Study on Localized Corrosion Induced by Non-metallic Inclusions in OCTG Steel

2022 ◽  
Author(s):  
Linzhu Wang ◽  
Yutang Li ◽  
Shufeng Yang ◽  
Junqi Li ◽  
Chaoyi Chen ◽  
...  
Keyword(s):  
Localized Corrosion ◽  
Metallic Inclusions

Initiation of Environment Induced Cracking in Pipeline Steel: Microstructural Correlations

1998 ◽  
Author(s):  
Y.-Z. Wang ◽  
R. W. Revie ◽  
M. T. Shehata ◽  
R. N. Parkins ◽  
K. Krist
Keyword(s):  
Crack Initiation ◽  
Pipeline Steel ◽  
Early Stage ◽  
Localized Corrosion ◽  
Dense Population ◽  
Corrosion Attack ◽  
Metallic Inclusions ◽  
Co2 Balance ◽  
Crystallographic Planes ◽  
Different Parts

Initiation of environment-induced cracks in pipeline steels involves interactions among microstructural features, loading conditions and environmental variables. Cyclic, or dynamic, loading has an important role in crack initiation, a competitive process in which cracks form first at the most favorable sites. Under simultaneous cyclic loading and exposure of a Grade 448 (X-65) pipeline steel to aqueous solution of near-neutral pH, NS-4 solution saturated either with CO2 or 5% CO2/ balance N2, cracks that initiated early in the process were associated with pits. A correlation between pits and non-metallic inclusions has been observed. Other locations favorable for localized corrosion attack, such as along the steel surface at the edge of a coating, were also found to be sites for crack initiation. The dense population of cracks that appeared at a later stage of exposure most likely developed from slip-dissolution along certain crystallographic planes. Cracks that formed at an early stage did not always remain as the largest cracks, as crack coalescence, dormancy and/or re-activation, as well as initiation of new cracks, all occurred simultaneously on different parts of the exposure surface.

TEM study of a biofilm on copper corrosion

1996 ◽  
Vol 54 ◽  
pp. 220-221
Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Copper Alloys ◽  
Pure Copper ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Copper Corrosion ◽  
New Approach ◽  
The Past ◽  
Copper Tolerant

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.

THE EFFECT OF NON-METALLIC INCLUSIONS AND FILMS ON THE CATHODE ON SOME PROCESSES DURING VACUUM DISCHARGES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-411-C7-412
Author(s):  
D. I. Proskourovsky ◽  
V. F. Puchkarev
Keyword(s):  
Metallic Inclusions

RESEARCH ON THE NON-METALLIC INCLUSIONS OF KILLED STEEL (I)

1956 ◽  
Vol 42 (10) ◽  
pp. 962-968
Author(s):  
Yosaku Koike ◽  
Sahei Noda
Keyword(s):  
Metallic Inclusions

Determination of non-metallic inclusions in metal alloys by spark atomic emission spectrometry (review)

2018 ◽  
Vol 84 (12) ◽  
pp. 5-19
Author(s):  
D. N. Bock ◽  
V. A. Labusov
Keyword(s):  
Spectral Line ◽  
Internal Standard ◽  
Detection Limits ◽  
Radiation Detectors ◽  
Metal Alloys ◽  
Emission Spectrometry ◽  
Direct Production ◽  
Metallic Inclusions ◽  
Dissolved Form

A review of publications regarding detection of non-metallic inclusions in metal alloys using optical emission spectrometry with single-spark spectrum registration is presented. The main advantage of the method - an extremely short time of measurement (~1 min) – makes it useful for the purposes of direct production control. A spark-induced impact on a non-metallic inclusion results in a sharp increase (flashes) in the intensities of spectral lines of the elements that comprise the inclusion because their content in the metal matrix is usually rather small. The intensity distribution of the spectral line of the element obtained from several thousand of single-spark spectra consists of two parts: i) the Gaussian function corresponding to the content of the element in a dissolved form, and ii) an asymmetric additive in the region of high intensity values ??attributed to inclusions. Their quantitative determination is based on the assumption that the intensity of the spectral line in the single-spark spectrum is proportional to the content of the element in the matter ablated by the spark. Thus, according to the calibration dependence constructed using samples with a certified total element content, it is possible not only to determine the proportions of the dissolved and undissolved element, but also the dimensions of the individual inclusions. However, determination of the sizes is limited to a range of 1 – 20 µm. Moreover, only Al-containing inclusions can be determined quantitatively nowadays. Difficulties occur both with elements hardly dissolved in steels (O, Ca, Mg, S), and with the elements which exhibit rather high content in the dissolved form (Si, Mn). It is also still impossible to determine carbides and nitrides in steels using C and N lines. The use of time-resolved spectrometry can reduce the detection limits for inclusions containing Si and, possibly, Mn. The use of the internal standard in determination of the inclusions can also lower the detection limits, but may distort the results. Substitution of photomultipliers by solid-state linear radiation detectors provided development of more reliable internal standard, based on the background value in the vicinity of the spectral line. Verification of the results is difficult in the lack of standard samples of composition of the inclusions. Future studies can expand the range of inclusions to be determined by this method.

Analysis of the Crack Initiation at Non-Metallic Inclusions in High-Strength Steels

2012 ◽  
Vol 49 (8) ◽  
pp. 468-479 ◽  
Author(s):  
P. Grad ◽  
B. Reuscher ◽  
A. Brodyanski ◽  
M. Kopnarski ◽  
E. Kerscher
Keyword(s):  
Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Metallic Inclusions

VLX 954

Alloy Digest ◽  
1995 ◽  
Vol 44 (4) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Sea Water ◽  
Heat Treating ◽  
Localized Corrosion ◽  
Temperature Performance

Abstract VLX 954 is an austenitic stainless steel with 6% (nominal) molybdenum. The alloy is particularly resistant to localized corrosion in sea water and chloride environments. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-589. Producer or source: DMV Stainless USA Inc.

Sign in / Sign up

Export Citation Format

Share Document