After the metal 3D printer is on fire, the metal 3D printing powder material will also be on fire, and the 3D printing metal powder market will maintain a high growth trend. At present, the domestic and foreign 3D printing metal powder manufacturing process-the latest development of aerosolization, Luoyang Tongrun analyzed the status of 3D printing metal powder preparation technology and put forward some opinions.
3D printing technology is a new type of printing technology. Its outstanding advantages are that it can directly generate any shape parts from computer graphics data without machining or any molds, thereby significantly shortening the product development cycle, increasing productivity, and reducing production. 3D printed metal powder is the essential raw material for 3D printing of metal parts, and its preparation method has attracted much attention. As the most critical part of the 3D printing industry chain of metal parts, 3D printed metal powder is also the most significant value.
The preparation process of Stainless Steel Powder For 3D Printing
At present, the powder preparation method can be mainly divided into the reduction method, electrolytic method, carbonyl decomposition method, grinding method, atomization method, and the like according to the preparation process.
Among them, it is more common to use powder produced by reduction, electrolysis, and atomization as raw materials in the powder metallurgy industry. However, the electrolytic method and reduction method are limited to the production of elemental metal powder, and these methods do not apply to alloy powder. The atomization method can produce alloy powder. At the same time, the modern atomization process can control the shape of the dust.
The continuously developing atomization cavity structure has dramatically improved the atomization efficiency, which makes the atomization method gradually grow into the main powder — production method. The atomization method meets the individual requirements of 3D printing consumable metal powder. The atomization method refers to a process of pulverizing a molten metal into particles having a size of less than about 150 μm by a mechanical process.
According to the method of crushing the molten metal, it can be divided into atomization methods including two-stream atomization method, centrifugal atomization, ultrasonic atomization, vacuum atomization, and the like. These atomization methods have their characteristics and have been successfully applied to industrial production. Among them, the water vapor atomization method has the advantages of simple production equipment and technology, low energy consumption, large batches, etc.. It has become the primary industrialized production method of metal powder.
In the production of atomized powder, the water atomization method is one of the cheap production methods. Because the atomizing medium water is not only cheap and easy to obtain， but also excellent. At present, the domestic water atomization method is mainly used to produce steel powder, carcass powder for diamond tools, pre-alloy powder for oil-containing bearings, powder for hard surface technology, and iron-based and nickel-based magnetic powder. Because the specific heats capacity of water is much larger than that of gas, during the atomization process, the broken metal droplets become irregular due to solidification too fast, which affects the sphericity of the powder.
Other metals or alloys with high activity will react with water. At the same time, due to the contact with water during the atomization process, the oxygen content of the powder will be increased. These problems limit the application of water atomization in the preparation of metal powders with high sphericity and low oxygen content. However, Luoyang Tongrun has invented a method for preparing spherical metal powder by water atomization, which uses a secondary cold water atomization nozzle under the water atomization nozzle to perform secondary atomization. The sphericity of the powder obtained by the invention is not only close to the effect of aerosolization, but also, the particle size of the powder is more beautiful than that of single water atomization.
The gas atomization is one of the primary methods for producing metal and alloy powders. The basic principle of gas atomization is the process of breaking a liquid metal stream into small droplets using a high-speed gas stream and solidifying it into a powder. Due to the advantages of high purity, low oxygen content, controllable powder particle size, low production cost, and high sphericity, the powder prepared has become the main development direction of high-performance and unique alloy powder preparation technology. However, the gas atomization method also has shortcomings. The energy of the high-pressure gas stream is far less than the power of the high-pressure water stream. Therefore, the atomization efficiency of the metal melt is lower than that of the water atomization, which makes the atomization efficiency of the gas atomization powder smaller, Therefore, the production cost of the atomized powder is increased.