Ship thick plate welding process

Abstract

The invention discloses a ship thick-plate welding technology. The ship thick-plate welding technology comprises the following steps that flat welding and balanced welding are adopted for ship thick plates; welding is conducted on a small part of the inner sides of the ship thick plates, and then balanced welding is conducted on the outer sides of the ship thick plates; welding is conducted on one part of the inner sides of the ship thick plates again, and carbon arc air gouging is conducted on the outer sides of the ship thick plates, wherein carbon arc air gouging is used for back chipping and beveling, and each air-gouged bevel needs to range from 50 degrees to 60 degrees; balanced welding is conducted on the outer sides of the ship thick plates and the inner sides of the ship thick plates after the outer sides of the ship thick plates are subjected to carbon arc air gouging, preheating is conducted firstly, the first layer is filled with metal, welding feet need to be small, and short-arc welding is adopted; temperature is measured through a point temperature gun before second welding is conducted; the inner sides of the ship thick plates are completely welded, wherein when the inner side is welded with one layer, the symmetrical outer side also needs to be welded with one layer, and the interlayer temperature is smaller than 100 DEG C or smaller than 250 DEG C; and the outer sides are completely welded, wherein after the last part of each inner side is completely welded, the corresponding outer side also needs to be completely welded, and the temperature is kept between 300 DEG C and 400 DEG C. Flat welding is adopted by the ship thick plates, the operation difficulty of flat welding positions is small for a welder, outer side stress can be better reduced by means of steel plate preheating and double-face balanced welding, and therefore the crack defect is effectively avoided.

Description

technical field [0001] The invention relates to a ship thick plate welding process, in particular to a ship thick plate flux cored arc welding (FCAW) welding process. Background technique [0002] High-efficiency and energy-saving rudder products for ships involve thick plate butt welding and T-welding. In the welding process, due to the thickness of the plate, the multi-layer welding method is often used, and the joint is very prone to crack defects. [0003] The following process improvements are made for the welding method of the cloud line: [0004] figure 1 , inside the cloud line is the T-shaped fillet weld between the outer plate and the inner plate, both of which are thick plates. Welding position: overhead welding; season: winter; no preheating. [0005] figure 2 It is a schematic diagram of a T-joint after welding in the prior art. [0006] In order: Figure 2a , weld the inner side first, Figure 2b , a small part of the outer side is welded, Figure 2c...

AI Technical Summary

Problems solved by technology

[0007] Quality problems caused by the above welding sequence: After ultrasonic flaw detection, it is found that the reflected wave of defects with the same depth in a long range is determined to be unqualified for this weld

Such defects are very severe in welds and have a high probability of fracture during product service

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