Ali Muhammad Hassaan, Han You Sung
Department of Mechatronics Engineering, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Korea.
Materials (Basel). 2021 Dec 19;14(24):7871. doi: 10.3390/ma14247871.
Due to its high production rates and low cost as compared to other metal additive manufacturing processes, wire arc additive manufacturing (WAAM) has become an emerging technology in the manufacturing industry. However, the residual stress generation and part distortion hinder its widespread adoption because of the complex thermal build-histories of WAAM parts. One of the ways to alleviate this problem is to consider the effects of scan strategies as it directly influences the thermal history of the built part. Since WAAM itself is an evolved welding process and even though it is evident from welding studies that phase transformations directly affect the residual stresses in welded parts, it remains unclear how the consideration of phase transformations for different scan strategies will affect the residual stresses and distortions in the WAAMed parts. A FEM study has been performed to elucidate the effects of phase transformations on residual stresses and the distortion for different deposition patterns. The current findings highlight that for the fabrication of low-carbon martensitic steels: The consideration of phase transformations for line-type discontinuous patterns (alternate and raster) do not significantly affect the residual stresses. Consideration of phase transformations significantly affects residual stresses for continuous patterns (zigzag, in-out and out-in). To accurately simulate complex patterns, phase transformations should be considered because the patterns directly influence the temperature history of the built part and will thus affect the phase transformations, the residual stresses and the warpage. During the fabrication of WAAM parts, whenever possible, discontinuous line scanning patterns should be considered as they provide the part with uniform residual stress and distortion. The alternate line pattern has been found to be the most consistent overall pattern.
与其他金属增材制造工艺相比，由于其高生产率和低成本，电弧增材制造（WAAM）已成为制造业中的一项新兴技术。然而，由于WAAM零件复杂的热累积历史，残余应力的产生和零件变形阻碍了它的广泛应用。缓解这个问题的方法之一是考虑扫描策略的影响，因为它直接影响成型零件的热历史。由于WAAM本身是一种改进的焊接工艺，并且尽管从焊接研究中可以明显看出相变直接影响焊接零件中的残余应力，但尚不清楚针对不同扫描策略考虑相变将如何影响WAAM零件中的残余应力和变形。已经进行了一项有限元研究，以阐明相变对不同沉积模式下残余应力和变形的影响。当前的研究结果表明，对于低碳马氏体钢的制造：对线型间断模式（交替和光栅）考虑相变不会显著影响残余应力。对连续模式（之字形、进出和出进）考虑相变会显著影响残余应力。为了准确模拟复杂模式，应考虑相变，因为这些模式直接影响成型零件的温度历史，从而会影响相变、残余应力和翘曲。在制造WAAM零件时，只要有可能，应考虑间断线扫描模式，因为它们能为零件提供均匀的残余应力和变形。交替线模式被发现是总体上最一致的模式。
