在不同沉积路径下采用冷金属过渡电弧增材制造技术制备了H13钢成形件,基于热-弹塑性有限元法对成形件的热历程进行了分析,并通过试验研究了成形件的显微组织和硬度.结果表明:同向和双向路径沉积得到5层单道和单层5道成形件的热历程基本一致,双向沉积5层单道成形件第3层中间点的峰值温度远高于双向沉积单层5道成形件第3道中间点,5层单道成形件的热累积效应更明显;5层单道成形件的板条状马氏体组织比单层5道成形件的粗大;同向沉积5层单道成形件在同一高度上的硬度略高于双向沉积成形件,同向沉积和双向沉积单层5道成形件在水平方向的硬度分布基本相同,5层单道成形件的平均硬度略低于单层5道成形件.

Wire-arc additive manufacturing (WAAM) has been considered as one of the potential additive-manufacturing technologies to fabricate large components. However, its industrial application is still limited by the existence of stress and distortion. During the process of WAAM, the scanning pattern has an important influence on the temperature field, distortion and final quality of the part. Four kinds of deposition patterns, including sequence, symmetry, in–out and out–in, were designed to deposit H13 steel in this study. An in situ measurement system was set up to record the temperature history and the progress of accumulated distortion of the parts during deposition. An S value was proposed to evaluate the distortion of the substrate. It was shown that the distortion of the part deposited by sequence was significantly larger than those of other parts. The distortion deposited by the out–in pattern decreased by 68.6% compared with sequence. The inherent strain method and strain parameter were introduced to expose the mechanism of distortion reduction caused by pattern variation.