Corrosion of Austenitic Stainless Steel Weldments

2006 ◽  
pp. 43-75
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Austenitic Stainless Steels ◽  
Control Measures ◽  
Microbiologically Influenced Corrosion ◽  
Face Centered Cubic ◽  
Corrosive Attack ◽  
Wide Range ◽  
Face Centered ◽  
And Control

Abstract Austenitic stainless steels exhibit a single-phase, face-centered cubic structure that is maintained over a wide range of temperatures. This chapter provides a basic understanding of grade designations, properties, and welding considerations of austenitic stainless steels. It also discusses general types of corrosive attack and their effects on service integrity as well as detection and control measures. The five corrosive attack mechanisms covered are intergranular corrosion, preferential attack associated with weld metal precipitates, pitting and crevice corrosion, stress-corrosion cracking, and microbiologically influenced corrosion.

scholarly journals Solidification Cracking Susceptibility of Stainless Steels: New Test and Explanation

2020 ◽  
Vol 99 (10) ◽  
pp. 255s-270s ◽  
Author(s):  
KUN LIU ◽  
◽  
PING YU ◽  
SINDO KOU
Keyword(s):  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Solidification Cracking ◽  
Transverse Motion ◽  
Back Diffusion ◽  
Face Centered Cubic ◽  
Grain Refining ◽  
Body Centered Cubic ◽  
Face Centered ◽  
Dendrite Boundary

The susceptibility of austenitic, ferritic, and duplex stain-less steels to solidification cracking was evaluated by the new Transverse Motion Weldability (TMW) test. The focus was on austenitic stainless steels. 304L and 316L were least susceptible, 321 was significantly more susceptible, and 310 was much more susceptible. However, some 321 welds were even less susceptible than 304L welds. These 321 welds were found to have much finer grains to better resist solidification cracking. Quenching 321 during welding revealed spontaneous grain refining could occur by heterogeneous nucleation. For 304L, 316L, and 310, a new explanation for the susceptibility was proposed based on the continuity of the liquid between columnar dendrites; a discontinuous, isolated liquid allows bonding between dendrites to occur early to better resist cracking. In 304L and 316L, the dendrite-boundary liquid was discontinuous and isolated, as revealed by quenching. The liquid was likely depleted by both fast back diffusion into -dendrites (body-centered cubic) and the L +  + reaction, which consumed L while forming . In 310, however, the dendrites were separated by a continuous liquid that prevented early bonding between them. Back diffusion into -dendrites (face-centered cubic) was much slower, and the L +  + reaction formed little . Quenching also revealed skeletal/lacy formed in 304L and 316L well after solidification ended; thus, skeletal/lacy did not resist solidification cracking, as had been widely believed for decades. The TMW test further demonstrated that both more sulfur and slower welding can increase susceptibility.

Occupational hazard in Malaysian traffic police: special focus on air pollutants

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Putri Anis Syahira Mohamad Jamil ◽  
Karmegam Karuppiah ◽  
Irniza Rasdi ◽  
Vivien How ◽  
Shamsul Bahri Mohd Tamrin ◽  
...  
Keyword(s):  
Occupational Injuries ◽  
Indicator System ◽  
Control Measures ◽  
Special Focus ◽  
Safety Measures ◽  
Traffic Police ◽  
Wide Range ◽  
And Control ◽  
Risk Occupation ◽  
High Risk Occupation

Abstract This paper provides a specific deliberation on occupational hazards confronted daily by Malaysian Traffic Police. Traffic police is a high-risk occupation that involves a wide range of tasks and, indirectly, faced with an equally wide variety of hazards at work namely, physical, biological, psychosocial, chemical, and ergonomic hazards. Thereupon, occupational injuries, diseases, and even death are common in the field. The objective of this paper is to collate and explain the major hazards of working as Malaysian traffic police especially in Point Duty Unit, their health effects, and control measures. There are many ways in which these hazards can be minimised by ensuring that sufficient safety measures are taken such as a wireless outdoor individual exposure indicator system for the traffic police. By having this system, air monitoring among traffic police may potentially be easier and accurate. Other methods of mitigating these unfortunate events are incorporated and addressed in this paper according to the duty and needs of traffic police.

scholarly journals Eccentricity based topological indices of face centered cubic lattice FCC(n)

2020 ◽  
Vol 44 (1) ◽  
pp. 32-38
Author(s):  
Hani Shaker ◽  
Muhammad Imran ◽  
Wasim Sajjad
Keyword(s):  
Wiener Index ◽  
Face Centered Cubic ◽  
Eccentric Connectivity Index ◽  
Zagreb Index ◽  
Cubic Lattice ◽  
Chemical Graph ◽  
Chemical Graph Theory ◽  
Wide Range ◽  
Unit Cells ◽  
Face Centered

Abstract Chemical graph theory has become a prime gadget for mathematical chemistry due to its wide range of graph theoretical applications for solving molecular problems. A numerical quantity is named as topological index which explains the topological characteristics of a chemical graph. Recently face centered cubic lattice FCC(n) attracted large attention due to its prominent and distinguished properties. Mujahed and Nagy (2016, 2018) calculated the precise expression for Wiener index and hyper-Wiener index on rows of unit cells of FCC(n). In this paper, we present the ECI (eccentric-connectivity index), TCI (total-eccentricity index), CEI (connective eccentric index), and first eccentric Zagreb index of face centered cubic lattice.

scholarly journals Crevice Corrosion Behavior of Nitrogen Bearing Austenitic Stainless Steels

1999 ◽  
Vol 48 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Alberto A. Ono ◽  
Tadashi Shinohara ◽  
Shigeo Tsujikawa
Keyword(s):  
Corrosion Behavior ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
Austenitic Stainless Steels

Developing New Cast Austenitic Stainless Steels With Improved High-Temperature Creep Resistance

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Philip J. Maziasz ◽  
John P. Shingledecker ◽  
Neal D. Evans ◽  
Michael J. Pollard
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Creep Strength ◽  
Stainless Steels ◽  
Creep Resistance ◽  
Austenitic Stainless Steels ◽  
Creep Rupture ◽  
Particulate Filter ◽  
Alloy Development ◽  
Wide Range

Oak Ridge National Laboratory and Caterpillar (CAT) have recently developed a new cast austenitic stainless steel, CF8C-Plus, for a wide range of high-temperature applications, including diesel exhaust components and turbine casings. The creep-rupture life of the new CF8C-Plus is over ten times greater than that of the standard cast CF8C stainless steel, and the creep-rupture strength is about 50–70% greater. Another variant, CF8C-Plus Cu/W, has been developed with even more creep strength at 750–850°C. The creep strength of these new cast austenitic stainless steels is close to that of wrought Ni-based superalloys such as 617. CF8C-Plus steel was developed in about 1.5 years using an “engineered microstructure” alloy development approach, which produces creep resistance based on the formation of stable nanocarbides (NbC), and resistance to the formation of deleterious intermetallics (sigma, Laves) during aging or service. The first commercial trial heats (227.5 kg or 500 lb) of CF8C-Plus steel were produced in 2002, and to date, over 27,215 kg (300 tons) have been produced, including various commercial component trials, but mainly for the commercial production of the Caterpillar regeneration system (CRS). The CRS application is a burner housing for the on-highway heavy-duty diesel engines that begins the process to burn-off particulates trapped in the ceramic diesel particulate filter (DPF). The CRS/DPF technology was required to meet the new more stringent emissions regulations in January, 2007, and subjects the CRS to frequent and severe thermal cycling. To date, all CF8C-Plus steel CRS units have performed successfully. The status of testing for other commercial applications of CF8C-Plus steel is also summarized.

Influence of Halides in Phosphoric Acid on the Corrosion Behavior of Stainless Steels

CORROSION ◽  
1975 ◽  
Vol 31 (9) ◽  
pp. 315-319 ◽  
Author(s):  
A. ALON ◽  
J. YAHALOM ◽  
M. SCHORR
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Stainless Steels ◽  
Chemical Reactivity ◽  
Austenitic Stainless Steels ◽  
Ion Concentration ◽  
Corrosive Attack ◽  
Ionic Size ◽  
Passive Current

Abstract The corrosion and electrochemical behavior of austenitic stainless steels in pure H3PO4, in the presence and absence of fluoride, chloride, and bromide, have been investigated in the 20 to 120 C (68 to 248 F) temperature range. Significant corrosive attack of Types 304 and 316 steels in pure H3PO4 starts to occur at about 60 C (140 F) and 90 C (194 F), repsectively. Up to these temperatures, these steels exhibit passivity, but with the increase of temperature, breakdown of passivity occurs, the potential becomes active, and an intense corrosive attack is established. The values of electrochemical parameters indicate corrosion, e.g., critical current density, change from system to system, in accordance with their respective corrosion rates. The presence of halide ions in H3PO4 affects the corrosion rate, the change in rate being dependent upon the free halide ion concentration, its chemical reactivity, and the ionic size. Values of the critical current density, passive current density, and corrosion potential change accordingly. The corrosion activity of halides in 30% and 50% H3PO4 follows the sequence: F− >Cl− >Br− and: Cl− > F− >Br− in 70% and 85% H3PO4.

Explicit Quantification of the Interaction Between the PWR Environment and Component Surface Finish in Environmental Fatigue Evaluation Methods for Austenitic Stainless Steels

2018 ◽  
Author(s):  
Thomas Métais ◽  
Andrew Morley ◽  
Laurent de Baglion ◽  
David Tice ◽  
Gary L. Stevens ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Surface Finish ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Polished Surface ◽  
Small Scale ◽  
Draft Code ◽  
Design Curve ◽  
Wide Range

Additional fatigue rules within the ASME Boiler and Pressure Vessel Code have been developed over the past decade or so, such as those in Code Case N-792-1 [1], which provides an acceptable method to describe the effects of BWR and PWR environments on the fatigue life of components. The incorporation of environmental effects into fatigue calculations is performed via an environmental factor, Fen, and depends on factors such as the temperature, dissolved oxygen and strain rate. In the case of strain rate, lower strain rates (i.e., from slow transients) aggravate the Fen factor which counters the long-held notion that step (fast) transients cause the highest fatigue usage. A wide range of other factors, such as surface finish, can have a deleterious impact on fatigue life, but their impact on fatigue life is typically considered by including transition sub-factors to construct the fatigue design curve from the mean behavior air curve rather than in an explicit way, such as the Fen factor. An extensive amount of testing and evaluation has been conducted and reported in References [2] [3] [4] [5] [6] [7] and [8] that were used to both revise the transition factors and devise the Fen equations contained in Code Case N-792-1. The testing supporting the definition of Fen was performed on small-scale laboratory specimens with a polished surface finish on the basis that the Fen factor is applicable to the design curve without any impact on the transition factors. The work initiated by AREVA in 2005 [4] [5] [6] suggested, in testing of austenitic stainless steels, an interaction between the two aggravating effects of surface finish and PWR environment on fatigue damage. These results have been supported by testing carried out independently in the UK by Rolls-Royce and AMEC Foster Wheeler (now Wood Group) [7], also on austenitic stainless steels. The key finding from these investigations is that the combined detrimental effects of a PWR environment and a rough surface finish are substantially less than the sum of the two individual effects. These results are all the more relevant as most nuclear power plant (NPP) components do not have a polished surface finish. Most NPP component surfaces are either industrially ground or installed as-manufactured. The previous studies concluded that explicit consideration of the combined effects of environment and surface finish could potentially be applicable to a wide range of NPP components and would therefore be of interest to a wider community: EDF has therefore authored a draft Code Case introducing a factor, Fen-threshold, which explicitly quantifies the interaction between PWR environment and surface finish, as well as taking some credit for other conservatisms in the sub-factors that comprise the life transition sub-factor used to build the design fatigue curve . The contents of the draft Code Case were presented last year [9]. Since then, other international organizations have also made progress on these topics and developed their own views. The work performed is applicable to Austenitic Stainless Steels only for the time being. This paper aims therefore to present an update of the draft Code Case based on comments received to-date, and introduces some of the research and discussions which have been ongoing on this topic as part of an international EPRI collaborative group on environmental fatigue issues. It is intended to work towards an international consensus for a final version of the ASME Code Case for Fen-threshold.

The Influence of the Synthesis Method on the Formation of Phase Composition and Catalytic Centers Gd2Zr2O7

2020 ◽  
Vol 1009 ◽  
pp. 69-74
Author(s):  
Ekaterina Borisovna Markova ◽  
Alexander Genrihovich Cherednichenko ◽  
V.V. Kurilkin ◽  
J.M. Serov
Keyword(s):  
Crystal Structure ◽  
Synthesis Method ◽  
Nanocrystalline Powders ◽  
Face Centered Cubic ◽  
Cubic Crystal ◽  
Wide Range ◽  
Physicochemical Methods ◽  
Degradation Reaction ◽  
Cubic Structure ◽  
Face Centered

The influence of the type of crystal structure of complex gadolinium oxides on their catalytic activity was studied using a wide range of physicochemical methods. It was shown that the synthesized nanocrystalline powders Gd2Zr2O7 form highly symmetric face-centered cubic crystal structures. In the course of catalytic experiments, it was found that the formation of a cubic structure increases the degree of conversion of propane and the shift of cracking temperatures to a lower area. The formation of various defects contributes to the course of the dehydrogenation or degradation reaction due to the different number of catalytic centers.

Methicillin-ResistantStaphylococcus aureusEpidemiology and Control in Belgian Hospitals, 1991 to 1995

1996 ◽  
Vol 17 (8) ◽  
pp. 503-508 ◽  
Author(s):  
Marc J. Struelens ◽  
Olivier Ronveaux ◽  
Béatrice Jans ◽  
Raf Mertens ◽  
Keyword(s):  
Participation Rate ◽  
Incidence Rates ◽  
Control Measures ◽  
National Guidelines ◽  
Surveillance Network ◽  
Wide Range ◽  
Combination Of Methods ◽  
Mrsa Strains ◽  
And Control ◽  
Median Incidence

AbstractObjectives:To describe the Belgian methicillin-resis-tantStaphylococcus aureus(MRSA) surveillance network, the evolution of methods used in Belgian hospitals for MRSA detection and control, and MRSA incidence from 1994 to1995.Design, Setting, and Participants:Questionnaire surveys; infection control physicians from acute-care hospitals in Belgium.Intervention:Publication of national guidelines for MRSA control in 1993.Results:The participation rate in surveys ranged from 42% to 57% of hospitals. In 1995, 88% of participants detected MRSA strains by disk diffusion tests, with little improvement in standardization since 1991. More centers employed the oxacillin agar screen method (27%), automated systems (29%), or a combination of methods (29%) than in 1991 (P<.005). Between 1991 and 1995, the proportion of hospitals reporting MRSA control measures increased from 68% to 95% (P<.01). Practices that were used increasingly included patient placement in private room (from 50% to 93%,P<.01) and hand decontamination with antiseptic (from 43% to 87%,P<.01). The proportion of centers that reported screening MRSA carriers and treating them topically increased two- and threefold, respectively (P<.05). Surveillance data from 1994 to 1995 showed that MRSA represented a mean of 21.3% ofS aureusclinical isolates (range, 1.6% to 62.4%). The median incidence of nosocomial MRSA acquisition was 2.8 per 1,000 admissions, with a wide range (0 to 13.7 per 1,000 admissions) across hospitals of all sizes. The median incidence decreased over the first three semesters of surveillance in hospitals with continuous participation.Conclusion:MRSA detection and control measures have improved in Belgian hospitals after publication of national guidelines. However, MRSA incidence rates show the persistence of nosocomial transmission, with large variations between centers. The national MRSA surveillance network should indicate whether control efforts eventually will curb the problem.

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