scholarly journals Effect of Small Variation in the Composition of Plates and Weld Filler Wires on the General Corrosion Rate of Ni-Cr-Mo Alloys

2005 ◽  
Author(s):  
David V. Fix ◽  
John C. Estill ◽  
Rau´l B. Rebak
Keyword(s):  
Corrosion Rate ◽  
Filler Metal ◽  
Small Variation ◽  
Weight Percent ◽  
General Corrosion ◽  
Nickel Chromium ◽  
Immersion Corrosion ◽  
Heat Treated ◽  
Alloy 22 ◽  
G 28

The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials within the range of the standards.

scholarly journals Effect of Chemistry Variations in Plate and Weld Filler Metal on the Corrosion Performance of Ni-Cr-Mo Alloys

2006 ◽  
Author(s):  
David V. Fix ◽  
Rau´l B. Rebak
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Filler Metal ◽  
Weight Percent ◽  
Corrosion Performance ◽  
Nickel Chromium ◽  
Immersion Corrosion ◽  
Heat Treated ◽  
Alloy 22 ◽  
G 28

The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials in the range of the standards.

scholarly journals Effect of Chemistry Variations of Wrought N06022 Plates on the Repassivation Potential in 1 M NaCl at 90°C

2008 ◽  
Author(s):  
Kevin G. Mon ◽  
Raul B. Rebak
Keyword(s):  
Chemical Composition ◽  
Potentiodynamic Polarization ◽  
Heat Treating ◽  
Weight Percent ◽  
Nacl Solution ◽  
Nickel Chromium ◽  
Repassivation Potential ◽  
Heat Treated ◽  
Alloy 22 ◽  
Cyclic Potentiodynamic Polarization

ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022). The composition of each element is given in a range (e.g., the lowest content of Mo is specified as 12.5 weight percent and the highest as 14.5 weight percent. It is important to determine the dependence of Alloy 22 electrochemical behavior on the composition of the alloying elements as they vary from the lowest to the highest end of the ranges specified in ASTM B 575 standard. Seven heats of Alloy 22 plate were melted and processed. The plates were tested in the mill annealed (MA) and solution heat treated (SHT) condition. Cyclic potentiodynamic polarization tests were performed in 1 M NaCl solution at 90°C. Results show no influence of Alloy 22 chemistry variations or heat treating on the measured repassivation potential.

Effect of Temperature and H2S Concentration on Corrosion of X52 Pipeline Steel in Acidic Solutions

2013 ◽  
Vol 743-744 ◽  
pp. 589-596 ◽  
Author(s):  
Meng Liu ◽  
Jian Qiu Wang ◽  
Wei Ke
Keyword(s):  
Corrosion Rate ◽  
Pipeline Steel ◽  
Corrosion Products ◽  
Effect Of Temperature ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
Ferrous Sulfide ◽  
Immersion Corrosion ◽  
Different Temperatures ◽  
Diffraction Patterns

The corrosion behavior of X52 pipeline steel in H2S solutions was investigated through immersion corrosion test which was carried out in a high temperature and high pressure autoclave at different temperatures and H2S concentrations. General corrosion rates were calculated based on the weight loss of samples. The morphology and the chemical composition of the corrosion products were obtained by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The crystal structure of corrosion products was analyzed by X-Ray diffraction patterns (XRD). The corrosion products consisted mainly of the sulfide compounds (mackinawite, cubic ferrous sulfide, troilite and pyrrhotite). The corrosion products included two layers: the inner iron-rich layer and the outer sulfur-rich layer. Under H2S concentrations of 27g/L, the corrosion rate increased with the increase of temperature up to 90°C and then decreased at 120°C, finaly increased again. The corrosion rate first increased with H2S concentrations then decreased at 120°C. The structure and stability of the corrosion products due to different corrosion mechanism had a major impact on the corrosion rate. The corrosion resistance of the corrosion products increased as follows: mackinawite < cubic ferrous sulfide < troilite < pyrrhotite.

scholarly journals Long-Term Corrosion Behavior of Alloy 22 in 5 M CaCl2 at 120°C

2006 ◽  
Author(s):  
John C. Estill ◽  
Gary A. Hust ◽  
Kenneth J. Evans ◽  
Marshall L. Stuart ◽  
Rau´l B. Rebak
Keyword(s):  
Corrosion Rate ◽  
Salt Concentration ◽  
Crevice Corrosion ◽  
Immersion Time ◽  
Corrosion Potential ◽  
Open Circuit ◽  
General Corrosion ◽  
Critical Potential ◽  
Alloy 22

In conditions where tight crevices exist in hot chloride containing solutions Alloy 22 may suffer crevice corrosion. The occurrence (or not) of crevice corrosion in a given environment (e.g. salt concentration and temperature), is governed by the values of the critical potential (Ecrit) for crevice corrosion and the corrosion potential (Ecorr). This paper discusses the evolution of Ecorr and corrosion rate (CR) of creviced Alloy 22 specimens in 5 M calcium chloride (CaCl2) at 120°C. Tested specimens included non-creviced rods and multiple creviced assemblies (MCA) both non-welded (wrought) and welded. Results show that Alloy 22 suffers crevice corrosion under the open circuit conditions in the aerated hot CaCl2 brine. However, after more than a year immersion the propagation of crevice corrosion was not significant. The general corrosion rate decreased or remained unchanged as the immersion time increased. For rods and MCA specimens, the corrosion rate was lower than 100 nm/year after more than a year immersion time.

scholarly journals Review of Corrosion Modes For Alloy 22 Regarding Lifetime Expectancy of Nuclear Waste Containers

2002 ◽  
Vol 757 ◽  
Author(s):  
Raúl B. Rebak ◽  
John C. Estill
Keyword(s):  
Corrosion Rate ◽  
Nuclear Waste ◽  
Outer Layer ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Corrosion Resistant ◽  
Waste Package ◽  
Environmentally Assisted Cracking ◽  
Alloy 22 ◽  
Lifetime Expectancy

ABSTRACTAlloy 22 (UNS N06022) was selected to fabricate the corrosion resistant outer barrier of a two-layer nuclear waste package container. This paper reviews the main corrosion degradation modes that are predicted for the outer layer of the container. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

Effects of Fluoride and other Anions on the Corrosion of Alloy 22

2002 ◽  
Vol 757 ◽  
Author(s):  
A. L. Pulvirenti ◽  
K. M. Needham ◽  
M. A. Adel-Hadadi ◽  
A. Barkatt ◽  
C. R. Marks ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Phosphoric Acid ◽  
Corrosion Inhibitor ◽  
General Corrosion ◽  
Corrosion Resistant ◽  
Electrochemical Tests ◽  
Corrosion Rates ◽  
Reducing Conditions ◽  
Constant Ph ◽  
Alloy 22

ABSTRACTSamples of Alloy 22 were tested in solutions containing various anions in order to determine their effect on the corrosion of the alloy. It was found that Alloy 22 is relatively corrosion resistant in HCl and HNO3 at pH 1 and 160°C (general corrosion rates on the order of 10 μm/year), but more susceptible to phosphoric acid, especially under reducing conditions. The presence of fluoride raised the corrosion rate of Alloy 22 to the order 1 mm/year at pH 1, and fluoride is still active towards Alloy 22 at pH levels as high as 3.5. Samples tested in solutions of 1000xJ13 in which the pH was altered during testing showed an increase in corrosion rate over solutions of constant pH. Preliminary electrochemical tests suggest that nitrate may be an effective corrosion inhibitor in fluoride containing solutions, while sulfate is not.

scholarly journals Methods to Calculate Corrosion Rates for Alloy 22 From Polarization Resistance Experiments

2006 ◽  
Author(s):  
Lana L. Wong ◽  
Sue I. Martin ◽  
Rau´l B. Rebak
Keyword(s):  
Corrosion Rate ◽  
Rapid Screening ◽  
General Corrosion ◽  
Absolute Value ◽  
Electrochemical Tests ◽  
Corrosion Rates ◽  
Alloy 22 ◽  
Fixed Set ◽  
Faraday Law ◽  
Current Potential

The general corrosion rate may be measured using immersion tests or electrochemical tests. The electrochemical tests are fast and can be used for a rapid screening of environmental effects such as temperature and electrolyte composition. The electrochemical tests are described in ASTM standards G 59 and G 102. The basis of these tests is to calculate the resistance to polarization (Rp) in a voltage vs. current plot and to convert these values to corrosion rates using the Faraday law. Commercial software can calculate the corrosion rate based on inputs from the operator. This paper discusses three ways of calculating the corrosion rate (Methods 1, 2 and 3) based on a fixed set of acquired data of voltage vs. current. The conclusions are that the way the corrosion rate is calculated does not impact greatly on the absolute value of the corrosion rate. Variations in the acquired data (current, potential) from one experiment to another seem more important that the manner the data is fitted with the Rp slope.

Corrosion Behavior of Alloy 22 and Ti Grade 7 in a Nuclear Waste Repository Environment

CORROSION ◽  
2004 ◽  
Vol 60 (8) ◽  
pp. 764-777 ◽  
Author(s):  
F. Hua ◽  
G. Gordon
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Nuclear Waste ◽  
Crevice Corrosion ◽  
Nuclear Waste Repository ◽  
General Corrosion ◽  
Corrosion Rates ◽  
Significant Difference ◽  
Alloy 22 ◽  
Waste Repository

Abstract Alloy 22 (UNS N06022) and Ti Grade 7 (UNS R52400) are the current corrosion-resistant materials of choice for fabricating the waste package outer barrier and the drip shield, respectively, for the proposed high-level nuclear waste repository at Yucca Mountain. In this work, the general and crevice corrosion behavior of annealed and welded Alloy 22 and Ti Grade 7 exposed in basic saturated water (BSW-12) for four and eight weeks at 60°C to 105°C were evaluated using the ASTM G78 method combined with surface analysis and statistical analysis of corrosion rate. The general corrosion rates for Alloy 22 and Ti Grade 7 were found to increase linearly with temperature but decrease with the exposure time. The mean corrosion rate was found to be 0.003 mpy (0.075 μm/y) at 60°C and 0.010 mpy (0.25μm/y) at 105°C for Alloy 22 and 0.008 mpy (0.20 μm/y) at 60°C and 0.022 mpy (0.56 μm/y) at 105°C for Ti Grade 7. No significant difference in corrosion behavior between the annealed and welded materials was observed. For both materials the surface imperfections inherited from materials processing did not seem to deteriorate the excellent corrosion resistance of the materials but might serve as the “traps” for corrosion products. The apparent activation energies for the temperature dependence of corrosion rates of Ti Grade 7 and Alloy 22 in BSW-12 environment were obtained as 25.3 (±5.5) KJ/mol and 23.7 (±4.5) KJ/mol, respectively. Although none of the materials was found susceptible to crevice corrosion under the test conditions, to conclude that these materials are immune to crevice corrosion in BSW-12 would require longer-term testing.

Fabrication and Characterization of a Biocompatible Coating Formed on a Heat-Treated Magnesium Alloy Using Micro-Arc Oxidation

2017 ◽  
Author(s):  
Hamdy Ibrahim ◽  
Mohammad Elahinia
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Mg Alloys ◽  
Corrosion Tests ◽  
Bone Fixation ◽  
Immersion Corrosion ◽  
Heat Treated ◽  
Micro Arc Oxidation

The fast corrosion rate of magnesium (Mg) alloys is the main problem associated with the use of such biocompatible alloys for bone fixation applications. The corrosion resistance of Mg alloys can be improved by different post-fabrication processes such as heat treatment and coating. We have heat-treated a biocompatible Mg-1.2Zn-0.5Ca (wt.%) alloy at optimized heat treatment parameters to achieve the highest mechanical strength and corrosion resistance. Afterwards, the heat-treated alloy was coated with a ceramic layer using micro arc oxidation (MAO) process to further enhance the corrosion resistance. The microstructure of the prepared samples was investigated using optical microscopy and scanning electron microscopy (SEM). The corrosion characteristics were determined by conducting in vitro electrochemical and immersion corrosion tests. The results showed that the heat treatment process successfully improved the mechanical and corrosion properties of the Mg-1.2Zn-0.5Mn (wt.%) alloy. Both the in vitro electrochemical and immersion corrosion tests showed that the MAO-coated samples have a significantly higher corrosion resistance which results in a significantly lower corrosion rate. This study indicated that the biocompatible coating produced by MAO process may be suitable for providing heat-treated Mg-Zn-Ca-based alloys with protection from corrosion towards synthesizing bone fixation materials in clinical application.

HAYNES 556 ALLOY FILLER METAL

Alloy Digest ◽  
2000 ◽  
Vol 49 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Filler Metal ◽  
Cobalt Alloy ◽  
Nickel Chromium ◽  
Iron Nickel ◽  
Haynes Alloy ◽  
Alloy Filler

Abstract Haynes alloy 556 filler metal is an iron-nickel-chromium-cobalt alloy that combines effective resistance to sulfidizing, carburizing, and chlorine-bearing environments with excellent strength and oxidation resistance at high temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as joining. Filing Code: SS-782. Producer or source: Haynes International Inc.

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