摘要
为优化制造工艺和提高生产效率,针对航天固体火箭发动机壳体用30Cr3超高强度钢进行激光焊接特性研究。在焊接过程中通过对匙孔和熔池的高速摄影进行实时观察,发现在所选激光功率范围内存在三种不同的焊接熔透模式,包括匙孔未穿透型熔透模式、匙孔临界穿透型熔透模式和匙孔稳定穿透型熔透模式。采用激光测振仪对熔池表面的波动幅度进行了定量测量,并讨论了不同熔透模式下焊接过程的动态稳定性。基于熔透模式的划分,分析了匙孔动态行为与焊接接头组织和力学性能之间的关系。结果表明,在匙孔临界穿透型熔透模式下焊缝组织晶粒大小不均且接头塑、韧性较差。比较三种焊接熔透模式,发现匙孔稳定穿透型熔透模式有助于获得致密、均匀且杂质少的焊缝组织,焊接接头具备最高的断后伸长率(22.8%)和最大的冲击吸收功(14.36 J)。
Objective 30Cr3 steel,developed in China,is a new type of ultra-high-strength steel mainly used in the manufacture of aerospace solid rocket engine shells.However,few studies have conducted welding tests on this material.The primary welding methods used in production are tungsten arc welding and electron beam welding;however,tungsten arc welding has disadvantages such as arc energy divergence,a wide heat-affected zone,and large welding deformation.Electron-beam welding must be performed in a vacuum environment.The shape and size of weldment are limited by the size of vacuum chamber as engine size increases.Laser welding has the advantages of high energy density and fast welding speed.The application of laser welding to the manufacture of solid rocket engine shells can significantly reduce costs and improve production efficiency.The present study systematically investigates the laser welding characteristics of 30Cr3 aerospace ultra-high-strength steel,providing an experimental basis and theoretical support for the efficient and high-quality welding of this material.Methods The base metal used in the test is a 30Cr3 ultra-high-strength steel plate with the dimension of 150 mm×75 mm×2.5 mm.The 30Cr3 base metal is in a quenched and tempered state,and the room temperature microstructure is tempered sorbite,composed of strip ferrite and granular carbide.A butt form is used for the welding joint.Based on the previous study,the laser power range selected is 3.4‒3.7 kW,the welding speed is 1.2 m/min,and the defocusing amount is 0.During the welding process,a high-speed photographic system is used to obtain images of the welding pool,and the dynamic behavior of the laser keyhole is directly observed through a high-temperature resistant quartz glass.The recording rate is 5000 frame/s.Based on laser Doppler effect,a laser vibrometer is used to collect the micron-level vibration signal of the molten pool surface during the welding process at a sampling frequency of 78000 Hz.Following welding,metallographic samples are cut
作者
刘招
潘丽华
李晓强
高健
张轲
Liu Zhao;Pan Lihua;Li Xiaoqiang;Gao Jian;Zhang Ke(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Space Propulsion Technology Research Institute,Shanghai 201100,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第12期27-40,共14页
Chinese Journal of Lasers
基金
国家自然科学基金(51875354,51875353,51775338)
上海市科委“科技创新行动计划”(19511105100)。
关键词
激光技术
焊接熔透模式
超高强度钢
激光焊接
焊接过程稳定性
晶粒结构
力学性能
laser technique
weld penetration modes
ultra-high strength steel
laser welding
welding process stability
grain structure
mechanical properties
