PREPARATION OF HIGH-QUALITY 316H AUSTENITIC STAINLESS-STEEL POWDER BY ELECTROSLAG REMELTING AND PLASMA-ROTATING ELECTRODE PROCESS

In this work, 316H austenitic stainless-steel was prepared by electroslag remelting, and spherical 316H steel powder was produced by a plasma-rotating electrode process. The powder was sieved through screens of different meshes. Oxygen and nitrogen analyzer, scanning electron microscope (SEM), laser particle size analyzer, and other analytical methods are used to study the oxygen content, surface morphology, flowability, apparent density, and tap density of powders with different particle sizes. The obtained results indicate that the total oxygen content of the 316H austenitic stainless-steel ingot prepared by electroslag remelting is 20. 10(-6), and the chemical composition of the ingot is uniform. The total oxygen concentration of the 316H austenitic stainless-steel powder prepared by plasma-rotating electrode atomization is 70. 10(-6), which is much lower than that during the conventional process. The resultant powder is characterized by bimodal particle size distribution, and the yield of fine powder is quite high. The particle size of 15 - 150, can accounts for nearly 80% of the powder. Flowability, apparent density, and tap density of the 316H steel powder were 14.83 s/50 g, 4.73 g cm(-3), and 5.4 g cm(-3), respectively. When the mass fractions of coarse powder accounted for a half, flow time was 12.91 s/50 g, which is much shorter than the initial flow time. At the coarse-to-fine powder ratio of 7: 3, the packing performance is the best, and the packing rate is the highest (70.6%). Long-time vacuum storage can reduce the charging performance of powder, reduce the repulsion between powder particles, and further improve the fluidity of powder. Applying electroslag remelting and plasma-rotating electrode process in combination is an effective method to prepare high-quality iron-based metal powder for 3D printing.

Automated summary

In this study, high-quality 316H austenitic stainless steel powder was prepared by combining electroslag remelting and plasma-rotating electrode process. The properties of powders with different particle sizes, such as oxygen content, surface morphology, and flowability, were studied. The results showed that the powder had a bimodal particle size distribution and good flowability, making it suitable for 3D printing.