Accelerating Corrosion Test Study on Galvanized Q345 Steel

2010 ◽  
Vol 139-141 ◽  
pp. 314-320 ◽  
Author(s):  
Xiao Hua Yang ◽  
Ding Zhang ◽  
Yong Zhang
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Corrosion Test ◽  
Turning Point ◽  
Zinc Coating ◽  
Uniform Corrosion ◽  
Matrix Metal ◽  
Test Study ◽  
The Matrix ◽  
Better Than

Galvanized Q345 steel specimens were accelerating corroded with accelerating environment spectrum for equivalent 1, 3, 4 and 5 years, and then its corrosion behavior was studied based on macro corrosion appearances, micro corrosion appearances, weight loss, pits depth and fatigue strength. The results show that, i because the zinc coating can protect the matrix metal from corroding, the corrosion resistance of galvanized Q345 is much better than Q345; ii between the 1st year and the 4th year, pitting corrosion is dominative, and after the 4th year, the corrosion form transforms from pitting corrosion to uniform corrosion; iii after corrosion for 5 years, the zinc coating was not destroyed completely, and with the turning point of the 4th year, the corrosion rate of the zinc coating becomes higher firstly and then gets lower, which agrees with previous study.

Corrosion resistance of zinc electrodeposited from acidic and alkaline electrolytes using pulse current

2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Matilda Zemanová
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Pulse Current ◽  
Zinc Coating ◽  
Accelerated Corrosion ◽  
X Ray ◽  
Before And After ◽  
Alkaline Electrolytes ◽  
Zinc Coatings ◽  
Chrome Iii

AbstractCorrosion resistance of zinc coatings was investigated in an accelerated corrosion test in a condensation chamber. Zinc was electrodeposited from alkaline and acidic electrolytes using direct current (DC) or pulse current (PC). The zinc coating was subsequently protected against corrosion with a chrome (III) layer. Morphology and structure of the coatings was investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the corrosion test. Corrosion resistance of alkaline zinc coatings electrodeposited with DC and PC under test conditions was found to be comparable. The corrosion resistance of zinc coatings deposited from acidic electrolytes by PC was lower in comparison with corrosion resistance of zinc coatings deposited using DC.

scholarly journals Investigation of the Localized Corrosion and Passive Behavior of Type 304 Stainless Steels with 0.2–1.8 wt % B

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2097 ◽  
Author(s):  
Heon-Young Ha ◽  
Jae Jang ◽  
Tae-Ho Lee ◽  
Chihyoung Won ◽  
Chang-Hoon Lee ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Localized Corrosion ◽  
Ingot Metallurgy ◽  
Passive Behavior ◽  
Pitting Corrosion Resistance ◽  
The Matrix ◽  
Type 304

The pitting corrosion resistance and passive behavior of type 304 borated stainless steels (Febalance–18Cr–12Ni–1.5Mn–(0.19, 0.78, and 1.76 wt %)B) manufactured through conventional ingot metallurgy were investigated. The alloys were composed of an austenitic matrix and Cr2B phase, and the volume fraction of Cr2B increased from 1.68 to 22.66 vol % as the B content increased from 0.19 to 1.76 wt %. Potentiodynamic polarization tests measured in aqueous NaCl solutions revealed that the pitting corrosion resistance was reduced as the B content increased and the pits were initiated at the matrix adjacent to the Cr2B phase. It was found that the reduced resistance to pitting corrosion by B addition was due to the formation of more defective and thinner passive film and increased pit initiation sites in the matrix.

Study on Chromium-Free Pretreatment Solution of Color Coated Sheet

2014 ◽  
Vol 490-491 ◽  
pp. 104-108
Author(s):  
Chang Rong Ran ◽  
Tai Xiong Guo ◽  
Quan Xu ◽  
Xue Qiang Dong
Keyword(s):  
Corrosion Resistance ◽  
Optimal Condition ◽  
Pitting Corrosion ◽  
Corrosion Test ◽  
Salt Spray ◽  
Experimental Results ◽  
Neutral Salt ◽  
Pretreatment Technology ◽  
Coated Sheet ◽  
Pretreatment Solution

Based on the inorganic and organic composite pretreatment technology, a new chromium-free pretreatment solution consisting of Ce (NO3)3, N-β (aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) and vinyltrimethoxysilane (KH171) was studied and used to treat galvanized sheet. Corrosion resistance of composite silane films on galvanized sheet surfaces was studied using CuSO4 pitting corrosion test and neutral salt spray test. Experimental results show that the corrosion resistance of composite silane film has improved significantly, compared to single silane film. The optimal condition of chromium-free pretreatment solution is that KH792/KH171 ratio is 4/1(v/v), Ce (NO3)3 content is 0.05%(w/w).

Hot Corrosion Behavior of Sputtered Fe-Y Alloy Coatings with Different Y Contents

2011 ◽  
Vol 391-392 ◽  
pp. 1263-1267
Author(s):  
Guang Yan Fu ◽  
Jing Yu Chen ◽  
Qun Liu ◽  
Yong Su
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Alloy Coating ◽  
Good Adhesion ◽  
Corrosion Scale ◽  
Measurement Results ◽  
The Matrix ◽  
Better Than

Three Fe-Y alloy coatings with differernt kinds of Y contents were prepared on stainless steel by magnetron sputtering. The hot corrosion behavior of sputtered alloy coatings with Na2SO4 deposits at 800 °C was investigated by discontinuous weigh measurement. Results show that the sputtered Fe-Y alloy coatings exhibit good adhesion with the matrix of stainless steel, and the hot corrosion kinetic curves of the specimens approximately follow the parabolic rate law. The Fe oxides are the main substances in the corrosion scale, and the hot corrosion rate of the three Fe-Y alloy coatings increases as the Y content increases. Therefore, the hot corrosion resistance of Fe-15Y alloy coating is better than that of Fe-20Y or Fe-30Y alloy coating.

Appearance of the Mechanical Plating Formed by Zn-Al Compounding Flake Powders and its Anticorrosion

2009 ◽  
Vol 79-82 ◽  
pp. 811-814 ◽  
Author(s):  
Jie Lu
Keyword(s):  
Corrosion Resistance ◽  
Fracture Surface ◽  
Cross Section ◽  
Corrosive Medium ◽  
Spherical Particles ◽  
Small Space ◽  
Matrix Metal ◽  
Aluminum Oxidation ◽  
The Matrix ◽  
Flake Structure

In this study, a comparison of appearance surface and fracture surface of mechanical plating was made, respectively formed by spherical Zn powders and Zn-Al compounding flake powders. It is found that the spherical particles are deposited and embedded on Zn plating. The deformation of granular Zn powders on coating superficial is relatively large, but there is little distortion of globe grain inside the coating, mainly with spheroidicity distorted. Besides, there are obvious gaps between the particles in Zn coating. In contrast, the flake structure granules of Zn-Al plating are densely and compactly laid out with small space. After contacting with air, the plating coat expands owing to aluminum oxidation, leading to the higher position of the plating coat on the cross section than the matrix metal. We then did salt mist test to verify the corrosion resistance of Zn-Al compounding flake coating. It was found that the Zn-Al compounding flake coating was superior to that formed by globe Zn powder. Results show that the addition of layers of flakes has a better shielding action resisting corrosive medium, leading to the decrease of the osmosis from corrosive medium to the coatings. And the coating can repair naturally after being damaged. We further passivate plating with molybdate to improve the anticorrosion of the coating.

UHB STAINLESS 34L

Alloy Digest ◽  
1977 ◽  
Vol 26 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Heat Treating ◽  
Intermetallic Phases ◽  
Uniform Corrosion ◽  
Low Carbon

Abstract UHB Stainless 34L is noted for its extra-low carbon content (0.03% max) and high molybdenum content (4.3%). It has excellent resistance to uniform corrosion and to pitting corrosion. Its tensile strength is approximately the same as that of other austenitic stainless steels. This steel is austenitic but certain intermetallic phases, such as sigma and chi, can occur; however, under normal conditions these intermetallic phases do not affect corrosion resistance and toughness. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-336. Producer or source: Uddeholm Aktiebolag.

Influences of Aging Precipitation on Corrosion Resistance of 18Cr-18Mn-2Mo-0.77N HNS

2009 ◽  
Vol 79-82 ◽  
pp. 1013-1016 ◽  
Author(s):  
Zu Rui Zhang ◽  
Hua Bing Li ◽  
Zhou Hua Jiang ◽  
Zhen Li ◽  
Bao Yu Xu
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Volume Fraction ◽  
Aging Treatment ◽  
High Nitrogen ◽  
Aging Precipitation ◽  
Pitting Corrosion Resistance ◽  
Nitrogen Steel ◽  
The Matrix ◽  
Nose Temperature

Influences of aging precipitation of Cr2N and Chi (χ) phases on the resistance to pitting corrosion and intergranular corrosion of 18Cr-18Mn-2Mo-0.77N high nitrogen steel (HNS) as a type of fundamental and structural materials were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) pattern and electrochemical methods. Intergranular, cellular Cr2N and χ phases precipitate gradually along grain boundaries and inward grains. The volume fraction of precipitation presents a C-curve with a nose temperature of 850°C during 2h aging treatment. The solution-treated (ST) HNS exhibits the highest pitting corrosion potential because of high nitrogen content in steel, and especially no precipitation. The pitting corrosion resistance of aged HNS decreases because of the formation of aging precipitation which results in the depletion of Cr and Mo in the matrix. The pitting corrosion potentials firstly decrease then increase as the same tendency as the amount of precipitation expect 850°C and 900°C. Double loop electrochemical potentiokinetic reaction (DL-EPR) results show that the change tendency of IGC susceptibility is well consistent with the amount of precipitation of aged HNS for 2h at various temperatures. With prolonging the aging time at 850°C, aged HNS presents more obviously intergranular sensitization due to the formation of aging precipitation which results in the depletion of Cr and Mo.

Effect of Microalloy Elements on Corrosion Resistance of High-Chromium-Containing Ferritic Stainless Steels in Chloride Solutions

CORROSION ◽  
2001 ◽  
Vol 57 (6) ◽  
pp. 547-556 ◽  
Author(s):  
H. Kim ◽  
Y-D. Lee
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Mechanical Damage ◽  
Chemical Compositions ◽  
Inclusion Type ◽  
Electrochemical Tests ◽  
Pitting Corrosion Resistance ◽  
The Matrix ◽  
The Difference

Abstract The effects of inclusions on corrosion resistance of high-Cr-containing ferritic steels were studied using electrochemical tests (anodic polarization and electrochemical noise [EN]) and a ferric chloride (FeCl3) test in chloride solution. For this purpose, the inclusion type and size in the matrix was controlled by the selective addition of alloying elements, their contents, and pickling treatment. Large inclusions such as titanium nitride (TiN), though chemically stable, caused surface cracks at the inclusion/matrix interface during mechanical treatments and decreased pitting corrosion resistance. Soluble inclusions located at the interface were preferentially attacked to form crevices even if the inclusions were as small as a submicron. Meanwhile, submicron inclusions such as Nb, C, or N did not affect pitting corrosion resistance. Unlike the chemical compositions and shape of inclusion, the surface area covered by inclusions did not affect pitting corrosion resistance. Hence, the main factor affecting corrosion resistance was the presence of a crevice, whether it was formed by dissolution or mechanical damage, and not the number of inclusions. EN testing revealed that the experimental alloys deoxidized by Si were more resistant to initial pitting corrosion resistance than those deoxidized by Al, though many steel manufacturers deoxidize stainless steels by Al. The discrepancy was attributed to the difference of the chemical stability and the feasability of crack formation depending on inclusion.

An Improvement in Tarnish and Corrosion Resistance of 94Ag-4Zn-Cu Alloys with Sn Addition

2014 ◽  
Vol 894 ◽  
pp. 138-142 ◽  
Author(s):  
Jirutthitikalpongsri Hirunyagird ◽  
Gobboon Lothongkum ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Single Phase ◽  
Corrosion Current ◽  
Eutectic Structure ◽  
Test Results ◽  
High Solubility ◽  
Cu Alloys ◽  
The Matrix ◽  
Tin Content

The tarnish and corrosion resistance of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy compared with Ag-5.95Cu alloy were investigated. The tarnish results show that the DE* value of Ag-5.95Cu alloy is higher than those of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy due to the sulfide formations such as Ag2S, Cu2S and CuS. The DE* value significantly decreases with increasing tin content. This is attributed to the matrix enrichment of tin which protects the sulfur reaction on surface. From corrosion test results, 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy provide the noble shift in the corrosion potentials and pitting potentials but the negative shift in the corrosion current density compared with Ag-5.95Cu alloy. Corrosion rate of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy decrease markedly compared with Ag-5.95Cu alloy because it depends on the alloying elements and the microstructural changes. Due to high solubility of zinc and tin, the microstructures of tin-rich alloys consist of the higher portion of single phase and less eutectic structure than that of Ag-5.95Cu alloy.

scholarly journals The Influence of Microstructure on the Passive Layer Chemistry and Corrosion Resistance for Some Titanium-Based Alloys

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1233 ◽  
Author(s):  
Nader El-Bagoury ◽  
Sameh I. Ahmed ◽  
Ola Ahmed Abu Ali ◽  
Shimaa El-Hadad ◽  
Ahmed M. Fallatah ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Photoelectron Spectroscopy ◽  
Volume Fraction ◽  
Electrochemical Impedance ◽  
Passive Layer ◽  
Layer Growth ◽  
Uniform Corrosion ◽  
Cyclic Polarization ◽  
X Ray

The effect of microstructure and chemistry on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys, was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing dynamic electrochemical impedance spectroscopy (DEIS). Corrosion studies were performed in 0.9% NaCl solution at 37 °C, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron spectroscopy (XPS) analysis. For all studied alloys, the microstructure consisted of α matrix, which was strengthened by β phase. The highest and the lowest values of the β phase’s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The susceptibility of the investigated alloys toward pitting corrosion was enhanced following the sequence: Ti-6Al-7Nb < Ti-6Al-4V << TC21. Ti-6Al-7Nb alloy recorded the lowest pitting corrosion resistance (Rpit) among studied alloys, approaching that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in the corrosion behavior of these materials.

Sign in / Sign up

Export Citation Format

Share Document