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Standard Test Method for Rust-Preventing Characteristics of Inhibited Mineral
Oils in the presence of Water

ASTM D665 is the standard method that evaluates the rust-preventing characteristics of inhibited mineral oils particularly steam-turbine oils, when they come mixed with water. Other oils, like hydraulic and circulating oils can also be tested by the ASTM D665 standard. Provisions are specified for heavier-than-water fluids as well as for the chemical resistance of holders and beakers in the testing of synthetic fluids like phosphate esters.

Corrosion is a serious threat to the integrity of installations and equipment of the Oil and Gas Industries. Conservative estimates from the World Corrosion Organization (WCO), the annual cost in maintenance and shutdowns amount to 2.5 billion dollars worldwide”. Its management involves monitoring pipelines, equipment and installations by remote visual inspection, ultrasound, digital radiography, electromagnetic methods and the direct analysis of streams, materials and lubricants. Additives and surface coatings are used in a widespread of formulations to mitigate the problem. Despite the big economic impact of the corrosiveness of products and materials, the methods are characterized by having a subjective operator’s visual rating with a considerable biased appreciation. The method revision and development strive to improve the precision and reduce bias as possible, so the automatic digital detection imaging rating technique is amply justified. (Aaron Mendez Ph.D.)

Method Summary:

Mix 300 mL of the oil with 30 mL of distilled water or synthetic sea water, at a temperature of 60 ± 1°C with a cylindrical steel test rod totally immersed in the vessel. The mineral oil rust prevention test is run for 4 h; however, this time might change depending on contract agreements. At the end of the mineral oil rust prevention test, the specimen is inspected for signs and degrees of rusting.

Signigicance and Use:

Lubricants in normal operation, can get in contact with steam and water affecting both the lubricity and the inherent resistance of them to oxidize pipelines and equipment. In the final formulations, certain proprietary dosage of rust inhibitors is added to control corrosion more efficiently. This method is widely used for the determination of specification of fresh products and for the monitoring of the performance of in-service oils.

Automatic Procedure for Digital Detection Imaging Rating:

ASTM D665 is strictly adhered to as described in the Standard’s Last Revision.

The apparatus description, Automatic Rating Test Procedure, Calibration, Validation, and Interpretation of Results will follow.
corrosion, n—chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties.
rust, n—corrosion product consisting primarily of hydrated iron oxide. Discussion—Rust is a term properly applied only to ferrous alloys.
Acronyms: FeDDI – Ferrum Digital Detection Imaging
Summary of Test Procedure
VISAYA Iron Digital Detection Imaging Device (FeDDI), improves the visual rating by determining the degree of corrosiveness digitally and integrally identifying exact levels of corrosion in a 4-step automated vision algorithm and classification process. FeDDI uses a high-resolution camera with CMOS Digital Detection algorithm. The system provides highly repeatable, mineral oil rust prevention test results by rotating the specimen integrally 360° recording high resolution images and integrating the total area of exposure to automatically quantify, rate and display the degree of corrosion of the sample on test.
Digital Detection Imaging (FeDDI) Rating Apparatus — FeDDI is the first high-tech optical powered visual testing instruments powered by sophisticated optics, that facilitates and improves on the visual rating of methods ASTM D665 and D7548.The digital detection imaging is achieved through a unique vision algorithm and light box that records, calculates and displays accurate corrosion ratings in a few seconds. This device shown in Figures 1a; 1b and 2 performs a standardized measurement of corrosion on the specimen while improves on visual ratings methods and sample handling procedures performed in current lab tests. FeDDI’s patent pending NFX Handle — provides a standardized method for holding the test specimen at the ideal angle and direction for analyses. FeDDI’s loading and fastening mechanism eliminates the use of fragile and costly glassware for viewing. A unique feature of the NFX Handle illustrated in Fig.3, is the integration of the stepper motor and electronics responsible for proper specimen rotation. By having the motor integrated into the NFX Handle, essentially all critical moving parts are placed in an easy to replace assembly for quick and easy serviceability. Proper handling of the sample is critical to an accurate rating both manually and by using the FeDDI technique.