采用大功率MIG电弧热源熔化沉积316L奥氏体不锈钢金属焊丝制备试样，研究电弧功率对成形试样组织、力学性能以及断裂行为的影响并分析其机理，为高效、低成本电弧增材制造大型金属构件提供技术基础和理论依据. 结果表明，大功率MIG电弧增材制造316L奥氏体不锈钢内部形成柱状晶并生成δ相和σ相呈蠕虫状分布在γ基体中. δ相分布在晶内和晶界起强化作用. 随着电弧功率从3 763 W增加8 400 W，316L试样晶粒尺寸变大，δ相含量减少而σ相含量增加，使得材料抗拉强度从578 MPa降低到533 MPa，屈服强度从310 MPa降低到235 MPa，断后伸长率从53%降低到44%，断面收缩率从67%下降到60%. 当电弧功率增加到8 400 W时，在晶界上形成较多的σ相，试样断裂模式由较低功率时的穿晶韧窝断裂转变为沿晶韧窝断裂.
The austenitic stainless steel 316L was fabricated by high power MIG arc additive manufacturing and its microstructure evolution, mechanical properties and fracture behavior were investigated. Results show that there are columnar grains forming in the MIG arc additive manufacturing 316L. The microstructure consists of vermicular δ and σ phases within γ matrix. The δ distributed both at grain boundaries and in the grains can strengthen the steel. With the arc power increasing from 3 763 W to 8 400 W, δ phases decrease and σ phases increase, as well as grain size increases. That leads to the ultimate tensile strength decrease from 578 MPa to 533 MPa, yield strength decrease from 310 MPa to 235 MPa, elongation decrease from 53% to 44%, reduction of area decrease from 67% to 60%. A pronounced feature is that the fracture type transfers from trans-granular dimple fracture to inter-granular dimpled fracture at the arc power of 8 400 W.
[1] Marshall P. Austenitic stainless steels: microstructure and mechanical properties[M]. Amsterdam: Elsevier, 1984.
[2] Wang H, Zhang S, Wang X. Progress and challenges of laser direct manufacturing of large titanium structural components[J]. Chinese J Lasers, 2009, 36(12): 3204-3209.
[3] 卢秉恒, 李涤尘. 增材制造(3D打印)技术发展[J]. 机械制造与自动化, 2013, 42(4): 1-4
Lu Bingheng, Li Dichen. Development of the additive manufacturing (3D pringting) technology[J]. Machine Building & Automation, 2013, 42(4): 1-4
[4] Frazier W. Metal additive manufacturing: a review[J]. Journal of Materials Engineering & Performance, 2014, 23(6): 1917-1928.
[5] 张海鸥, 王超, 胡帮友, 等. 金属零件直接快速制造技术及发展趋势[J]. 航空制造技术, 2010, 8: 43-46
Zhang Haiou, Wang Chao, Hu Bangyou. Direct rapid manufacturing technology for metal oarts and its development trends[J]. Aeronautical Manufacturing Technology, 2010, 8: 43-46
[6] 熊江涛, 耿海滨, 林鑫, 等. 电弧增材制造研究现状及在航空制造中应用前景[J]. 航空制造技术, 2015, 493(23-24): 80-85
Xiong Jintao, Geng Haibin, Lin Xin,et al. Research status of wire and additire manufacture and its application in aeronautical manufacturing[J]. Aeronautical Manufacturing Technology, 2015, 493(23-24): 80-85
[7] 李超, 朱胜, 沈灿铎, 等. 焊接快速成形技术的研究现状与发展趋势[J]. 中国表面工程, 2009, 22(3): 7-12
Li Chao, Zhu Sheng, Shen Canduo, et al. Present state and development trend of welding rapid forming technology[J]. China Surface Engineering, 2009, 22(3): 7-12
[8] 苗玉刚, 李春旺, 张鹏. 不锈钢旁路热丝等离子弧增材制造接头特性分析[J]. 焊接学报, 2018, 39(6): 35-38
Miao Yugang, Li Chunwang, Zhang Peng. Joint characteristics of stainless steel by pass-current wire-heating PAW on additive manufacturing[J]. Transactions of the China Welding Institution, 2018, 39(6): 35-38
[9] 李雷, 于治水, 张培磊. TC4钛合金电弧增材制造叠层组织特征[J]. 焊接学报, 2018, 39(12): 37-43
Li Lei, Yu Zhishui, Zhang Peilei. Microstructure characteristics of wire and arc additive manufacturing of TC4 components[J]. Transactions of the China Welding Institution, 2018, 39(12): 37-43
[10] Skiba T, Baufeld B, Biest O V D. Microstructure and mechanical properties of stainless steel component manufactured by shaped metal deposition[J]. ISIJ international, 2009, 49(10): 1588-1591.
[11] Kevin H, Peter M. 3DPMD-Arc-based additive manufacturing with titanium powder as raw material[J]. China Welding, 2019, 28(1): 15-19.
[12] Xiong J, Zhang G. Adaptive control of deposited height in GMAW-based layer additive manufacturing[J]. Journal of Materials Processing Technology, 2014, 214(4): 962-968.
[13] 尹紫秋, 熊俊. 基于ACT匹配的GMA增材制造熔池形貌三维重建[J]. 焊接学报, 2019, 40(1): 49-52
Yin Ziqiu, Xiong Jun. Three-dimensional reconstruction of molten pool appearance in GMA additive manufacturing based on ACT stereo matching algorithm[J]. Transactions of the China Welding Institution, 2019, 40(1): 49-52
[14] Katayama S, Fujimoto T, Matsunawa A. Correlation among solidification process, microstructure, microsegregation and solidification cracking susceptibility in stainless steel weld metals (Materials, Metallurgy & Weldability)[J]. Transactions of Jwri, 1985, 14: 123-38.
[15] 干勇, 田志凌, 董翰, 等. 中国材料工程大典. 第3卷, 钢铁材料工程[M]. 北京: 化学工业出版社, 2006.
