CN114749754A - Vacuum brazing evaluation test piece for vacuum brazing process evaluation - Google Patents

Abstract

In order to solve the technical problems that a test piece used in the conventional vacuum brazing process assessment does not meet the requirements of a full-size test piece and the brazing gap setting cannot simulate actual production, the embodiment of the invention provides a vacuum brazing assessment test piece for the vacuum brazing process assessment, which comprises the following steps: a second workpiece having a strip-like structure; a first passage penetrating the second workpiece in a length direction of the second workpiece; the first workpiece is provided with a cavity, and the cavity is used for being matched with the strip-shaped structure of the second workpiece to form an overlap brazing seam and a butt brazing seam; wherein, the lap brazing seam is communicated with the butt brazing seam; the second channel penetrates through the first workpiece along the length direction of the first workpiece and is communicated with the first channel to form a through hole; and the brazing filler metal is arranged in the brazing filler metal groove and is used for filling the brazing filler metal into the lap joint brazing seam and the butt joint brazing seam through the brazing filler metal groove. The embodiment of the invention avoids the defects that the test piece used in the conventional vacuum brazing process evaluation does not meet the requirements of a full-size test sample and the brazing gap setting cannot simulate the actual production.

Description

A vacuum brazing qualification test piece for vacuum brazing process qualification

technical field

The invention relates to a vacuum brazing evaluation test piece used for vacuum brazing process evaluation.

Background technique

The low temperature superconducting magnet system consists of superconducting coil, cladding, superconducting coil support and cooling system. The cooling system is the key system to maintain the thermal stability of superconducting magnets. The cooling system contains a large number of stainless steel and copper alloy components; the size, structure and joints are complex and varied, and the brazed joints are of high quality. According to the relevant requirements of welding quality management, brazing process evaluation needs to be carried out before mass production to verify the reliability of the brazed joint in service in the liquid helium temperature region.

However, after searching, it was found that all the test pieces recommended by the existing two standards on brazing, such as EN13134 vacuum brazing process evaluation and ASME volume IX welding and brazing process evaluation, have the following two deficiencies: 1) Due to There is a huge difference in thermal properties. The stainless steel copper heterometallic joint will generate huge thermal stress in the liquid helium temperature region. Therefore, a full-scale sample that can test its mechanical properties in the liquid helium temperature region is required; In some standards, only one brazing gap can be considered for all joints, and there is a big deviation from the actual situation that the brazing gap of a joint is in a jumping range in the actual brazing production process.

SUMMARY OF THE INVENTION

In order to solve the technical problem that the test piece used in the existing vacuum brazing process evaluation does not meet the requirements of the full-size sample and the brazing gap setting cannot simulate actual production, the embodiment of the present invention provides a vacuum brazing process evaluation method. Vacuum brazing qualification test pieces.

The embodiment of the present invention is realized by the following technical solutions:

In a first aspect, an embodiment of the present invention provides a vacuum brazing evaluation test piece for vacuum brazing process evaluation, including:

The second workpiece has an elongated structure;

The first channel penetrates the second workpiece along the length direction of the second workpiece;

The first workpiece is provided with a cavity, and the cavity is used for cooperating with the elongated structure of the second workpiece to form an overlap brazing seam and a butt brazing seam; wherein, the overlapping brazing seam and the butt welding seam are communicated;

a second channel, penetrating the first workpiece along the length direction of the first workpiece, and communicating with the first channel to form a through hole;

and a brazing filler metal inlet groove, which is arranged on the first workpiece and is used for filling brazing filler metal into the lap brazing seam and the butt brazing seam through the brazing filler metal inlet groove.

Further, the central axis of the first channel and the second channel coincide;

The solder filling groove includes a first filling groove for filling filamentous or paste-like solder that doubles as a vent hole and a second filling groove for filling a foil or filamentary solder that doubles as a vent hole. ;

The first filling groove penetrates the first workpiece along the length direction of the outer side wall of the first workpiece and communicates with the lap joint; the second filling groove penetrates the first workpiece along the length direction of the outer side wall of the first workpiece And connected with the lap brazing seam.

Further, the lap brazing seam is arranged along the length direction of the second workpiece and the length direction of the first workpiece, and is arranged between the outer surface of the second workpiece and the inner wall of the cavity of the first workpiece.

Further, the butt brazing seam is arranged along the width direction of the second workpiece and the width direction of the first workpiece, and is arranged between the end of the second workpiece extending into the cavity and the inner bottom wall of the cavity of the first workpiece. ; The lap joint brazing seam is an annular structure.

Further, the cavity is matched with the elongated structure of the second workpiece by means of splicing, overlapping or butt joint.

Further, the elongated structure includes rod shape, tube shape or plate shape.

Further, the solder in the overlap solder joint is in the form of wire, powder or foil; the solder in the butt solder joint is in the form of wire, powder or foil.

Further, the width of the butt brazing seam is greater than the width of the overlapping brazing seam.

Further, the second workpiece and the first workpiece are respectively made of copper and stainless steel.

Further, the gap width of the overlapping brazing seam is 0.02-0.08 mm; the deviation of the gap width of the overlapping brazing seam is not more than 0.01 mm; the gap width of the butt brazing seam is 0.02-0.08 mm; The deviation of the gap width of the slit is not more than 0.01mm.

Compared with the prior art, the embodiment of the present invention has the following advantages and beneficial effects:

A vacuum brazing evaluation test piece for vacuum brazing process evaluation according to an embodiment of the present invention, through the brazing filler metal entering the groove, the second workpiece, the first workpiece, the first channel, the second channel, the lap brazing seam and the butt joint The brazing seam avoids the defects that the test piece used in the existing vacuum brazing process evaluation does not meet the requirements of the full-size sample and the brazing gap setting cannot simulate the actual production.

Description of drawings

In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only illustrate some embodiments of the present invention, Therefore, it should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can also be obtained from these drawings without any creative effort.

Figure 1 is a schematic diagram of the structure of the vacuum brazing evaluation test piece used for vacuum brazing process evaluation.

Figure 2 is a schematic cross-sectional structural diagram of a vacuum brazing evaluation test piece used for vacuum brazing process evaluation.

FIG. 3 is a schematic structural diagram of a superconducting heat shielding member.

FIG. 4 is a schematic structural diagram of the vacuum brazing evaluation test piece of Example 1. FIG.

The marks in the attached drawings and the corresponding parts names:

1-First workpiece, 2-Second workpiece, 3-Overlap brazing seam, 4-Butt brazing seam, 5-First filling slot, 6-Second filling slot, 7-Through hole, 8-Superconducting Heat shield parts, 9-Copper alloy & stainless steel composite pipe, 10-CuCrZr pipe, 11-Stainless steel pipe, 12-Brazing gap, 13-Assembly gap.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. as a limitation of the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail in order to avoid obscuring the present invention.

Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in the present invention in at least one embodiment. Thus, appearances of the phrases "one embodiment," "an embodiment," "one example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combination and/or subcombination in one or more embodiments or examples. Furthermore, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and that the drawings are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of the present invention, the terms "front", "rear", "left", "right", "top", "bottom", "vertical", "horizontal", "high", "low", "inside" The orientation or positional relationship indicated by ", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific Orientation, construction and operation in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present invention.

Example

In order to solve the technical problem that the test piece used in the process evaluation of the existing vacuum brazing does not meet the requirements of the full-size sample and the brazing gap setting cannot simulate the actual production, the embodiment of the present invention provides a vacuum brazing method. The vacuum brazing evaluation test piece for welding process evaluation, as shown in Figs. 1 and 2, includes: a second workpiece 2, which has a long strip structure; a first channel, which penetrates the second workpiece along the length direction of the second workpiece; The workpiece 1 is provided with a cavity, and the cavity is used to cooperate with the elongated structure of the second workpiece to form an overlap brazing seam and a butt brazing seam; wherein, the overlapping brazing seam 3 and the butt welding seam 4 communicate with each other. The second channel, which runs through the first workpiece along the length direction of the first workpiece, is used to communicate with the first channel to form a through hole 7; Fill the lap and butt joints with solder.

Therefore, the embodiment of the present invention avoids the test used in the process evaluation of the existing vacuum brazing through the brazing material entering the groove, the second workpiece, the first workpiece, the first passage, the second passage, the lap brazing seam and the butt brazing seam. The parts do not meet the requirements of full-size specimens and the brazing gap setting cannot simulate the actual production defects.

Referring to Figure 2, the vacuum brazing evaluation test piece includes a first workpiece 1 and a second workpiece 2; in order to facilitate the evaluation of the vacuum brazing process of the lap joint in the liquid helium temperature region in the fusion reactor, the first workpiece and the second workpiece are The material used for the workpiece can be adjusted according to the actual situation. The first workpiece and the second workpiece can be made of the same material or different materials. For example, both the first workpiece and the second workpiece can be made of stainless steel; the first workpiece and the second workpiece can also be made of stainless steel and copper respectively; it can be determined according to the material used for the lap joint and the vacuum brazing process. Certainly.

The upper part of the second workpiece 2 is a long strip structure, which can extend into the cavity of the first workpiece to form overlapping brazing seams and butt welding seams; the shape and size of the long strip structure on the upper part of the second workpiece 2 can be adjusted according to actual needs. The shape of the cavity of the first workpiece 1 is adapted to the actual needs, such as cylindrical, plate-shaped, etc. Referring to Figure 2, the lap brazing seam is the gap between the outer periphery of the elongated structure and the cavity of the first workpiece; The butt brazing seam is the gap between the upper end of the second workpiece 2 and the bottom of the cavity; the widths of the overlapping brazing seam and the butt brazing seam can be adjusted by adjusting the relative position and size of the first workpiece in the cavity.

The overlapping brazing seam and the butt welding seam are connected to each other; in order to facilitate filling of the brazing filler metal into the overlapping brazing seam and the butt welding seam, the second workpiece 2 is provided with a brazing filler metal slot. Solder can be fed into lap joints and butt joints through solder feed slots.

Optionally, the central axis of the first channel and the second channel are coincident; with reference to FIG. 2 , when the central axis of the first channel and the central axis of the second channel are coincident, the first channel and the second channel form a The central axis is the through hole of the central line. The through hole 7 formed by the first channel and the second channel can be used for the low temperature pipeline to pass through the vacuum brazing evaluation test piece to simulate the low temperature pipeline joint, so that the vacuum brazing evaluation test piece is in a preset low temperature environment for mechanical properties. and other tests.

Optionally, the overlapping brazing seam is arranged along the length direction of the second workpiece and the length direction of the first workpiece, and is arranged between the outer surface of the second workpiece and the inner wall of the cavity of the first workpiece; the butt brazing seam is along the length direction of the first workpiece. The width direction of the second workpiece and the width direction of the first workpiece are arranged between the end of the second workpiece extending into the cavity and the inner bottom wall of the cavity of the first workpiece; the lap brazing seam is annular structure.

Referring to FIG. 2 , the lap brazing seam 3 is arranged from top to bottom along the length direction of the first workpiece and the second workpiece. Between the left or right inner walls; the butt brazing seam 4 is arranged between the upper end of the second workpiece and the bottom of the cavity; thus, the lap brazing seam and the butt brazing seam can extend into the cavity of the first workpiece by adjusting the second workpiece. The shape and position of the elongated structure in the cavity, thereby adjusting the size of the lap joint and the butt joint.

Optionally, the overlapping brazing seam may be a circular or elliptical annular structure or a polygonal annular structure; the overlapping brazing seam is communicated with the butt welding seam to facilitate the feeding of the brazing filler metal; in order to facilitate the entering of the brazing filler metal, the second workpiece is provided with Solder into the groove.

The solder filling groove includes a first filling groove 5 for filling filamentous or paste-like solder that doubles as an air vent and a second filling groove 5 for filling foil or filamentary solder that doubles as an air vent. Slot 6; the first filling slot 5 penetrates the first workpiece along the length direction of the outer side wall of the first workpiece and communicates with the lap brazing seam; the second filling slot 6 is along the length of the outer side wall of the first workpiece The direction runs through the first workpiece and communicates with the lap braze.

In order to facilitate the brazing filler metal of various shapes and forms to enter the lap brazing seam and the butt brazing seam through the brazing filler metal slot, the inner wall of the second workpiece is provided with a first filling groove 5 and a second filling groove which communicate with the lap brazing seam. Into the groove 6; as shown in Figure 2, the first filling groove longitudinally along the left end of the first workpiece near the bottom of the cavity penetrates the first workpiece and is connected with the lap brazing seam; the second filling groove longitudinally along the second One end of the right side of the workpiece close to the bottom of the cavity penetrates the first workpiece and communicates with the lap brazing seam.

The first filling groove and the second filling groove also serve as exhaust holes; when the solder is fed into the first filling groove and the second filling groove, gas will be generated; the generated gas will flow from the first filling groove and the second filling groove. 2. Fill the tank and discharge. Therefore, the first filling groove and the second filling groove also function as exhaust holes.

In order to adapt to the feeding of different forms of brazing material, the first filling groove and the second filling groove are respectively made into shapes suitable for the entering of different states or shapes of the brazing material. Optionally, the solder in the overlap solder joint is in the form of wire, powder or foil; the solder in the butt solder joint is in the form of wire, powder or foil.

Further, the cavity is matched with the elongated structure of the second workpiece by means of splicing, overlapping or butt joint. The elongated structure includes rod-shaped, tubular-shaped or plate-shaped.

Further, the width of the butt brazing seam is greater than the width of the overlapping brazing seam.

Further, the second workpiece and the first workpiece are respectively made of copper and stainless steel.

Further, the gap width of the overlapping brazing seam is 0.02-0.08 mm; the deviation of the gap width of the overlapping brazing seam is not more than 0.01 mm; the gap width of the butt brazing seam is 0.02-0.08 mm; The deviation of the gap width of the slit is not more than 0.01mm.

Therefore, the evaluation test piece can be applied to the evaluation of the vacuum brazing process of stainless steel & copper brazing in the liquid helium temperature region in the fusion reactor. Brazing process qualification for brazing filler metal forms (wire, powder, foil), various specimen forms (rod, tube, plate). Compared with the test piece forms recommended by other existing standards, this test piece form can not only accurately cover the range of important process elements such as the assembly gap and brazing gap of the brazed parts. And the test piece after brazing can be tested for leak inspection, non-destructive testing, normal and low temperature tensile, normal and low temperature fatigue mechanical performance test, as well as macro and micro metallographic, hardness, brazing rate and other tests. In addition to the extremely low temperature environment of the fusion reactor, the test piece form proposed by the present invention can also be used for vacuum brazing process evaluation of homogeneous and heterogeneous joints under normal temperature, low temperature and high temperature service conditions in other industries.

Example 1 Brazing process evaluation of 316LN stainless steel & CuCrZr composite pipe lap joint

Referring to FIG. 3 , the key components in the superconducting shielding member 8 are composed of a copper alloy & stainless steel composite tube 9 . The 316L stainless steel tube has 10k and 5bar helium refrigerant inside. The vacuum brazed joint of the composite tube is required to have the following properties: the brazing adhesion rate of the 200mm stainless steel tube and the copper plate vacuum brazed joint reaches more than 95%, and can serve stably at 4K 2) The strength of the brazed joint at room temperature is greater than 200MPa, 4.2K 3) good sealing performance, and its leakage requirement is 1x10-10Pa.m ³ /s.

Adopt the vacuum brazing evaluation test piece of the embodiment of the present invention to carry out process evaluation:

Referring to Figure 4, the first workpiece of the vacuum brazing evaluation test piece adopts a stainless steel tube 11, specifically a Φ18*3mm316LN stainless steel tube plated with a 2um-8um Ni layer on the outer layer; the second workpiece adopts a CuCrZr tube 10, specifically: Φ26*3mmCuCrZr pipe; the lap brazing seam of the first workpiece and the second workpiece is represented as brazing gap 12; the butt brazing seam is represented as assembly gap 13; use a feeler gauge to check the assembly gap of the lap welding seam before brazing, Control its deviation shall not exceed 0.01mm.

Specific steps are as follows:

1. Before brazing, the stainless steel tube and CuCrZr tube are subjected to: pickling - ultrasonic cleaning with deionized water - ultrasonic cleaning with absolute ethanol - drying.

2. The recommended assembly gap between the first workpiece and the second workpiece is 0.02-0.08mm. In order to ensure the smooth progress of the assembly, the steel pipe soaked in liquid nitrogen is inserted into the CuCrZr pipe;

Use paste Agcu28 solder to fill the CuCrZr tube into the groove, and the flow direction of the solder is vertical downward flow.

After brazing several test pieces, carry out inspection and testing according to the following requirements, sort out the test results, and complete the brazing evaluation:

a. Conduct leak checks;

b. Use water invasive ultrasonic testing for non-destructive testing;

c. Take a sample to remove the copper that you want to keep outside the brazing gap by machining, and then carry out the low temperature tensile and fatigue mechanical properties test of the prototype in the liquid helium temperature zone;

d. Sampling for macro and micro metallographic, hardness, brazing rate and other tests.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a vacuum brazing evaluation test piece for vacuum brazing process evaluation, is characterized in that, comprises: The second workpiece has an elongated structure; The first channel penetrates the second workpiece along the length direction of the second workpiece; The first workpiece is provided with a cavity, and the cavity is used for cooperating with the elongated structure of the second workpiece to form an overlap brazing seam and a butt brazing seam; wherein, the overlapping brazing seam and the butt welding seam are communicated; a second channel, penetrating the first workpiece along the length direction of the first workpiece, and communicating with the first channel to form a through hole; and a brazing filler metal inlet groove, which is arranged on the first workpiece and is used for filling brazing filler metal into the lap brazing seam and the butt brazing seam through the brazing filler metal inlet groove. 2. The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 1, wherein the central axis of the first channel and the second channel is coincident; The solder filling groove includes a first filling groove for filling filamentous or paste-like solder that doubles as a vent hole and a second filling groove for filling a foil or filamentary solder that doubles as a vent hole. ; The first filling groove penetrates the first workpiece along the length direction of the outer side wall of the first workpiece and communicates with the lap joint; the second filling groove penetrates the first workpiece along the length direction of the outer side wall of the first workpiece And connected with the lap brazing seam. 3. The vacuum brazing evaluation test piece for vacuum brazing process evaluation as claimed in claim 1, wherein the lap brazing seam is arranged along the length direction of the second workpiece and the length direction of the first workpiece, and between the outer surface of the second workpiece and the inner wall of the cavity of the first workpiece. 4. The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to any one of claims 1-3, wherein the butt brazing seam is along the width direction of the second workpiece and the width of the first workpiece The direction is set, and it is arranged between the end of the second workpiece extending into the cavity and the inner bottom wall of the cavity of the first workpiece; the lap brazing seam is an annular structure. 5. The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4, wherein the cavity is connected to the elongated structure of the second workpiece by means of splicing, overlapping or butt jointing Cooperate. 6 . The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4 , wherein the elongated structure comprises a rod shape, a tube shape or a plate shape. 7 . 7. The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4, wherein the solder in the lap brazing seam is in the form of wire, powder or foil; butt brazing seam Solder in the form of wire, powder or foil. 8 . The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4 , wherein the width of the butt brazing seam is greater than the width of the overlapping brazing seam. 9 . 9 . The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4 , wherein the second workpiece and the first workpiece are respectively made of copper and stainless steel. 10 . 10 . The vacuum brazing evaluation test piece for vacuum brazing process evaluation according to claim 4 , wherein the gap width of the overlapping brazing seam is 0.02-0.08 mm; the gap of the overlapping brazing seam is 0.02-0.08 mm. The deviation of the width is not more than 0.01mm; the gap width of the butt brazing seam is 0.02-0.08mm; the deviation of the gap width of the butt brazing seam is not more than 0.01mm.

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