scholarly journals Behavioral Analysis of Hydrogen in Metals under the Effect of H2S Corrosion Using a Layer-stripping Micro-hardness Technique

2020 ◽  
Vol 26 (3) ◽  
pp. 287-294
Author(s):  
Lei GU ◽  
Jing WANG ◽  
Xiaoyang LI
Keyword(s):  
Hydrogen Sulfide ◽  
Hydrogen Diffusion ◽  
Hardness Test ◽  
Micro Hardness ◽  
Hydrogen Distribution ◽  
Hydrogen In Metals ◽  
H2s Corrosion ◽  
Saturated Layer ◽  
Structural Carbon ◽  
Structural Carbon Steel

In order to study the distribution behavior of hydrogen in metals under the condition of H2S corrosion, a layer-stripping micro-hardness test was designed to analyze the hydrogen distribution along the depth of hydrogen-charged 45 high-quality structural carbon steel at three different hydrogen sulfide concentrations and four corrosion periods in this study. The results show that there is a terminal solid solubility of hydrogen in the metal for hydrogen sulfide solutions over various concentrations and corrosion periods. A hydrogen-saturated layer is produced by hydrogen diffusing through the metal from an unsaturated state to a fully saturated state. The hydrogen-saturated layer is not affected by the concentration of the corrosion, but its thickness increases as the corrosion period increases. In this way, we established a new hydrogen diffusion model in metals.

USS COR-TEN A

Alloy Digest ◽  
1972 ◽  
Vol 21 (11) ◽  
Keyword(s):  
United States ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Atmospheric Corrosion ◽  
Heat Treating ◽  
Steel Composition ◽  
United States Steel Corporation ◽  
Structural Carbon ◽  
Minimum Yield ◽  
Structural Carbon Steel

Abstract USS COR-TEN A, the original COR-TEN Steel composition (see U.S.S. COR-TEN, Alloy Digest SA-17, April 1954), has 5 to 8 times the atmospheric corrosion resistance of structural carbon steel and a minimum yield point of 50,000 psi in sections through 1/2-inch thick. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-283. Producer or source: United States Steel Corporation.

Evaluation of the Resistance of Individual Si Die to Cracking

1998 ◽  
Author(s):  
R. Berriche ◽  
R.K. Lowry ◽  
M.I. Rosenfield
Keyword(s):  
Thermal Cycling ◽  
Hardness Test ◽  
Mechanical Stresses ◽  
Test Method ◽  
Processing Conditions ◽  
Micro Hardness ◽  
Test Methodology ◽  
Vickers Micro Hardness

Abstract The present work investigated the use of the Vickers micro-hardness test method to determine the resistance of individual die to cracking. The results are used as an indicator of resistance to failure under the thermal and mechanical stresses of packaging and subsequent thermal cycling. Indentation measurements on die back surfaces are used to determine how changes in wafer backside processing conditions affect cracks that form around impressions produced at different loads. Test methodology and results obtained at different processing conditions are discussed.

Micro-Hardness and Morphology of LDPE Influenced by Beta Radiation

2014 ◽  
Vol 606 ◽  
pp. 253-256 ◽  
Author(s):  
Martin Ovsik ◽  
Petr Kratky ◽  
David Manas ◽  
Miroslav Manas ◽  
Michal Stanek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hardness Test ◽  
Polymer Materials ◽  
Beta Radiation ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Depth Sensing ◽  
Surface Layers ◽  
Hardness Values ◽  
Different Doses

This article deals with the influence of different doses of Beta radiation to the structure and mico-mechanical properties of Low-density polyethylene (LDPE). Hard surface layers of polymer materials, especially LDPE, can be formed by radiation cross-linking by β radiation with doses of 33, 66 and 99 kGy. Material properties created by β radiation are measured by micro-hardness test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 66 and 99 kGy, when the micro-hardness values increased by about 21%. The changes were examined and confirmed by X-ray diffraction.

scholarly journals Characterization of Enamel After the Use of Oral Hygiene Auxiliaries with Whiteners

2019 ◽  
pp. 227-236
Author(s):  
Norma Verónica Zavala-Alonso DDS, MSc, PhD ◽  
Jorge Humberto Ramírez-González DDS, MSc ◽  
Mariana Ramírez-Vergara DDS ◽  
José Gilberto Roque-Márquez DDS, MSc ◽  
Flores Daniel Silva-Herzog DDS, MSc, PhD
Keyword(s):  
Oral Hygiene ◽  
Dental Enamel ◽  
Hardness Test ◽  
Study Groups ◽  
Micro Hardness ◽  
Sem Images ◽  
Group 4 ◽  
Group 2 ◽  
Mouth Wash ◽  
Group 1

The purpose of this study was to evaluate the effect of the use of the combined auxiliaries of oral hygiene with whitening agents on the micro-hardness and micro-morphology of dental enamel. Materials and Methods. 40 human incisors were used and sectioned to obtain 4x4mm samples and divided into four study groups. Group 1: Electric brushing with Toothpaste (BTP); Group 2: Electric brushing with Toothpaste+mouthwash (BTP+MW); Group 3: Electric brushing with Toothpaste+whitening pen (BTP+WP); Group 4: Electric brushing with Toothpaste+mouth wash+whitening pen (BTP+MW+WP). Samples were submitted toVickers micro-hardness test and visualized using scanning electron microscopy (SEM). Results. All groups, with the exception of group 1, showed a decrease in micro-hardness values after applying the treatments (p<0.05). Likewise, when comparing the values after the treatments between the groups, significant statistical differences were found in all of comparisons except for those of groups 2 and 4. SEM images showed changes in the morphology in all the study groups with the exception of group 1. Conclusion. Significant changes such as decrease in micro-hardness as well as in the topography of the enamel surface such as elevations, craters, porosities and etching patterns were founded after the use of the combination of auxiliaries of oral hygiene with whitening agents.  

scholarly journals Research on hydrogen-induced cracking behavior of normalized pipeline steel

2018 ◽  
Vol 175 ◽  
pp. 01027
Author(s):  
Hai Zhang ◽  
Shaopo Li ◽  
Wenhua Ding ◽  
Ning Hao
Keyword(s):  
Hydrogen Sulfide ◽  
Corrosion Test ◽  
Pipeline Steel ◽  
Plate Thickness ◽  
Hardness Test ◽  
Propagation Path ◽  
Cracking Behavior ◽  
Hydrogen Induced Cracking ◽  
Sulfide Corrosion ◽  
Hydrogen Sulfide Corrosion

Hydrogen sulfide corrosion test was used to test the hydrogen-induced cracking sensitivity of the normalized BNS pipeline steel. The microstructure and morphology of hydrogen induced crack(HIC) of the normalized BNS pipeline steel after hydrogen sulfide corrosion test were observed with optical microscopy(OM), scanning electron microscopy(SEM). Combined with electron probe microanalyzer(EPMA) and hardness test, the hydrogen-induced cracking behavior of BNS pipeline steel was studied from the aspects of microstructure, crack morphology, center segregation and harness. The results showed that the pearlite band with high hardness caused by center segregation of C and Mn was the main crack initiation and propagation path for the long-size and linear shape hydrogen induced crack at the center of plate thickness, and the type of crack propagation was transgranular. Some tiny hydrogen induced crack nucleated from the small calcium-aluminate inclusion and the tiny hydrogen induced crack would not propagate to form long-size cracks with no suitable propagation path existing around the inclusion.

Correlation of Barreling Effect with Boundary Friction Coefficient during Upsetting of Various Materials Workpieces under Processing Conditions

2020 ◽  
Vol 992 ◽  
pp. 751-756
Author(s):  
Volodymyr V. Kukhar ◽  
Eduard S. Klimov ◽  
S.M. Chernenko ◽  
E.Yu. Balalayeva
Keyword(s):  
Friction Coefficient ◽  
Boundary Surface ◽  
Functional Relation ◽  
Strain Range ◽  
Height Ratio ◽  
Qualitative And Quantitative ◽  
Linear Dimensions ◽  
Closed Die Forging ◽  
Structural Carbon ◽  
Structural Carbon Steel

The necessity of taking into account the barreling effect at the design of die cavities, and open die and closed die forging processes on the basis of pre-forming of billets by upsetting is shown. The division of ideas about the indices of “bulk” and “linear” barreling (barrel shape), which is determined by the ratio of the bulk and linear dimensions of the workpiece after upsetting by flat dies, was made. The functional relation (correlation) between these indices and the friction coefficient on the boundary surface between flat dies and the upsetted workpiece has been determined. The qualitative and quantitative effect of workpiece dimensions (diameter-to-height ratio), strain range, temperature (conditions of cold and hot processing) and type of forming material (structural carbon steel, some of Cu-grades and Al-grades) on the barreling effect and friction coefficient during upsetting was found. The developed method makes it possible to predict a change in the friction coefficient during the upsetting of various material workpiece under given conditions of forming and to monitor their effect to the final shape.

Coupled Diffusion-Mechanical Model of NiTi Alloys Accounting for Hydrogen Diffusion and Ageing

2020 ◽  
Vol 12 (04) ◽  
pp. 2050039
Author(s):  
Wissem Elkhal Letaief ◽  
Tarek Hassine ◽  
Fehmi Gamaoun ◽  
Riheme Sarraj ◽  
Nabil Ben Kahla
Keyword(s):  
Shape Memory ◽  
Hydrogen Diffusion ◽  
Chemical Potential ◽  
Coupled Model ◽  
Transformation Strain ◽  
Hydrogen Desorption ◽  
Hydrogen Distribution ◽  
Hydrogen Atoms ◽  
Finite Element Software ◽  
Coupled Diffusion

Certain shape memory alloys (SMAs) are considered to be good absorbents of hydrogen atoms (e.g., NiTi). However, upon the absorption of hydrogen atoms, SMAs exhibit deteriorated effects of superelasticity and shape memory mechanisms. In this paper, we have developed a coupled model, based on experimental results, that demonstrates the effects of hydrogen diffusion on NiTi SMAs. The proposed model has been derived thermodynamically while appending the chemical potential of hydrogen to the energy balance law. The effects of hydrogen distribution on the mechanical behavior have been taken into consideration to simulate the ageing effects. Moreover, the model considers the saturation of transformation stress, the preservation of the transformation strain of the hydrogen-induced residual martensite and the recovery of superelasticity after hydrogen desorption. The model has been simulated by means of UMAT and UMATHT subroutines and ABAQUS finite-element software. The numerical results indicate a strong agreement with the experimental ones.

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