308L不锈钢热丝等离子弧增材构件组织和性能

Microstructures and mechanical properties of stainless steel component deposited with 308L wire by hot wire plasma arc additive manufacturing process

随着增材构件重量的大幅度增加和形状复杂性的急速提升,增材时间成本占比越来越高,为了在保持焊枪达到尽可能多空间位置的基础上,提高熔敷效率,降低时间成本比例,提出了热丝等离子弧增材制造工艺.分别采用冷丝等离子弧增材制造(CW-PAM)和热丝等离子弧增材制造(HW-PAM)两种工艺进行了50层直壁体增材对比试验,研究了HW-PAM工艺的特性,并对增材试样的显微组织和力学性能进行对比分析.结果表明,HW-PAM工艺的平均熔敷效率提高了105%,在电弧行进速度为20 cm/min时,熔敷金属损失率最多可降至1.42%,比CWPAM工艺降低了6.18%.在电弧行进速度为50 cm/min时,试样内部存在大量非等轴铁素体,平均晶粒直径从CW-PAM工艺的8.37μm细化到7.62μm.HW-PAM试样的抗拉强度均在700 MPa以上,断后伸长率最高可达到53%,比CW-PAM工艺提高了6.25%.

Shapes of deposited components are more complicated and their weights are obviously heavier than before,therefore the ratio of deposited time cost in sum production cost increases dramatically.Hot wire plasma arc additive manufacturing process is proposed to reduce deposited time cost,by increasing deposition rate while keeping welding torch reaches more deposition positions as much as possible.Both CW-PAM process and HW-PAM process were used to manufacture 50 layers walls with 308L filler wire,and the investigation of fundamental characterization of HW-PAM process was implemented,then under different torch speeds,microstructures and mechanical properties of deposited sample by two processes were compared in details.Experiment results show that the deposition rate of HW-PAM process increased by 105%on an average.Its maximum wire lose rate reduced to 1.42%,which is lower 6.18%than the CW-PAM process at the torch speed of 20 cm/min.In addition,when the travel speed is 50 cm/min,lots of non-equiaxed ferrites exist in the samples deposited by HW-PAM process,the mean grain diameter refined to 7.62μm from 8.37μm of CW-PAM process.The ultimate tensile strengths of the HW-PAM samples are all above 700 MPa,and the maximum elongation reaches 53%,which raised by 6.25%in contrast to the CWPAM process.