The Evaluation of Material Degradation in Modified 9Cr-1Mo Steel by Electrochemical and Magnetic Property Analysis

2006 ◽  
Vol 321-323 ◽  
pp. 486-491
Author(s):  
Yang Ki Hyun ◽  
Soon Ho Won ◽  
Jae Ho Jang ◽  
In Bae Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Vibrating Sample Magnetometer ◽  
Material Degradation ◽  
Creep Tests ◽  
Laves Phases ◽  
M23c6 Type ◽  
Service Exposure ◽  
Evolution Of Microstructure ◽  
Heat Resistant Steels

Evolution of microstructure due to service exposure to high temperature has a strong effect performance of heat resistant steels. In case of modified 9Cr-1Mo steels, precipitation of Fe2Mo-type laves phases and coarsening of M23C6-type carbides are the primary cause of degradation of mechanical properties such as creep resistance, tensile strength and toughness. Therefore creep tests have been carried out on modified 9Cr-1Mo steels to examine the effect of aging and stress on the creep strength. Additionally vibrating sample magnetometer is used to measure hysteresis loop.

scholarly journals Study of Mechanical Behavior and Microstructure for Low-Hardness P92 Steel

2021 ◽  
Vol 2101 (1) ◽  
pp. 012074
Author(s):  
Weixin Yu ◽  
Zhen Dai ◽  
Jifeng Zhao ◽  
Lulu Fang ◽  
Yiwen Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Maximum Size ◽  
Rapid Decrease ◽  
Laves Phases ◽  
P92 Steel ◽  
A Chain ◽  
The Stability ◽  
Evolution Of Microstructure

Abstract The strength of P92 steel (tensile strength, specified plastic elongation strength) will decrease after its hardness is reduced, ferrite and carbides forming the structure. Carbides of grain size 5-6 are precipitated in the grains and grain boundaries. The martensite lath shape has completely disappeared. M23C6 carbide coarsened obviously, with a maximum size of about 500nm; The Laves phase is also aggregated and coarsened, connecting in a chain shape with a maximum size of more than 500nm. Evolution of microstructure, namely the obvious coarsening of M23C6 carbides and the aggregation and connection of Laves phases in a chain shape, are the main causes for rapid decrease in the stability of the material substructure and evident decline in mechanical properties and hardness. In addition, the MX phase did not change significantly, hardly affecting the hardness reduction of P92 steel.

scholarly journals Hybrid Composites Based on Polypropylene with Basalt/Hazelnut Shell Fillers: The Influence of Temperature, Thermal Aging, and Water Absorption on Mechanical Properties

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 18 ◽  
Author(s):  
Anna Kufel ◽  
Stanisław Kuciel
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Water Absorption ◽  
Thermal Aging ◽  
Hybrid Composites ◽  
Coefficient Of Thermal Expansion ◽  
Tensile Modulus ◽  
Charpy Impact ◽  
Creep Tests ◽  
Influence Of Temperature

The aim of the research was to study the effects of adding natural fillers to a polypropylene (PP) matrix on mechanical and physical properties of hybrid composites. The 10%, 15%, and 20% by weight basalt fibers (BF) and ground hazelnut shells (HS) were added to the PP matrix. Composites were produced by making use of an injection molding method. Tensile strength, tensile modulus, strain at break, Charpy impact strength, and the coefficient of thermal expansion were determined. The influence of temperature, thermal aging, and water absorption on mechanical properties was also investigated. In addition, short-time creep tests were carried out. To characterize the morphology and the filler distribution within the matrix, a scanning electron microscope (SEM) was used. The results showed that the addition of the two types of filler enhanced mechanical properties. Furthermore, improvements in thermal stability were monitored. After water absorption, the changes in the tensile properties of the tested composites were moderate. However, thermal aging caused a decrease in tensile strength and tensile modulus.

scholarly journals Tensile Strength and Creep Resistance in Nanocrystalline Cu, Pd and Ag

1990 ◽  
Vol 206 ◽  
Author(s):  
G. W. Nieman ◽  
J. R. Weertman ◽  
R. W. Siegel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Yield Strength ◽  
Creep Resistance ◽  
Room Temperature ◽  
True Strain ◽  
Constant Load ◽  
Creep Tests ◽  
Grain Sizes

ABSTRACTMeasurements of tensile strength and creep resistance have been made on bulk samples of nanocrystalline Cu, Pd and Ag consolidated from powders by cold compaction. Samples of Cu-Cu2O have also been tested. Yield strength for samples with mean grain sizes of 5–80 nm and bulk densities on the order of 95% of theoretical density are increased 2–5 times over that measured in pure, annealed samples of the same composition with micrometer grain sizes. Ductility in the nanocrystalline Cu has exceeded 6% true strain, however, nanocrystalline Pd samples were much less ductile. Constant load creep tests performed at room temperature at stresses of >100 MPa indicate logarithmic creep. The mechanical properties results are interpreted to be due to grain size-related strengthening and processing flaw-related weakening.

Experimental Study on Welding Process of TC4 Titanium Alloy with Different Welding Wires

2021 ◽  
Vol 1035 ◽  
pp. 57-62
Author(s):  
Guo Qiang Shang ◽  
Li Ping Li ◽  
Xin Nan Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Cross Section ◽  
Welding Process ◽  
Alloy Wire ◽  
Tc4 Titanium Alloy ◽  
Weld Area ◽  
Evolution Of Microstructure

In present study, the effects of different welding wires on the evolution of microstructure and mechanical properties of TC4 titanium alloy test plates were studied. The results show that the test plates welded by TA20 titanium alloy wire, TC3 titanium alloy wire and TC4 titanium alloy wire are well formed, no defects are found in the cross section of the weld. The microstructures of these test plates are similar, and needle-like martensite exists in the weld area. In comparison, this is little obvious difference in tensile strength among these test plates welded by different welding wires, while the plates welded by TC4 titanium alloy has better elongation, contraction of aera, impact toughness and better balance of strength and toughness.

Thermal and Loading Effects on Mechanical Properties of a Hot Isostatically Pressed Si3N4

1994 ◽  
Author(s):  
Jagannathan Sankar ◽  
Jayant Neogi ◽  
Suneeta S. Neogi ◽  
Marvln T. Dixie ◽  
Ranji Vaidyanathan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silicon Nitride ◽  
Elevated Temperatures ◽  
Heat Engine ◽  
Tensile Tests ◽  
Tensile Creep ◽  
Uniaxial Tensile ◽  
Creep Tests ◽  
Loading Effects

The effect of thermal soaking on the mechanical properties of a candidate material for advanced heat engine applications namely, hot isostatically pressed (HIPed) silicon nitride (GTEPY6) are reported here. Pure uniaxial tensile tests conducted at room and at elevated temperatures indicated that the tensile strength of this material dropped significantly after 1000°C. The residual tensile strength of PY6 material after thermal soaking at 1200° and 1300°C was also investigated. Test results showed that thermal soaking at 1200° and 1300°C increased the residual tensile strength. The thermal soaking time had a greater effect on the residual tensile strength at 1300°C. Tensile creep tests performed at 1200° and 1300°C showed that the steady state creep rate was influenced by both the temperature and the applied stress. The higher stress exponent in HIPed as compared to a sintered silicon nitride shows higher creep resistance in the case of HIPed materials.

FFS Assessment for Material Degradion due to Fire Damage of Pressure Equipment

2013 ◽  
Author(s):  
Tsutomu Kikuchi ◽  
Tomoyuki Kurihara ◽  
Toru Nishikawa ◽  
Tomoyuki Fujishiro ◽  
Satoshi Nagata ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Heat Exposure ◽  
Evaluation Criteria ◽  
Fire Damage ◽  
Material Degradation ◽  
Elapsed Time ◽  
Metallurgical Analysis ◽  
Damaged Materials

The fire damage FFS assessment is based on the material degradation associated with heat exposure. The proposed identification of heat exposure zone will be provided in the API 579-1/ASME FFS-1 Standard. As the useful judgments, temper colors and mechanical properties such as tensile strength, hardness, impact energy, ductility and so on for the damaged materials. However, the reference temper colors are shown only by the names of colors without photographic examples and the details of metallurgical analysis are not available in the Standard. This paper presents the temper color reference shows by presenting several photographic examples of different exposed temperature, elapsed time and cooling rates for carbon steel and stainless steel. The metallurgical analysis guide describes typical degradations in mechanical properties and appearances in microstructure observed in the materials exposed to fire, evaluation criteria, procedure for replica preparation, personnel qualification and so on.

Microstructure and Porous Defects of a Spray-Formed and Hot Worked 7000 Aluminum Alloy

2016 ◽  
Vol 879 ◽  
pp. 1778-1782
Author(s):  
Shu Hui Huang ◽  
Zhi Hui Li ◽  
Bai Qing Xiong ◽  
Yon Gan Zhang ◽  
Xi Wu Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Hot Isostatic Pressing ◽  
Aging Treatment ◽  
Hot Extrusion ◽  
Evolution Of Microstructure ◽  
Scanning Electron

The evolution of microstructure and porous defects of a spray-formed 7000 Aluminum alloy is researched in this paper. The spray-formed alloy is treated by hot isostatic pressing (HIP), homogenization, hot extrusion, solution and aging treatment. Metallographic microscope, scanning electron microscope (SEM) and tensile test are used to research the microstructure and mechanical properties. The results show that, there are two kinds of porous defects in spray-formed alloy, which has gas and no gas. The porous defects of spray-formed ingot can be mostly eliminated by HIP and hot extrusion. After solution and aging treatment, the tensile strength and elongation reach 757MPa and 10.2%, respectively.

Effect of Al on the Castability, Tensile and Creep Properties of Mg-xAl-Zn

2006 ◽  
Vol 321-323 ◽  
pp. 1370-1373
Author(s):  
C.W. Lee ◽  
Dae Hyun Song ◽  
K.Y. Nam ◽  
B.H. Choi ◽  
Yong Ho Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Transportation Systems ◽  
Creep Tests ◽  
Creep Properties ◽  
Al Content ◽  
Zn Alloy ◽  
Zn Alloys ◽  
Main Factor

The effect of Al content on the castability, tensile and creep properties of Mg-xAl-Zn alloy was investigated. The molten Mg-(3~11)Al-Zn alloys of 700 °C were poured into the mould designed to estimate castability. Tensile and creep tests were performed for the alloys. It has been shown that creep resistance decreased while tensile strength improved with increasing Al amount. Microstructure study revealed that morphology of Mg17Al12 is main factor determining the tensile and creep properties of as cast Mg-xAl-Zn alloys. The final purpose of this study is to develop the heat resistant Mg alloys to apply transportation systems such as automobile. Further study on effect of heat treatment and additional alloying elements on the microstructure and mechanical properties of Mg-xAl alloys is going to be performed.

The Influence of Phase Transformations on Creep Resistance in Fe-Ni-Cr Alloys for Reformer Tube Applications

2007 ◽  
Author(s):  
Johanne Laigo ◽  
Franck Tancret ◽  
Rene´ Le Gall ◽  
Fre´de´ric Christien ◽  
Jader Furtado
Keyword(s):  
Mechanical Properties ◽  
Phase Transformations ◽  
Creep Resistance ◽  
Critical Role ◽  
Thermal Conditions ◽  
Dislocation Motion ◽  
Creep Tests ◽  
Modelling Techniques ◽  
Heat Resistant Steels

Heat resistant steels of the HP-series have widespread uses in the petrochemical industry in pyrolysis and reformer furnaces. The alloys are carbon-rich Fe-Ni-Cr alloys, with additions like Mn, Si, Nb, Ti, W... The typical microstructure of as-cast HP alloys is an austenite matrix with intergranular eutectic-like primary chromium carbides of the M7C3 type and niobium carbides of the MC type. Upon ageing, phase transformations occur. Intragranular secondary M23C6 carbides precipitate, which is thought to restrict dislocation motion, and intergranular M7C3 transforms into M23C6. Under certain thermal conditions, a partial transformation of the primary niobium carbides into a nickel-niobium silicide called G phase can occur. These phases may play a critical role during creep, but neither their role on mechanical properties nor the mechanisms of phase transformations are clearly identified. The aim of this study is to understand the role of each phase or phase transformation in the creep resistance of HP alloys. Consequently, a critical review of phase formation and transformations in such alloys is presented using a set of experimental and modelling techniques (electron microscopy, Castaing microprobe, creep tests at high temperature and neural networks modelling of mechanical properties...).

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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