阅读说明：本技术 一种消除焊缝气胀缺陷的端塞 (End plug for eliminating welding seam gas expansion defect ) 是由 鲁杭杭 蔡振方 皇泽中 温丰 张洲峰 刘斌 邢文军 郭庆祥 于 2020-04-10 设计创作，主要内容包括：本发明涉及核燃料元件制造技术领域,具体公开了一种消除焊缝气胀缺陷的端塞,端塞插入包壳管内的配合段为圆柱体结构,其余部分加工为锥面；在端塞与包壳管的配合段上加工有导气槽,作为焊接过程中产生的气体排入包壳管内腔的通道。本发明端塞结构能够有效消除燃料棒端塞与包壳管焊缝中的气胀缺陷,将焊缝中的气胀缺陷率降到3％以下,提高了焊缝成品率。(The invention relates to the technical field of nuclear fuel element manufacturing, and particularly discloses an end plug for eliminating the defect of welding seam gas expansion, wherein a matching section of the end plug inserted into a cladding tube is of a cylindrical structure, and the rest part of the end plug is processed into a conical surface; and a gas guide groove is processed on the matching section of the end plug and the cladding tube and is used as a channel for discharging gas generated in the welding process into the inner cavity of the cladding tube. The end plug structure can effectively eliminate the gas expansion defect in the welding seam of the fuel rod end plug and the cladding tube, reduce the gas expansion defect rate in the welding seam to be below 3 percent, and improve the yield of the welding seam.)

1. An end plug for eliminating weld seam ballooning defects is characterized in that: the matching section of the end plug (3) inserted into the cladding tube (2) is of a cylindrical structure, and the rest part of the end plug is processed into a conical surface.

2. An end plug for eliminating weld ballooning defects as set forth in claim 1, wherein: the length of the matched section of the end plug (3) and the cladding tube (2) is 0.4-0.9 mm.

3. An end plug for eliminating weld ballooning defects as set forth in claim 2, wherein: the taper of the conical surface is more than or equal to 1 degree.

4. An end plug for eliminating weld ballooning defects as set forth in claim 3, wherein: the total length of the end plug (3) inserted into the cladding tube (2) is more than 1.5 mm.

5. An end plug for eliminating weld ballooning defects as set forth in claim 1, wherein: and a gas guide groove (5) is processed on the matching section of the end plug (3) and the cladding tube (2) and is used as a channel for discharging gas generated in the welding process into the inner cavity (7) of the cladding tube.

6. An end plug for eliminating weld ballooning defects as recited in claim 5, wherein: the air guide groove (5) is spirally and circularly arranged along the circumferential direction of the end plug (3).

7. An end plug for eliminating weld ballooning defects as recited in claim 6, wherein: the depth of the air guide groove (5) is 0.005-0.015 mm, and the width is 0.1-0.2 mm.

8. An end plug for eliminating weld ballooning defects as recited in claim 7, wherein: the air guide grooves (5) are arranged with 2-9 circles at equal intervals.

9. An end plug for eliminating weld ballooning defects as set forth in claim 1, wherein: the total length of the end plug (3) inserted into the cladding tube (2) is more than 1.5mm, the length of a matching section of the end plug (3) and the cladding tube (2) is 0.4-0.9 mm, and the taper of the conical surface is more than or equal to 1 degree;

and a gas guide groove (5) is processed on the matching section of the end plug (3) and the cladding tube (2) and is used as a channel for discharging gas generated in the welding process into the inner cavity (7) of the cladding tube.

10. An end plug for eliminating weld ballooning defects as recited in claim 9, wherein: the air guide groove (5) is spirally and circularly arranged along the circumferential direction of the end plug (3).

Technical Field

The invention belongs to the technical field of nuclear fuel element manufacturing, and particularly relates to an end plug for eliminating a weld joint gas expansion defect.

Background

Welding of fuel rod end plugs to cladding tubes is an essential link in nuclear fuel element manufacture. As shown in FIGS. 1 to 3, the length of the matching section of the currently used end plug and the cladding tube is larger than 1.5mm, so that the weld seam ballooning defect is easily generated in the welding process of the end plug and the cladding tube. The existence of the defect can reduce the effective section of the welding seam, reduce the weld penetration, reduce the mechanical strength of the welding joint, seriously affect the air tightness and cause the leakage of the fuel rod.

The current method for eliminating the weld joint ballooning defect is as follows: firstly, the end plugs and the pipe orifices are strictly cleaned before welding; secondly, enough plug pressing force is adopted; and thirdly, selecting proper welding process parameters. However, even with the above method, the defect rate of the ballooning in the weld can still reach more than 20%, resulting in a large number of defective products.

Therefore, there is a need to solve the above problems by designing a new end plug structure that eliminates the ballooning defect.

Disclosure of Invention

The invention aims to provide an end plug for eliminating the defect of welding seam gas expansion so as to eliminate the defect of gas expansion in the welding seam of a fuel rod end plug and a cladding tube.

The technical scheme of the invention is as follows:

the fitting section of the end plug inserted into the cladding tube is of a cylindrical structure, and the rest part of the end plug is processed into a conical surface.

The length of the matched section of the end plug and the cladding tube is 0.4-0.9 mm.

The taper of the conical surface is more than or equal to 1 degree.

The total length of the end plug inserted into the cladding tube is > 1.5 mm.

And a gas guide groove is processed on the matching section of the end plug and the cladding tube and is used as a channel for discharging gas generated in the welding process into the inner cavity of the cladding tube.

The air guide grooves are spirally and circularly arranged along the circumferential direction of the end plug.

The depth of the air guide groove is 0.005-0.015 mm, and the width of the air guide groove is 0.1-0.2 mm.

The air guide grooves are arranged with 2-9 circles at equal intervals.

The total length of the end plug inserted into the cladding tube is larger than 1.5mm, the length of a matching section of the end plug and the cladding tube is 0.4-0.9 mm, and the taper of the conical surface is larger than or equal to 1 degree;

and a gas guide groove is processed on the matching section of the end plug and the cladding tube and is used as a channel for discharging gas generated in the welding process into the inner cavity of the cladding tube.

The air guide grooves are spirally and circularly arranged along the circumferential direction of the end plug.

The invention has the following remarkable effects:

(1) according to the invention, the matching length of the end plug and the cladding tube is reduced to 0.4-0.9 mm, so that gas generated in the welding process is easier to discharge into the inner cavity of the cladding tube, and the occurrence of an air inflation defect is avoided.

(2) According to the invention, the air guide groove structure is designed on the matching length of the end plug and the cladding tube, so that gas generated in the welding process is discharged into the inner cavity of the cladding tube to form a channel, and the welding gas expansion defect is better avoided.

(3) The end plug structure can effectively eliminate the gas expansion defect in the welding seam of the fuel rod end plug and the cladding tube, reduce the gas expansion defect rate in the welding seam to be below 3 percent, and improve the yield of the welding seam.

Drawings

FIG. 1 is a schematic view of an original design end plug;

FIG. 2 is a cladding tube schematic view;

FIG. 3 is a schematic view of the assembly of an end plug and cladding tube of the original design;

figure 4 is a schematic view of an end plug according to the invention;

FIG. 5 is an enlarged view at I of FIG. 4;

fig. 6 is a schematic view of an end plug and cladding tube assembly of the present invention.

In the figure: 1. the method comprises the steps of originally designing an end plug, 2. a cladding tube, 3. an end plug, 4. an air inflation defect, 5. an air guide groove, 6. a welding line and 7. an inner cavity of the cladding tube.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

In the end plug for eliminating the weld seam ballooning defect shown in fig. 4-6, the total length of the end plug 3 inserted into the cladding tube 2 is more than 1.5 mm; the matching section of the end plug 3 and the cladding tube 2 is of a cylindrical structure, the length is 0.4-0.9 mm, the matching length is reduced compared with the prior art, and gas generated in the welding process is easy to discharge into the inner cavity of the cladding tube; the other part is processed into a conical surface, the taper is more than or equal to 1 degree, so that the gap between the end plug 3 and the cladding tube 2 is gradually enlarged, and gas generated in the welding process is conveniently and smoothly discharged into the inner cavity 7 of the cladding tube.

And a spirally-surrounded gas guide groove 5 is processed on the matching section of the end plug 3 and the cladding tube 2 along the circumferential direction of the end plug 3 and is used as a channel for discharging gas generated in the welding process into an inner cavity 7 of the cladding tube, so that the welding gas expansion defect is avoided.

The air guide grooves 5 are arranged with 2-9 circles at equal intervals, the depth is 0.005-0.015 mm, and the width is 0.1-0.2 mm.