Susceptibility of Lasioderma serricorne (Coleoptera: Anobiidae) Life Stages to Elevated Temperatures Used During Structural Heat Treatments

2011 ◽  
Vol 104 (1) ◽  
pp. 317-324 ◽  
Author(s):  
Chun Yu ◽  
Bhadriraju Subramanyam ◽  
Paul W. Flinn ◽  
Jeffrey A. Gwirtz
Keyword(s):  
Elevated Temperatures ◽  
Heat Treatments ◽  
Life Stages ◽  
Lasioderma Serricorne

scholarly journals Susceptibility of Tribolium castaneum Life Stages Exposed to Elevated Temperatures during Heat Treatments of a Pilot Flour Mill: Influence of Sanitation, Temperatures Attained Among Mills Floors, and Costs

2012 ◽  
Vol 105 (2) ◽  
pp. 709-717 ◽  
Author(s):  
Monika Brijwani ◽  
Bhadriraju Subramanyam ◽  
Paul W. Flinn ◽  
Michael R. Langemeier ◽  
Michelle Hartzer ◽  
...  
Keyword(s):  
Tribolium Castaneum ◽  
Elevated Temperatures ◽  
Heat Treatments ◽  
Life Stages ◽  
Flour Mill

scholarly journals The Influence of Post-Heat-Treatments on the Tensile Strength and Surface Hardness of Selective Laser Melted AlSi10Mg

2017 ◽  
Vol 370 ◽  
pp. 171-176 ◽  
Author(s):  
Leonhard Hitzler ◽  
Amandine Charles ◽  
Andreas Öchsner
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Precipitation Hardening ◽  
Elevated Temperatures ◽  
Surface Hardness ◽  
Heat Treatments ◽  
Age Hardening ◽  
Material Strength ◽  
Post Heat Treatment ◽  
Treatment Procedure

Recent investigations revealed major fluctuations in the material properties of selective laser melted AlSi10Mg, which corresponded with the varying precipitation-hardening state of the microstructure, caused by the differing dwell times at elevated temperatures. It was indicated that a subsequent heat treatment balances the age-hardening and results in a homogenized material strength. In order to further investigate this statement selective laser melted AlSi10Mg samples were subject to multiple post-heat-treatments. Subsequently, the surface hardness and tensile strength was determined and compared with the as-built results. The post-heat-treatment led to an arbitrary occurrence of rupture, indicating a successful homogenization, coupled with a remarkable improvement in ductility, but to the costs of a lowered tensile strength, which was highly dependent on the chosen heat-treatment procedure.

Mechanical Properties of X80 Grade UOE Pipe for Long-Term Exposure at Elevated Temperature

2004 ◽  
Author(s):  
Ryuji Muraoka ◽  
Mitsuhiro Okatsu ◽  
Nobuyuki Ishikawa ◽  
Shigeru Endo ◽  
Shinichi Kakihara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Mechanical Tests ◽  
Heat Treatments ◽  
Oil Sand ◽  
Operation Condition ◽  
Long Time ◽  
Simulated Condition ◽  
Installation Cost

Recently, X80 grade UOE pipes have been planned to apply to steam injecting oil sand recovery systems to increase the volume of steam to be injected and lowering installation cost. The pipes for systems are subjected to high temperature for a long time, such as 350-C, for 20 years. Before real applications of the pipes, it is important to ensure the reliability of the pipes during and after long-term operations. In this study, in order to establish simulation conditions for 350-C × 20 years of operation, the change in microstructure and resulting mechanical properties of X80 grade pipes after a long-term exposure at elevated temperatures were investigated. Then, mechanical properties of the pipes subjected to the established simulated condition were examined. Change in the microstructure was quite small after exposure of 400-C and lower temperatures. Tensile strengths of the base metal and seam weld after up to 400-C of heat treatment can be arranged with the Larson-Miller parameter composed with temperature and holding time of the heat treatments. Therefore, heat treatments at 400-C for shorter than 20 years can be simulation conditions for the operation condition of the systems. As a result of mechanical tests simulating long-term exposure, satisfied performance of X80 grade pipes can be obtained.

The Dynamics of Mgo Surface Faceting

1997 ◽  
Vol 3 (S2) ◽  
pp. 741-742
Author(s):  
Svetlana V. Yanina ◽  
Matthew T. Johnson ◽  
C. Barry Carter
Keyword(s):  
Elevated Temperatures ◽  
Film Growth ◽  
Heat Treatments ◽  
Santa Barbara ◽  
Contact Mode ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The {001} surface of magnesium oxide (MgO) has been the focus of numerous studies, which were prompted by the importance of MgO for its use as a substrate for thin film growth and also as a chemical catalyst. In the present work, atomic force microscopy (AFM) was used for studying the dynamics of surface processes of MgO which occur at elevated temperatures. AFM was chosen, in part, because it allows for imaging of topographical details at the atomic level with minimal sample preparation. Additionally, because the surface morphology of the same area was traced through a series of heat treatments, scanning electron microscopy analysis would be difficult because no conductive coating could be used (such a coating may have altered the surface between subsequent heat treatments).AFM images were recorded in contact mode, in air, on a Nanoscope III (Digital instruments, Santa Barbara, CA) using Si3N4 cantilevers (Ultralevers, Park Inst., Sunnyvale, CA) with a nominal applied force of 10-15 nN.

Physical Metallurgy and Properties of β-solidifying TiAl Based Alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
Helmut Clemens ◽  
Thomas Schmoelzer ◽  
Martin Schloffer ◽  
Emanuel Schwaighofer ◽  
Svea Mayer ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Volume Fraction ◽  
High Energy ◽  
Heat Treatments ◽  
Hot Working ◽  
Physical Metallurgy ◽  
Compression Tests ◽  
Phase Volume Fraction ◽  
Β Phase

ABSTRACTIn this paper, the physical metallurgy and properties of a novel family of high-strength γ-TiAl-based alloys is reviewed succinctly. These so-called TNM™ alloys contain Nb and Mo additions in the range of 3 - 7 atomic percent as well as small additions of B and C. For the definition of the alloy composition thermodynamic calculations using the CALPHAD method were conducted. The predicted phase transformation and ordering temperatures were verified by differential scanning calorimetry and in situ high-energy X-ray diffraction. TNM alloys solidify via the β-phase and exhibit an adjustable β-phase volume fraction at temperatures, where hot-working processes are performed. Due to the high volume fraction of β-phase these alloys can be processed isothermally as well as under near conventional conditions. In order to study the occurring deformation and recrystallization processes during hot-working, in situ diffraction experiments were conducted during compression tests at elevated temperatures. With subsequent heat-treatments a significant reduction of the β-phase is achieved. These outstanding features of TNM alloys distinguish them from other TiAl alloys which must exclusively be processed under isothermal conditions and/or which always exhibit a high fraction of β-phase at service temperature. After hot-working and multi-step heat-treatments, these alloys show yield strength levels > 800 MPa at room temperature and also good creep resistance at elevated temperatures.

scholarly journals Electron Backscattered Diffraction to Estimate Residual Stress Levels of a Superalloy Produced by Laser Powder Bed Fusion and Subsequent Heat Treatments

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4643
Author(s):  
Mathieu Terner ◽  
Jiwon Lee ◽  
Giulio Marchese ◽  
Sara Biamino ◽  
Hyun-Uk Hong
Keyword(s):  
Residual Stress ◽  
Elevated Temperatures ◽  
Heat Treatments ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Electron Backscattered Diffraction ◽  
Significant Drop ◽  
Powder Bed ◽  
Stress Relieving ◽  
Stress Levels

Metal Additive Manufacturing and Laser Powder Bed Fusion (LPBF), in particular, have come forth in recent years as an outstanding innovative manufacturing approach. The LPBF process is notably characterized by very high solidification and cooling rates, as well as repeated abrupt heating and cooling cycles, which generate the build-up of anisotropic microstructure and residual stresses. Post-processing stress-relieving heat treatments at elevated temperatures are often required in order to release some of these stresses. The effects of 1 h–hold heat treatments at different specific temperatures (solutionizing, annealing, stress-relieve and low-temperature stress-relieve) on residual stress levels together with microstructure characterization were therefore investigated for the popular Alloy 625 produced by LPBF. The build-up of residual stress is accommodated by the formation of dislocations that produce local crystallographic misorientation within grains. Electron backscattered diffraction (EBSD) was used to investigate local misorientation by means of orientation imaging, thereby assessing misorientation or strain levels, in turn representing residual stress levels within the material. The heavily constrained as-built material was found to experience full recrystallization of equiaxed grains after solutionizing at 1150 °C, accompanied by significant drop of residual stress levels due to this grains reconfiguration. Heat treatments at lower temperatures however, even as high as the annealing temperature of 980 °C, were found to be insufficient to promote recrystallization though effective to some extent to release residual stress through apparently dislocations recovery. Average misorientation data obtained by EBSD were found valuable to evaluate qualitatively residual stress levels. The effects of the different heat treatments are discussed and suggest that the peculiar microstructure of alloys produced by LPBF can possibly be transformed to suit specific applications.

Cause and Prevention of Stress-Relief Cracking in Quenched and Tempered Steel Weldments

1972 ◽  
Vol 94 (1) ◽  
pp. 336-341 ◽  
Author(s):  
C. F. Meitzner
Keyword(s):  
High Temperature ◽  
Heat Affected Zone ◽  
Elevated Temperatures ◽  
Stress Relief ◽  
Heat Treatments ◽  
Intergranular Cracking ◽  
Quenched And Tempered Steel ◽  
Postweld Heat ◽  
Tempered Steel

The paper reviews the causes and characteristics of stress-relief cracking, i.e., intergranular cracking in the heat-affected zone that occurs during the exposure of welded assemblies to the elevated temperatures produced by postweld heat treatments or high-temperature service. The findings presented are based largely on work at the Homer Research Laboratories with quenched and tempered steels. Means for preventing cracking during fabrication and service are discussed.

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