Swirl elimination device of steam-water separator of secondary reheating boiler

Abstract

The invention provides a swirl elimination device of a steam-water separator of a secondary reheating boiler. The swirl elimination device mainly solves the problem that the cracking phenomenon exists in a fillet weld seam between a water delivery pipe and a fixing steel plate of a swirl elimination device which is located in a steam-water separator and adopts a high-grade heat-resistant steel material. A sleeve (1) and one end of each connecting steel plate (2) are welded and fixed, and fixing steel plates (3) are correspondingly welded and fixed to the other ends of the four connecting steel plates (2). The fixing steel plates (3) are in an arc shape, are attached to the inner wall of a pipe connector (4) and support the inner wall of the pipe connector (4). The four connecting steel plates (2) are arranged on the sleeve (1) in the mode that the included angle between every two adjacent connecting steel plates (2) is 90 degrees. The four connecting steel plates (2) are welded and fixed in the mode of being perpendicular to the outer surface of the sleeve (1). Two to four stress release grooves are formed in the sleeve (1). The swirl elimination device has the advantages of being simple in design structure and easy to process and achieve. The mode that the stress release grooves are manually formed is ingeniously utilized to relieve the situation of the constraint stress concentration of the connector, and the cracking hidden danger is thoroughly eliminated.

Description

technical field [0001] The invention relates to a racemization device for a steam-water separator of a secondary reheating boiler. Background technique [0002] The steam-water separator is an important device for separating the boiler feed water and saturated steam during the boiler start-up process. The racemization device itself is a rigid welded structural part, which is welded together with the water delivery outlet pipe, and plays a role in guiding the boiler feed water and steam. Racemation and separation, its quality will directly affect the steam-water separation effect and the fluid impact and vibration of the lower water storage tank and are very important. [0003] Combined with the manufacturing experience of a secondary reheating boiler project, there is cracking in the fillet weld between the fixed steel plate and the water pipe in the derotation device in the steam-water separator made of high-grade heat-resistant steel, which cannot be eliminated and improve...

AI Technical Summary

Problems solved by technology

[0003] Combined with the manufacturing experience of a secondary reheating boiler project, there is cracking in the fillet weld between the fixed steel plate and the water pipe in the derotation device in the steam-water separator made of high-grade heat-resistant steel, which cannot be eliminated and improved even after PWHT after welding

[0004] The design of this device itself is a rigid and fixed welding structure; during manufacture, the fixed steel plate is pre-welded on the inner wall of the pipe (equivalent to the role of the pre-welded part), limited by the structure and shape, at this time the back of the single-sided fillet weld cannot Full penetration (that is, there is an opening effect), and when the racemization device is welded to the center of the fixed steel plate, the material itself requires a high heating temperature (≥200°C), and the molten pool continuously experiences high-temperature heat release during the welding process , heat dissipation process, but due to the large difference between the thickness of the fixed steel plate and the temperature rise and fall speed and the pipe joint, under the action of reciprocating thermal stress, a large tensile stress is formed on the fillet weld between the fixed steel plate and the pipe joint; The material of the rotating device (12Cr1MoV) is of high grade and complex in composition, and its welding with the water delivery outlet pipe (SA-182F91) is a fillet weld of dissimilar steel, and it is in a state where the structure is narrow and the space is closed, resulting in excessive restraint stress concentration , other welds are butt joints of the same steel material

When the local joint stress is concentrated and after welding, even after PWHT, it cannot be effectively released through deformation, and the restraint state still cannot be relieved and improved, and finally accumulates to a critical value, causing the fillet weld to fail

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