Submerged-arc welding technology for 304L stainless steel thick plates

Abstract

The invention provides a submerged-arc welding technology for 304L stainless steel thick plates. The submerged-arc welding technology comprises the steps that firstly, welding grooves are machined; secondly, preparation before welding is carried out; thirdly, welding is carried out, wherein a welding trolley is adopted for carrying out priming coat welding on the grooves in the front surfaces, andthen front surface submerged-arc welding is carried out after priming coat welding is completed; the two 304L stainless steel thick plates with the front surface submerged-arc welding completed are turned over, and then plasma carbon arc air gouging back chipping is carried out on the grooves in the back surfaces; and the welding trolley is adopted for carrying out back surface submerged-arc welding on the back surface grooves with back chipping completed; and fourthly, postweld treatment is carried out. According to the submerged-arc welding technology for the 304L stainless steel thick plates, according to the components and the performance of 304L stainless steel, the dimensions of the welding grooves and the welding technology are optimized, and welding materials are reasonably matched to ensure the quality of welded joints, defects such as shrinkage distortion, slag inclusion, air holes and bulky crystal particles are avoided, good mechanical performance at minus 20 DEG C is achieved, and good low temperature impact toughness is achieved especially.

Description

technical field [0001] The invention belongs to the technical field of welding, and in particular relates to a submerged arc welding process for a 304L stainless steel thick plate used in the shipbuilding process. Background technique [0002] At present, in order to adapt to the harsh marine working environment, the inner bottom plates of some ultra-large container ships are welded with 304L stainless steel plates with a thickness of 45mm to meet the strength, stiffness, stability and low-temperature impact performance of large container ships such as double fuel tank areas. Corrosion resistance requirements. 304L stainless steel belongs to austenitic stainless steel, which has the characteristics of small thermal conductivity, low melting point, and large linear expansion coefficient. During welding, if the weld metal stays at high temperature for a long time, it is easy to form a coarse as-cast structure (that is, coarse grains) ), resulting in greater stress and deforma...

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Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a submerged arc welding process for 304L stainless steel thick plates, to optimize the X-shaped groove size for the specific composition range and technical conditions of 304L stainless steel thick plates, Reasonably match welding consumables and optimize welding process parameters to solve problems such as coarse grains and intergranular corrosion caused by welding deformation and large welding heat input, improve the quality of welded joints, ensure that they have good mechanical properties, and ensure that the flaw detection is qualified at one time

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