01. What is a storage tank? The storage tank is the structural system of the rocket. On the one hand, it can store propellants (liquid oxygen kerosene, liquid oxygen methane), pressurized transportation, etc.; on the other hand, it is similar to the bones of the human body and plays a supporting role. It is the core key component related to the reliability of the rocket. 02. The height, weight and value of the tank are about 2/3 of the total length of the rocket, the weight is about 60-80% of the dry weight of the rocket structure (excluding fuel), and the cost is about 25% of the total cost of the rocket. 03. Production materials: First generation: aluminum-magnesium alloy; second generation: aluminum-copper alloy; third generation: aluminum-lithium alloy. In addition to metal materials, composite materials are also gradually used in rocket storage tanks. Compared with aluminum alloy materials, composite materials have lower density, higher specific strength and better fatigue resistance. 04. Forming process If aluminum alloy material is selected, machine milling process and welding process are mainly used. The rocket’s storage tank is relatively large, and multiple barrel sections need to be welded to meet the size requirements. The welding process of the storage tank mainly includes the welding of the tank bottom and the welding of the barrel section. Among them, the welding of the bottom of the box is the most difficult, mainly including the welding of melon petals and melon petals, the welding of the ellipsoid surface of the melon petals, the fork-shaped ring and the top cover, etc. A box bottom consists of 8 melon petals, 1 top cover, and 1 transition ring welded together. 05.The reason why it is expensive
1. Low material utilization rate: If high-strength aluminum alloy is selected, the actual material utilization rate is only 10% to 15% because machine milling process is required;
2. Equipment prices are high: Equipment for manufacturing aluminum alloy storage tanks is generally high-end customized equipment.
06.Major companies that produce storage containers
Factory 211 of the First Institute of Aerospace Science and Technology, Factory 149 of the Eighth Institute of Aerospace Science and Technology, Institute 7102 of the Seventh Institute of Aerospace Science and Technology, Beijing Jiutianxingge Aerospace Technology Co., Ltd., Qingdao Huanyu Qiankun Aerospace Special Equipment Co., Ltd., Lightyear Exploration (Jiangsu) Space Technology Co., Ltd., etc. 07. Main equipment supplier China Ordnance Wuhan Heavy Machine Tool Group Co., Ltd. Extended reading: 1. Liquid-filled deep drawing forming technology: The liquid-filled deep drawing forming technology that “conquers rigidity with softness” allows the invisible liquid to understand “instructions” and achieve real-time precise control. Specifically, it is equivalent to filling nearly 10,000 bottles of mineral water in a huge closed swimming pool while draining water out. The liquid’s “softness overcomes rigidity” characteristics overcome the international problem of wrinkles at the bottom of the box during one-time forming, and meet the stamping pressure and support function of the plate. China Aerospace Science and Technology Corporation Shanghai Aerospace Technology Research Institute Factory 149 has broken through the liquid-filled deep drawing forming technology. At present, Shanghai Aerospace 149 Factory has built China’s first 3-meter integrated box bottom manufacturing production line, forming an annual mass production capacity of 300 pieces of integrated box bottoms. 2. Stainless steel bulging tank design and manufacturing technology: Lightyear Exploration (Jiangsu) Space Technology Co., Ltd. is the first in China to develop the stainless steel bulging tank design and manufacturing technology. Musk’s company SpaceX uses stainless steel in the design of its Starship rocket. The key to the success of stainless steel bulging tank design and manufacturing technology lies in the excellent elongation of stainless steel. In addition, due to the “cold work hardening” effect, stainless steel becomes harder and harder as it is stretched. As long as the steel plate is stretched by 25%, its yield strength will increase by more than three times, which provides the possibility for stainless steel to manufacture storage tanks.
