Browse Client Types

Browse past lab clients by general industry sectors

Trial Number 1

Client Number 69

Project Number 2

Trial Purpose:

To evaluate supplied product for compatibility with steel coupons.

Date Run:

03/31/2006

Experiment Procedure:

Testing was conducted following ASTM G21-72 (2004) Standard Practice for Laboratory Immersion Corrosion Testing of Metals. This practice, rather than a standardized procedure is presented as a guide so that some of the pitfalls of such testing may be avoided. Coupon corrosion testing is predominantly designed to investigate general corrosion.

Coupons with a large surface-to-mass ratio and a small ratio of edge area to total area were used. Two inch square coupons were used that had a thickness of 0.034" thick.

The temperature was held at 71 F +/- 2 F.

The volume of the test solution should be large enough to avoid any appreciable change in its corrosivity during the test, either through exhaustion of corrosive constituents or by accumulating of corrosion products that might affect further corrosion. The lab filled one 400 ml Pyrex beakers with 350 ml of the solution.

Three cold rolled steel coupons (CR 1020) were precleaned for five minutes in a 5% solution of Armakleen M Aero in an ultrasonic tank. Cleaned coupons were rinsed in tap water at 120 F for 15 seconds and dried using compressed air for 30 seconds. The coupons were then weighed to establish baseline weights. Three coupons were immersed into each solution, suspended by stainless steel hooks. Beakers were then covered with parafilm to reduce evaporation or contamination of the solutions. The soak time was set at 24 hours (1440 minutes). At the end of the soak time, coupons were removed from the beakers and observations were made prior to cleaning.

Coupons were cleaned for 15 seconds in M Aero 5% solution using immersion soaking. Coupons were not rinsed but were dried using compressed air for 15 seconds. Dry coupons were then weighed to determine the amount of weight loss if any. After reweighing, coupons were examined for the presence of pits.

Interpretation of Results
The mass loss during the test period can be used as the principal measure of corrosion. Average corrosion rate can be calculated from the following equation:

Corrosion Rate = (K*W)/(A*T*D)
K = a constant
T = time of exposure in hours to the nearest 0.01 h
A = area in cm2 to the nearest 0.01 cm2
W = mass loss in g, to the nearest 1 mg (corrected for any loss during cleaning)
D = density in g/cm3

Corrosion Rate Units Desired Constant (K) in Corrosion Rate Equation
mils per year (mpy)                     3.45 x 10^6
inches per year (ipy)                   3.45 x 10^3
inches per month (ipm)                  2.87 x 10^2
   
millimeters per year (mm/y)             8.76 x 10^4
micrometers per year (um/y)             8.76 x 10^7
picometers per second (pm/s)            2.78 x 10^6
   
g per sq. meter per hour (g/m2-h)       1.00 x 10^4 x D

Trial Results:

Data used in calculation:
K = 8.76 x 10^4 in millimeters per year (mm/y)
T = 22 h
A = 50 cm^2
w = 0.0091 g

Coupon Initial 24 Soak Wt Loss Ave Change Coupon Obs
1 31.7543 31.7428 0.0115   darkened
2 31.7261 31.7202 0.0059 0.0091 darkened   
3 31.7972 31.7873 0.0099   darkened   

All coupons were a dark grey color - Original coloring was light grey/silver

Product      Coupon type       Corrosion Rate
Tigmar 521   Steel Coupons        0.000725 mm/y

Success Rating:

A cleanliness study, addressing only various analytical techniques.

Conclusion:

The Tigmar 521 had more effect on the steel coupons than on the aluminum coupons. The rate of corrosion on steel was found to be 0.000725 mm/y as compared to 0.000024 mm/y on aluminum.

Save Report as a PDF