Ratchet tie-down, also known as ratchet straps or tie-down ratcheting straps, are essential tools for securing and transporting loads. With their robust construction and convenient ratcheting mechanism, these versatile straps are widely used in various industries such as logistics, construction, and transportation. In this blog post, we will explore the uses, benefits, and proper handling of ratchet tie-down.

Ratchet straps are specifically designed to provide a secure and reliable method of securing cargo. They are made up of durable materials like polyester webbing, which offers excellent strength and resistance to abrasion and UV rays. The mechanism of a ratchet strap consists of a ratcheting device, which allows for easy tightening and release of the strap. This mechanism ensures that the load remains firm and secure during transportation, preventing any movement or potential damage.

One of the primary uses of ratchet tie-down is securing heavy loads during transportation. Whether you're transporting goods in a truck, trailer, or on a roof rack, ratchet straps can effectively fasten the cargo in place. They are commonly used to secure items such as furniture, machinery, appliances, construction materials, and even vehicles. The adjustable length of the strap allows for versatile usage, accommodating various load sizes and shapes.

The benefits of using ratchet tie-down are numerous. Firstly, their ratcheting mechanism enables precise tensioning, providing a tight and secure hold on the load. This significantly reduces the risk of the cargo shifting or becoming loose during transit. Secondly, the strength and durability of polyester webbing ensure that the strap can withstand the stresses associated with heavy loads. This gives users peace of mind knowing that their cargo is well-protected.

Proper handling and usage of ratchet tie-down are crucial for ensuring safety and maximizing effectiveness. Here are a few important guidelines to follow:

1. Select the appropriate ratchet strap for your specific application, considering factors such as load weight, size, and transportation method.

2. Carefully inspect the strap before each use to ensure there are no signs of wear, cuts, or damage. Replace any worn-out or damaged straps immediately.

3. When securing the load, make sure the strap is positioned correctly and evenly distributed across the cargo. Avoid twisting or overloading the strap.

4. Once the load reaches its destination, release the tension slowly using the ratchet mechanism, and carefully remove the strap.

By following these guidelines, you can ensure safe and effective use of ratchet tie-down for your cargo securing needs.

Ratchet tie-down are indispensable tools for safely securing and transporting loads. Whether you're hauling equipment, materials, or personal belongings, these reliable straps provide the strength and convenience you need. Remember to choose high-quality ratchet straps and adhere to proper handling techniques to ensure the safety of your cargo. Invest in ratchet tie-down today and experience the peace of mind that comes with secure load.

Zoyn, in collaboration with China Jiliang University, DMEGC, and Earth-Panda, has made significant research breakthroughs in the precise detection and control technology of strategic key metal elements in magnetic materials, as well as its industrial application. This achievement has been nominated for the First Prize of the Zhejiang Provincial Scientific and Technological Progress Award.

The project addresses critical challenges in the detection of strategic key metal elements in magnetic materials, the influence of element site occupancy on magnetic properties, and precise control of key elements. Supported by national key R&D programs, National Natural Science Foundation key projects, and provincial key R&D initiatives, the research has achieved a series of significant outcomes:

1. Established precise detection technologies to monitor the distribution and lattice site occupancy of strategic key metal elements during production, enabling quantitative analysis of their distribution and state within materials.

2. Studied the migration behavior of key elements during non-equilibrium phase transitions and sintering processes, constructing a mapping model between element states and macroscopic performance.

3. Advanced multi-element, multi-step grain boundary diffusion control technology for heavy rare earth elements and crystal field regulation techniques for permanent magnetic ferrites.

These achievements enable the efficient utilization of strategic key metal elements, establish critical technologies for synergistically enhancing the formulation, processing, and performance of magnetic materials, and facilitate the development of high-performance rare-earth permanent magnets and ferrite products. Expert evaluations have recognized the results as internationally leading in the areas of precise detection of heavy rare earth and precious metals and resource-efficient utilization technologies.

The project has resulted in 32 core invention patents, 25 published papers, and three validated rare-earth element state detection technologies. Additionally, a Curie temperature detection device for magnetic materials was developed, with five national standards led and contributions to 13 other national standards. The research has also led to the development of 35 new products.

Introduction:

Magnets play a crucial role in powering today’s industries, from advanced robotics to renewable energy systems. Among these, high-performance magnets like neodymium, ferrite, and Samarium Cobalt (SmCo) have become indispensable for their strength, versatility, and reliability. At ZOYN, we specialize in manufacturing premium-quality magnets designed to meet the unique needs of diverse industries.

Why High-Performance Magnets Matter: 

Modern applications demand magnets that deliver exceptional performance and withstand extreme conditions. Here’s why high-performance magnets are in demand:

• Enhanced Efficiency: Boosting the performance of motors, generators, and sensors.
• Miniaturization: Allowing smaller, more powerful components for compact devices.
• Environmental Benefits: Enabling renewable energy solutions like wind turbines and solar trackers.

Applications Across Industries: 

1. Automotive: High-performance magnets power essential components like electric motors, power steering systems, and sensors in electric and hybrid vehicles.

2. Renewable Energy: In wind turbines and solar energy systems, magnets play a key role in converting energy efficiently and reliably.

3. Robotics: Magnets enable precise movements in robotic arms and automation systems, ensuring accuracy and repeatability.

4. Medical Devices: From MRI machines to small surgical instruments, magnets are critical for precision and functionality in healthcare.

5. Electronics: High-performance magnets are found in speakers, headphones, and compact motors, improving audio and device efficiency.

Our Commitment to Excellence: 

At ZOYN, we focus on:

• Quality Assurance: Every magnet is manufactured with precision and tested to meet rigorous standards.
• Customization: We tailor magnets to meet your specific requirements, ensuring optimal performance.
• Sustainability: Our production process minimizes waste and promotes eco-friendly practices.

Why Partner with Us?

• Factory Direct Advantage: Competitive pricing with no middleman.
• Broad Product Range: From sintered neodymium to bonded magnets, we have it all.
• Expert Support: Our team works closely with you to deliver the perfect solution for your needs.

Conclusion: 

High-performance magnets are the backbone of innovation, enabling industries to achieve greater efficiency, sustainability, and reliability. Whether you’re in automotive, energy, or healthcare, ZOYN is here to provide magnets that power your success.

Contact us today to learn more about our products and how we can support your next project!

In today’s fast-paced manufacturing environment, the demand for precision and efficiency is higher than ever. Companies are continually seeking ways to improve their production capabilities. At ACU, we understand the challenges manufacturers face, and that’s why we offer cutting-edge solutions, including high-performance sheet metal machines, roll forming machines, and pipe making machines. Our products are designed to help businesses streamline operations while ensuring the highest quality standards.

Optimized Sheet Metal Machines for Precision and Speed

ACU’s sheet metal machines are at the forefront of the industry, offering robust solutions for businesses that rely on precision sheet metal fabrication. Whether you're producing components for automotive, electronics, or other industries, our sheet metal machines deliver superior performance. With advanced control systems and precise cutting capabilities, our machines ensure accuracy while maintaining speed and efficiency throughout the production process. This makes them an essential asset for businesses that prioritize both high-quality and high-volume output.

Roll Forming Machines: The Key to Efficient Production

Our roll forming machines provide an efficient, cost-effective solution for creating metal profiles for various applications. From roofing and siding panels to custom components, ACU’s roll forming machines deliver unparalleled consistency and quality. With adjustable settings and quick changeovers, our roll forming systems can easily handle a wide range of materials, including steel, aluminum, and more. This versatility, combined with energy-efficient operations, makes ACU’s roll forming machines an invaluable tool for manufacturers looking to increase productivity while minimizing costs.

Advanced Pipe Making Machines for High-Quality Pipes

When it comes to pipe manufacturing, ACU’s pipe making machines are built to exceed industry standards. These machines are capable of producing high-quality pipes in various sizes and specifications to meet the needs of industries like construction, plumbing, and manufacturing. Our pipe making solutions are engineered to ensure smooth and seamless operation, reducing downtime and increasing output. Whether you're producing steel pipes, plastic pipes, or other materials, ACU’s pipe making machines guarantee superior strength, durability, and precision.

Why Choose ACU?

At ACU, we don’t just sell machines—we provide comprehensive manufacturing solutions tailored to your specific needs. Our machines are designed to optimize performance and ensure longevity, making them an investment that pays off over time. We offer exceptional customer support, from machine installation to after-sales service, ensuring that your business runs smoothly and efficiently.

Our commitment to quality, innovation, and customer satisfaction has made ACU a trusted name in the manufacturing industry. Whether you need sheet metal machines, roll forming machines, or pipe making machines, ACU has the right solution for you. Contact us today to learn more about how our advanced machinery can transform your production processes and help you stay ahead of the competition.

Roll forming machines have become a key player in modern manufacturing processes, particularly in industries that require high-volume production of metal profiles with consistent precision. These machines are essential for shaping a wide variety of materials, including steel, aluminum, and other metals, into long, continuous profiles that can be further processed or used directly in construction and fabrication.

One standout application of roll forming technology is the photo frame roll forming machine, which is designed specifically to produce high-quality metal photo frames. This machine's ability to shape metal with such fine detail makes it indispensable in the production of decorative frames for both commercial and personal use. The precision of the roll forming process ensures that each piece is uniform, saving time and reducing waste in the manufacturing process.

In addition to photo frames, the steel framing roll forming machine is a must-have for the construction and building materials industry. This machine excels in producing steel framing systems, which are integral in the construction of modern buildings. The robust structure and strength of steel make it an ideal material for creating durable, long-lasting framing systems, and the roll forming machine ensures these profiles are produced with high efficiency and minimal variation. This machine is ideal for companies looking to streamline their production of steel framing components.

Another innovative application is the automated curtain rod machine, a perfect example of how roll forming can meet the needs of specialized manufacturing. The automated system ensures precision in producing curtain rods of various shapes and sizes, improving both efficiency and accuracy. With automated capabilities, manufacturers can produce large volumes of curtain rods without sacrificing quality or increasing labor costs.

ACU, a leader in the manufacturing of roll forming machinery, offers more than just high-performance machines. The company provides comprehensive OEM and ODM services, allowing clients to customize machines to meet specific production needs. ACU’s expertise in the industry ensures that you get the machine best suited to your requirements. Additionally, ACU’s exceptional after-sales service guarantees that customers receive continuous support, from installation to maintenance, ensuring that their operations run smoothly for years to come.

With ACU's commitment to quality and innovation, customers not only gain access to advanced roll forming technology but also the benefit of expert guidance and service, making ACU the perfect combination for any manufacturing need.

Webbing slings are an indispensable tool in various industries where heavy lifting is involved. They provide a versatile, lightweight, and reliable means of lifting and securing loads safely. In this comprehensive guide, we will explore the different types of webbing slings, their key features, proper usage guidelines, and the importance of adhering to safety protocols to ensure efficient and secure lifting operations.

Webbing slings consist of durable polyester or nylon woven straps designed to lift and secure loads. They come in various configurations, including round slings, flat slings, and endless slings, each suitable for different lifting applications. Understanding the specific characteristics and capabilities of each type is crucial for selecting the appropriate sling for the task at hand.

The Working Load Limit (WLL) and Safe Working Load (SWL) are vital considerations in using webbing slings safely. WLL refers to the maximum weight that a sling can safely lift under ideal conditions, while SWL indicates the recommended weight limit for day-to-day working scenarios. It is crucial to carefully assess and determine the WLL and SWL for each lifting operation, considering factors such as load weight, sling angle, and environmental conditions.

When selecting a webbing sling, several factors need to be taken into account. These include the type and weight of the load, the lifting method (such as vertical, choker, or basket hitch), working conditions (including temperature and chemical exposure), and the desired level of flexibility or abrasion resistance. Properly assessing these factors will ensure the right sling is chosen for enhanced safety and efficiency.

Regular inspection and maintenance are critical for the longevity and safe operation of webbing slings. Visual inspections should be conducted before and after each use to check for signs of wear, cuts, or fraying. Additionally, periodic thorough inspections, as well as cleaning and storing the slings properly, will help prevent potential hazards and extend the lifespan of the slings.

Adhering to safety standards and regulations is imperative when working with webbing slings. These standards, such as those set by organizations like the Occupational Safety and Health Administration (OSHA) and the European Norm (EN), provide guidelines for proper sling usage, inspection, and maintenance. By complying with these standards, companies can mitigate risks, ensure worker safety, and avoid potential legal consequences.

Unlocking the Potential of Magnetic Materials in Automotive, Renewable Energy, and Manufacturing.

In today’s fast-paced industrial landscape, magnetic materials are powering advancements across multiple sectors, from electric vehicles (EVs) to renewable energy and advanced manufacturing. As a leading provider of high-performance magnetic solutions, our company is proud to support the evolution of these industries with innovative products like sintered neodymium magnets, bonded neodymium, Alnico, SmCo, ferrites, and injection-molded magnets. In this post, we’ll explore the vital role that magnetic materials play in each of these fields, highlighting how our solutions are helping clients stay ahead of the curve.

Driving the Future of Automotive with Magnetics.

As the automotive industry accelerates toward electrification, the demand for powerful, efficient, and durable magnetic materials has never been higher. In electric vehicles (EVs) and hybrid models, magnets are the backbone of several critical systems, including electric motors, battery management, and regenerative braking. Our high-performance neodymium magnets, for example, offer the strength and reliability necessary to increase EV range and efficiency. With their high torque density and energy efficiency, these magnets are essential for maximizing vehicle performance while reducing environmental impact.

But magnets in the automotive field go beyond EV propulsion. Sensors and actuators powered by magnetic materials help ensure vehicle safety, supporting features like Anti-lock Braking Systems (ABS), Electronic Stability Control (ESC), and power steering. In modern cars, everything from audio systems to navigation relies on specialized magnets that provide durability and precision in compact spaces. Our custom magnet solutions are tailored to meet the diverse needs of the automotive industry, ensuring high performance across all vehicle types.

Advancing Renewable Energy with Magnetic Innovation.

Renewable energy is a rapidly expanding field where magnetic solutions are essential. Wind turbines and hydroelectric generators depend on magnets to convert kinetic energy into electrical power efficiently. Our Samarium Cobalt (SmCo) magnets, known for their temperature stability and corrosion resistance, are ideal for the challenging environments of offshore wind farms and hydroelectric systems. These magnets are engineered to withstand extreme conditions, ensuring long-lasting, low-maintenance solutions that maximize energy generation.

Solar energy systems also benefit from magnetic technology, particularly in solar tracking mechanisms that allow panels to follow the sun throughout the day. Our custom magnets support smooth, precise tracking, helping increase the efficiency of solar energy capture. By providing highly durable, reliable magnets, we’re proud to play a part in the world’s transition to cleaner, more sustainable power sources.

Optimizing Industrial Automation and Manufacturing.

In the realm of industrial automation and manufacturing, magnetic materials enable efficiency, precision, and productivity. Injection-molded magnets and magnetic assemblies are commonly used in robotic systems, CNC machines, and automated conveyor belts to ensure accurate movement and reliable operation. For manufacturing processes that require exact positioning, magnetic fixtures and clamps offer a non-invasive, secure solution that reduces setup time and increases production throughput.

Sensors and actuators using magnets allow for non-contact measurement and control, which is essential in automated environments where speed and accuracy are critical. Our magnets, available in various strengths and forms, meet the specific requirements of high-performance manufacturing systems. With custom magnetic assemblies and advanced magnetic materials, we help industries achieve greater precision and productivity.

Our Commitment to Innovation and Quality.

As industries evolve, so do the demands for reliable, high-performing magnetic materials. Our commitment to quality ensures that every product meets stringent standards, from material selection to production and final testing. By staying at the forefront of magnetic material research, we’re able to provide custom solutions that help our clients remain competitive and efficient.

At our company, we understand that no two projects are alike. That’s why we offer a range of services, including technical consultation, custom design, prototyping, and quality control. Whether you’re developing a next-generation EV, building a wind farm, or optimizing a manufacturing line, our experts are here to guide you every step of the way.

Embracing the Future with Magnetic Solutions.

The future of magnetic materials is bright, with advancements continuously unlocking new possibilities. By supporting innovations in automotive, renewable energy, and industrial automation, we’re proud to contribute to a world that’s smarter, cleaner, and more efficient. Explore our range of magnetic solutions and discover how we can partner with you to achieve success in your industry.

Contact us today to learn more about our products, services, and commitment to quality. Together, let’s harness the power of magnetic materials to drive the innovations of tomorrow.

Introduction:

Ferrite magnets, also known as ceramic magnets, have been a cornerstone of the magnetic materials industry for decades. Their affordability, durability, and versatility make them indispensable in various applications, from industrial machinery to everyday consumer electronics. At ZOYN, we pride ourselves on producing high-quality ferrite magnets tailored to meet diverse needs.

Why Choose Ferrite Magnets?

Ferrite magnets stand out due to their unique properties:

• Cost-Effectiveness: Made primarily from iron oxide and barium or strontium, ferrite magnets are one of the most affordable magnetic materials available.
• Durability: Resistant to corrosion and able to withstand high temperatures, ferrite magnets are ideal for outdoor and high-stress applications.
• Wide Range of Applications: They are used in motors, speakers, magnetic assemblies, and more.

Applications of Ferrite Magnets:

1. Automotive Industry: Ferrite magnets are integral to motors, sensors, and ignition systems, offering reliable performance in extreme conditions.

2. Renewable Energy Systems: From wind turbines to solar trackers, ferrite magnets contribute to energy efficiency and sustainability.

3. Consumer Electronics: These magnets are commonly used in loudspeakers, microwave ovens, and magnetic latches, demonstrating their versatility in household devices.

4. Industrial Equipment: Ferrite magnets play a critical role in separators, conveyor belts, and electric motors in factories and manufacturing units.

Our Commitment to Quality:

At ZOYN, we manufacture ferrite magnets that meet the highest standards of quality and performance. Our factory employs advanced production techniques to ensure precision and consistency in every product. Whether you need custom shapes, sizes, or specific magnetic properties, we deliver solutions tailored to your requirements.

Why Partner with Us?

• Expertise: Decades of experience in magnetic material manufacturing.
• Customization: Tailored solutions for unique applications.
• Sustainability: Environmentally responsible production processes.

Conclusion:

Ferrite magnets continue to be a go-to choice for industries worldwide, offering a perfect balance of cost, performance, and durability. If you’re looking for reliable, factory-direct ferrite magnets, ZOYN is your trusted partner. Contact us today to learn more or request a quote.

Meeting the Unique Demands of Today’s Technological Landscape.

In an era of rapid technological advancement, industries such as automotive, renewable energy, and manufacturing face unique challenges that demand precision, durability, and efficiency. At ZOYN, we specialize in providing custom magnet solutions that meet these exacting standards, ensuring that each project receives the highest quality magnetic materials tailored to specific applications. In this post, we’ll explore why custom magnet solutions are essential and how they drive innovation across various sectors.

The Power of Custom Magnet Solutions.

Standard magnets often fall short when it comes to meeting the specialized needs of advanced industries. Whether it’s a neodymium magnet for an electric vehicle motor or a corrosion-resistant magnet for offshore wind turbines, customization ensures that the magnetic properties, shape, size, and coating align perfectly with the application. Custom magnet solutions allow manufacturers to achieve optimal performance, maximize energy efficiency, and extend the lifespan of their products.

Applications of Custom Magnets Across Industries.

• Automotive Industry: Enhancing Electric Vehicle Performance.

The automotive industry is undergoing a transformative shift with the rise of electric vehicles (EVs). To meet performance and range expectations, EV motors require high-torque, energy-efficient magnets. Our custom neodymium magnets provide the necessary power-to-weight ratio, improving motor efficiency and helping extend vehicle range. Additionally, we offer magnets for regenerative braking and battery management, supporting the goal of eco-friendly and energy-efficient vehicles.

• Renewable Energy: Optimizing Energy Production.

Renewable energy applications, particularly wind and hydroelectric power, rely on durable, high-performance magnets. Offshore wind turbines, for example, face harsh environmental conditions that require corrosion-resistant materials. Our samarium cobalt and coated neodymium magnets are engineered to withstand extreme temperatures and moisture, ensuring reliable, efficient power generation. By providing custom magnetic solutions tailored for these settings, we help reduce maintenance needs and support sustainable energy goals.

• Industrial Automation: Driving Precision and Efficiency.

In the world of industrial automation, magnets enable high-speed operations, precision control, and efficient power usage. From robotic arms in assembly lines to conveyor belt systems, custom magnetic assemblies provide the accuracy and durability needed for automated processes. Our custom magnets are crafted to exact specifications, ensuring flawless integration and dependable performance in even the most demanding industrial environments.

Why Work with ZOYN?

At ZOYN, we pride ourselves on our expertise in magnet technology and our commitment to innovation. Our team collaborates closely with clients to understand their specific needs, offering technical consultation, prototyping, and rigorous quality control. Whether you’re seeking custom magnet solutions for automotive, energy, or industrial applications, we ensure that every project is optimized for success.

Our Capabilities Include.

• Custom Material Selection: From high-performance neodymium to resilient ferrite and Samarium Cobalt, we provide the ideal material for each application.
• Shape and Size Customization: We offer a range of shapes and sizes tailored to fit seamlessly within various mechanical and electronic systems.
• Specialized Coatings: Our magnets are available with protective coatings to improve durability and resist environmental impacts, ensuring a longer lifespan.

Embracing the Future with Custom Magnet Solutions.

As industries push toward smarter, greener, and more efficient technologies, the need for custom magnetic solutions continues to grow. We’re committed to staying at the forefront of these changes, providing clients with cutting-edge magnetic solutions that power next-generation technologies.

If you’re ready to explore how custom magnet solutions can benefit your project, contact us today. Together, let’s harness the power of magnets to drive the future of technology forward.

I. What Is Eddy Current Testing

Eddy-current testing (also commonly seen as eddy current testing and ECT) is one of many electromagnetic testing methods used in nondestructive testing (NDT) making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

ECT principle

In its most basic form - the single-element ECT probe - a coil of conductive wire is excited with an alternating electrical current. This wire coil produces an alternating magnetic field around itself in the direction ascertained by the right-hand rule. The magnetic field oscillates at the same frequency as the current running through the coil. When the coil approaches a conductive material, currents opposed to the ones in the coil are induced in the material - eddy currents.

Variations in the electrical conductivity and magnetic permeability of the test object, and the presence of defects causes a change in eddy current and a corresponding change in phase and amplitude that can be detected by measuring the impedance changes in the coil, which is a telltale sign of the presence of defects. This is the basis of standard (pancake coil) ECT.

ECT has a very wide range of applications, including crack inspection, weld inspection, heat exchanger tube inspection, auto parts inspection, heat treatment inspection, material sorting and so on. There are also physical limits to generating eddy currents and depth of penetration (skin depth).

Skin effect

Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor. The electric current flows mainly at the "skin" of the conductor, between the outer surface and a level called the skin depth. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. The skin effect is due to opposing eddy currents induced by the changing magnetic field resulting from the alternating current.

Skin depth

The AC current density J in a conductor decreases exponentially from its value at the surface JS according to the depth d from the surface, as follows:

where δ is called the skin depth. The skin depth is thus defined as the depth below the surface of the conductor at which the current density has fallen to 1/e (about 0.37) of JS.

The current density which is smaller than 1/e (about 0.37) of JS is too weak to test. So eddy current testing is used for surface and subsurface inspection.

II. What Is Magnetic Flux Leakage

Magnetic flux leakage (TFI or Transverse Field Inspection technology) is a magnetic method of nondestructive testing that is used to detect corrosion and pitting in steel structures, most commonly pipelines and storage tanks. The basic principle is that a powerful magnet is used to magnetize the steel. At areas where there is corrosion or missing metal, the magnetic field "leaks" from the steel. In an MFL (or Magnetic Flux Leakage) tool, a magnetic detector is placed between the poles of the magnet to detect the leakage field. Analysts interpret the chart recording of the leakage field to identify damaged areas and to estimate the depth of metal loss.

III. What Is Low Frequency Testing

Low frequency testing is a method between eddy current and magnetic flux leakage. Eddy current is mainly for surface and subsurface crack and magnetic flux leakage is for corrosion of thick material. Low frequency can test more thick material than eddy current and it doesn’t need to magnetize the material like MFL. So LFT can be used to detect big corrosion for thick material, of course the testing sensitivity is not as high as eddy current and magnetic flux leakage.

IV. What Is Metal Magnetic Memory

Metal magnetic memory testing is to determine the stress concentration area. Experiment proves that under the action of the alternative loading, the normalization phenomenon of the magnetic domain occurs at the places containing defects and inclusions in in-service ferromagnetic components, and leakage magnetic field arises on it. At the places of defects or internal stress relative concentration the metal magnetic conductivity is in possession of minimum value, and the tangent component of its magnetic field is in possession of maximum value, and therefore the sign of the normal component is changed and its value is zero. The stress concentration areas can be located by detecting the normal component of leakage magnetic field on the surface.