深冷奥氏体钢应变强化PAW-GTAW组合焊接头组织结构演变及超低温性能研究

应变强化作为一种轻量化技术，在深冷奥氏体钢容器设计制造中具有广阔的应用前景。针对奥氏体钢应变强化产品最薄弱的焊接接头存在微观形变不均匀、组织成分差异大、低温（-196℃）性能稳定性差等问题，本项目以深冷奥氏体钢应变强化等离子弧焊与填丝钨极氩弧组合焊(PAW-GTAW)接头为研究对象，以接头各区域非匀质微观应变强化效应为核心，系统研究深冷条件下应变强化奥氏体钢PAW-GTAW组合焊接头组织发生诱导相变的机制、分区超低温性能的评价、深冷疲劳寿命的预测及组织结构演变内在相关性等关键科学问题，从理论上阐明应变强化和深冷处理对奥氏体不锈钢组合焊接头区组织相变与低温性能的影响规律，揭示应变强化奥氏体钢PAW-GTAW接头组织性能增益机制，有助于开辟一个新的极限环境应用领域，为轻量化战略的深冷结构关键制造技术提供理论基础，对促进应变强化储运设备的发展和实现安全与资源节约并重具有重要的意义。

Strain strengthening has a broader prospect in the design of cryogenic austenitic stainless steel vessel as a lightweight technology. Welding joint after strain strengthening of stainless steel will be the object in this work due to the problem including micro- inhomogeneous deformation, composition differences and unstable cryogenic (-196℃) performance. A combined welding technology will be conducted by PAW-GTAW in austenitic stainless steel and micro-strain effect of the whole joint will be the core in this project. Then some key scientific problems including microstructure evolution, partition performance evaluation, cryogenic fatigue life prediction and relationship between microstructure and stress-strain in PAW-GTAW joint under the condition of strain strengthening will be resolved by advanced research measures.The theoretic and inherent regulation of the microstructure evolution with the performance at low temperature in PAW-GTAW joint of austenitic stainless steel after strain strengthening will be clarified. A new approach will be put forward to control cryogenic and stable properties in austenitic stainless steel by strain strengthening. This can provide a theoretical and technical support for the key technology to develop lightweight structures. It is also great significance to promote the development of strain strengthened cryogenic storage and transportation equipment, and to realize both safety and resource saving.