Coupon immersion tests

Corrosion data of materials in HI, are extremely limited. The most comprehensive set is from Trester and Staley. Table 4.12 lists a summary of the immersion coupon test results from their work. The test temperature is similar to that for extractive... 

Factors may throw off these rates—these are outlined in ASTM G3I, Standard Practice for Laboratory Immersion Corrosion Testing of Metals. Coupon-type tests cannot be correlated with changing plant conditions that may dramaticahy affect process equipment lifetimes. Other methods must be used if more frequent measurements are desired or correlation with plant conditions are necessary. 

ASTM G 31, Practice for Laboratory Immersion Corrosion Testing of Metals—This method describes typical test vessels, metal specimens (coupons), process controls, aeration techniques, coupon placement and supports, exposure times, and corrosion rate calculations. 

Exposure of coupons to the solution of interest with posttest evaluation according to accepted standards, such as ASTM G 31, Practice for Laboratory Immersion Corrosion Testing of Metals, is the most directly applicable method of testing in organic liquids. Because of the general lack of data on corrosion in organic liquids, coupon testing often... 

Field coupon testing employs small flat and/or U-bend [10,13] samples to average the effects of real world solution contaminants and process transients. Full immersion conditions are easy to reproduce. Splash, waterline, condensing, velocity, and hot wall conditions are more difficult to reproduce. Management of field coupon testing requires effective handoffs between different job functions on the piant site. 

The simplest type of laboratory test corrsists of exposing coupons to the liquid phase only. Simple immersion tests are performed using some form of glassware, such as a flask or a resin kettle, and a condenser for refluxing. A typical setup is a 1000-mL flask containing 500 mL of liquid. Laboratory coupon testing is described in ASTM G31 [16],... 

Weight-loss cotrports are widely used in REM irrhibitor research tmder variously selected errvirorrmerrlal conditions. Davo et al. carried out a typical coupon test to study the irrhibiting effects of REM salts (CeClj-and LaClj) on Al-Li-Cu (8090) alloy corrosiom The metallurgical phases responsible for the corrosion and irrhibition process were identified with a scarming electron microscope (SEM) coupled to an energy dispersion spectroscopy system (EDS), before and after 1-horrr, 96-horrr arrd 1-month immersion in a 3.56% (w/w) NaCl solution open to air. The compotrrtds formed on the 8090 alloy surface were analyzed by X-ray photoelectron spectroscopy (XPS). 

Shi et al. studied the inhibition of AA2024-T3 corrosion in O.OSMNaCl solution by cerirrm cinnamate. The test solutions were produced by dissolving supersaturated cerirrm cinnamate into O.OSMNaCl solution. The couports were abraded, washed, rirrsed and immersed in the aerated test solutiorts for different periods at 20 °C. SEM observations of the morphologies of coupons were carried out after 2 days immersion in test solutions with and without the presence of cerium cinnamate. The inhibitor film was also observed by an atomic force microscope (AFM). XPS was used for the identification of different elements present on corrosion coupon surfaces. 

The primaiy use of this laboratoiy technique today is as a quick check to determine the order of magnitude of a corrosion reaction. Sometimes the calculated rate from an immersion test does not look correct when compared to the visual appearance of the metal coupon. 

A common chemical laboratory test for corrosion resistance is a simple exposure test using metal coupons. The ASTM standard G48 —Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution—describes a simple exposure test. The material coupons (e.g., 60 x 60 mm) are placed on a glass cradle and immersed in the solution in such a way that the coupons are evenly exposed. 

Laboratory Corrosion Test. The laboratory test procedure for the determination of corrosion rates of coal slurry used in this study was adapted from the method developed by Bomberger (26). The corrosion rates were determined by using ASTM Standard Corrosion Test, also known as the Total Immersion Method (27). The Bomberger technique consists of keeping coal slurry in suspension in a two-liter reaction vessel at a constant temperature. The corrosion rates are determined either by actual weight loss of steel coupons... 

The ASTM Corrosion Test procedure by Total Immersion Method requires that all specimens in a test series should have the same dimensions when comparisons are to be made. In these experiments, carbon steel was used representing the pipeline material. The coupons were cleaned, polished and weighed. Coal-water slurry, 10 to 40 weight percent, was used in the corrosion tests. For the coal-water slurry the intitial pH of the medium varied from 2.3 to 2.6 and the test series containing the nutrient media, the microorganisms and the inhibitors the pH varied from 2 to 2.5. Specimens were immersed in the reaction vessel maintained at a constant temperature of 86°F for 72 hours or the specified time. The coupons were removed, washed with deionized water, dried and weighed. The loss in weight of the specimen, before and after the test was attributed to corrosion. 

Zr705 coupon that has been immersed in a HIJ-H2SO4 static acid mixture. The test was conducted at 120°C for 450 h. Rapid corrosion of Zr705 in the area where it is in contact with HI has been observed. 

FIGURE 4.14 A Ta-2.5W coupon with an e-beam weld that has been immersion tested in HL at 310°C. 

For each series of experiments, the same stainless steel coupon (4 cm X 3.5 cm X 0.1 cm) was precleaned, coated with the test contaminant, and then placed in the autoclave for testing. For precleaning, the coupon was either washed first in a chloroform bath, rinsed with acetone, and then dipped in an acetone bath or immersed in a 1,1,1-trichloroethane bath and wiped with a tissue to remove any residue. After precleaning, the coupon was weighed to determine when the mass of the coupon was within 0.1 mg of its original weight. This was set as the standard for perfect cleanness of the coupon. 

Clear casting coupons (3" x V x 0.125") cured with an aliphatic amine XU 19036.00 for 14 days at 25°C and 50% relative humidity. Coupons were immersed in the chemical and tested for percentage weight gain the above values are for 3 day and 28 day exposures. 

There is a specific terminology used for hypothesis tests. One migjit ask, for example, whether the rate of corrosion obtained for an aged steel coupon immersed in seawater is equal to that found in city drinking water. 

To evaluate the hostile effects of various oxygenated solvents on PVC, static immersion tests were conducted wherein test specimens having an approximate surface area of 19.4 cm and an edge thickness of approximately 0.381 cm were exposed to from 20 to 200 ml of solvent. The tests were run at 25 0 in glass test chambers having glass racks on which the coupons... 

The simplest form of compatibility test is to immerse standard ASTM coupons in a liquid or vapor in the lab. Coupons can be installed in the field in a stream. However making a coupon assembly for installation in a pipe or a vessel may be difficult and persuading plant operators even more so. Lab testing is easy to carry out but will not replicate real life conditions such as flow, agitation, stress (compression for gaskets) and one-sided exposure. For this reason, lab dunk tests are usually done for screening reasons. Application temperature is easy to achieve by space heaters. 

Measure radionuclide sorption on the surface of a test coupon that represents the container wall that is immersed in the solution. 

The method consists of taking cylindrical test coupons of specified dimensions and surface finish, and suspending them in a specified volume of a specified test solution representative of a moderately aggressive supply water for a period of 24 hours. The immersions are repeated ten times using fresh test solution. Metals are determined using the extract from the final 24-hom period. 

The salt water immersion test (SWI) and the standard salt spray (fog) test (SS) were conducted for both ISPCs and control baking enamels applied on bare CRS, iron phosphated B-1000, and BD+P60 panels. The painted coupons of about 1.0 mil dry film thickness cured at 163 C for 15 minutes were X-cut through the film to the substrate and then either immersed in a 3% NaCI solution (SWI test) or subjected to a continuous salt-solution spray in a test chamber (SS test). After a specified duration of testing, the specimens were removed from the salt solution, and the coated surface was immediately dried. A DUCK brand tape (Manco, Inc., Westlake, OH) was applied over the X-cut and then removed, and the protective performance was... 

Additional corrosion racks were provided to the CRP participants in March 1998 at the second RCM. Most of these racks had been immersed in the individual basins by mid-1998. The surveillance racks were monitored visually for corrosion, and when corrosion was detected, the coupons were removed from the water and analysed. As found in earlier testing, water quality proved to be the key to good performance. Crevice corrosion was seen between most of the crevice couples as expected, because the pH was lower by 0.5-1.0 unit in the crevice. In poorer quality water, further corrosion was observed, espedally between bimetallic crevice coupons, to the extent that coupons had to be forced apart. The results of the individual participating laboratories were presented at the third and final RCM, held in Bangkok, Thailand, in October 2000. 

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