Prize-winning project: "Research, development and application of Jiaolong manned submersible" project (First-class prize of National Scientific and Technological Progress)

Ningbo Participating Organization: Ningbo XINGJIAN Aerospace Machinery Co.

With a number of technological research, the "Jiaolong manned submersible R&D and application" project won the First Prize of National Scientific and Technological Progress. Behind the honor, there is a solid figure of "Ningbo Smart Manufacturing" - Ningbo private enterprises as a project participant, for the "Jiaolong" has undertaken a number of protection tasks.

XINGJIAN puts on the "swim bladder" for Jiaolong

The "swim bladder" that allows "Jiaolong" to float and dive on its own is actually a ballast box system, whose fittings are in direct contact with seawater, demanding in terms of production precision, and also needing to resist high pressure and corrosion. This "swim bladder" of multiple control valves is completed by Ningbo XINGJIAN Aerospace Machinery Co.

"From the beginning of the development of 'Jiaolong', we have been involved in the whole process." XINGJIAN senior engineer Gao Zepu said, the main function of these valves, is to control the high-pressure air, open when floating, injecting high-pressure air, squeezing out the water inside the tank, thus reducing the self-weight of the submersible, and vice versa. XINGJIAN developed the valve group, light weight, high strength, can help the submersible precise fine-tuning of the depth of the dive, to help the staff to accurately capture effective information, "and every dive, we have been involved in the development of the 'Jiaolong', which was completed by Ningbo XINGJIAN Aerospace Machinery Co. "And every time we dive, we will 'update' the valve manifold according to the reality." Gao Zepu said.

When taking over this development task, the domestic research in this field is still blank, and material selection is the first problem encountered by XINGJIAN. Calculations show that at 7000 meters water depth, "Jiaolong" needs to withstand 7000 tons of weight per square meter area, so the system should have light weight, safe and reliable, compact size, strong anti-corrosion ability and other characteristics. After repeated tests and verification, Gao Zepu team and CSIC Wuxi No. 702 Research Institute, selected titanium alloy as the main material of the valve group. "Previously, titanium alloy materials are mainly used in the aerospace field, we found in our research, its use in deep sea equipment is more ideal." Gao Zepu said, titanium alloy is not only high strength, but also flexible, can be in the process of diving and surfacing, to maintain no deformation, to provide a safe space for the submariner, and at the same time, its corrosion resistance is also very good.

However, the welding process of titanium alloy is extremely difficult, and a little inattention can lead to cracks in the material. Gao Zephyr's team carried out thousands of operations, gradually fine-tuning the current, temperature and other factors, and finally overcame the difficulties, broke through the titanium alloy welding technical difficulties, and passed the product acceptance.