Effect of Sulphite Sediment on Hydrogen Embrittlement Susceptivity of Hot-Dip Galvanized Steel Exposed to Simulated Marine Atmosphere

2011 ◽  
Vol 197-198 ◽  
pp. 1617-1620
Author(s):  
Da Lei Zhang ◽  
You Hai Jin ◽  
Yan Li ◽  
Xiao Tang
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Hydrogen Permeation ◽  
Zinc Coating ◽  
Galvanized Steel ◽  
Atmospheric Environment ◽  
Percentage Elongation ◽  
Fracture Characteristics ◽  
Microscopy Technique ◽  
Galvanized Steels

Hydrogen permeation and embrittlement behavior of hot-dip galvanized steels with different sulphite sediment on surface exposed to stimulant marine atmospheric environment was investigated by hydrogen permeation current measurement using modified Devanathan-Stachurski cell, slow strain rate tensile test and scanning electron microscopy technique. The results indicated that hydrogen permeation curves were increasing along with the sediment rising gradually. On the other hand, it was found that hydrogen absorption was accelerated by the cathodic protection of scratched steel surface afforded by zinc coating. Hydrogen absorption and permeation reduced the percentage elongation after fracture of galvanized steel specimens; meanwhile, the fracture characteristics of samples fringe occurred some lacerated phenomena, i.e., galvanized steels show a higher susceptivity of hydrogen embrittlement when exposed to marine atmospheric environment with sulphite.

Hydrogen Embrittlement Susceptivity of Hot-Dip Galvanized Steel in Wet-Dry Cyclic Simulated Marine Atmospheric Environment

2011 ◽  
Vol 197-198 ◽  
pp. 1443-1446
Author(s):  
Da Lei Zhang ◽  
Yan Li ◽  
You Hai Jin ◽  
Xiao Tang
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Hydrogen Permeation ◽  
Galvanized Steel ◽  
Atmospheric Environment ◽  
Percentage Elongation ◽  
Fracture Characteristics ◽  
Scanning Electron Microscopy Technique ◽  
Microscopy Technique ◽  
Galvanized Steels

Hydrogen permeation and embrittlement behavior of hot-dip galvanized steels in wet-dry cyclic simulated marine atmospheric environment was investigated by hydrogen permeation current measurement using modified Devanathan-Stachurski cell, slow strain rate tensile test and scanning electron microscopy technique. It was found that hydrogen absorption was accelerated in wet-dry cyclic environment. On the other hand, hydrogen absorption and permeation reduced the percentage elongation after fracture of galvanized steel specimens; meanwhile, the fracture characteristics of samples fringe occurred some lacerated phenomena, i.e., galvanized steels show a higher susceptivity of hydrogen embrittlement when exposed to wet-dry cyclic marine atmospheric environment.

Hydrogen Permeation Characterization of Hot-Dip Galvanized Steel in Simulated Marine Atmospheric Environment

2009 ◽  
Vol 79-82 ◽  
pp. 1051-1054 ◽  
Author(s):  
Da Lei Zhang ◽  
Yan Li
Keyword(s):  
Hydrogen Permeation ◽  
Zinc Coating ◽  
Galvanized Steel ◽  
Atmospheric Environment ◽  
Effect Of Temperature ◽  
Marine Atmosphere ◽  
Current Curve ◽  
Moist Environment ◽  
Coating Defect

Hydrogen permeation current curve of galvanized steel with hot-dip zinc coating exposed to simulated marine atmosphere was measured using a modified Devanathan-Stachurski cell. Effect of temperature, humidity and coating defect on its hydrogen permeation behaviour was also investigated. The results indicated that hydrogen permeation current density and the amount of hydrogen accumulated increased evidently with temperature and humidity rising at moist environment; meanwhile, hydrogen absorption when coating defect occurred was accelerated by the cathodic protection of the exposed steel surface afforded by surrounding zinc coating.

Comparison of Behaviour of Different Variants of Hydrogenated TRIP Steels at Slow Strain Rate Tests

2019 ◽  
Vol 810 ◽  
pp. 70-75
Author(s):  
Petra Váňová ◽  
Jaroslav Sojka ◽  
Kateřina Konečná ◽  
Taťána Radkovská
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Potassium Thiocyanate ◽  
Tensile Tests ◽  
Fracture Characteristics ◽  
Trip Steels ◽  
Hydrogen Charging ◽  
Metallic Inclusions ◽  
Significant Difference ◽  
Fracture Micromechanism

The paper describes effect of hydrogen on mechanical properties and fracture characteristics of two types of C-Mn-Si TRIP steel; laboratory prepared steel TRIP 800 and commercially manufactured steel TRIP 780. TRIP steels are very promising materials thanks to their combination of a very good strength and toughness. However, these steels can be embrittled by hydrogen during technological operations related to galvanizing. That is why the knowledge of effects of hydrogen on the properties and fracture characteristics of the TRIP steels is of particular importance. In the presented study, effects of hydrogen were studied by tensile tests after electrolytical hydrogen charging. Electrolytical hydrogen charging was performed in 0.05 M solution of sulfuric acid with addition of potassium thiocyanate to promote hydrogen absorption. Hydrogen provoked embrittlement in both steel variants and changed their fracture micromechanism. Hydrogen embrittlement manifested itself mainly by a loss of plasticity. Index of hydrogen embrittlement, expressed on the basic of a relative drop of elongation to fracture, reached values about 77 % for the steel variant TRIP 800, resp. 83 % for the steel variant TRIP 780. No significant difference was observed between two steel variants studied. Concerning fractographic characteristics, steels containing hydrogen displayed quasi-cleavage fracture mostly on the edges of the sample and around elongated non-metallic inclusions.

Strengthening Mechanism of TiB2-TiC Complex Phases Coated Electrode

2012 ◽  
Vol 433-440 ◽  
pp. 251-255 ◽  
Author(s):  
Ping Luo ◽  
Shi Jie Dong ◽  
Zhang Qiang Mei ◽  
Zhi Xiong Xie
Keyword(s):  
Failure Mechanism ◽  
Current Density ◽  
Spot Welding ◽  
Single Phase ◽  
Welding Process ◽  
Strengthening Mechanism ◽  
Galvanized Steel ◽  
Steel Weld ◽  
Galvanized Steels ◽  
Coated Electrode

TiB2-TiC complex phases coating deposited onto the surface of electrodes by electro-spark deposition (ESD) in order to prolong the life of single phase coated electrode (TiB2 or TiC) during resistance welding of galvanized steels. The microstructures and TiB2-TiC complex phases coatings were characterized by SEM and XRD. The results indicate that life of TiB2-TiC complex phases coated electrode is prolonged significantly than life of single-phase coated electrode （TiB2 or TiC ）, failure mechanism of TiB2-TiC complex phases coated electrode is mainly wear to cause diameter increase on electrode tip, which results in lower current density during welding process, and then nugget size cannot satisfy the requirement of resistance spot welding. The failure mechanism of TiB2-TiC complex phases coated electrode is obviously different from uncoated electrode, the failure mechanism of uncoated electrode is wear and alloying between electrode tip surface and molten Zn on galvanized steel weld surface.

Effect of Hydrogen on Mechanical Properties of Pipeline API 5L X70 Steel

2011 ◽  
Vol 146 ◽  
pp. 213-225 ◽  
Author(s):  
T. Bellahcene ◽  
J. Capelle ◽  
Méziane Aberkane ◽  
Z. Azari
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Fatigue Tests ◽  
The Finite Element Method ◽  
Effective Distance ◽  
Bending Tests ◽  
Fatigue Initiation ◽  
Api 5L X70 Steel ◽  
Special Soil

The aim of this work is to study the effects of hydrogen absorption on mechanical properties of pipe API 5L X70 steel. This study is conducted in special soil solution NS4 with pH 6.7 It show that the tensile properties like yield stress, ultimate strength and elongation at failure reduced under hydrogen embrittlement. Several fatigue tests (three (03) points bending tests) on roman tile specimens with notch are performed. Fatigue initiation is detected by acoustic emission. A comparison between specimens electrolytically charged with hydrogen and specimens without hydrogen absorption is made and it has been noted that fatigue initiation time is reduced when hydrogen embrittlement occurs. The field of elastoplastic stresses near the notch is computed by the finite-element method with the Abaqus software package. Effective distance and stress are calculated with the volumetric approach and the Notch intensity Factor of the roman tile specimen is determined for each loading value used in our tests.

scholarly journals The impact of exploitation and environmental factors on the degradation of steel road safety equipment

2018 ◽  
Vol 231 ◽  
pp. 01012
Author(s):  
Joanna Kobus ◽  
Lech Kwiatkowski ◽  
Rafał Lutze
Keyword(s):  
Road Safety ◽  
Zinc Coating ◽  
Low Carbon Steel ◽  
Environmental Parameters ◽  
Galvanized Steel ◽  
Traffic Intensity ◽  
Low Carbon ◽  
Zinc Corrosion ◽  
The Impact

The work is aimed at determining the corrosivity of atmosphere in the vicinity of roads, taking into account the characteristics of local emission sources, including traffic intensity of vehicles along with climatic and exploitation factors. Determination of the corrosivity of atmosphere was carried out according to the procedures described in PN EN ISO standards. Samples for testing were made of low carbon steel DC05, zinc and hot dip galvanized steel. Samples were assembled at 19 sites in the close vicinity of roads and highways near the measurement points of vehicle traffic intensity. The mass loss of exposed samples was the basis for determination the atmosphere corrosivity at each of 19 test sites. Regarding steel, the corrosivity category of C4 was observed at 8/19 sites. Corrosion losses outside roads are 2-4 times lower and ranged within the categories of C2 and C3. Zinc corrosion losses classified to category C4 occurred at 2/19 stations. In the remaining ones they corresponded to category C3. In areas outside of roads, zinc corrosion losses are about 20-100% lower (C2). The first attempts to model the dependence of operating and environmental parameters on zinc and zinc coating corrosion losses indicate significant correlation between zinc and zinc coating corrosion losses as a function.

Hydrogen Permeation Properties of Nb-Based Two-Phase Compounds

2007 ◽  
Vol 561-565 ◽  
pp. 467-470
Author(s):  
Yuji Yamaguchi ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui ◽  
Sho Tokui ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Permeation ◽  
Membrane Surface ◽  
Hydrogen Permeability ◽  
Eutectic Structure ◽  
Growth Direction ◽  
Directionally Solidified ◽  
Two Phase ◽  
Cast Sample ◽  
Lamellar Type

Nb-NiTi and Nb-CoTi eutectic alloys were directionally solidified in an optical floating zone furnace. Rod-type eutectic structures with Nb rods aligned parallel to the growth direction are obtained for Nb-41Ni-40Ti grown at relatively slow growth rates below 1.0mm/h, while lamellar-type eutectic structures are obtained for Nb-35Co-34Ti grown at the same condition. The hydrogen permeability for the Nb-41Ni-40Ti DS alloy with Nb rods perpendicular to the membrane surface is 2.60×10-8mol H2 m-1 Pa-1/2 at 673K, which is about 2.5 times higher than that of as-cast sample. No hydrogen embrittlement is observed between 573 and 673K, indicating that the Nb-NiTi rod-type eutectic structure effectively suppresses the hydrogen embrittlement of Nb during hydrogen permeation.

SURFACE DAMAGE BEHAVIOR OF GALVANIZED STEEL SHEETS IN FORMING PROCESS UNDER TENSION-BENDING

2010 ◽  
Vol 24 (30) ◽  
pp. 5877-5884 ◽  
Author(s):  
Z. Q. YU ◽  
Y. K. HOU ◽  
S. H. LI ◽  
Z. Q. LIN ◽  
W. G. ZHANG
Keyword(s):  
Sheet Metal Forming ◽  
Metal Forming ◽  
Surface Damage ◽  
Galvanized Steel ◽  
Forming Process ◽  
Damage Resistance ◽  
Steel Sheets ◽  
Galvanized Steels ◽  
Part Surface ◽  
Forming Tools

The surface damage behaviors of different galvanized steel sheets were investigated under the condition of tension-bending. The U-channel forming tests were performed for HDGI (hot-dip galvanized) and HDGA (hot-dip galvannealed) steels. Experimental results indicate that HDGI steel shows better damage resistance than HDGA steel in sheet metal forming. Scratching is the main surface damage in the forming of HDGI steel while exfoliating and scratching of coating are two types of surface damage for HDGA steel. And tool hardness and surface topography have crucial effects on part surface damage in the forming of the two kinds of galvanized steels. Different surface treatments should be applied to the forming tools in the forming of HDGI and HDGA steels for better surface qualities of products.

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