Stress-Corrosion Cracking of Steels In Agricultural Ammonia

Abstract Stress-corrosion cracking has been determined as the cause of failure of carbon steel tanks in agricultural ammonia service. Effects of ammonia contaminants, such as air, water, carbon dioxide, oil, etc on failure rates were studied. In general, air contamination increased stress-corrosion cracking and water in small amounts inhibited the attack. For prevention of such failures, it was recommended that high residual stresses in ammonia vessels be avoided by the use of stress relieving treatments, that air be eliminated from agricultural ammonia systems and that the ammonia should have a minimum water content of 0.20 percent. 3.5.8

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Stress Corrosion Cracking (SCC) of Nickel-Base Weld Metals in PWR Primary Water

Materials Science Forum ◽

10.4028/www.scientific.net/msf.747-748.723 ◽

2013 ◽

Vol 747-748 ◽

pp. 723-732 ◽

Cited By ~ 2

Author(s):

Ru Xiong ◽

Ying Jie Qiao ◽

Gui Liang Liu

Keyword(s):

Residual Stresses ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Surface Condition ◽

Cold Work ◽

Corrosion Cracking ◽

Pressurized Water ◽

Weld Metals ◽

Surface Residual Stresses ◽

Primary Water

This discussion reviewed the occurrence of stress corrosion cracking (SCC) of alloys 182 and 82 weld metals in primary water (PWSCC) of pressurized water reactors (PWR) from both operating plants and laboratory experiments. Results from in-service experience showed that more than 340 Alloy 182/82 welds have sustained PWSCC. Most of these cases have been attributed to the presence of high residual stresses produced during the manufacture aside from the inherent tendency for Alloy 182/82 to sustain SCC. The affected welds were not subjected to a stress relief heat treatment with adjacent low alloy steel components. Results from laboratory studies indicated that time-to-cracking of Alloy 82 was a factor of 4 to 10 longer than that for Alloy 182. PWSCC depended strongly on the surface condition, surface residual stresses and surface cold work, which were consistent with the results of in-service failures. Improvements in the resistance of advanced weld metals, Alloys 152 and 52, to PWSCC were discussed.

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Electrochemical Noise for Detection of Stress Corrosion Cracking of Low Carbon Steel Exposed to Synthetic Soil Solution

Materials Research ◽

10.1590/1980-5373-mr-2016-0183 ◽

2017 ◽

Vol 20 (5) ◽

pp. 1201-1210 ◽

Cited By ~ 5

Author(s):

Antonio Contreras ◽

Melchor Salazar ◽

Andres Carmona ◽

Ricardo Galván-Martínez

Keyword(s):

Carbon Steel ◽

Stress Corrosion ◽

Soil Solution ◽

Stress Corrosion Cracking ◽

Electrochemical Noise ◽

Low Carbon Steel ◽

Corrosion Cracking ◽

Low Carbon ◽

Detection Of Stress

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Weld Residual Stresses and Primary Water Stress Corrosion Cracking in Bimetal Nuclear Pipe Welds

Volume 6: Materials and Fabrication ◽

10.1115/pvp2007-26297 ◽

2007 ◽

Cited By ~ 11

Author(s):

Frederick W. Brust ◽

Paul M. Scott

Keyword(s):

Water Stress ◽

Residual Stresses ◽

Weld Metal ◽

Stress Corrosion ◽

Crack Growth ◽

Stress Corrosion Cracking ◽

Pressure Vessel ◽

Large Diameter ◽

Corrosion Cracking ◽

Primary Water

There have been incidents recently where cracking has been observed in the bi-metallic welds that join the hot leg to the reactor pressure vessel nozzle. The hot leg pipes are typically large diameter, thick wall pipes. Typically, an inconel weld metal is used to join the ferritic pressure vessel steel to the stainless steel pipe. The cracking, mainly confined to the inconel weld metal, is caused by corrosion mechanisms. Tensile weld residual stresses, in addition to service loads, contribute to PWSCC (Primary Water Stress Corrosion Cracking) crack growth. In addition to the large diameter hot leg pipe, cracking in other piping components of different sizes has been observed. For instance, surge lines and spray line cracking has been observed that has been attributed to this degradation mechanism. Here we present some models which are used to predict the PWSCC behavior in nuclear piping. This includes weld model solutions of bimetal pipe welds along with an example calculation of PWSCC crack growth in a hot leg. Risk based considerations are also discussed.

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Mechanistic model of stress corrosion cracking (scc) of carbon steel in acidic solution with the presence of H2s

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/50/1/012072 ◽

2013 ◽

Vol 50 ◽

pp. 012072 ◽

Cited By ~ 1

Author(s):

Y P Asmara ◽

A Juliawati ◽

A Sulaiman ◽

Jamiluddin

Keyword(s):

Carbon Steel ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Acidic Solution ◽

Mechanistic Model ◽

Corrosion Cracking

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Strategies for Treating Weld Residual Stresses in Probabilistic Fracture Mechanics Codes

ASME 2011 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2011-57937 ◽

2011 ◽

Author(s):

Frederick W. Brust ◽

R. E. Kurth ◽

D. J. Shim ◽

David Rudland

Keyword(s):

Fracture Mechanics ◽

Residual Stresses ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Nuclear Power ◽

Power Plants ◽

Degradation Mechanism ◽

Welding Process ◽

Corrosion Cracking ◽

Uncertainty Sources

Risk based treatment of degradation and fracture in nuclear power plants has emerged as an important topic in recent years. One degradation mechanism of concern is stress corrosion cracking. Stress corrosion cracking is strongly driven by the weld residual stresses (WRS) which develop in nozzles and piping from the welding process. The weld residual stresses can have a large uncertainty associated with them. This uncertainty is caused by many sources including material property variations of base and welds metal, weld sequencing, weld repairs, weld process method, and heat inputs. Moreover, often mitigation procedures are used to correct a problem in an existing plant, which also leads to uncertainty in the WRS fields. The WRS fields are often input to probabilistic codes from weld modeling analyses. Thus another source of uncertainty is represented by the accuracy of the predictions compared with a limited set of measurements. Within the framework of a probabilistic degradation and fracture mechanics code these uncertainties must all be accounted for properly. Here we summarize several possibilities for properly accounting for the uncertainty inherent in the WRS fields. Several examples are shown which illustrate ranges where these treatments work well and ranges where improvement is needed. In addition, we propose a new method for consideration. This method consists of including the uncertainty sources within the WRS fields and tabulating them within tables which are then sampled during the probabilistic realization. Several variations of this process are also discussed. Several examples illustrating the procedures are presented.

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NRC/EPRI Residual Stress Validation Program Phase I: Experimental Specimen Modeling and Measurement

ASME 2011 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2011-57677 ◽

2011 ◽

Cited By ~ 1

Author(s):

J. Broussard ◽

P. Crooker

Keyword(s):

Residual Stress ◽

Residual Stresses ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Phase 1 ◽

Measurement Techniques ◽

Corrosion Cracking ◽

Welding Residual Stress ◽

Hole Drilling ◽

Pressurized Water

The US Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are working cooperatively under a memorandum of understanding to validate welding residual stress predictions in pressurized water reactor primary cooling loop components containing dissimilar metal welds. These stresses are of interest as DM welds in pressurized water reactors are susceptible to primary water stress corrosion cracking (PWSCC) and tensile weld residual stresses are one of the primary drivers of this stress corrosion cracking mechanism. The NRC/EPRI weld residual stress (WRS) program currently consists of four phases, with each phase increasing in complexity from lab size specimens to component mock-ups and ex-plant material. This paper describes the Phase 1 program, which comprised an initial period of learning and research for both FEA methods and measurement techniques using simple welded specimens. The Phase 1 specimens include a number of plate and cylinder geometries, each designed to provide a controlled configuration for maximum repeatability of measurements and modeling. A spectrum of surface and through-wall residual stress measurement techniques have been explored using the Phase 1 specimens, including incremental hole drilling, ring-core, and x-ray diffraction for surface stresses and neutron diffraction, deep-hole drilling, and contour method for through-wall stresses. The measured residual stresses are compared to the predicted stress results from a number of researchers employing a variety of modeling techniques. Comparisons between the various measurement techniques and among the modeling results have allowed for greater insight into the impact of various parameters on predicted versus measured residual stress. This paper will also discuss the technical challenges and lessons learned as part of the DM weld materials residual stress measurements.

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