Repair welding method of austenite stainless steel casted nuclear pump shell

Abstract

The invention provides a repair welding method of an austenite stainless steel casted nuclear pump shell. The repair welding method comprises the specific steps of defect detection and treatment; welding slot treatment; welding rod treatment: baking a welding rod at the temperature of 150 DEG C, and keeping the temperature for standby application; preheating of a to-be-welded zone; repair welding of the to-be-welded zone: carrying out repair welding layer by layer and pass by pass; confirmation of the repair welding effect: carrying out flaw detection on a repair welding zone of a pump body through rays, confirming the repair welding effect, and guaranteeing that the repair welding zone does not have weld defects; and solution treatment: carrying out solution treatment on workpieces subjected to repair welding. According to the repair welding method, samples do not have relatively large welding deformation through adoption of symmetrical arc-shaped welding slots, pre-welding preheating and postwelding thermal treatment; stress after repair welding is reasonably distributed through requirements on shape and radian of the welding slots and pre-welding thermal treatment; the content of impurity elements can be controlled and weld joints do not have obvious defects through surface roughness control and cleaning for the welding slots, and baking treatment for the welding rod; and intergranular corrosion resistance of austenite of the repair welding zone of a nuclear pump can be improved through postwelding solution treatment for a corresponding zone of the nuclear pump body.

Description

technical field [0001] The invention relates to a defect repair of a nuclear pump casting shell, mainly a welding process for remediating the surface defect of the casting shell. Background technique [0002] The nuclear pump is the "heart" of the operation of the nuclear power plant. It is bulky and complex in structure, such as figure 1 As shown, it is generally done by casting. Usually, casting will produce defects such as cracks, sand holes, inclusions, shrinkage cavities, and porosity. Repair welding of defects after casting is inevitable. However, the cast austenitic stainless steel nuclear pump is bulky and complex in structure. The method is also changeable. What the present invention relates to is the repair welding repair of the shell defects of the first-stage nuclear pump formed by casting SA-351 CF8A austenitic stainless steel. SA-351CF8A austenitic stainless steel is an austenitic type under the ASME standard, also known as 304 austenitic stainless steel, wh...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a repair welding method for austenitic stainless steel casting nuclear pump casing, which can improve the direction and uneven distribution of welding stress, control impurity elements, and prevent porosity, segregation, lack of fusion, and welding in the repair welding area. Welding defects such as impermeability and microcracks, and improving the intergranular corrosion resistance of austenite in the repair welding area of ​​nuclear pumps

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