A pretreatment method for repair welding of austenitic stainless steel cast nuclear pump shell

Abstract

The invention provides a pretreatment method for repair welding of an austenitic stainless steel cast nuclear pump case. The pretreatment method comprises the following specific steps of: defect determining, defect coarse grinding, nondestructive flaw detection, symmetrical grinding, to-be-welded region accurate grinding and to-be-welded region cleaning, wherein during symmetrical grinding, positions which are symmetrical with defects with sizes greater than equal to 15 cm are ground at the same degree after the defects are completely ground off, so that welding slots which are symmetrical with the defects are formed; during to-be-welded region accurate grinding, front surfaces of the accurately ground welding slots are oval surfaces, and portions, which are 30 mm or less outside the borders, of the welding slots, are accurately ground; and during to-be-welded region cleaning, residual impurities and greasy dirt, which are 30 mm or less outside a to-be-welded region and the borders of the welding slots, caused by grinding and nondestructive flaw detection are eliminated. The method provided by the invention ensures that welding stress distribution is uniform after repair welding, and symmetrical participating stress can limit occurrence of deformation; and moreover, fewer impurity elements are introduced, and a repair welding region is free of welding defects, so that problems in repair welding are improved, occurrence of secondary defects is avoided, and the repair welding success rate of the austenitic stainless steel cast nuclear pump case is increased.

Description

technical field [0001] The invention relates to the technical field of repairing defects of nuclear pump casting shells, in particular to a pretreatment method for repair welding of austenitic stainless steel casting nuclear pump shells. Background technique [0002] The austenitic stainless steel casting nuclear pump shell is bulky and complex in structure, and there may be casting defects such as cracks, sand holes, inclusions, shrinkage cavities, and looseness, so repair welding of defective parts will be inevitable; a scientific, strict and reasonable An effective pre-treatment method for repair welding of austenitic stainless steel casting nuclear pump shell is an important basis for good repair welding of casting defects. [0003] The traditional pre-weld treatment for repair welding of this type of austenitic stainless steel cast nuclear pump shell is not comprehensive enough to eliminate defects such as segregation, lack of fusion, weld impermeability, and microcrack...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the above technical problems, to provide a pretreatment method for repair welding of austenitic stainless steel cast nuclear pump casing, which can improve the austenitic stainless steel cast nuclear pump casing caused by unreasonable pretreatment before repair welding After body repair welding, the stress direction and distribution are uneven, and more impurity elements are introduced, especially when there are defects exceeding 15cm in size.

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