The development of fast boats has improved the competitiveness of water transportation and made the shipbuilding industry enter a new stage of development. This new market demand, the world's increasing concern for environmental protection, efficient use of materials and energy consumption, requires the shipbuilding industry to seek new materials and new manufacturing technologies to meet the market demand.
Friction stir welding (FSW) is a new joining technology invented by the Welding Research Institute in 199 1, which is protected by the world patent and opens a new page for joining light alloy structural parts in the industrial manufacturing field. With the invention and development of friction stir welding, it is a revolutionary progress in shipbuilding field to realize high-integration prefabricated modular manufacturing by friction stir welding instead of traditional ship flat-stiffened plate structure manufacturing.
In the field of shipbuilding abroad, friction stir welding has been deeply and meticulously studied and developed, and has been successfully applied. In Norway, Japan and Australia, many shipbuilding companies have used friction stir welding technology to manufacture aluminum alloy structural parts of large ships. These prefabricated structural components are usually plates or extruded profiles. Friction stir welding can make the assembly of ship manufacturing more accurate, simple and time-saving, and make the ship manufacturing change from the manufacture and assembly of parts to the assembly of prefabricated structural parts of ship deck and shell.
In China, based on the great advantages and potential industrial application prospects of friction stir welding in welding methods, mechanical properties, manufacturing costs and environment, in April 2002, Beijing Institute of Aeronautical Manufacturing Engineering and TWI established China Friction stir welding center on the basis of comprehensive patent license and technical cooperation, which marked the official start of friction stir welding in China and was another brand-new milestone in the history of welding technology development in China. It is predicted that friction stir welding will be widely used in shipbuilding industry in China in the near future.
Friction stir welding manufacturing technology of profile assembly plate
In recent years, with the increasing demand for fast ships in shipbuilding industry, shipbuilding requires not only the improvement of speed, but also the improvement of performance-price ratio. Therefore, high-performance aluminum alloy materials should be selected as far as possible to reduce the weight of the ship. The traditional connection methods of aluminum alloy materials are rivet connection and arc welding connection, which increases the manufacturing time, manpower and material consumption; In addition, cracks, pores, deformation and smoke are easy to occur when aluminum alloy is welded, which limits the use of arc welding in aluminum alloy components.
The invention of friction stir welding and its successful application in industrial manufacturing field, as well as its great advantages in manufacturing feasibility, weight, quality and cost, provide the best scheme for the connection of aluminum alloy structural parts in shipbuilding.
1 structural member of sectional splicing wallboard
As early as 1996, Marine Company and Maritime Company in Norway developed and studied the assembly line manufacturing technology of splicing flat plates and profiles of friction stir welding ships into large plates. At the same time, with the help of Norwegian Research Council, Hydro, Kvaerner, DNV, SINTEF and Norwegian University of Science and Technology cooperated to complete the friction stir welding project of splicing profiles into panels.
Aluminum alloy extruded profiles are mature industrial products in the market. The use of aluminum alloy profiles in shipbuilding can effectively improve the standardization and mass production of shipbuilding and save time. Therefore, the shape and size of profiles for shipbuilding should meet the industry standards as far as possible, so as to increase the batch of aluminum alloy profiles for ships and reduce the material cost. Figure 1 shows the different geometric shapes and friction stir welding connections of profiles commonly used in shipbuilding. Among them, C is a trapezoidal closed box extrusion profile structure, which has good torsional structural strength and structural rigidity, is easy to ensure the dimensional accuracy and flatness of structural parts during assembly, and has great openness to friction stir welding, so it is widely used in ship structure manufacturing; In addition, the trapezoidal top of this structure is designed with a lower flange, which can help clamp and fix cables, water and ventilation pipes and avoid welding and bolting on structural members, which will destroy the integrity of the hull structure.