October 13,2026
The core reason bearings require non-magnetic properties or Non-magnetic Required is magnetic interference in strong magnetic field environments. Conventional bearing steel (high-carbon chromium bearing steel) becomes magnetized, disrupting the equipment's magnetic field or causing torque fluctuations due to magnetic field effects.
Medical Imaging Equipment (MRI)
Magnetic resonance imaging equipment operates in extremely strong magnetic fields. If conventional bearings are used, they become magnetized and disturb the magnetic field, affecting scanning accuracy; meanwhile, bearing operating torque also fluctuates severely due to magnetic field effects, affecting the smooth rotation of the scanner. Motors and patient table moving components in MRI equipment all require non-magnetic bearings.
Semiconductor Manufacturing and Inspection Equipment
Electron beam lithography systems and electron beam inspection equipment use electron beams for processing or inspection, and magnetic fields are extremely sensitive to electron beam deflection. If bearings are magnetic, they deflect the electron beam, degrading exposure or inspection accuracy. In addition, semiconductor manufacturing equipment often simultaneously requires non-magnetic, low-particle-generation, and low-outgassing properties.
Superconductivity-Related Equipment
Superconducting material applications involve strong magnetic field environments, and bearings must not disturb the magnetic field distribution.
Demagnetization Equipment and Precision Instruments
Demagnetization equipment and precision measuring instruments operating in strong magnetic field environments require bearings that do not attract iron particles or generate magnetic interference.
Near Metal Detection Equipment
In metal detection scenarios, metal bearings may trigger false alarms in detectors, requiring the use of non-magnetic materials such as plastics.
Hybrid Ceramic Bearings (Non-Magnetic Stainless Steel Rings + Ceramic Balls)
These use non-magnetic stainless steel for rings, silicon nitride (Si₃N₄) ceramic for rolling elements, fluorocarbon resin for cages, and fluoropolymer solid lubrication. Relative permeability is approximately 1.01 or below, suitable for MRI, semiconductor manufacturing equipment, superconducting equipment, and similar applications.
Full Ceramic Bearings
Inner and outer rings and rolling elements are all made of ceramic materials, offering complete non-magnetic properties (relative permeability approximately 1.001 or below). They offer excellent corrosion resistance and wear resistance, suitable for atmospheric to vacuum environments. Typical applications include semiconductor inspection equipment and laser inspection equipment. Note that full ceramic bearings are not filled with grease; solid lubrication is provided by the cage material.
Pure Titanium Bearings
Rings are made of pure titanium material combined with ceramic balls, offering both non-magnetic and insulating properties. Suitable for medical equipment, low-temperature environments, and etching equipment.
Plastic Bearings
Made entirely of engineering plastics, they are non-magnetic and insulating, and will not trigger metal detectors. Suitable for scenarios near metal detection equipment and coating tanks where metal contamination must be avoided.
Special Non-Magnetic Alloy Bearings
Special alloys such as THK-NM1 have a relative permeability of less than 1.005, hardness approaching bearing steel, and load capacity superior to austenitic stainless steel. Suitable for MRI linear guides, semiconductor equipment, and other strong magnetic field environments.
Selection Considerations
Some austenitic stainless steels (such as SUS304) are theoretically non-magnetic, but turning or grinding processes may cause crystal structure changes that induce magnetism, requiring demagnetization treatment; when demagnetization is not possible, full ceramic bearings are recommended. Additionally, if both non-magnetic and conductive properties are required (such as electron beam equipment needing static discharge), silicon nitride ceramic is not suitable due to its insulating nature, and other solutions such as non-magnetic superhard alloys should be considered.
If your equipment requires non-magnetic required bearings but standard bearings cannot meet the requirements, please feel free to contact us. We can provide customized solutions tailored to your specific needs.
