JPS62134187A - Liquid phase defusion joining method - Google Patents

Abstract

PURPOSE:To increase the mechanical strength of a joined part by preventing a shield gas being caught in the inserting material in case of performing a liquid phase diffusion joining of a metallic material each other by using a shield gas and inserting material. CONSTITUTION:Both metallic material 1, 2 are put into a chamber 10 by supporting them with supporter 3, 4 in case of performing the liquid phase diffusion joining of the metallic material 1, 2 of stainless steel, etc. The inside of the chamber 10 is made the inert gas atmosphere of Ar, N, He, etc. and the inserting material in <=70mum thickness of same or dissimilar quality is interposed at the joined part of both metallic materials 1, 2 as well. It is heated by the heater 9 on the outer periphery of the joined part in this state and because of the inserting material being melted at the temp. >= its liquidus line both materials 1, 2 are separated so s to cause 0.3-1.0mm gap and after holding for 5-20sec both materials 1, 2 are cooled by press-contact once again. The mechanical strength at the joined part after the soldification by cooling is increased due to the shield gas which has been enclosed in the inserting material at the time when both materials 1, 2 are separated being released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a liquid phase diffusion bonding method using an insert material and a shielding gas in combination.

[Conventional technology]

The liquid + eye diffusion bonding method, which metallurgically joins the wave-welded surfaces of the materials to be welded by pressurizing and melting by heating, is less likely to cause thermal deterioration of the welded area and change in composition as in the case of welding, so stainless steel Mainly used for joining high-grade materials such as steel. There are two surfaces between the surfaces to be joined, one in which the insert material is fully inserted and one in which it is not inserted, and the time required for joining is greatly shortened compared to the case where the insert material is inserted and the scaffolding is not inserted.

On the other hand, it is necessary to maintain the surrounding area of the surface to be joined in a heated, non-oxidizing atmosphere. There are two methods for this: one in which the materials to be joined are placed in a total vacuum, and the other in which the materials to be joined are encapsulated in a shielding gas. From a perspective, the latter is far more advantageous.

For this reason, the insert material and shielding gas are excellent, making it an extremely convenient method for use outdoors such as at construction sites.

However, even such an efficient method has the following major problems due to the shielding gas and insert material used.

[Problem that the invention seeks to solve]

In the liquid phase diffusion bonding method that uses both shielding gas and insert material, the insert material sandwiched between the surfaces of the materials to be joined is heated in a shielding gas atmosphere, and as the heating temperature increases, the material and material to be joined are bonded together. Start melting the bath from the uncontacted outer peripheral side toward the center. At this time, shielding gas is trapped within the insert material, which causes a reduction in the mechanical properties of the joint, especially the impact resistance. The mechanism can be roughly estimated as follows.

Before the insert material is bath melted, that is, in a solid state, it is difficult to completely eliminate all the shielding gas from between the surfaces to be joined. When the insert material starts to melt, at time t, a shielding gas having approximately the same pressure as the bonding atmospheric pressure remains between the surfaces to be joined, so that this residual gas is sealed inside the insert material when it starts to melt. Once sealed, the shielding gas does not react with the materials to be joined and is not removed even if the joining time is extended. In this way, the shielding gas that accumulates between the surfaces to be joined not only collects metal after joining, but also prevents the shrinkage of the gap between the surfaces to be joined during welding, and obstructs the metallurgical bonding of the surfaces to be joined. Mechanical properties, sword
However, it will result in a complete decrease in front impact resistance.

The invention is to prevent the shielding gas from being captured by the insert material in a liquid phase diffusion bonding method that uses both a shielding gas and an insert material, thereby improving the mechanical properties of the bonded part.
Above all, the purpose is to improve 1. 1. Shock Notebook.

As mentioned above, the method of using both shielding gas and insert material is a highly efficient method that requires simple equipment, short joining time, and eliminates the problem of shielding gas being trapped in the insert material. If it is solved, its utility value will increase.7. It goes without saying that it will increase exponentially.

[Means for solving problems]

By the way, when an insert material is used in the liquid phase diffusion bonding method, bath melt stirring of the insert material can be expected on the surface Lml to be bonded. In other words, the insert material that is inserted between the surfaces to be joined starts to melt as the thermal temperature rises from its solidus line to the liquidus line, and melting and stirring reaches its peak when the liquidus line is reached. . This is thought to be due to the onset of wetting of the bath-molten insert material to the welded materials and the effect of suppressing wetting due to surface tension. Note that, as time passes, the amount of the insert material subjected to stirring decreases due to the progress of diffusion of the insert material into the materials to be joined, and the stirring becomes slow.

The inventors focused on stirring the insert material and repeated experiments as a means of removing the shielding gas trapped in the insert material. As a result, if the insert material is bath-melted and the wave-welded material is forcibly separated slightly at stage t, the molten insert material between the surfaces to be joined will maintain contact with the surface to be joined due to the surface tension, and the melting and stirring will continue at t. It has been found that a space for gas release is also formed between the materials to be joined, and that the shielding gas trapped in the insert material can be efficiently released to the outside.

The invention was made based on this knowledge, and its gist is that when the insert material is closely inserted between the surfaces to be welded of the wave-welded materials, at least the inserted portion of the insert material is heated to a temperature below the liquidus temperature of the insert material. After heating the door to a temperature higher than 100 degrees to melt all of the insert material, all the joining materials are forcibly separated once to such an extent that the bath-melted insert material does not separate from the surfaces to be joined.
The liquid phase diffusion bonding method is characterized in that the process then proceeds to a predetermined pressurization and heating pattern.

Hereinafter, the invention will be explained in more detail with reference to the drawings.

Fig. 1 is a vertical side view showing an example of a device suitable for demonstrating inventiveness, (11121 is the material to be joined, f3) (
41 is a top and bottom holder that holds the material to be joined (11<21;
fi) (61 is the upper and lower pressure ram, (7) is the lower pressure ram (5
) Hydraulic cylinder that can be moved up and down, (8) is an upper pressurizing ram (
The load cell (9) is placed on the material to be welded (11).
(A heater provided to surround the vicinity of the surface to be joined of 21,
00 is a chamber that completely surrounds the material to be joined (1) <21, and a shielding gas is injected into the chamber αq.

To fully implement the invention using this device, first remove the chamber αOf, and lower the hydraulic cylinder (7) completely.
In this state, the material to be welded (1) (
2) Set all. Next, the hydraulic cylinder (7) is fully raised and the chamber α is set, but the material to be welded (1)
(The insert material must be held tightly in contact with the surfaces to be joined between the 2+ surfaces.
When the preparation is completed, shielding gas is filled inside the chamber Oa, and the entire vicinity of the surfaces to be joined of the materials to be joined (11+, 21) is heated using the heater (9).The procedure from 7JD heating is shown in Figure 2 (A).
It will be explained step by step in detail by ~.

First, as shown in FIG.
Machining is started with the insert material sandwiched between the surfaces to be joined. When the temperature of the applied temperature exceeds the liquidus temperature of the insert material, that is, when the insert material is bath melted, the wave bonding material (11 < 21 gold, molten Store the insert material in such a way that it does not deviate from the surface to be joined)
Let J. The specific static distance, separation, and separation time will be described later.

The material to be joined (11 < 21, if the distance is 11
< 21 is pressurized, and after a predetermined period of time, the pressurization is released and cooled as shown in the same figure. The pressure here is not for adhesion, but is the pressure originally necessary for diffusion bonding.
Heating is also necessary for joining the materials to be joined (11 < 21). Figures 3 (a) and 3 (b) show heating patterns and pressure patterns when the same materials are all diffusion bonded using the conventional method and the uninvented method. ?As an example, after the start of pressurization in the uninvented method (A
The heating and pressing pattern in -A) is the same as the pattern in CB-B) after the start of pressing in the conventional method.

In the examples shown in Figures 1 and 2, the surfaces to be joined (11 < 21) are held horizontally and pressure is applied from above and below. Furthermore, the surfaces to be joined may face in other directions.

Also, in this example, the entire part of the material to be joined (1)<21 is covered with the shielding gas, but it is sufficient that at least the vicinity of the surface to be joined is covered with the shielding gas.

In the uninvented liquid phase diffusion bonding method performed by the above-described procedure, the insert material may have the same composition as the material to be bonded or may have a different composition, and is appropriately selected from a normal selection range. However, from a structural standpoint, an amorphous material is preferable since it has no crystalline inclusions and promotes metallurgical bonding of the surfaces to be joined.

The thickness of the insert material is preferably 70 μm or less.

As mentioned above, the liquid phase diffusion bonding method using insert material is characterized by short bonding time.

If the thickness of the insert material exceeds 70 .mu.m2, it will take time to completely melt the insert material and the above-mentioned features will be diminished, so it is preferably kept to 70 .mu.m or less.

The shape of the insert material may match the shape of the surface of the material to be joined.

Examples of shielding gas include argon gas, window element gas,
Helium gas, a mixed gas of argon and hydrogen, etc. are suitable.

The spacing distance of the corrugated bonding material is preferably 0.3 to X, OTm.

If it is less than 0.3 mm, the melt welding of the insert material will not be promoted, there will be a shortage in the opening area specified for one constant gas release, the overall shielding gas release efficiency will decrease, and the separation time will be extended, so it is preferable. do not have. Also 1, Q 7Mr f,
If the materials to be welded are placed between IQ and IQ in excess of Problems such as being recaptured by the insert material, etc.
However, if the joining materials are superimposed from side to side, the insert material will gather at the bottom between the parts to be joined due to gravity, and there will be places where there is no insert material at the top, causing the same problem. Sometimes.

If the separation time rwJ is less than 5 seconds, the release of the shielding gas trapped in the insert material may be insufficient.
5 seconds or more is preferable. However, if it exceeds 20 seconds, the gas release effect will be saturated, and further separation is meaningless.
It is preferable to keep the time to 20 seconds or less.

The pressure pattern and heating pattern after the materials to be joined are completely separated may be set under the same conditions as in a normal diffusion bonding method.

[Effect]

According to the liquid phase diffusion bonding method of the present invention, the wave bonding material is separated at the stage where the insert material is melted, so that by this stage, the shielding gas contained in the insert is released from the gap between the materials to be bonded. Ru. Further, when the materials to be joined are fully pressurized, there is no room for shielding gas to enter the insert material. In this way, the shielding gas in the insert material is discharged, and as a result, the mechanical strength of the joint is improved.

In addition, as a technology similar to non-invention, Japanese Patent Application Laid-Open No. 57-28
There is a diffusion bonding method proposed in Publication No. 689. When performing diffusion bonding in a high vacuum, the materials to be bonded are interlayered in advance and heated with a foot-shaped &Q to completely clean the surfaces to be bonded.
Diffusion bonding is performed by heating and pressurizing the entire surface to be bonded, and neither shielding gas nor insert material is used. Therefore, non-invention means not only that the underlying joining method is completely different, but also that the purpose of separating the materials to be joined is different, and the regular situation is also different.Also, when the two are completely compared in terms of method. , In contrast to the non-inventive method, where the entire insert material to be joined must be sandwiched and brought into close contact with each other at the beginning of the heating head, it is similar to the above.

The technique is based on the premise that the materials to be joined are separated from each other at the beginning of the heating head, and the methods themselves are also very different.

〔Example〕

Using all the equipment shown in Figure 1, 11 eyebrow squares of SUS 304 'ff: An uninvented method! l Liquid phase diffusion bonding was performed.

The composition of 5US304 is shown in Table 1, and the composition and liquidus temperature of the insert material (amorphous, thickness a o ILm ) used is shown in Table 2. The heating pattern and pressure pattern are shown in Figure 8 (b), and the distance between the materials to be joined is 0.
．． The tests were conducted at two different distances: 56 and 1.0 M, and separation times of 20 seconds and 5 seconds. In addition, for comparison, all liquid phase diffusion bonding was carried out using the conventional method (all other conditions were the same, with no separation of the materials to be bonded). Regarding the obtained bonding material, 4p of the bonded part
Measuring strength (T, Q), elongation, stiffness and impact resistance. The results are shown in Table 3.

As is clear from Table 3 of Charpy's bar sizes, the mechanical properties of the joints, especially the 1m impact resistance, have improved significantly due to uninvented practice. There is also a clear improvement in other eEl f'l& content pages.

Please note that Table 4 shows the results of all similar comparative tests for 5US316IC, and it is clear that the effect of non-inventiveness is large in this test as well.

〔Effect of the invention〕

The uninvented liquid phase diffusion bonding method eliminates the shielding gas in the insert material even though the insert material and shielding gas are used together, completely preventing the deterioration of the mechanical properties of the joint due to the intrusion of the shielding gas. It is possible. Also, in the uninvented method, the shielding gas can be removed extremely easily by utilizing the natural phenomenon of bath melting. Therefore, according to the invention, only the drawbacks can be completely eliminated without completely reducing the gain by using the insert material and the 7-rud gas in combination, and high-performance liquid phase diffusion can be easily achieved. Bonding may be performed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing an example of an apparatus suitable for carrying out the invention, FIG. ) is a t-graph illustrating all the application and pressure patterns of the conventional method and the uninvented method. In the figure, 1, 2: materials to be joined, 3.4: upper and lower holders, 5.6
: Upper and lower pressure rams, 7: Hydraulic cylinder, 8: Load cell, 9: Heater, 10: Chamber. Figure 1 Figure 2 (A”) (0) (C)
(d) Impregnation 8 Processing tank Figure 3 (a)

Claims (1)

[Claims] (1) With the insert material closely inserted between the surfaces of the materials to be joined, at least the part into which the insert material is inserted is heated to a temperature above the liquidus temperature of the insert material in a shielding gas atmosphere to melt the insert material. After that, the materials to be joined are forcibly separated to an extent that the molten insert material does not separate from the surfaces to be joined, and then the process moves to a predetermined pressurization and heating pattern. .