Accurately judging the inspection results of industrial endoscopes is the core link to ensure the precision of equipment defect detection. It requires a comprehensive analysis based on the visual features of defects, light adjustment techniques, equipment operation norms, and multi-dimensional verification methods. At the same time, through standardized archiving, result traceability and comparison can be achieved to avoid maintenance decision-making deviations caused by a single observation Angle or misjudgment. Industrial endoscopes can accurately identify six common types of defects: corrosion, cracks, peeling, excess debris, pits, and weld leaks. Each type of defect presents unique shapes, colors, and light and shadow characteristics under light. Mastering the key points of identification and distinction techniques can significantly enhance the reliability of the inspection results.

Corrosion is a common defect in industrial equipment, often caused by medium erosion, changes in environmental humidity or material aging. Its core identification feature is abnormal surface roughness. Under uniform beam irradiation, the corroded area presents an uneven surface in the form of blocks, points or strips, creating a distinct texture difference from the surrounding intact substrate. When magnified for observation, uneven erosion marks can be clearly seen. Uniform corrosion is manifested as large areas of slight pockmarks, while local pitting corrosion presents as depressions of varying depths in the form of holes. In some metal materials, the corroded areas may also be accompanied by color changes such as rust and oxide layers (such as yellowish-brown or grayish-black). When making a judgment, it is necessary to distinguish between corrosion and surface stains: stains can be removed by wiping, and the underlying substrate is smooth and intact, while corrosion marks are irreversible and the damage to the substrate itself can still be seen when magnified. For different materials such as stainless steel and aluminum alloy, the corrosion manifestations vary slightly. Stainless steel is prone to pitting corrosion and holes, while aluminum alloy mostly shows uniform corrosion with large areas of oxidation and whitening. It is necessary to combine the material characteristics to assist in judgment.

The core of crack identification lies in "linear features" and "edge morphology". Under light illumination, they mostly appear as black dark lines or bright lines, with flexible line directions (which can be straight, curved or forked), irregular edges and no obvious width pattern. After magnification, the clarity of the lines will be significantly improved. Some fine cracks need a magnification of more than 40 times to be fully presented. The recognition effect can be enhanced by adjusting the Angle of the light source during detection When exposed to direct light, the crack appears as a black dark line because the light cannot enter. When exposed to side light, the edge of the crack will form a contrast of light and dark, making it easier to distinguish the crack from the scratch. The edge of the scratch is neat and smooth, with uniform width and no bifurcation, while the edge of the crack is rough and often accompanied by small sawtooth-shaped protrusions. Some cracks will also show a gradual change in width in the direction of extension. For key components such as aero engine blades and high-pressure pipelines, it is necessary to focus on inspecting fatigue cracks. These cracks often start at stress concentration points and present the characteristics of being "thin at both ends and wide in the middle". The risk level should be comprehensively judged in combination with the operating conditions of the equipment.

The core feature of peeling defects is "interlayer separation", which often occurs on the surface of coatings, plating layers or substrates. Under the irradiation of parallel light beams, a distinct shadow will be formed behind the protruding surface layer. When the irradiation Angle is changed (such as from 0° to 45°), a clear dividing line between the peeling area and the substrate can be seen. Some peeling areas may also be accompanied by slight shaking or peeling signs. When making a judgment, it is necessary to distinguish between peeling and structural deformation: the deformed area has no obvious interlayer separation, and although there are protrusions on the surface, it is seamlessly integrated with the base material without any dividing lines. The protruding part that has peeled off is completely separated from the base material. When the probe is pressed and slightly vibrated, the loose peeling part will shift. For scenarios such as coating equipment and anti-corrosion pipelines, peeling is often accompanied by coating discoloration and bulging. It is necessary to record the area and distribution range of peeling to provide a basis for subsequent repairs.

Foreign objects refer to those inside the equipment that do not belong to the original structure. The key to identification lies in "differential contrast" - regardless of how the light Angle is adjusted, foreign objects have obvious differences from the surrounding substrate in terms of color, structure or brightness, and are independent in shape and not connected to the substrate. Common residues include metal shavings (with strong reflection and sharp edges), dust particles (dull color and no reflection), residual colloidal substances (semi-transparent or viscous), and casting sand cores (with a grayish-white color and loose texture), etc. During the detection, you can observe whether the foreign object follows the movement by moving the probe, or slightly touch the probe (be sure to avoid damaging the equipment) to confirm whether it is an attached foreign object rather than a defect of the base material itself. For precision equipment (such as aero engines and electronic components), even tiny foreign objects can cause serious malfunctions. It is necessary to pay special attention to recording the size, location and material characteristics of the foreign objects.

The core identification points of the pit defect are "boundary continuity" and "light and shadow variation". Its boundary is naturally connected to the surrounding substrate without obvious dividing lines. Under the illumination of a light source, the side of the pit closer to the light source will form a shadow, while the side far from the light source will show a bright shadow. By adjusting the distance of the probe, the variation in light and shadow intensity caused by the depth of the pit can be observed. When making a judgment, it is necessary to distinguish between pits and pores: pores are mostly round or oval in shape, with a relatively shallow depth and a smooth inner wall, while pits have irregular shapes, varying depths, and are often accompanied by rough surfaces or scratches. The pits in some castings may be caused by pouring defects, and it is necessary to combine the manufacturing process of the equipment for auxiliary judgment. For pressure-bearing components such as pressure vessels and the inner walls of pipelines, it is necessary to measure the depth and diameter of the pits to assess whether they affect the structural strength.

Weld leakage defects are commonly found in welding process scenarios. Their core feature is "molten connection" - the protrusions formed by weld leakage are seamlessly integrated with the original molten metal without obvious boundaries. The surface presents a smooth or rough texture after melting, and the color is consistent with that of the weld metal (mostly silver-gray or dark black). When making a judgment, it is necessary to distinguish between weld leakage and weld bead: A weld bead is a protrusion formed by excessive accumulation during welding, with a faint boundary line between it and the weld seam, and it has an independent shape. Weld leakage is caused by the overflow of molten metal during the welding process and is completely connected to the weld seam without any signs of separation. During the inspection, it is necessary to repeatedly observe from multiple angles around the weld edge, joints and other positions prone to weld leakage. Some minor weld leaks can only be clearly seen after magnification. Images should be taken simultaneously, and the impact should be comprehensively evaluated in combination with welding parameters, equipment operating pressure and other working conditions.