Exploring the magnetic particle flaw detection technology of cast iron parts: the “fire eyes and golden eyes” that protect quality

In the field of mechanical manufacturing, cast iron parts are widely used in various mechanical equipment due to their good castability, shock absorption and wear resistance. However, cast iron parts may produce defects such as cracks, pores, slag inclusions, etc., during the production process. These defects are like “mines” hidden in the dark, which may cause equipment failures at any time or even cause safety accidents. And magnetic particle flaw detection technology is the “fire eyes and golden eyes” that discover these defects.

The principle of magnetic particle flaw detection is actually not complicated. It is based on the magnetic properties of ferromagnetic materials. When the cast iron parts are magnetized, if there are defects on the surface or near the surface of the cast iron parts, the magnetic resistance at the defects will increase, the magnetic lines of force will be distorted, and some magnetic lines of force will leak out of the surface of the cast iron parts, forming a leakage magnetic field. At this time, sprinkle magnetic powder on the surface of the cast iron parts; the magnetic powder will be adsorbed by the leakage magnetic field, forming obvious magnetic marks at the defects, thereby intuitively presenting the defects.

The process of magnetic particle inspection generally includes pretreatment, magnetization, application of magnetic powder, observation and recording, and post-processing. In the pretreatment stage, the surface of the cast iron parts should be cleaned and rust-free to ensure that there are no interference factors, such as oil, rust, etc., on the surface, so as to prepare for subsequent flaw detection. Magnetization is a key link. The cast iron parts are usually magnetized by alternating current, direct current or permanent magnets to generate a magnetic field inside the cast iron parts. Subsequently, magnetic powder is evenly sprinkled on the surface of the cast iron parts. The magnetic powder can be dry powder or suspended in a liquid to form a magnetic suspension. If there are defects in the cast iron parts, the magnetic powder will gather at the defects to form clear magnetic marks. By observing the shape, size and position of the magnetic marks, the operator can accurately judge the nature and severity of the defects. Finally, post-processing such as demagnetization and cleaning is carried out to avoid the residual magnetism from affecting the subsequent use of the cast iron parts.

Magnetic particle inspection technology has many advantages. It is relatively simple to operate, does not require complex equipment and expensive costs, and can quickly and effectively detect tiny defects on the surface and near the surface of cast iron parts. Moreover, magnetic particle inspection can directly display defects, and even inexperienced operators can easily identify defects. However, this technology also has certain limitations. It can only detect ferromagnetic materials, but not non-ferromagnetic materials.

In the production and maintenance of cast iron parts such as rail car accessories and machine tool beds, magnetic particle inspection technology plays a vital role. By regularly performing magnetic particle inspection on cast iron parts, potential quality problems can be discovered and dealt with in a timely manner, equipment failures and production accidents caused by defects in cast iron parts can be avoided, and the stable operation of mechanical equipment can be ensured. With the continuous advancement of science and technology, magnetic particle inspection technology is also constantly innovating and improving, providing more reliable technical support for the quality inspection of cast iron parts and safeguarding the safe development of the machinery manufacturing industry.

Supplier

Luoyang Fonyo Heavy Industries Co., Ltd,founded in 1998,is a manufacturer in cast railway parts.Our factory covers an area of 72,600㎡, with more than 300 employees, 32 technicians, including 5 senior engineers, 11 assistant engineers, and 16 technicians.Our production capacity is 30,000 tons per year. Currently, we mainly produce casting, machining, and assembly for locomotive,railcar,high-speed trains, mining equipment,wind power,etc.Our products have been exported to Russia, the United States, Germany, Argentina, Japan, France, South Africa,Italy and other countries.
Contact: Stella Liu
Email:sales@railwaypart.com
Mobile:+8615515351287