◽  
2024 Aluminum Alloy

The paper is focused on creep-rupture tests of samples made of the 2024 alloy in the T3511 temper under uniaxial tensile stress conditions. The basic characteristics of the material at the temperatures of 100, 200 and 300 °C were determined, such as the Young’s modulus E, yield point σy, ultimate tensile strength σc and parameters K and n of the Ramberg–Osgood equation. Creep tests were performed for several different levels of nominal axial stress (load) at each temperature. It was observed that in the process of creep to failure at 200 and 300 °C, as the stress decreases, the creep time increases and, at the same time, the strain at rupture increases. However, such a regularity is maintained until a certain transition stress value σt is reached. Reducing the stress below this value results in a decreased value of the strain at rupture. A simple model of creep damage accumulation was proposed for the stress range above the transient value. In this model, the increase in the isotropic damage state variable was made dependent on the value of axial stress and the increase in plastic axial strain. Using the results of experimental creep-rupture tests and the failure condition, the parameters of the proposed model were determined. The surface of fractures obtained in the creep tests with the use of SEM technology was also analyzed.

Stress Relaxation Damage Analysis for High Temperature Bolting

2012 ◽  
Vol 455-456 ◽  
pp. 1429-1433
Author(s):  
Jin Quan Guo ◽  
Xiao Hong Sun ◽  
Hui Chao Shi
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Stress Relaxation ◽  
Life Prediction ◽  
Creep Damage ◽  
Damage Analysis ◽  
Damage Mechanisms ◽  
Life Evaluation ◽  
Relaxation Characteristics ◽  
Life Prediction Model

The paper analyzes the stress relaxation damage mechanisms of high temperature (HT) bolts of ultra-supercritical steam turbine units. Based on creep damage mechanisms and relaxation characteristics, the paper proposes a life prediction model, and by which to predict relaxation damage life of HT bolting material 1Cr10NiMoW2VNbN. Validation results indicate that the developed model has led to better consistent results with experimental data and thus can be recommended in relaxation life evaluation of HT materials.

scholarly journals Transition in Deformation Mechanism of AZ31 Magnesium Alloy during High-Temperature Tensile Deformation

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Masafumi Noda ◽  
Hisashi Mori ◽  
Kunio Funami
Keyword(s):  
High Temperature ◽  
Deformation Mechanism ◽  
Tensile Deformation ◽  
Initial Strain Rate ◽  
Grain Boundary Sliding ◽  
Mg Alloy ◽  
Uniaxial Tensile ◽  
Specific Strength ◽  
Az31 Mg Alloy ◽  
High Temperature Tensile

Magnesium alloys can be used for reducing the weight of various structural products, because of their high specific strength. They have attracted considerable attention as materials with a reduced environmental load, since they help to save both resources and energy. In order to use Mg alloys for manufacturing vehicles, it is important to investigate the deformation mechanism and transition point for optimizing the material and vehicle design. In this study, we investigated the transition of the deformation mechanism during the high-temperature uniaxial tensile deformation of the AZ31 Mg alloy. At a test temperature of 523 K and an initial strain rate of 3×10−3 s-1, the AZ31 Mg alloy (mean grain size: ~5 μm) exhibited stable deformation behavior and the deformation mechanism changed to one dominated by grain boundary sliding.

Effects of Microstructure Evolution on High-Temperature Mechanical Deformation of 95Sn-5Sb

2008 ◽  
Author(s):  
Harry Schoeller ◽  
Shubhra Bansal ◽  
Aaron Knobloch ◽  
David Shaddock ◽  
Junghyun Cho
Keyword(s):  
High Temperature ◽  
Lead Free ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Second Phase ◽  
Creep Tests ◽  
Well Drilling ◽  
Deep Well ◽  
High Homologous Temperature ◽  
Lead Free Solders

Lead-free solders have garnered much attention in recent years due to legislation banning the use of lead in electronics. As use of lead solders is phased out, there is a need for lead-free alternatives for niche applications such as high temperature environments where traditionally high lead solders are used. Electronics and sensors exposed to high-temperature environments such as those associated with deep well drilling require solder interconnects that can withstand high thermal-mechanical stresses. In an effort to characterize solder alloys for such applications, this study focuses on deformation behavior of the Sn95-Sb5 solder under high-temperature exposures (from 298°K to 473°K). As compared to conventional high-temperature Pb-based solder 90Pb–10Sn, Sn95–Sb5 exhibited very high tensile strength and modulus, as well as superior creep properties despite its lower melting temperature. Importantly, high-temperature deformation was shown to be influenced by the presence of the second phase (SnSb) distributed within the Sn-rich matrix. These second phase precipitates appeared to be dissolved into the Sn-rich phase above 453°K, which converted the solder into a single-phase alloy and resulted in a change in its deformation mechanism. Furthermore, as the service temperature is of such high homologous temperature (T > 0.5Tm), creep deformation will contribute significantly toward the life of the solder joint during thermal cycling. In order to characterize the creep behavior and to identify controlling mechanism(s), creep tests were carried out, from which the stress exponent and activation energy were determined. In this study, detailed microstructures under high-temperature are presented in conjunction with the corresponding mechanical behavior to further understand the controlling deformation mechanisms.

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