Recently, the eighth research laboratory completed the development and bearing test of the first set of titanium alloy frame of abyssal in-situ scientific experimental station in China, marking that the Seventh Five year plan institute has become the first research and testing unit of the frame of in-situ scientific experimental station in China. The construction technology of this product represents the highest level of such products in China and fills the gap in the manufacturing field of titanium alloy frame of submarine experimental station in China.

Figure: Bearing Test of main frame of abyssal in-situ scientific experiment station

The abyssal seabed in-situ scientific experimental station can support the continuous seabed scientific research task for up to half a year. The titanium alloy frame is the supporting skeleton of the whole experimental station, which not only provides the installation base for the buoyancy block and various equipment, but also bears the weight of the whole experimental station in the process of lifting and recycling, mother ship carrying and sinking on the seabed. The frame manufacturing is an important part of the whole project.

The frame of titanium alloy experimental station is developed for the first time in China. The frame bears large and complex load under service conditions. At the same time, the structural welds are dense, the structural rigidity is low, and it is easy to produce welding deformation. Therefore, the technical index requirements are very strict. All main welds are fully welded, the overall structure dimensions are accurate to millimeter level, and the upper, middle and lower three-layer structures are accurately butt jointed. In the process of frame development, we should not only meet the structural weld strength, but also control the structural welding deformation.

The project has successfully broken through many key technologies, such as efficient profile welding, overall heat treatment, deformation control of complex welded structural parts and so on. Under the condition of full penetration of the main weld of the frame, the welding deformation of the whole frame is effectively controlled and meets the requirements of technical indicators. Finally, eight rooms completed the original 10 day self weight limit bearing test of the experimental station in only 3 days, and obtained the strain value and deformation of key parts. Through the test, the design reliability and manufacturing quality are verified, and the structural strength and stability of the frame are checked, which lays a solid foundation for the stable operation of the subsequent experimental station.