J&L Laboratories follows the methodologies prescribed in NACE RP0775-2005, “Preparation, Installation, Analysis, and Interpretation of Corrosion Coupons in Oilfield Operations.”  After the implementation of the customer’s corrosion inhibition program (choose product by Wheel Testing or other corrosion performance tests), it is possible to monitor corrosion rates.  Corrosion rates are indirectly monitored by installing a pre-weighed steel alloy “coupon” supplied by J&L Laboratories.  After an exposure time of at least 30 days, the coupon is removed and turned in for analysis.

J&L Laboratories utilizes a heated solvent soak to remove hydrocarbons, before placing the coupons into inhibited 15% hydrochloric acid (if necessary, to remove hard scale).  After neutralization, the coupons are then placed in a rotating basket bead-blaster.  Blank coupons are used to monitor mass lost during the cleaning process.  The coupons are then weighed to provide a mass loss measurement.  Pitting measurements are then taken to locate the deepest pit. 

Customer notes:

Due to differences in surface areas and alloys from various suppliers, J&L will only analyze coupons that were supplied by J&L.  In addition, it is best practice to utilize the specific calibrated analytical balance that was used to pre-weigh the coupon.  Differences in climate, altitude, HVAC, and non-dampened vibrations will adversely affect analytical balance performance. 

Corrosion rates cannot be provided on scale coupons as the geometry of the coupon (holes) can induce corrosion when exposed to flow velocity.  Scale coupons generally give much higher mpy rates than corrosion coupons, for that reason J&L will not provide mpy rates on scale coupons.

Reports include average corrosion rate and maximum pitting rate.  One “mpy” unit is equivalent to 0.001” per year.  See table below for interpretation of results (source:  NACE RP0775).  Coupons can be returned to the customer after analysis when requested.