The surface quality of 304 stainless steel forgings is crucial for its application in many fields. Accurate detection technology and effective defect repair methods can ensure the performance and reliability of the product.
First of all, in terms of surface quality detection technology, visual inspection is the most basic method. Experienced inspectors can directly observe the surface of forgings with the naked eye and find obvious defects such as scratches, pits, and wrinkles. However, this method has limited detection capabilities for subtle defects. In order to improve the detection accuracy, magnetic particle detection technology is often used. For 304 stainless steel forgings, due to its certain weak magnetism, after magnetization, surface or near-surface defects will cause magnetic field line distortion, causing magnetic powder to gather at the defect, thereby clearly showing the location and shape of the defect. For example, when testing some 304 stainless steel forgings pipe connection parts that are subjected to high pressure, magnetic particle detection can effectively detect possible surface crack hazards and ensure their safety during use.
Secondly, penetration testing is also one of the commonly used methods. The penetrant containing pigment or fluorescent agent is applied to the surface of the forging to penetrate into the defect, and then the excess penetrant is removed and the developer is applied. The penetrant in the defect will be adsorbed and the defect trace will be displayed. This method is not limited by the magnetism of the forging material and can detect various defects that open on the surface, such as tiny pores and cracks. It is widely used in the detection of 304 stainless steel forgings with complex shapes, such as valves, pump bodies and other parts.
Furthermore, for the repair method of surface defects of 304 stainless steel forgings, when the defects are shallow and small in area, such as slight scratches or small pits, mechanical grinding can be used. Use sandpaper, grinding wheel and other tools to grind the defective part flat, and then polish it to restore the surface finish. However, during the grinding process, pay attention to controlling the grinding depth to avoid excessive grinding that affects the dimensional accuracy and performance of the forging. For deeper cracks or larger defects, welding repair methods can be used. Select welding materials with similar composition to 304 stainless steel, fill and repair the defective parts through appropriate welding processes, such as tungsten inert gas welding, and then grind, polish and perform necessary heat treatment on the weld to eliminate welding stress and restore the performance of the forging.
Finally, with the development of science and technology, some new detection technologies such as laser profile scanning and electron microscope detection are gradually applied to the surface quality inspection of 304 stainless steel forgings. These technologies can provide more accurate surface morphology and defect information, provide a more scientific basis for the formulation of defect repair plans, further improve the surface quality control level of 304 stainless steel forgings, and meet the needs of high-end manufacturing for high-quality stainless steel forgings.
