In the absence of special provisions, appearance inspection shall be carried out according to the following conditions:
Normal inspection can be carried out under natural light or near natural light with an illumination of 300 to 600LX (such as 40W fluorescent lamp, 500mm distance) and a distance of 200 to 350mm. A magnifying glass can also be used for reference inspection. In order to prevent the reflection of the test piece from affecting the normal line of sight, it is allowed to use translucent white paper to separate the light source for inspection.

Electro galvanized
The electroplating required by this specification is only suitable for general environments. Process identification includes electroplated zinc color passivation (color zinc), black passivation (black zinc) or blue-white passivation (blue zinc).

Exterior
1. All specimens shall be visually inspected.
2. The crystallization of the coating is uniform, detailed and continuous.
3. Slight clamp marks are allowed.
4. Not allowed: rough coating, pitting, black spots, blistering, peeling and severe streaks; loose passivation film, powdering, and severe traces of passivation liquid; partial no coating.

5. The color of the colored zinc coating is as follows: the colored passivation film after galvanizing should be a bright rainbow color with green, yellow and purple colors;
6. The color of black zinc coating is as follows: the black passivation film after galvanizing should be uniform black.
7. The color of blue and white zinc coating is as follows: The blue passivation film after galvanizing should be uniform and consistent light blue. Level 1 is not allowed to have other colors. Levels 2 and 3 are allowed to be slightly yellow at the edge of the sample outline.

Coating thickness
1. All samples should be tested for thickness.
2. Conduct thickness testing in accordance with ISO 2178. When there is a dispute over the test results, conduct an arbitration test in accordance with ISO 1463. Measure 10 points on each sample (only 3 to 5 points can be taken for barrel plating samples), and the values should be within the following range.
Colored zinc: 8～12μm
Black zinc: 8～12μm
Blue and white zinc: Grade 1 is 5～8μm; Grade 2 or 3 is 8～12μm.

Bond strength
1. Conduct a bonding strength test on 3 specimens; the test should be conducted 24 hours after plating is completed.
2. According to the test method of ISO 2409, draw hundreds of grids on the sample, and then pull it with standard tape. There should be no peeling off of the passivation film or coating.

Corrosion resistance
1. Carry out a corrosion resistance test on 3 specimens. The test method is carried out according to IEC 60068-2-11. The test should be started 24 hours after the electroplating or passivation is completed.

2. For colored zinc: After a 72-h neutral salt spray test, no white or black corrosion spots should appear on the test surface of each sample.
3. For black zinc: After a 48-hour neutral salt spray test, no white or black corrosion spots should appear on the test surface of each sample.
4. For blue and white zinc: it is divided into the following three grades:
Level 1: After a 24-hour neutral salt spray test, no white or black corrosion spots should appear on the test surface of each sample.
Level 2: After a 72-h neutral salt spray test, no white or black corrosion spots should appear in areas greater than 5mm from the edge.
Level 3: After 120 hours of neutral salt spray test, no white or black corrosion spots should appear in areas greater than 5mm from the edge.

Coating brittleness
1. Carry out coating brittleness test on 3 samples.
2. Place the sample into a constant temperature oven at 190±10°C for 0.5 to 1 hour, then take it out and cool it naturally. Check that there is no bubbling or falling off of the coating.

Conductivity
1. Conduct conductivity tests on 3 specimens.
2. Using a microohmmeter, two electrodes are in contact with the surface to be measured. The area of each electrode is 1cm2 and the electrode pressure is 1.4MPa (that is, the pressure is 14kgf). Take any two points on the surface of the sample for measurement, and measure a total of 5 points. , the resistance value at each point should not be greater than 50 mΩ.

Hexavalent chromium content
1. Detect the presence of hexavalent chromium in the passivation film according to the hexavalent chromium presence test method in ISO 3613.
2. If hexavalent chromium is found to be present, the hexavalent chromium content should be quantitatively detected using the colorimetric method in ISO 3613. It is required that the hexavalent chromium content in the conversion coating should not be higher than 1000ppm.