A stainless steel panel used as an insulating panel for various outdoor applications required surface analysis to determine the integrity of the oxide layer.
Figure 1 shows the possible sources of free ion particles and other contaminants on a panel where Area 1 is the iron-steel layer, Area 2 is the interlayer of chromium oxide and iron and Area 3 is the surface area.
Figure 1 – Surface contamination of panel
Table 1: ASTM A380-06 tests
|7.2||Gross Inspection||Ensure surface free of contaminants before testing|
|7.2.1||Stereo Microscope Inspection||Visual inspection under light microscope||Ensure surface free of atmospheric deposits and welding flux|
|7.2.2||Wipe test||Surface wiped and product sent for scanning electron microscopy||Determine nature of contaminants|
|7.2.4||Water-breaktest||Pattern of wetting is observed after continuous water flow.||Detect the presence of hydrophobic contaminants.|
|7.2.5||Tests for free iron: Gross indications|
|188.8.131.52 Water-wetting and drying test||Distilled water sprayed on surface of every 8 hours for 24 hours. Signs of corrosion noted.||Perform accelerated corrosion to determine the degrees of corrosion on as-received steel. No rust or rusting patterns should be observed|
|184.108.40.206 High humidity test||Panel exposed to 95-100% humidity at 38-46°C for 24-26 hours.||Test the humidity level to which steel was exposed. Should be no corrosion.|
|220.127.116.11 Copper sulphate test||Solution of copper sulphate applied for 6 minutes. Sample rinsed and dried to prevent loss of copper deposits.||Determine the type of stainless steel. To check for corrosion by testing for metallic iron oxide.|
|7.3.1||Solvent ring test||High purity solvent placed on microscopic slide, residual pattern after evaporation is observed. Solvent placed on clean panel, drop of resulting mixture is placed on new microscopic slide for comparison.||Determine if contaminants/foreign material has been dissolved by the steel. To test for the presence of adherent transparent films.|
|7.3.2||Black light inspection||Panel is inspected under ultraviolet lamp for trace contaminants.||Detect the presence of certain oil films not present under white light|
|7.3.3||Atomiser test||Water sprayed on surface and the pattern of wetting is observed.||Test for the presence of hydrophobic films.|
|7.3.4||Ferroxyl test for free iron||Solution of potassium ferricyanide and nitric acid spread on clean panel.||Detect iron contamination.|