In the development history of the hottest ship man

The development history of shipbuilding (middle)

for hull plates with spatial shapes such as curvature, corner or edge folding, forming processing is also required after steel plate cutting, mainly using roll bending machine and roller press for cold bending; Or adopt the processing method of hydrothermal forming, that is, add oxygen acetylene drying torch on the plate according to the preset. The center introduced the overview of the technological process of micro milltm method to the delegation, and used water to track and cool, so that the plate was locally deformed and bent into the required curved shape. For profiles used as ribs, etc., the cold bending machine for ribs is often used for bending and forming. With the development of digital control technology, the digital control frame cold bending machine has been used, and then the digital control bending machine has been developed. Hull parts processing has progressed from mechanization to automation

hull assembly and welding the process of assembling the components of the hull structure into the whole hull. It is generally constructed in sections, which are divided into three stages: assembly and welding of components, assembly and welding of sections and assembly and welding of slipway

① assembly and welding of components: also known as small interference. The process of combining the processed steel plate or section steel into plate rows, T-sections, frame frames, fore and aft columns and other components is carried out on the assembly and welding platform in the workshop

② sub (general) assembly and welding: also known as middle closure. Assemble parts and components into plane segments, curved segments or three-dimensional segments, such as bulkheads, bottoms, sides and superstructures; Or combined into annular three-dimensional segments that cross the main hull in the direction of the captain, which are called segments, such as bow segments, stern segments, etc. The assembly and welding of sections are carried out on the assembly and welding platform or moulding bed. The division of sections mainly depends on the characteristics of the hull structure and the lifting and transportation conditions of the shipyard. With the large-scale of ships in terms of import amount and the increase of crane capacity, the segment and total segment are also increasing, and their weight can reach more than 800 tons

③ slipway (dock) assembly and welding: that is, the general assembly of the hull, also known as large closure. Finally, assemble and weld the hull parts, sections and assemblies on the slipway (or dock) to form the hull. In order to ensure the safety of launching, large ships with a displacement of more than 100000 tons are generally assembled in the dock. The commonly used general assembly methods include: Taking the general section as the general assembly unit, and lifting from the middle of the ship to the bow and stern, which is generally applicable to the construction of small and medium-sized ships; First hoist a bottom section at the midship and stern of the ship, and use this as the construction basis to hoist adjacent sections to the bow, stern and upper layer. The lifting range is pagoda shaped, so you can basically choose a tower construction method for your model; There are 2 ~ 3 construction benchmarks, which are built by tower construction method and finally connected to the hull, called island construction method; When the first ship is built at the end of the slipway (or dock), the tail of the second ship is built at the front of the slipway at the same time. After the first ship is launched, the tail of the second ship is moved to the end of the slipway, and other segments are hoisted until the whole hull is assembled. At the same time, the tail of the third ship is built at the front of the slipway, and so on. This method is called series construction method; The hull is divided into two sections, the first and the second, which are built on the slipway, launched, and then closed on the water. The selection of various assembly methods depends on the characteristics of the hull structure and the specific conditions of the shipyard

the workload of hull assembly and welding accounts for more than 75% of the total workload of hull construction, of which welding accounts for more than half. Therefore, welding is the key work of shipbuilding, which is not only directly related to the construction quality of ships, but also related to shipbuilding efficiency. Since the 1950s, welding methods have developed from full manual welding to submerged arc automatic welding (see submerged arc welding), semi-automatic welding, electroslag welding and gas shielded arc welding. Since the mid-1960s, there have been new technologies such as single-sided welding and double-sided forming, gravity welding, automatic fillet welding, vertical welding and horizontal automatic welding. Welding equipment and welding materials have also developed accordingly. Due to the complexity of the hull structure, manual welding is still needed where it is difficult to implement automatic welding and semi-automatic welding

combined with the development of welding technology, since the 1960s, T-section assembly and welding lines and plane section assembly and welding lines have been used in hull components and section assembly respectively. T-shaped bar is the basic component of plane segmented skeleton. Plane segments account for a considerable proportion in the hull structure. For example, on large bulk carriers and oil tankers, plane segments can account for more than 50% of the total body weight of the automatic display of ship elongation. The plane sectional assembly and welding line includes all kinds of special assembly and welding equipment. It uses the conveyor to continuously carry out feeding, panel welding, assembly and welding skeleton and other operations, which can significantly improve the mechanization of sectional assembly and become one of the main contents of the technical transformation of modern shipyards. Some shipyards in the world also adopt assembly line production method for assembly welding and dock assembly of three-dimensional sections of large oil tankers produced in batch

after the final assembly of the hull, the tightness test must be carried out on the hull, and then the shafting and rudder system must be aligned at the tail, and the shafting, propeller and rudder must be installed. Prepare for launching after completing various underwater works

ship launching is the process of moving the ship that has been assembled at the slipway (dock) from the land to the water area. The moving direction of the ship during launching is either parallel to or perpendicular to the captain, which is called longitudinal launching and transverse launching respectively. The water slides are mainly wooden slides and mechanized slides. The former relies on the self weight of the ship to glide into the water, which is widely used; The latter uses a trolley to carry the hull and pull it into the water on the track, which is mostly used in small and medium-sized inland river shipyards