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ABSTRACT: Stainless steels resist corrosion through formation of an oxygen-rich passive film. Halide ions damage this film and promote localized attack. Chloride ions are the most prevalent halide ions in our environment and are involved in many stainless steel corrosion failures. Bromine compounds have many important technological uses and localized corrosion caused by bromide ions is a significant problem, but one that has been less studied. The types and uses of bromides include lithium bromide for absorption refrigeration, volatile bromine compounds concentrated during thermal desalination of seawater, zinc bromide in heavy drilling fluids, bromine compounds used as less oxidizing disinfectants in spas and pools, and bromide feeds for FGD mercury control. Titanium is very resistant to chloride containing environments. However, it can corrode via pitting in bromide containing solutions depending on conditions. In many cases the bromides are present alongside chlorides. Reliable corrosion data is needed to support materials selection and process design for such environments. Experiments were conducted to determine the critical pitting temperature of several alloys (S31603, S32003, S32205, N08367, S32760, N06110, N06022, N10276 alloys and Grade 2 titanium) in calcium bromide solutions using the ASTM G150 electrochemical critical pitting test procedures. Similar experiments were also conducted in solutions containing equal concentrations (by weight) of chlorides and bromide. Corrosion of S32003, N08367, Grade 1 titanium and other alloys in LiBr solutions was studied. The results of these experiments are described in this paper. INTRODUCTION Stainless steels resist corrosion by formation of an oxygen rich passive layer. It is well known that halide ions damage the passive layer causing localized attack. Uses or sources of bromides include lithium bromide for absorption refrigeration,1 calcium and zinc bromide in drilling completion fluids,2 bromine compounds used as less oxidizing disinfectants in spas and pools,3 and bromide feeds for FGD mercury control.
- Well Drilling > Drilling Fluids and Materials (1.00)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT: Stainless steels resist corrosion through formation of an oxygen-rich passive film. Halide ions damage this film and promote localized attack. Chloride ions are the most prevalent halide ions in our environment and are involved in many stainless steel corrosion failures. Failures typically are manifested as pitting or crevice corrosion. Several laboratory tests are used to measure resistance to these modes of attack. Among the commonly-used tests are the ASTM(1) G1501 Electrochemical Critical Pitting Temperature (CPT) test, the ASTM G482 Practices A, C, and E CPT tests, the ASTM G48 Practices B, D, and F Critical Crevice Temperature (CCT) tests, and ASTM G613 Cyclic Polarization tests. While all tests measure resistance to chloride-induced local corrosion, the existence of multiple tests allows multiple, inconsistent measurements of corrosion resistance. Different alloy types – austenitic stainless steels, duplex stainless steels, and nickel alloys – may exhibit different relationships among the various CPT and CCT determinations. Fabrication, especially welding, may affect further the relationship among the various tests. The CPT and CCT temperatures of several alloys (UNS S31603, S32003, S32205, and N08367 alloys) in these tests will be compared and insights into the relationship between laboratory test results and predicted in-service corrosion performance will be developed. INTRODUCTION Susceptibility to localized corrosion, typically caused by chlorides, is one of the major shortcomings of stainless steels and nickel alloys. This localized corrosion is typically expressed as pitting or crevice corrosion. While crevice corrosion is generally the more severe mode of attack and is the failure mechanism more often encountered in-service, pitting corrosion has fewer variables and is often considered to be of greater theoretical interest. Many tests have been developed to measure resistance to these modes of attack. The oldest are in-service or simulated service exposures to the environment of interest.
- Europe (0.68)
- North America > United States > Texas (0.19)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)
ABSTRACT: The corrosion resistance of welded stainless steel depends on a number of factors, including selection of proper weld procedures, selection of welding filler metal and post weld surface treatment. Guidance on stainless steel fabrication gives great attention to the first two items, while giving little practical guidance on post weld clean-up. Pickling of welds is a commonly specified post weld clean-up procedure, but cost and environmental considerations lead many to skip or modify the process. Sufficient time must be allowed to dissolve heat tint or other contaminants introduced during welding. Duplex stainless steels, which may rely on chromium for more of their resistance to pitting, may be more affected by improper post-weld cleaning than other stainless steels. Data show large increases in pitting breakdown potential with longer pickling times. There is also a benefit to fabrication productivity of mechanical surface treatments with a pickling treatment, especially for 25Cr superduplex which are intrinsically resistant to pickling solutions. The welding process and procedures used may have some bearing on the results obtained. In an extreme case, as welded, unpickled 2205 duplex stainless steel did not show any passive behavior whatsoever. For maximum pitting resistance, a mechanical surface treatment followed by pickling is required. INTRODUCTION Although duplex stainless steels were invented shortly after the invention of the other families of stainless steels, they remained little-used curiosities for almost half a century. Following the recognition of the benefits of nitrogen alloying and the widespread adoption of the Argon- Oxygen Decarburization (AOD) a little over 30 years ago, they began making more substantial inroads into widespread commercial utilization. Welding was quickly identified as a critical factor in the advancement of these materials, and many conferences were held and hundreds, probably thousands, of papers were published in journals and conference proceedings.
- Europe (1.00)
- North America > United States > Texas (0.18)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Materials and corrosion (1.00)