Moreno Joao Sartori, Conde Fabio Faria, Correa Celso Alves, Barbosa Luiz Henrique, da Silva Erenilton Pereira, Avila Julian, Buzolin Ricardo Henrique, Pinto Haroldo Cavalcanti
Mechanical Department, Federal Technological University of Paraná, Cornelio Procópio 86300-000, Brazil.
Materials Engineering Department, São Carlos School of Engineering, University of São Paulo, São Carlos 13563-120, Brazil.
Materials (Basel). 2022 Apr 7;15(8):2715. doi: 10.3390/ma15082715.
The low carbon martensitic stainless AWS 410NiMo steel has in its chemical composition 13% chromium, 4% nickel, and 0.4% molybdenum (wt.%) and is used in turbine recovery, rotors, and high-pressure steam pump housings due to its resistance to impact at low temperatures, as well as to corrosion and cavitation. Those applications of the AWS 410NiMo steel frequently demand repair, which is performed by welding or cladding. Arc welding is a well-established technique for joining materials and presents several parameters that influence the mechanical performance of the weld bead. Although numerous welding processes exist, optimizing welding parameters for specific applications and materials is always challenging. The present work deals with a systematic study to verify the correlation between the pulsed fluxed core arc welding (FCAW) parameters, namely pulse current and frequency, welding speed, and contact tip work distance (CTWD), and the bead morphology, microstructure formation, residual stress, and hardness of the martensitic clad. The substrate used was the AISI 1020 steel, and the AWS 410NiMo steel was the filler metal for clad deposition. From the initial nine (9) samples, three (3) were selected for in-depth characterization. Lower heat input resulted in lower dilution, more elevated hardness, and lower compressive residual stresses. Therefore, the results highlight the need for selecting the proper heat input, even when using a pulsed FCAW procedure, to achieve the desired performance of the clad. In the present case, a higher heat input appears to be more advantageous owing to the lower convexity index, smooth hardness transition between fusion and heat-affected zones in addition to more elevated compressive stresses.
低碳马氏体不锈钢AWS 410NiMo钢的化学成分中含有13%的铬、4%的镍和0.4%的钼（重量百分比），由于其在低温下具有抗冲击性以及抗腐蚀和抗气蚀性，因此被用于涡轮回收、转子和高压蒸汽泵壳体。AWS 410NiMo钢的这些应用经常需要进行修复，修复方式为焊接或熔覆。电弧焊是一种成熟的材料连接技术，有几个参数会影响焊缝的机械性能。尽管存在众多焊接工艺，但针对特定应用和材料优化焊接参数始终具有挑战性。目前的工作是一项系统研究，旨在验证脉冲药芯电弧焊（FCAW）参数，即脉冲电流和频率、焊接速度以及导电嘴工作距离（CTWD），与马氏体熔覆层的焊缝形态、微观结构形成、残余应力和硬度之间的相关性。所用的基材是AISI 1020钢，AWS 410NiMo钢是用于熔覆沉积的填充金属。从最初的九个（9）样本中，选取了三个（3）进行深入表征。较低的热输入导致较低的稀释率、较高的硬度和较低的压缩残余应力。因此，结果突出了即使使用脉冲FCAW工艺，也需要选择合适的热输入以实现熔覆层所需性能的必要性。在当前情况下，较高的热输入似乎更具优势，这是因为凸度指数较低、熔合区和热影响区之间的硬度过渡平滑，以及压缩应力较高。
