JPH01286971A - Frictional pressure welding between ceramics or ceramic and metal - Google Patents

Abstract

PURPOSE:To accomplish the title pressure welding along with great joint strength, by firmly setting, in advance, an insert made of ductile metallic material on the surface of a ceramic or metal to be bonded to a second ceramic. CONSTITUTION:For example, when ceramics 1 of round bar or pipe are to be bonded to each other, an insert 3 made of ductile metallic material (e.g., Al, Cu, Ni, Ti, Mo) is firmly set on the surface of one of the ceramics 1 to be bonded to the other. Without said insert, the ceramic(s) 1 would be liable to crack due to the collision at the onset of contact and the thermal stress on the bond surface; but in the presence of said insert, the impact at the onset of contact will be released, thus protecting the ceramic 1 from breaking. Also, in general, metals are higher in thermal conductivity than ceramics, the stress developed through the thermal expansion of said insert 3 is relaxed and the heat transfer through the bond surface is accelerated, thus preventing the ceramic from breaking due to the thermal stress along with enhancing the bond strength of said surface. Firm setting such as through caulking of a pipe 2 of ductile metallic material on the circumference of a ceramic 1 cylinder will adequately hold said ceramic 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a friction welding method when one or both of the materials is ceramic.

[Prior Art] In recent years, ceramics have attracted attention as materials with excellent heat resistance, corrosion resistance, and wear resistance, and it is difficult to mold complex shapes and large parts, and the establishment of bonding technology is a solution to these problems. Waiting.

Conventionally, there have been many research reports and practical examples regarding friction welding of metal materials, and there are problems with ceramics, which are brittle materials, such as being easily broken by the impact at the start of contact and being easily broken by thermal stress on the joint surface. Therefore, it has not been put into practical use.

[Problems to be Solved by the Invention] An object of the present invention is to make friction welding with high joint strength, work efficiency, and energy efficiency applicable to joining ceramic materials.

Means and Effects for Solving the Problem] In order to achieve the above object, the present invention is characterized in that, as a pre-step, an insert of a ductile metal material is fixed to the bonding surface of ceramics and ceramics or metals.

To explain the present invention in detail based on the drawings, an insert (3) made of a ductile metal material is fixed to the joining surface of a ceramic (1) to be joined. In this case, in friction welding, the material must have a circular cross section such as a round bar or pipe, so the ceramic (1) etc. is a round bar or pipe, and the insert (3) of ductile metal material is, for example , aluminum, copper, nickel, titanium, molybdenum, etc.

The ceramic (1) is easily broken by collision at the beginning of contact, and also by thermal stress on the joint surface.The present invention fixes an insert (3) of a ductile metal material to the joint surface of the ceramic (1). Therefore, the impact at the start of contact is alleviated by the insert, and damage to the ceramic can be prevented. In addition, since metals generally have better thermal conductivity than ceramics, the insert (3) not only relieves the stress caused by thermal expansion, but also helps heat conduction at the bonding surface, prevents damage to the ceramics due to thermal stress, and improves the bonding process. It relieves stress and increases bonding strength.

Moreover, as shown in FIG. 4, the ceramic (1) and the metal round bar (4) can also be friction-welded.

In addition, if the pipe (2) made of a ductile metal material is fixed to the cylindrical outer peripheral surface of the ceramic (1) by caulking or the like,
The pipe (2) relieves stress concentration during chucking, making it possible to grip the ceramic (1) sufficiently without destroying it (see Figure 1). This pipe (2) can be removed by cutting after joining, or it can be left in place and used effectively as a buffer material that can withstand external stress.

〔Example〕

(Example 1) Friction welding of ceramics and carbon steel The material to be welded was a 95% alumina ceramic (A (!20i) round bar with an outer diameter of φ15.5 x 50■■ and an outer diameter of φi
ax 50mm partially stabilized zirconia ceramics (
psz) round bar and a carbon steel (320G) round bar with an outer diameter of 70 x
), a pure aluminum (JIS-A1050) round bar with an outer diameter of φtax 70 mm is used for the purpose of preventing impact cracking of ceramics due to rotation and pressurization and alleviating stress caused by the difference in thermal expansion between ceramics and metal. Friction welding was performed.

The welding sequence is as follows: First, aluminum and carbon steel are friction welded, and then the upset of the aluminum-carbon steel joint is removed by turning, and then the aluminum-carbon steel joint is welded at a position approximately 10m away from the joint boundary on the carbon steel side toward the aluminum side. That is, the aluminum is cut at a position leaving about 10 m of aluminum from the bonding boundary of the carbon steel. The end faces of the cut samples are finished by turning, and after cleaning the end faces to be joined with acetone to remove oil and dirt, the ceramics are friction welded. Further, a pressurization cycle regarding the strength of the press-welded joint was performed as shown in FIG. When welding aluminum and carbon steel, we use the two-stage pressure method (Fig. 5A), and when welding aluminum-carbon steel joints and ceramics, we use the three-stage pressure method (Fig. 5A).
Figure 5B) was adopted.

Tables 1 and 2 show the pressure welding conditions.

Table 1 (Carbon steel-aluminum pressure welding conditions) Pressure welding conditions
(812-320G) 8Q: φiax 7h heavy, RING used 520 (:
:φ 18x 10x φ20X 120mm Table 2 (Carbon steel/alumina-ceramics pressure welding conditions)
Po = Preheating pressure (Kgf/am2) P, : Friction pressure (Kgf/mm”) P2: Upset pressure (Kgf/am2)
m■2) to two preheating time (sec) tt: Friction time (sec) N: Rotation speed (rpm) Figure 6 shows pure aluminum used as the insert (3), partially stabilized zirconia (PSZ) and carbon steel. This shows the relationship between the tensile strength of a pressure welded joint and the thickness of the intermediate layer when friction welding is performed.■The aluminum thickness of the intermediate layer is approximately 2
In (2), the tensile strength of the pressure welded joint is the strength of the aluminum base material, and if the thickness is less than (2), rupture occurs at the boundary between aluminum and carbon steel, and the strength decreases. (3) 2mm
At a thickness above 28% near the boundary between aluminum and PSZ
It broke in two parts, and the value was lower than that of the base material of aluminum, but
It was revealed that the bonded surface was strong without breaking at the interface between aluminum and PSz, and that a new layer such as a reaction layer was formed at the interface between aluminum and ceramics, resulting in bonding.

(Example 2) A round bar of 95% alumina ceramics (hereinafter referred to as "alumina") with an outer diameter of 16.3 x 5 ha was used as the pressure welding material.
And use a pipe material with outer diameter φ16.3 x inner diameter 5 x length 50 mm, and as insert (3), in the case of pressure welding of round bar material, outer diameter φ16.4 x 2 ms, in the case of pipe material, outer diameter φ16.4 x inner diameter A thin plate of pure aluminum (JIS-A-1050) with a diameter of 7 mm and a thickness of 2 mm was fitted into both bonding end faces and pressure welded. Note that if the outer periphery of the sample is tightly tightened directly with a hydraulic chuck, etc., alumina, which is a brittle material, may break due to impact cracking and sudden temperature gradients near the joint due to one rotation of tightening force or pressurizing force. As this is quite possible, as shown in Figure 1, the outer circumference of the sample is
For example, using thin-walled tubes made of aluminum, copper, nickel, etc.
An alumina sample was inserted into a thin-walled tube, the outer periphery of the alumina was slightly contracted using the planetary ball die method, and the sample was prepared and pressure welded, taking care not to spin idly against rotational force and pressure.

Figure 7 shows aluminum (outside diameter φ16.4 x thickness 2m5) inserted into the insert (3) using alumina round bars.
4 The change in thickness of the aluminum piece of the joint that was fitted into the joint end face and joined at one rotation speed of 400 ° rpm, friction pressure Pt2Kgf/mm", upset pressure P23 gf/mm", and pressure welding time t□20 seconds is shown. This is an example. As seen in FIG. 7, the shape of the aluminum piece is extruded to the outer periphery of the alumina due to frictional heat and pressure, and the thickness of the aluminum piece becomes thinner in the center.

Therefore, if the friction time is increased, the thickness will gradually become thinner, and when the welding is completed, the alumina round bars can be welded together.

Furthermore, in an experiment of joining alumina vibrator materials, as shown in FIG. 1, there was no aluminum piece near the joint, and alumina pipe materials could be joined together. In addition, to describe the results of a tensile test of a joint between alumina round bars, the rotation speed was 4000 rpm, and the friction pressure was P+2.
Kgf/*m”, upset pressure Pt3Kgf/am2
The joint welded under pressure welding conditions of 15 to 20 seconds broke at the base material of the alumina round bar when the tensile strength σ: 8Kgfβ was 71112 or more.
It was found that the joint was strong.

[Effects of the Invention] The present invention provides the following advantages:
Since the impact at the start of contact between ceramics is alleviated and the stress caused by thermal expansion is also alleviated, it is possible to perform friction welding of ceramics, which are brittle materials, and the bonding strength is increased.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the sample structure, Figure 2 is [;! ! + is a cross-sectional view when ceramics are joined together, Figure 3 is an electron micrograph showing the joint between ceramics and ceramics and the surrounding ceramic structure, Figure 4 is a cross-sectional view when metal and ceramics are joined, Figure 5A. B is a diagram showing the pressure cycle related to pressure welding work, Figure 6 is a diagram showing the tensile strength during friction welding of metal and ceramics, and shows the relationship between the H of the intermediate layer and the tensile strength, and Figure 7 is a diagram showing the relationship between the H of the intermediate layer and the tensile strength. It is a figure which shows the change of the thickness of a joint at the time of friction welding. (1) Ceramic round bar. (2)...Metal vibrator, (3)...Insert. Designated agent: Agency of Industrial Science and Technology Nagoya Industrial Technology Laboratory Director Mitsuo Isotani 41 Fig. 2gl$ Fig. 3 Fig. 4B Fig. 5 2nd stage 27 type % type % ) Po2 preheating pressure 7: l(ni)shi mm") Pl: Karo% i'LJE'hupu (ni) dry/m
m2)P2:7Put pressure 77(gf/rnrn2
) Length O: Preheating inspection (sec) tl: Heating time (sec) t2: 7 heating time (sec) Figure 6 Intermediate layer thickness (mm) /rln1 procedure correction teeth (method) 1. Indication of the case 1986 patent mNIJ26H82 No. 2, name of the invention Method of friction welding of ceramics and ceramics or metals 3, person making the amendment Relationship to the case Patent applicant address Tokyo 1-3-1 Kasumigaseki, Chiyoda-ku (114)
Name Director of the Agency of Industrial Science and Technology Yuki Iizuka 34゜ Contents of the designated agent amendment (1) “Figure 3 is an electron micrograph” stated in page 10, lines 16 to 18 of the specification has been replaced with “Figure 3 is an electron micrograph” The figure is a photomicrograph used as a substitute for a drawing showing the metal structure of the insert at the joint between ceramics.'' Designated Agent Mitsuo Isotani, Director of Nagoya Industrial Technology Laboratory, Agency of Industrial Science and Technology

Claims (1)

[Claims] 1. A method for friction welding ceramics and ceramics or metals, characterized in that, as a pre-process, an insert of a ductile metal material is fixed to the joining surfaces of ceramics and ceramics or metals.