This research work is the first step in evaluating the feasibility of producing industrial components by using Laser Metal Deposition with duplex stainless steel Wire (LMDw). The influence of Ar and N₂ shielding gases was investigated in terms of nitrogen loss and in the microstructure and austenite content of different deposited geometries. The evolution of the microstructure in the build-up direction of the Ar and N₂-shielded blocks was compared in the heat-treated and as-deposited conditions. The susceptibility for oxygen pick-up in the LMDw deposits was also analyzed, and oxygen was found to be in the range of conventional gas-shielded weldments. Nitrogen loss occurred when Ar-shielding was used; however, the use of N₂-shielding prevented nitrogen loss. Austenite content was nearly doubled by using N₂-shielding instead of Ar-shielding. The heat treatment resulted in an increase of the austenite content and of the homogeneity in the microstructure regardless of the shielding gas used. The similarity in microstructure and the low spread in the phase balance for the as-deposited geometries is a sign of having achieved a stable and consistent LMDw process in order to proceed with the build-up of more complex geometries closer to industrial full-size components.

这项研究工作是评估使用带有双相不锈钢线（LMDw）的激光金属沉积技术来生产工业组件的可行性的第一步。从氮损失，不同沉积几何形状的显微组织和奥氏体含量的角度研究了Ar和N ₂保护气体的影响。在热处理和沉积条件下，比较了在Ar和N ₂屏蔽的嵌段沿堆积方向的微观结构的演变。还分析了LMDw沉积物中氧吸收的敏感性，发现氧在常规气体保护焊件的范围内。使用氩气防护时会发生氮流失。但是，使用N ₂-屏蔽防止氮损失。通过使用N ₂屏蔽而不是Ar屏蔽，奥氏体含量几乎翻倍。不管使用哪种保护气体，热处理都会导致奥氏体含量的增加和微观结构的均匀性的提高。所沉积的几何结构的微观结构相似且相平衡分布低，这表明已经实现了稳定且一致的LMDw工艺，以便逐步建立更接近工业标准尺寸零件的更复杂几何结构。