[0028] The present invention will be described in further detail below in conjunction with the embodiments.
[0029] The welding method of the thin steel plate of the present embodiment includes the following steps:
[0030] 1. Preparation before welding:
[0031] 1. The board should be leveled before assembly to make the board surface flat;
[0032] 2. The profiles should be leveled before assembly;
[0033] 3. The edge blanking is processed by a planer or plasma cutting to ensure a uniform assembly gap;
[0034] 4. When assembling the panels by arc welding, the assembly gap should be less than 0.5mm; the staggered edge of the panel e<0.15t, if the local gap is uneven and out of tolerance, grinding or shovel edge should be used to make it smooth, and oxygen-acetylene cutting is not allowed Make it deformed; t≤8mm;
[0035] 2. Positioning welding:
[0036] 1. Before welding, oil, water and rust debris should be completely removed from the 30mm range on both sides of the butt weld and in the groove. Except for the shop primer, the fillet weld must be cleaned of debris;
[0037] 2. The length and spacing of position welding are uniform, the length of butt weld tack welding is 20mm, the spacing is 50mm, the length of fillet weld tack welding is 30mm, and the spacing is 60mm; when the plate thickness t≤4mm and submerged arc welding is used, welding should be used. The point diameter is about 8-12, the spacing is 30mm, and the dense point positioning method;
[0038] 3. The welds after tack welding should be welded in time to avoid rust, water or dirt in the groove;
[0039] 3. Welding:
[0040] 1. When assembling and welding on the platform, the ballast iron should be pressed on both sides of the weld, and the periphery of the assembled plate should be pressed on the platform with small code plates, and the spacing between the small code plates is 300mm;
[0041] 2. The body segment and the three-dimensional segment should be stillborn when welded on the tire frame;
[0042] 3. The maximum diameter of the manual electrode cannot exceed Φ4.0mm. When welding the weld with the thickness t≤4mm, use the electrode below Φ3.2. When the plate thickness t ≤ 4mm and submerged arc welding is used, the dense spot positioning method with a welding spot diameter of about 8-12 and a spacing of 30 mm should be used.
[0043] 4. The welding parameters of current, voltage and speed in welding should be adjusted on the test plate before welding;
[0044] 5. When welding, the width of the butt weld and the height of the weld seam, the butt seam: the width is 1.5-2.0t, the excess height is 0-1mm, and t is the thickness of the plate;
[0045] 6. Welding sequence: welding should be carried out from the middle to the front, back, left and right, and jump welding is used around the center. Welding should not be concentrated in one area, so that the heat will be too concentrated and cause large deformation. ;
[0046] 7. The structural parts with weak rigidity or openings must be temporarily reinforced, and the reinforcement should be removed after the surrounding welding is completed and cooled to room temperature;
[0047] 8. After welding, the butt weld should be hammered to relieve stress, but the iron hammer should not directly hammer the weld;
[0048] 9. Deformation after welding should be corrected in time.
[0049] The above-mentioned manual arc welding or carbon dioxide welding process parameters are: a. The assembly gap of the fillet weld should be ≤ 2mm, b. The type of electrode should match the strength of the plate to be welded and the electrode approved by the ship's class, c. The diameter of the electrode, when the plate When the thickness t≤5mm, use Φ3.2mm; when the plate thickness t>5mm, use Φ4mm welding rod, d, the form of tack welding seam, when the plate thickness t≤5mm, use the dense spot with a diameter of 6-8mm and a spacing of 30mm For the welding method, when the plate thickness t>5mm, the short-track positioning method with a positioning welding length of 30 to 50 mm and a spacing of 200 to 250 mm is used.
[0050] The above-mentioned frame segment assembly vertical welding process requirements: the deck is the base surface, the tire is constructed in reverse, and the longitudinal and transverse formwork spacing of the tire frame is set according to the thickness of the thin plate. If the plate thickness δ=5~6mm, the vertical and horizontal formwork spacing is 1000mm, if the plate thickness δ≥7mm is less than 8mm, the vertical and horizontal formwork spacing is 1200; 200mm, the thickness must be ≥10mm; the height of the tire frame pillar should not be less than 800mm.
[0051] The present invention is further described below:
[0052] The welding deformation of the thin plate hull is mainly manifested as: the so-called "skinny horse phenomenon" in which the frame of each frame is printed on the surface; the "wave deformation" with a large area of unevenness in the longitudinal direction;
[0053] Locally uneven "bumps and deformations" within the range; "orange peels" caused by firework and beating
[0054] These different forms of post-weld deformation seriously affect the appearance quality of the hull. There are many factors that lead to the welding deformation of the thin plate. At present, the anti-deformation technology of thin plate welding mainly focuses on the research of process technology.
[0055] In order to ensure the welding quality of the thin plate (T≤8mm) structure and reduce the welding deformation of the thin plate structure, the welding of the thin plate should follow the following process regulations:
[0056] 1. Preparation before welding
[0057] 1. The plate should be leveled before assembly to reduce its deformation and internal stress as much as possible to make the plate surface flat.
[0058] 2. Profiles should be leveled before assembly.
[0059] 3. The edge blanking should be processed with a planer or plasma cutting as much as possible to ensure a uniform assembly gap.
[0060] 4. When gas cutting must be used to trim the allowance for segmented production and slipway convergence, a small cutting nozzle should be used as much as possible to improve the cutting quality. When submerged arc welding is used, the weld after gas cutting should be ground, and plasma cutting should be used as much as possible to reduce deformation if conditions permit.
[0061] 5. When submerged arc welding, the assembly gap should be less than 0.5mm, and the assembly gap of other welds should be less than 2mm. The wrong side of the board edge e<0.15t (t≤8mm).
[0062] 6. If the local gap is uneven or out of tolerance, grinding or shovel edge should be used to make it meet the standard, and oxygen-acetylene cutting should not be used to deform it.
[0063] 7. The gap of the fillet weld should be as small as possible.
[0064] 8. When assembling, it is not allowed to use hard pulling to cause additional stress to increase.
[0065] 2. Positioning welding
[0066] 1. Before tack welding, the 30mm range on both sides of the butt weld and in the groove should be thoroughly cleaned of oil, water, rust and other debris. Except for the shop primer, other debris must be removed from the fillet weld.
[0067] 2. The length and spacing of tack welding should be uniform, butt weld tack welding length is 20mm, spacing is 50mm; fillet weld tack welding length is 30mm, spacing is 60mm;
[0068] 3. When the plate thickness t≤4mm and submerged arc welding is used, the dense spot positioning method should be used, that is, the diameter of the welding spot is about 8--12, and the spacing is 30mm.
[0069] 4. The welded seam after tack welding should be welded as soon as possible to avoid rust, water or dirt in the groove caused by dew, rain and other contaminants.
[0070] 3. Welding
[0071] 1 When assembling and welding on the platform, the ballast iron should be pressed on both sides of the weld. The distance between the ballast iron should be as small as possible under normal operation. The periphery of the plate should be pressed on the platform with a small code plate , the spacing is 300mm.
[0072] 2. The body segment and the three-dimensional segment should be stillborn when welded on the tire frame.
[0073] 3. Butt welds (except submerged arc welds) and fillet welds should use CO as much as possible 2 It is not allowed to use iron powder electrodes in thin plate welding.
[0074] 4. The diameter of the manual electrode must be limited, and the maximum cannot exceed Φ4.0mm. When welding the weld with the thickness t≤4mm, the electrode below Φ3.2 must be used.
[0075] 5. The welding parameters (current, voltage, speed) in the welding specification should be adjusted on the test plate before welding. The welding current should not be too large, and the small specification welding parameters should be used as much as possible.
[0076] 6. During welding, the size of the fillet weld and the weld width of the butt weld should be carefully controlled according to the drawings. The weld height should not exceed the standard to control the deformation, namely:
[0077] Fillet weld: 0.9K1≤K≤1.1K1 (K1 is the size of the weld foot in the drawing)
[0078] Butt seam: width 1.5-2.0t and height 0-1mm
[0079] 7. The specified welding sequence should be strictly followed during welding.
[0080] (1) The welding should be carried out from the middle to the front, back, left and right, and the jump welding method should be used around the center. The welding should not be concentrated in one area, so that the heat is too concentrated and large deformation occurs. Not too many people.
[0081] (3) Manual welding and CO 2 During welding, the segmental de-welding method or the sub-segment de-soldering method should be adopted according to the length of the weld. The length of the segment can be determined according to the length of the weld, and the shorter the length of the segment, the better without affecting the efficiency.
[0082] (4) When welding fillet welds, refer to Figure 6 for flat fillet welding. For vertical fillet welding, try to use downward welding (approved by the process and approved by the shipowner and ship inspection), and the upward welding should be de-welded from top to bottom as shown in Figure 7 Its segment length is the same as (3).
[0083] 8. The structural parts with weak rigidity or openings must be temporarily reinforced, and the reinforcement should be removed after cooling to room temperature after the surrounding welding is completed.
[0084] 9. After welding, hammer the butt weld to relieve stress, but the hammer cannot directly hammer the weld, and it should be padded with an iron plate.
[0085] 10. The deformation after welding should be corrected in time, and the pyrotechnic correction must be operated by an experienced master.
