Effect of solution and aging on microstructure and hardness of 316L stainless steel block formed by SLM

doi:10.13251/j.issn.0254-6051.2022.08.040

Abstract

Abstract: 316L stainless steel block was successfully prepared by selective laser melting (SLM) technology. The effect of aging temperature(650 ℃ and 850 ℃) on microstructure and microhardness of 316L stainless steel block formed by SLM was studied by means of optical microscope (OM), scanning electron microscope (SEM) and Vickers hardness tester. The results show that the microstructure of 316L stainless steel block formed by SLM is mainly composed of fine columnar grains and honeycomb grains. The boundaries of “layer-layer” and “channel-channel” molten pools are clearly visible. After solution and aging, the boundaries of “layer-layer” and “channel-channel” molten pools disappear, but the grain boundaries are clearly visible and the recrystallized grain grows in a combined growth mode. A small amount of M₂₃C₆ are distributed at grain boundaries in specimen after aging at 650 ℃, and the microhardness is relatively high. With the increase of aging temperature, the grain of specimen after aging at 850 ℃ grows further, and a large amount of discontinuous M₂₃C₆ are formed along the grain boundaries.

Key words: selective laser melting, 316L stainless steel, molten pool boundary, solution and aging, microhardness

CLC Number:

TG142

Zhu Derong, Li Hao, Liu Yi, Wang Lige, Chen Zhiyong, Zhang Huixian, Liang Li. Effect of solution and aging on microstructure and hardness of 316L stainless steel block formed by SLM[J]. Heat Treatment of Metals, 2022, 47(8): 237-241.

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