Metal weld inspection refers to the process of evaluating the quality of welded joints by adopting various testing technologies. Weld quality inspection is a key link to ensure the safety and reliability of engineering structures. Below, the core content of weld quality inspection is systematically elaborated from the dimensions of visual inspection, mechanical property testing, and macroscopic & microscopic examination.
1.Visual Inspection (Magnetic Particle Tester)
Conduct visual inspection to check the weld surface for defects such as cracks, blowholes, slag inclusions, and incomplete fusion; measure dimensions including width, height, weld reinforcement, and misalignment to ensure compliance with design requirements. Meanwhile, use a magnetic particle tester to detect surface and near-surface defects in ferromagnetic materials, apply penetrant testing agents to identify surface defects (e.g., blowholes, cracks) in non-porous materials, utilize an ultrasonic thickness gauge to test weld reinforcement, base metal thinning or internal defects, and adopt a weld surface roughness tester to evaluate whether the surface quality of ground welds meets the standards.
2.Macroscopic and Microscopic Examination (Optical Penetration Depth Microscope and Metallographic Microscope)
Macroscopic examination involves using an optical microscope to observe the macrostructural characteristics of areas such as the weld fusion zone and heat-affected zone. It features simple operation and can quickly identify obvious defects in welds, making it suitable for the preliminary screening of large batches of products.
Microscopic examination involves observing the microstructure of welds using a metallographic microscope to evaluate welding quality and the size of the heat-affected zone. It also checks for defects such as overheating and burning.
3.Mechanical Property Testing (Tensile Testing Machine and Vickers Hardness Tester)
Mechanical property testing comprehensively evaluates weld performance through tensile tests (for measuring strength and plasticity), bending tests (for verifying plasticity and toughness), impact tests (for assessing impact toughness), and hardness tests (for measuring hardness distribution).
During the welding process, the base metal, weld metal and heat-affected zone undergo a complex thermal cycle, resulting in significant changes in the microstructure and the subsequent formation of regions with uneven hardness distribution. Through Vickers hardness testing, the hardness gradient of each region of the welded joint can be accurately quantified, which provides a scientific basis for process optimization, quality control and failure analysis.
4.Ultrasonic Internal Defect Detection (Flaw Detector and Thickness Gauge)
Ultrasonic flaw detectors and ultrasonic thickness gauges are used to inspect internal defects such as cracks and slag inclusions.
Post time: Jan-08-2026
