Two interesting experiments dealing with corrosion resistant sucker rod materials have been conducted by oil companies in West Texas. One of the materials consisted of nickel-plated sucker rods. The plating was applied over the standard SAE 4620 composition, which is widely used for sucker rods in corrosive wells.
After about six years' exposure these nickel-plated rods were examined and it was found that the 0.006-inch thickness of nickel had not been perforated and the rods were apparently in excellent condition. These rods were in a string with a special alloy rod more corrosion resistant than the normal 4620, and it is interesting to note that the special alloy rods in this string failed after about three years' exposure.
The thought naturally arose that if the nickel plating were once penetrated, strong galvanic effects would take place. Some of the nickel-plated rods in the corrosive brine wells of Arkansas rubbed against...
