阅读说明：本技术 一种用于超导磁铁的加长型bladder气囊电子束焊接工艺 (Lengthened blade air bag electron beam welding process for superconducting magnet ) 是由 王旺林 姚俊杰 雷超 俞树孝 于 2021-07-13 设计创作，主要内容包括：本发明公开了一种用于超导磁铁的加长型bladder气囊电子束焊接工艺,包括以下步骤：1)下料；2)刻印找正线；3)焊接水接头；4)bladder焊接；5)切割bladder；6)气密性测试；本发明采用卧式装夹固定,便于找正对齐bladder上板和下板,大大降低了焊接找正难度,有助于提高焊接精度,保证焊接质量；通过本工艺制造bladder气囊一次合格率由不足10%提高至99%,大大提高产品的合格率。(The invention discloses an electron beam welding process of an elongated blade air bag for a superconducting magnet, which comprises the following steps of: 1) blanking; 2) marking alignment lines; 3) welding a water joint; 4) performing blader welding; 5) cutting the blader; 6) testing air tightness; the invention adopts horizontal clamping for fixation, is convenient for aligning the upper plate and the lower plate of the blade, greatly reduces the welding alignment difficulty, is beneficial to improving the welding precision and ensures the welding quality; the one-time qualification rate of the bladder air bag manufactured by the process is improved from less than 10% to 99%, and the qualification rate of products is greatly improved.)

1. An elongated blade air bag electron beam welding process for a superconducting magnet is characterized by comprising the following steps of:

1) blanking: selecting a stainless steel plate with a flat plate surface and no warping deformation, and cutting and blanking by using laser;

2) marking alignment lines: engraving an alignment line on the plate surface by using laser engraving, ensuring that the mark of the alignment line is clear and does not penetrate through the stainless steel plate; a plurality of alignment lines are engraved along the length direction, namely a first transverse alignment line, a second transverse alignment line … … and an Nth transverse alignment line; a plurality of alignment lines are engraved along the width direction, namely a first longitudinal alignment line, a second longitudinal alignment line … … and an Nth longitudinal alignment line;

the distance between the (N-1) th transverse alignment line and the Nth transverse alignment line of the first transverse alignment line and the second transverse alignment line, the third transverse alignment line and the fourth transverse alignment line … … is equal to the width of the cavity of the bladder airbag;

the distance between the (N-1) th longitudinal alignment line and the Nth longitudinal alignment line of the first longitudinal alignment line and the second longitudinal alignment line, the third longitudinal alignment line and the fourth longitudinal alignment line … … is equal to the length of the cavity of the bladder airbag;

3) welding a water joint: welding a water joint on the lower plate of the bladder air bag through electron beam welding;

4) welding a blader air bag: horizontally fixing the upper plate of the BLADER air bag prepared in the step 2) and the lower plate of the BLADER air bag prepared in the step 3) on a fixture, aligning the upper plate and the lower plate, fixing the upper plate and the lower plate, and performing one-step welding forming along a transverse alignment line and a longitudinal alignment line by using electron beam welding, wherein the welding parameters of the electron beam welding are as follows:

the accelerating voltage is 120-150 KV; the focusing current is 1800-2000 mA; defocusing current 10 mA; the beam intensity is 2.3-2.8 mA; the welding speed is 2400 mm/min; circular scanning is selected for deflection scanning, the scanning diameter is 0.2mm, and the scanning frequency is 800 Hz;

5) cutting a blader air bag: cutting between two adjacent transverse alignment lines and two adjacent longitudinal alignment lines by using laser cutting equipment to form a plurality of single piece of bladder air bags after cutting;

6) and (3) air tightness test: connecting the bladder airbag prepared in the step 5) to pressure measuring equipment, filling compressed air, testing the pressure at 40Mpa, keeping the pressure for 30min, and detecting the bladder airbag to be qualified if no leakage exists.

2. The electron beam welding process for the extended blade air bag of the superconducting magnet as claimed in claim 1, wherein the stainless steel plate in the step 1) is 304 stainless steel plate with a thickness of 0.3 mm.

3. The electron beam welding process for the elongated blade air bag of the superconducting magnet as claimed in claim 1, wherein the cut length of the stainless steel plate in the step 1) is 977 ± 0.15mm, and the width thereof is 429 ± 0.15 mm.

4. The electron beam welding process for the extended blade airbag of the superconducting magnet as claimed in claim 3, wherein the transverse alignment line in the step 2) comprises 6, the longitudinal alignment line comprises 2, and the step 5) cuts the blade airbag to form 3 blade airbags.

5. The electron beam welding process for the lengthened blade air bag of the superconducting magnet as claimed in claim 1, wherein the clamp in the step 4) comprises a base, a bottom plate, a long-side pressing plate, a short-side pressing plate and a water joint pressing plate; the base is fixed on the welding equipment, the bottom plate is rectangular and fixed on the base, the long-edge pressing plate is used for fixing the long edge of the blader air bag, the short-edge pressing plate is used for fixing the short edge of the blader air bag, and the water joint pressing plate is used for fixing a water joint; the long-edge pressing plate, the short-edge pressing plate and the water joint pressing plate are fixed through screws respectively.

6. The electron beam welding process of the elongated blade air bag for the superconducting magnet as claimed in claim 1, wherein the electron beam welding device is an SST electron beam welding machine.

Technical Field

The invention belongs to the technical field of welding processes, and particularly relates to an electron beam welding process for an elongated blade air bag of a superconducting magnet.

Background

The newly developed high-flux heavy ion accelerator device and the low-energy high-flux ion accelerator device both adopt the world first fourth generation electron cyclotron resonance ion source FECR which runs at 45 GHz. In order to meet the high performance requirement of the device, the recent physical research institute of the Chinese academy of sciences is developing a 45GHz high-charge state electron cyclotron resonance ion source based on the all-niobium three-tin stranded wire composite superconducting magnet, and the Fourth generation of the all-superconducting ECR ion source device (FECR for short) is firstly established internationally, which will challenge the bottleneck of the existing niobium three-tin superconducting magnet technology and the limit of generating the high-charge heavy ion beam by heating 45GHz high-power microwave plasma.

The coil of the FECR ion source magnet prototype consists of six niobium-tin six-pole coils and two niobium-tin solenoid coils, the six-pole coils are formed by winding a single niobium-tin superconducting wire, and the coils are sensitive to stress after reaction, so that in the design of the Mirror model, a Bladder & Key accurate prestress assembly technology derived from and developed in LBNL is selected and used based on a shell-based supporting structure, and the FRIB superconducting ion source magnet adopts a Bladder & Key prestress application technology in room-temperature assembly.

The blader air bag is composed of two stainless steel sheets with the thickness of 0.3mm and a water connector, the blader air bag is generally formed by laser welding or electron beam welding, the total length of the air bag is 952mm, the highest bearing pressure is 40Mpa, water does not flow out of the water connector, and the blader air bag is qualified because the blader air bag does not break. The Bladder air bag and the backing plate thereof are inserted into the magnet structure as a whole, and the plastic deformation of the Bladder air bag is correspondingly increased along with the increase of water pressure. Under the action of the blader air bag, a gap is opened at the position corresponding to the loading key, the loading key is taken out and stacked with a thin gasket with a certain thickness, the loading key with interference is inserted into the magnet structure, and finally the pressure of the blader air bag is released to be 0. The magnet mechanical structure realizes room-temperature pre-tightening on the coil through a loading key with interference magnitude.

The length of the original blade air bag is about 500mm, the original blade air bag is manufactured by laser welding, and the primary qualified rate of products is less than 10%. The length of the Blader air bag for the test is 1 time longer than that of the conventional Blader air bag, the welding process difficulty is greatly increased, the welding is difficult to realize in the conventional process, and the leakage risk is easily caused due to the leakage welding.

Disclosure of Invention

The invention provides an electron beam welding process for an elongated blade air bag of a superconducting magnet, and aims to solve the technical problem.

Therefore, the invention adopts the following technical scheme:

an elongated blade air bag electron beam welding process for a superconducting magnet comprises the following steps:

1) blanking: selecting a stainless steel plate with a flat plate surface and no warping deformation, and cutting and blanking by using laser;

2) marking alignment lines: engraving an alignment line on the plate surface by using laser engraving, ensuring that the mark of the alignment line is clear and does not penetrate through the stainless steel plate; a plurality of alignment lines are engraved along the length direction, namely a first transverse alignment line, a second transverse alignment line … … and an Nth transverse alignment line; a plurality of alignment lines are engraved along the width direction, namely a first longitudinal alignment line, a second longitudinal alignment line … … and an Nth longitudinal alignment line;

the distance between the (N-1) th transverse alignment line and the Nth transverse alignment line of the first transverse alignment line and the second transverse alignment line, the third transverse alignment line and the fourth transverse alignment line … … is equal to the width of the cavity of the bladder airbag;

the distance between the (N-1) th longitudinal alignment line and the Nth longitudinal alignment line of the first longitudinal alignment line and the second longitudinal alignment line, the third longitudinal alignment line and the fourth longitudinal alignment line … … is equal to the length of the cavity of the bladder airbag;

3) welding a water joint: welding a water joint on the lower plate of the bladder air bag through electron beam welding;

4) welding a blader air bag: horizontally fixing the upper plate of the BLADER air bag prepared in the step 2) and the lower plate of the BLADER air bag prepared in the step 3) on a fixture, aligning the upper plate and the lower plate, fixing the upper plate and the lower plate, and performing one-step welding forming along a transverse alignment line and a longitudinal alignment line by using electron beam welding, wherein the welding parameters of the electron beam welding are as follows:

the accelerating voltage is 120-150 KV; the focusing current is 1800-2000 mA; defocusing current 10 mA; the beam intensity is 2.3-2.8 mA; the welding speed is 2400 mm/min; circular scanning is selected for deflection scanning, the scanning diameter is 0.2mm, and the scanning frequency is 800 Hz;

5) cutting a blader air bag: cutting between two adjacent transverse alignment lines and two adjacent longitudinal alignment lines by using laser cutting equipment to form a plurality of single piece of bladder air bags after cutting;

6) and (3) air tightness test: connecting the bladder airbag prepared in the step 5) to pressure measuring equipment, filling compressed air, testing the pressure at 40Mpa, keeping the pressure for 30min, and detecting the bladder airbag to be qualified if no leakage exists.

Further, the stainless steel plate in the step 1) is a 304 stainless steel plate with the thickness of 0.3 mm.

Further, the cutting length of the stainless steel plate in the step 1) is 977 +/-0.15 mm, and the width of the stainless steel plate is 429 +/-0.15 mm.

Further, the number of the transverse alignment lines in the step 2) is 6, the number of the longitudinal alignment lines in the step 2) is 2, and 3 bladder air bags are formed after the bladder air bags are cut in the step 5).

Further, the clamp in the step 4) comprises a base, a bottom plate, a long-side pressing plate, a short-side pressing plate and a water joint pressing plate; the base is fixed on the welding equipment, the bottom plate is rectangular and fixed on the base, the long-edge pressing plate is used for fixing the long edge of the blader air bag, the short-edge pressing plate is used for fixing the short edge of the blader air bag, and the water joint pressing plate is used for fixing a water joint; the long-edge pressing plate, the short-edge pressing plate and the water joint pressing plate are fixed through screws respectively.

Furthermore, the electron beam welding equipment adopts an SST electron beam welding machine.

The invention has the beneficial effects that:

1. the stainless steel plate is fixed by horizontal clamping, so that the upper plate and the lower plate of the blader can be aligned conveniently, the welding alignment difficulty is reduced, the welding precision is improved, and the welding quality is ensured; the one-time qualification rate of the bladder air bag manufactured by the process is improved from less than 10% to 99%, and the qualification rate of products is greatly improved;

2. according to the invention, an electron beam single-side fusion welding process is adopted, and the single sides of the upper plate and the lower plate of the blader are fused and formed at one time, so that the welding strength is increased, the welding defect is avoided, the pressure resistance of the blader air bag is greatly improved, and the product quality is improved;

3. the invention can manufacture three bladder airbags by one-time clamping, the welding cost is reduced by 30 percent, the processing efficiency is improved by 2 times, and the invention has great improvement and promotion compared with the prior art.

Drawings

FIG. 1 is a schematic view of the alignment line of the bladder airbag of the present invention;

FIG. 2 is a schematic view of the clamping of the bladder airbag of the present invention;

FIG. 3 is a front and side view of a bladder airbag of the present invention;

in the figure: 1-base, 2-bottom plate, 3-long edge pressing plate, 4-short edge pressing plate, 5-water joint pressing plate, 6-screw, 7-doubler air bag and 8-water joint.

Detailed Description

The invention is further illustrated below:

an elongated blade air bag electron beam welding process for a superconducting magnet comprises the following steps:

1) blanking: a304 stainless steel plate with a flat plate surface and a thickness of 0.3mm and without warping deformation is selected, laser cutting blanking is used, the cutting length of the 304 stainless steel plate is 977 +/-0.15 mm, and the width of the 304 stainless steel plate is 429 +/-0.15 mm.

2) Marking alignment lines: engraving an alignment line on the plate surface by using laser engraving, ensuring that the mark of the alignment line is clear and does not penetrate through the stainless steel plate; a plurality of alignment lines are engraved along the length direction, namely a first transverse alignment line … … and a 6 th transverse alignment line … …; 2 alignment lines, namely a first longitudinal alignment line and a second longitudinal alignment line, are engraved along the width direction;

the distance between the first transverse alignment line and the second transverse alignment line, the distance between the third transverse alignment line and the fourth transverse alignment line, the distance between the fifth transverse alignment line and the sixth transverse alignment line are equal to the width of the cavity of the bladder airbag; the distance between the first longitudinal alignment line and the second longitudinal alignment line is equal to the length of the cavity of the bladder airbag.

3) Welding a water joint: the water joint 8 is welded to the lower plate of the bladder airbag by electron beam welding.

4) Welding a blader air bag: fixing the upper plate of the bladder air bag prepared in the step 2) and the lower plate of the bladder air bag prepared in the step 3) on a clamp, aligning the upper plate and the lower plate, and performing one-step welding forming along a transverse alignment line and a longitudinal alignment line by using electron beam welding, wherein an SST electron beam welding machine is selected as the electron beam welding equipment;

the clamp comprises a base 1, a bottom plate 2, a long-edge pressing plate 3, a short-edge pressing plate 4 and a water joint pressing plate 5, wherein the base 1 is fixed on welding equipment, the bottom plate 2 is rectangular and fixed on the base 1, the long-edge pressing plate 3 is used for fixing the long edge of a blader air bag 7, the short-edge pressing plate 4 is used for fixing the short edge of the blader air bag 7, and the water joint pressing plate 5 is used for fixing a water joint 8; long limit clamp plate 3, short side clamp plate 4 and water joint clamp plate 5 are fixed through screw 6 respectively, and the welding parameter that the electron beam welded is as follows:

the accelerating voltage is 120-150 KV; the focusing current is 1800-2000 mA; defocusing current 10 mA; the beam intensity is 2.3-2.8 mA; the welding speed is 2400 mm/min; circular scanning is selected for deflection scanning, the scanning diameter is 0.2mm, defocusing is increased by 10mA at the scanning frequency of 800Hz focusing current, the welding strength can be increased, and welding defects are avoided; by adopting circular oscillation welding, the generation of root tip defects can be inhibited, and the degassing rate of a welding seam molten pool is improved.

5) Cutting a blader air bag: a laser cutting device is used to cut between the two adjacent transverse alignment lines and the longitudinal alignment line, and a single piece of bladder balloon is formed after cutting (as shown in fig. 3).

6) And (3) air tightness test: connecting the bladder airbag prepared in the step 5) to pressure measuring equipment, filling compressed air, testing the pressure at 40Mpa, keeping the pressure for 30min, and detecting the bladder airbag to be qualified if no leakage exists.

It should be noted that the above are only some embodiments of the present invention, and it should be noted that, for those skilled in the art, many modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.