CorrView Corrosion Testing

Interest to establish the corrosion characteristics of CorrView under well maintained chemical treatment conditions prompted further testing of the same type metal specimens evaluated under Series B, C, D, and F. Testing involved CorrView ^® models in 1-1/2 in. and 3/4 in. ASTM 1018 steel, and commercially available ASTM 1010 and 1018 corrosion coupons typically used in coupon racks to estimate pipe wall losses.

In addition, comparison was simultaneously made against the most commonly installed pipe for HVAC and process water systems - ASTM A53, A106, A135, and A795. Testing was not performed using any recognized corrosion testing method.

A two gallon clear plastic container was used to house the 9 test samples. Coupons of ASTM 1010 and 1018 mild carbon steel, typically used in the corrosion rate evaluation of HVAC piping systems, were purchased from Metal Samples.

Examples of actual ASTM A53, A106, A135, and A795 pipe were also acquired on the open market, and fabricated into sample coupons. Weights of the individual samples were not recorded, since an ultrasonic measurement of true wall loss would be used as the basis for corrosion rate, rather than weight loss.

Above View Of Test Assembly

     The wall thickness of one end of each corrosion coupon and pipe sample coupon was measured ultrasonically at 15 individual locations according to a standard grid pattern of specific dimension. Both CorrView ^® models were similarly measured according to a specified grid at 15 individual locations at its center. All wall thickness data was recorded into a spreadsheet to establish a baseline.

     A small hole was drilled into one end of each pipe coupon in order to provide a means to suspend the sample into the test chamber. Monofilament line was attached to each test sample and marked to indicate its origin. Test samples # 1-7, comprising actual corrosion coupons and pipe materials were suspended into the chamber with sufficient isolation between samples. The CorrView ^® samples were rested on the bottom of the test chamber with their wear surfaces facing upward.

     A small circulating pump was introduced into the upper area of the test chamber in order to provide a continuous movement of water against all samples.

Chemical corrosion inhibitor "Sureguard 4500" was provided by Sentry Water Management Corporation of Wayne, NJ. This formulation provided an approximate 200 PPM concentration of sodium molybdate and 6-10 PPM of sodium triazole. The plastic container was filled to ensure complete coverage of all test subjects. Neither the temperature nor pH of the solution was maintained at any specific value, and instead allowed to equalize to ambient conditions. All test subjects were exposed to the same conditions during the entire test period.

Testing was continued and the results observed. On the first cycle of exposure at 15 days, the samples were removed from the test chamber and allowed to dry, then photographed. No rust deposits were observed on any metal samples and no wall loss was evident.

     Results showed no wall loss for any sample of metal over the 15 day exposure period. Ultrasonic thickness testing of the test subjects showed no measurable wall loss and therefore a zero corrosion rate has been assumed for each.

     While it is possible that some small degree of wall loss may have occurred at some samples, and may be measurable using a weight loss analysis rather than wall thickness measurement, any such loss would be extremely small. A measurement of wall loss would likely be possible over a more extended period of time, and for that reason, this testing is being extended over an additional 90 day period.

     Our testing shows dramatic difference in results from prior salt fog tests, as would be expected. While the salt fog method is intended as an accelerated test for corrosion susceptability, and produces far greater wall losses than under normal corrosive conditions, the difference between Series G tests and those shown in Series B, C, D, and F well illustrate the benefit of good corrosion control methods.

The below set of tables offers a visual and statistical comparison of results for the two corrosion coupons, five pipe sample coupons, and two CorrView ^® products tested. Shown at the left is the original metal sample prior to testing, and in its original form. The right side photograph shows the same sample after exposure, and without any surface preparation or modification to its surface.

Our 15 day exposure shows no measureable amount of wall loss at any of the test subjects. We show zero wall loss for all samples under well maintained chemical inhibitor conditions. A visual comparison of the samples shows minor discoloration for some of the test subjects, but no rust product.

Metal Sample # 1 - Corrosion Coupon 1010 Steel


Specimen - Standard corrosion coupon from Metal Samples. ASTM 1010 mild carbon steel. Exposure - 15 Days Original Wall Thickness - 0.065 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 2 - Corrosion Coupon 1018 Steel


Specimen - Standard corrosion coupon from Metal Samples. ASTM 1018 mild carbon steel. Exposure - 15 Days Original Wall Thickness - 0.063 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 3 - Steel Pipe ASTM A106


Specimen - 2 in. ASTM A106 Grade B mild carbon steel pipe, schedule 10. Exposure - 15 Days Original Wall Thickness - 0.099 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 4 - Steel Pipe ASTM A795


Specimen - 1-1/2 in. ASTM A795 Grade A mild carbon steel pipe, schedule 10. Exposure - 15 Days Original Wall Thickness - 0.104 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 5 - Steel Pipe ASTM A53


Specimen - 1-1/4 in. ASTM A53 Grade B mild carbon steel pipe, schedule 40. Exposure - 15 Days Original Wall Thickness - 0.131 in. Wall Loss - 0.000 in. at two surfacesCorrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 6 - Steel Pipe ASTM A53


Specimen - 2 in. ASTM A53 Grade B mild carbon steel pipe, schedule 40. Exposure - 15 Days Original Wall Thickness - 0.149 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 7 - Steel Pipe ASTM A135


Specimen - 2-1/2 in. ASTM A135 Grade B mild carbon steel pipe, schedule 10. Exposure - 15 Days Original Wall Thickness - 0.108 in. Wall Loss - 0.000 in. at two surfaces Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 8 - 1-1/2 in. NPT CorrView Monitor


Specimen - CorrView ^® Model # P3S1-NF1-BC, 1-1/2 in. NPT, 1018 mild carbon steel Front Wear Thickness - 0.098 in. Exposure - 15 Days Wall Loss - 0.0041 in. at one surface Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Metal Sample # 9 - 3/4 in. NPT CorrView Monitor


Specimen - CorrView ^® Model # P1S2-NF1-BC, 3/4 in. NPT, 1018 mild carbon steel Front Wear Thickness - 0.051 in. Exposure - 15 Days Wall Loss - 0.000 in. at one surface Corrosion Rate - 0.0 MPY Percent Variation From Mean Pipe Corrosion Rate - 0%

Additional corrosion rate comparison testing is presented on this Internet site under the above Testing heading, and is currently underway. Results will be presented here as soon as it is available. A second set of results from this group of test samples will be available on approximately 05/1/05.

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