As a new manufacturing technology, metal 3D printing powder has developed rapidly in recent years. However, in the field of industrial metal 3D printing, powder consumption is still one of the important factors limiting the application of this technology. At present, there is no standard or national standard about the process specification and part performance standard of metal 3D printing powder. The evaluation indexes of industrial metal powder mainly include chemical composition, particle size distribution, powder sphericity, fluidity and bulk density. Among them, chemical composition and particle size distribution are used to evaluate the quality of commonly used indicators in the field of metal 3D printing powder, and sphericity, fluidity and apparent density can be used as reference indicators for quality evaluation.

At present, chemical analysis and spectral analysis are widely used. Chemical analysis determines the composition of metal through chemical reaction, and thus makes qualitative and quantitative analysis on the chemical composition of metal 3D printing powder. Spectral analysis was carried out by using high temperature and high energy metal elements. Excited by its own special characteristic spectrum, it determines the metal content in the chemical composition of metal 3D printing powder, and is widely used for qualitative analysis of metal chemical composition. The above two methods should use professional testing equipment and be conducted by professional testing institutions.

    The technology for metal 3D printing powder is novel, and there is no corresponding industry standard or national standard in this industry. The assessment method recognized by the industry is to use the corresponding metal powder casting standard, or based on the expansion index requirements of both parties.

    For metal 3D printing powder, because elements appear in the form of gas after remelting metal in the printing process, porosity and other defects in local areas may affect the compactness and mechanical properties of the workpiece. Therefore, the oxygen content of metal powder in different systems is an important index in industry. In the process of metal 3D printing powder, the general index is 1500 ppm, and the metal ratio of oxygen is between 0. 13 and 0. 15%. In special application fields, such as aerospace quality, customer requirements are more stringent. Some customers also need to control the nitrogen content, which usually requires less than 500ppm in the process of metal 3D printing powder, which means that the mass percentage of nitrogen in metal is less than 0.05%.