1. Raw material preparation and pretreatment
Process introduction: pre-process raw materials for weighing, crushing, material breaking and rust removal.
Process equipment: steel bar cutting machine, drum polishing machine, etc.
2. Smelting
Process introduction: The pre-processed raw materials praseodymium neodymium, pure iron, ferroboron, etc. are proportioned according to the proportion, added to the vacuum melting furnace, and smelted at high temperature under argon protection. Make the product components uniform, high crystal orientation, good organization consistency, and avoid the formation of ɑ-Fe.
Process equipment: vacuum melting furnace
3. Hydrogen explosion
Process description: The hydrogen explosion (HD) process is to use the hydrogen absorption characteristics of the rare earth intermetallic compound to place the neodymium iron boron alloy in a hydrogen environment. The cracking at the neodymium-rich phase layer ensures the integrity of the main phase grains and the interphase of the neodymium-rich grains. The HD process makes the flakes of NdFeB very loose, which greatly improves the pulverizing efficiency of the jet mill and reduces the production cost.
Process equipment: vacuum hydrogen treatment furnace
4. Milling
Process introduction: Air milling powder is crushed by the high-speed collision of the material itself, without abrasion and pollution on the inner wall of the mill, and the powder can be prepared with high efficiency.
Process equipment: jet mill
5. Molding orientation
Process description: The role of orientation is to make the c-axis of the easily-magnetized direction of the powders with chaotic orientation turned to the same direction, so as to obtain the maximum remanence. The main purpose of the compaction is to crush the powder into a certain shape and size, while maintaining the degree of grain orientation obtained in the magnetic field orientation as much as possible. We design to use molding magnetic field press and isostatic press for secondary molding. For special-shaped magnets, special mold tooling is used for direct molding. After sintered magnets, only a slight surface treatment can be put into use, which greatly saves materials And subsequent processing costs.
Process equipment: magnetic field press, isostatic press
6. Sintering
Process Introduction: Sintering is a series of physical and chemical changes that cause crushing at high temperature. It is a simple and inexpensive method that can change the microstructure of the material to improve the magnetic properties of the material. Sintering is the final forming process of the material and has a very important effect on the density and microstructure of the magnet.
Process equipment: vacuum sintering furnace
7. Mechanical processing
Process introduction: The neodymium iron boron magnets obtained after sintering are blanks, and further mechanical processing is required to obtain products of various sizes, sizes and shapes. Because NdFeB magnets are relatively brittle and have poor mechanical properties, they can generally only be processed by grinding and cutting.
Process equipment: plane grinder, double end grinder, chamfering machine
8. Surface treatment
Process introduction: surface treatment of rare earth permanent magnets of various shapes, such as electrophoresis, galvanization, nickel, nickel copper nickel and phosphating, etc., to ensure the appearance and corrosion resistance of the product.
9. Finished product inspection and packaging
Brief introduction of the process: test the various magnetic properties, corrosion resistance, high temperature performance, etc. of the products, and package them after meeting the standards to meet the various needs of customers.
