What Are N38 Magnets: Understanding the Basics
N38 is a mid-grade neodymium magnet, offering a balance between strength and cost. It falls between lower grades like N28 and N35, and stronger but more expensive ones like N42 or N52. This section covers its composition, production, and how it compares to other grades.
The Composition and Manufacturing Process of N38 Magnets
N38 magnets are made of neodymium (28-30%), iron (65-70%), and boron (1-2%), and some other small compounds such as dysprosium or cobalt. Together these make the NdFeB alloy which is known for its large return that carries a strong magnetic design.
The manufacturing of N38 magnets begins with grinding the NdFeB alloy into fine powder. This powder is then aligned in a magnetic field, compacted into shape, and sintered at around 1080°C. After cooling, the magnets are precisely machined and magnetized using strong electromagnetic pulses.
N38 Magnets vs. Other Neodymium Grades
N38 material is commonly referred to as strong/medium energy or middle of the road and type grade N38 has equal to or more than 12500 gauss. These have more magnetic power than N35 magnets and yet are priced lower than the higher grade N42, N52 magnets.
| Grade | Maximum Energy Product (MGOe) | Remanence (T) | Coercivity (kA/m) | Relative Cost |
|---|---|---|---|---|
| N35 | 35 | 1.17-1.21 | ≥876 | Lower |
| N38 | 38 | 1.21-1.25 | ≥899 | Medium |
| N42 | 42 | 1.28-1.32 | ≥955 | Higher |
N38 magnets are great for applications that involve strong but not super cold or super hot temperatures. They offer good value for electronics, general industrial use.
Key Properties and Specifications of N38 Magnets
Knowing the details of what N38 magnets can and cannot do is important for choosing and using them correctly. This article describes their magnetic, physical and thermal characteristics to assist engineers and purchasers in making the proper selection.
Magnetic Properties: BHmax, Br, Hcj, and Hci Values
N38 magnets are so named based on material with a maximum energy product (BHmax) of 38 MGOe. This is the amount of energy that the magnet can store. Larger values mean stronger magnets.
For N38 magnets, the remanence (Br) ranges between 1.21-1.25 Tesla. This is a measure of retention flux density. Coercivity (Hcj) measures resistance to demagnetization generally ≥899 kA/m for N38.
Hci is the demagnetization resistance of external field. N38 magnet has Hci of ≥ 955 kA/m It is ten times more powerful than the ordinary ceramic magnets.
Physical and Mechanical Characteristics
The density of N38 magnets is around 7.6 g/cm³. They are of high hardness (Vickers hardness: 550-650 HV). Compressive strength is 950 MPa, but tensile strength is low at 75 to 80 MPa.
These magnets are fragile, and can easily chip. It is sensitive to the installation method and should be handled with care during installation. Their thermal expansion coefficient is 4×10⁻⁶/K in the magnetization direction.
Machining N38 magnets involves dedicated diamond tools. Metalworking them using standard techniques can ruin them. They are fragile, and require to be well packed while in transit and to be handled with care during erection.
Temperature Ratings and Thermal Stability
Average N38 magnets work up to 80°C reliably and at higher temperatures their magnetic flux performance is reduced. This loss is irreversible above their maximum operating temperature.
Temperature-boosted versions N38Hbr N38SHbr N38UH (all can reach 120 150 180 respectively). These grades include other elements such as dysprosium and to increase thermal stability.
For all neodymium magnets the same temperature coefficients are valid. N38 magnets exhibit a temperature coefficient of approximately -0.12% per degree Celsius for remanence (Br). This means that for every 1°C increase above room temperature, the magnetic strength decreases by 0.12%. Beyond their maximum operating temperature, this loss becomes irreversible.
Practical Applications of N38 Magnets
N38 magnets are used in a wide variety of fields due to its perfect balance of price and strength. This portion discusses how these versatile magnets address real-world problems across many industries.
Industrial and Manufacturing Applications
N38 magnets perform well in most industrial motors that require high levels of power and torque in compact space. Industrial, manufacturing, and engineering applications frequently employ neodymium magnets in magnetic separators for removing ferrous contaminants during production processes.
Automation systems use sensors and position devices with N38 magnets. They are suitable for conveyor systems and robotic end effectors. Magnetic workholding such workholding magnets hold metal parts for machining.
These magnets are used for electric power generation of a wind turbine generator, and it is the most effective in order to increase energy conversion efficiency. Their high strength-to-weight ratio enables a reduction in the size of the generator and height without loss of power output.
Consumer Electronics and Automotive Uses
Smartphone makers employ N38 magnets with speakers, vibration motors, and cameras’ autofocus systems. Their small form factor can help thinner profile devices with equivalent performance.
N38 magnets are used in automotive sensors for position sensing in ABS systems and throttle controls. These magnets are used for electric vehicle motors to provide maximum power density and efficiency. The headphone drivers are made with N38 magnets with a strong audio response for both high and low frequencies for an impressive sound.
N38 magnets are used in voice coil motors inside hard disk drives, where they provide precision control for the read/write head. These magnets are inside locks, switches and security sensors that smart home devices rely on.
Creative and DIY Projects with N38 Magnets
10mm × 2mm N38 disc magnets are used by crafters for closing jewelry and decorative closures. Tool holders hold up to 3kg power for each 25mm x 5mm disk – made by yourself.
Learning projects will benefit from 5mm cube magnets for teaching about magnetic fields. Levitating screens are manufactured using 20x10mm diameter ring magnets set into repelling arrays by the manufacturers.
Home organization system uses 12mm x 3mm discs for concealed cabinet latches. The visualization artists are developing interactive installations with 10mm × 5mm cylinders arrays. Neodymium magnets with 8mm diameter and 3mm thickness fitted below the decorative surfaces in magnetic boards.
Handling and Safety Guidelines for N38 Magnets
N38 magnets are so strong they are dangerous properly handling them is a must. This section describes important safety procedures in order to avoid injury as well as damage to the equipment and accidents while operating with such bold magnets.
Proper Handling Techniques and Tools
Always use safety goggles whenever handling N38 magnets. It pinches the more if you have bigger magnets, they need to be handled with leather gloves. Keep magnets in between separated until you need to use them.
Non-magnetic tools, such as plastic or wood utensils, should be used to manipulate. Vary magnet repulsion by sliding magnets together at an angle instead of straight approach. Wooden wedges assist with removing stuck magnets safely.
For work of precision, employ tweezers of aluminium or brass. For building magnetic arrays, use jigs made of non-magnetic materials to keep them in their place. Stick to nonmetallic surfaces to prevent random movements.
Storage and Transportation Considerations
Keep N38 NIB magnets away from each other in the package they come in with keeper plates between them. In storage containers, plastic dividers should be used to avoid unscheduled contact. Store magnets in low humidity environments to avoid rusting.
Ship magnets in magnetically-shielded containers. Use a mu-metal or steel housing for larger numbers. Package it adequately cushioned for protection from impacts.
Mark the packings with warnings of “STRONG MAGNETS”. Keep 15cm away from electronic devices when travelling. Observe carrier rules for magnetic materials; some may need special paperwork for air transport.
Health and Safety Risks and Precautions
⚠️ WARNING: Strong neodymium magnets pose a serious pinch and ingestion hazard, especially to children. Small magnets can cause severe injury if swallowed. Keep away from mouth and body openings. Seek immediate medical attention if magnets are ingested.
Keep away from pacemakers and other medical implants by at least 30cm. The high magnetic fields could disrupt operation of the devices. Do not place magnets near floppy disks or magnetic storage media as data can be destroyed.
For pinch injuries, ice the area and consider seeking medical attention if severe. Specify safety areas in workshops where magnets are in use. Develop training for all staff prior to entering strong magnetic field areas.
How to Select the Right N38 Magnets for Your Project
Selecting the superior N38 magnets is the trade off between performance needs and practical limitations. This section will walk you through some critical factors to ensure you get the performance you need in your application.
Calculating Required Magnetic Force
Calculate the minimum pull force required for your application. Include a safety margin by multiplying the force by 1.5-2.0. Air gaps significantly diminish the strength of the magnetic field, keep that in mind.
Use this equation for pulling applications: Required pull force (kg)= Weight to pull (kg) × Safety factor × Surface efficiency factor. Efficiency on the surface is 0.5-0.9 according to the material evenness.
On direct steel contact this one 25mm x 5mm N38 disc supplies around 5.5kg pull force. This decreases to 2.8kg with a 0.5mm gap. For use in shear force applications the rated pull force must be taken approximately 30-40%.
Environmental Factors and Operating Conditions
Factor in variations in temperatures in the environment where you will use your application. Magnet grades N38 perform at their best under 80°C. For elevated temperatures, N38H (120°C) or N38SH (150°C) versions may be more suitable.
Evaluate exposure to moisture and chemicals. For outdoor use the nickel-copper-nickel (Ni-Cu-Ni) coated with epoxy. Dry marine applications require unique anti-corrosion coatings.
Check mechanical stress influences, e.g. vibrations and impacts. For constant vibration applications, adhesively-bonded magnets are not reliable and mechanically retained magnets are used. High-shock environments may need auxiliary mechanical latching and holding devices.
Cost-Benefit Analysis: When to Choose N38 vs. Other Grades
N38 magnets are the best value for a majority of applications. They offer 8% more strength compared to N35 and cost 5% more. This makes them excellent for applications with tight control over cost and performance.
Stronger grades like N42 or N45 make sense only when weight/size is a deciding factor and the 10-15% higher price is justified by savings on space. For consumer electronics and precision instruments these higher grades are preferred.
Lower grades might suit for not critical applications with plenty of room for space. Not every educational project or decoration task needs full N38 strength. Always consider total system cost rather than magnet cost when evaluating system purchases.
Frequently Asked Questions
What is the rare earth magnet strength chart and where does N38 fit?
The following table lists the magnetic strength of neodymium magnets and others according to their grade which ranges from N35 to N52 with their energy range listed in MGOe (Mega Gauss Oersteds). N38 falls roughly in the middle of the grade range providing 8.6% stronger than an N35 and roughly 13.8% stronger than an N30 and is half the price of the N52.
How does the N38 neodymium magnet compare on the gauss magnet strength chart?
The surface field strength of an N38 magnet typically ranges from 12,200 to 12,500 gauss, depending on the shape and size of the magnet. Field intensity is higher near edges and corners due to flux concentration.
What does the N38 designation mean in the NdFeB magnet grades chart?
“N” is for neodymium-iron-boron “38” is for 38 MGOe maximum energy product. Other suffixes such as H, SH, and UH represent the temperature stability ratings (120°C, 150°C and 180°C).
How do N38 magnets compare to other grades on the magnetic strength chart?
A 10mm × 5mm N38 disc results in ~2.5kg pull force, N52 of the same size would give you 3.2kg (28% stronger) but costs 40% more. N35 gives 2.3kg (8% worse) at 5% less cost.
What are the specifications for N38 neodymium magnets sized 50mm x 30mm?
For example, a 50mm × 30mm N38 disc has a weight of 442g and 40kg pull force on steel. It has a surface field of 12,300 gauss, with 15cm safety distance from electronics and medical devices.
