CN115727210A

CN115727210A - Forming method for elbow joint on middle header of waste heat boiler

Info

Publication number: CN115727210A
Application number: CN202211577583.5A
Authority: CN
Inventors: 张丽华; 刘林生; 支晨
Original assignee: Wuxi Huaguang Environment and Energy Group Co Ltd
Current assignee: Wuxi Huaguang Environment and Energy Group Co Ltd
Priority date: 2022-12-09
Filing date: 2022-12-09
Publication date: 2023-03-03

Abstract

The invention relates to the technical field of waste heat boiler module manufacturing, in particular to a method for forming a bent pipe joint on a waste heat boiler header, which can ensure accurate size and improve product quality, and is specifically operated to reduce the length of a bending section on the bent pipe joint, reduce the designed length to the minimum standard length and increase or not change the angle of a bent pipe.

Description

Forming method for elbow joint on middle header of waste heat boiler

Technical Field

The invention relates to the technical field of waste heat boiler module manufacturing, in particular to a method for forming an upper elbow joint of a middle header of a waste heat boiler.

Background

The header is an important part in the exhaust-heat boiler, as required, the header surface need be connected in bank's pipe, connects through elbow fitting between pipe and the header, and elbow fitting's shaping step is as follows: blanking → field lofting in workshop → bending pipe → measuring wall thickness at elbow → batch bending after qualified. After the elbow joint and the header are welded, the distance between adjacent pipes needs to be measured, a process plate with a hole is generally adopted, if the pipe joint can smoothly penetrate through the hole, the pipe joint meets the size requirement, in the actual assembly process, after the elbow joint is welded on the header, the deviation of the size is found by utilizing the process plate after detection, the elbow joint with the diameter of 57 multiplied by 5 and the material of 12Cr1MoVG/GB5310 is taken as an example, the elbow angle is 12.5 degrees, the actual measurement of the distance between the left elbow joint and the right elbow joint is close to 123mm, the design drawing is 113mm, the deviation of about 10mm exists, after the inspection and the physical test of a pipe bending die in a workshop, a workshop master lays out samples and bends the pipes according to the drawing requirement, the size is not problematic, and after the analysis, the reverse deformation is generated after the bending of the elbow, and an effective solution is not available.

Disclosure of Invention

The invention provides a method for forming a bent pipe joint on a header of a waste heat boiler, which can ensure accurate size and improve product quality, and aims to solve the problem that the size is inaccurate after welding due to the fact that reverse deformation occurs after an existing bent pipe.

The technical scheme is as follows: a method for forming a bent pipe joint on a waste heat boiler header is characterized in that the length of a bending section on the bent pipe joint is reduced, the designed length is reduced to the minimum standard length, and the angle of a bent pipe is increased or not changed.

After the bent pipe joint is adopted, the length of the bending section on the bent pipe joint is reduced, the stress influence is reduced, and the anti-deformation amount can be reduced, so that the bent pipe joint is welded on the header, the design size of the pipe interval can be ensured, and the product quality is improved.

Drawings

FIG. 1 is a schematic diagram showing a comparison between a design drawing of a conventional product and actual products made of different materials;

FIG. 2 is a schematic view of the product after processing by the method of the present invention.

Detailed Description

Referring to fig. 1 and 2, the method for forming the elbow joint on the waste heat boiler header reduces the length of the bending section on the elbow joint, adopts phi 57 multiplied by 5 and is made of 12Cr1MoVG/GB5310, reduces the original design length of 85mm to the minimum standard length of 70mm, enables the original design length to meet the standard TSG11-2020 of boiler safety technical code, and ensures that the angle of the elbow is not changed and is still 12.5 degrees.

In actual production, the material of the elbow joint plays the same role except that the dimensional change affects the reverse deformation amount, and as shown in fig. 1, the material of 12Cr1MoVG/GB5310 has the largest reverse deformation amount, and the SA213M T has the smallest influence on the material. In practical application, however, 12Cr1MoVG/GB5310 and 12Cr1MoVG/GB5310 belong to low-alloy hot-strength steel which are comprehensively considered and selected, so that the requirements of high-temperature working on parts are met, and a series of steel with high endurance strength and good oxidation resistance are established on the basis of low-carbon alloy steel. Chromium is added into carbon steel to form alloy ferrite, so that the high-temperature strength of the steel can be improved, and the high-temperature oxidation resistance and corrosion resistance of the steel can be improved.

At the initial stage of design, because the size deviation that is caused by the anti-deformation amount, the first consideration is to change the return bend angle, following is the experimental result, reduce 12.5 on the design drawing to 10 °, the section length that starts to bend is unchangeable, still be 85mm, weld on the header after the processing, through actually measuring the pipe spacing and be 120mm, change not big, with design value 113mm deviation too big, follow-up through the continuous research innovation of designer, change angle change direction, increase return bend angle, and to the length reduction of the section that starts to bend, pipe spacing L design value is 45.1mm, obtain following data through multiunit test:

it can be seen that the appropriate increase angle can be similar to the design value, or not.

Comprehensively considering that the angles of the 12Cr1MoVG/GB5310 bent pipe are 13.5 degrees and 12.5 degrees, and the length of the bending section is 70mm, so that the design requirement of a drawing can be met.

1300 tubes are produced in batches by a company, so that the production is realized, the counter-work condition is avoided, the assembly and welding are convenient, and the size is accurate and qualified. By adopting the structure of the invention, the generation of inferior-quality products is greatly reduced, and the working efficiency is increased.

Claims

1. A method for forming a bent pipe joint on a waste heat boiler header is characterized in that the length of a bending section on the bent pipe joint is reduced, the designed length is reduced to the minimum standard length, and the angle of a bent pipe is increased or not changed.