AN EVALUATION OF THE PERFORMANCE OF

Agents evaluate their performances to assess progress, learn, and improve. In doing so, they refer to criteria of various kinds. Some criteria are deeply encoded in mental models, organizational procedures, or cultural norms and logics, while other evaluative criteria are adaptive and may upregulate or downregulate, depending on the agent’s goals, expectations, and context. Here, too, digitalization is transformative. Artificial agents bring unprecedented power to the evaluation of performance, including the rapid intra-cyclical evaluation of ongoing processes. These mechanisms support feedforward guidance in real time. Therefore, when human and artificial agents combine in the evaluation of augmented performance, they face additional risks. Artificial evaluative processing could be fast and precise, while at the same time, human evaluation may be relatively sluggish and imprecise. Overall evaluations of performance could be distorted and dysfunctional.


OBJECT OF STUDY:
To evaluate the use of ZRC Cold Galvanizing Compound as a repair compound for welded areas on G90 specified hot-dip galvanized steel in 5% salt spray as defined in ASTM B 117.

PROCEDURES:
In this experiment, 11 gauge panels of G90 specified hot-dip galvanized steel (ASTM A 526) were obtained from Ledford Steel Company, Winchester, KY and employed as the substrate. Two panels of the substrate were MIG-welded together to create the test area. Figure 3 shows the test piece after welding. The welded area was then Power Tool Cleaned (SSPC-SP 11). The surrounding area was Hand Tool Cleaned (SSPC-SP 2). The surface of the whole test piece was then Solvent Cleaned (SSPC-SP 1) using MEK. Figure 4 illustrates the test piece after cleaning.

Figure 3 Figure 4 Showing a representative
Showing ZRC test piece test piece after MIG welding. after surface preparation.
Two coats of ZRC were applied from a randomly chosen can (after stirring) by brush to a total dry film thickness of 4.3 mils (recorded with a Positector 6000 series magnetic film thickness gauge, per SSPC-PA 2), allowing a 24-hour dry time at 25°C between coats. ZRC was overlapped 1.5 inches over the galvanized surface on either side of the weld. Figure 5 shows the panel after ZRC application.

Figure 5
Showing test piece after application of ZRC.
The above substrate preparation and coating application was done according to the requirements of ASTM A 780, Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings.
The test piece was allowed two weeks to dry under laboratory conditions (25°C, 50% relative humidity), before being exposed to 5% salt spray as per ASTM B 117 for 3500 hours, after which time the test was terminated, the test piece visually inspected and corrosion and blistering resistance evaluated using ASTM D 610 and ASTM D 714, respectively. Figure 1 shows the condition of our control test piece, which received no surface preparation before testing. Over the course of 3500 hours salt fog testing, it has formed copious amounts of zinc salt on its surface as a result of the galvanic reaction caused when zinc sacrifices itself to protect the underlying substrate. However, it now exhibits a very significant amount of red rust across its surface, ASTM D 610 Rust Grade 0. The weld itself is totally corroded. Figure 2 shows the condition of the ZRC Cold Galvanizing Compound coated test piece. On the uncoated area of the hot-dip galvanizing, similar to the control test piece, this panel has also formed copious amounts of zinc salt, followed by very significant amounts of red rust, ASTM D 610 Rust Grade 0. However, where ZRC has been applied to the weld and surrounding area, there is light formation of zinc hydroxycarbonate salt, typical of bonafide zinc rich coatings, and a few very small rust spots just beginning to show on the right edge of the weld. No blistering was observed on the weld. Medium blistering was observed across the ZRC coated surface (ASTM D 714 6-MD) with slightly larger blisters at the interface between ZRC and the uncoated hot-dip galvanizing, ASTM D 714 4-MD, seemingly caused by the formation of the copious amounts of zinc salt on the uncoated area bleeding over.

CONCLUSION:
The results of this evaluation illustrate that ZRC Cold Galvanizing Compound, when applied according to ASTM A 780, Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings, affords outstanding protection against corrosion to welded and/or damaged areas of G90 hot-dip galvanized steel.