JPH02224881A - Resistance heating type solid phase seam joining method - Google Patents

Abstract

PURPOSE:To carry out the subject solid phase seam joining by a diffusion phenomenon, etc., of atoms on the joining surfaces by setting a welding current carried to between electrodes at a low value so as to increase pressurizing force and applying the welding current under welding conditions that a nugget is not formed in resistance seam welding to heat the joining surfaces by resistance heating. CONSTITUTION:Materials 1 and 1 to be joined are superposed on each other and subjected to seam joining by resistance heating while being pressed by the discoid electrodes 2 and 2. In this case, resistance hating type solid phase seam joining is carried out in the range shown by the figure where the nugget is not formed in the range with high pressurizing force between the electrodes 2 and 2 and the fairly low welding current. As a result, the fused nugget is not formed on a joining part of the material 1 and 1 between the electrodes 2 and 2 and resistance heat by application of the welding current is generated. Accordingly, the above-mentioned joining part is in a state applied with the high pressurizing force simultaneously with being heated and the diffusion phenomenon of atoms is generated between the joining surfaces and a kind of joining like diffusion joining is carried out. As a result, deformation due to solidification and shrinkage of the fused nugget is prevented and the flat surfaces of the materials to be joined are obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resistance heating type solid phase seam welding method that enables seam bonding in a solid state without forming a nugget. This is to prevent deformation of the material.

[Conventional technology] Resistance seam welding is one of the methods for joining containers that require airtightness or watertightness. In this method, the materials to be welded are sequentially welded while being pressurized and advanced using a rotating disk electrode. , it is possible to perform seam welding by making nuggets continuous.

In such a resistance seam welding method, when current is applied while pressurizing the materials to be welded with a disc electrode, resistance heat generation occurs on the contact surface of the materials to be welded, and this heat forms a molten nugget.
This completes the joining of the parts of the materials to be joined that are clamped and pressed by the disk electrodes.

[Problems to be Solved by the Invention] However, in such resistance seam welding, pressure is applied with a disk electrode while a molten nugget is formed.
There is a problem in that the surface of the materials to be joined after welding is deformed due to contraction during solidification of the molten nugget, and this method cannot be used as a seam joining method for products that do not like deformation of the surface of the materials to be joined. .

This invention was made in view of the problems of the prior art, and by changing the welding conditions of conventional resistance seam welding, resistance heating can be performed without forming molten nuggets that cause deformation of the welded materials. By doing this, we discovered that a type of diffusion bonding-like bonding surface could be obtained, and we developed a resistance heating solid phase seam bonding method that allows seam bonding in a solid state while heating the materials to be bonded using resistance heat between electrodes. This is what we are trying to provide.

[Means for Solving the Problems] In order to solve the above problems, the resistance heating type solid phase seam joining method of the present invention has a method for seam joining a plurality of materials to be joined together by resistance heating while stacking them and pressing them with $ poles. , the welding current applied between the electrodes is kept low and the pressing force is increased to maintain resistance seam welding conditions in which no nuggets are formed, while preventing deformation of the materials to be joined due to the atomic diffusion phenomenon occurring at the joint. It is characterized by the following.

[Function] According to this resistance heating type solid phase seam joining method, the welding conditions are set so that the welding current flowing between the electrodes is low and the pressing force is high, so that nuggets are not formed in resistance seam welding. Under such welding conditions, electricity is applied to heat the bonded surfaces using resistance heat, and the bonding occurs in a solid state without melting due to atomic diffusion phenomena at the bonded surfaces.

Therefore, deformation due to solidification and shrinkage of the molten nugget is eliminated, making it possible to perform seam joining in which a flat surface of the materials to be joined is obtained.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1 and 2 are explanatory diagrams of welding conditions and a schematic configuration diagram of a joining apparatus according to an embodiment of the resistance heating type solid phase seam joining method of the present invention.

In this resistance heating type solid phase seam welding method, by appropriately selecting welding conditions, the welding is performed by diffusion bonding in a solid phase state without forming molten nuggets as in conventional resistance seam welding.

In order to perform this resistance heating type solid phase seam joining method, it is important to set welding conditions that do not form molten nuggets and reduce diffusion bonding, but in general, the type of materials to be joined,
Welding conditions vary significantly depending on plate thickness, surface condition, number of stacked plates, etc.

First, the pressurizing force of the materials to be joined and the welding current, which are the main factors among the various elements of the welding conditions for -a resistance seam welding, will be explained with reference to FIG.

(1) Pressure force on the materials to be welded If the pressure on the materials to be welded is too high, the current density will decrease due to an increase in the contact area of the joint, and as a result, no nugget will be formed.

On the other hand, if the pressing force is too low, contact parts will be formed in addition to the joint parts, and the welding current will be dispersed, resulting in no nuggets being formed.

(2) Welding current On the other hand, if the welding current is too low, the necessary current density cannot be secured, the materials to be joined will not melt, and no nuggets will be formed.

On the other hand, if the welding current is too large, the current density becomes too high and the nugget becomes too large, causing molten metal to scatter, so-called "splatter", resulting in welding defects.

Therefore, the suitable welding conditions for forming nuggets in the conventional resistance seam welding method are the range N surrounded by four lines that satisfies the four conditions of the lower and upper limits of the welding force and the lower and upper limits of the welding current. becomes.

However, within the range N of welding conditions in which such nuggets are formed, it is not possible to suppress deformation, which is the object of the present invention.

Therefore, the welding conditions for the resistance heating type solid phase seam joining method of the present invention are such that the welding force is high within the range of the pressurizing force and welding current (range other than welding condition N) in which nuggets are not formed, and the welding current is high. is a sufficiently low range, and becomes the range A in which no nugget is formed, which is surrounded by diagonal lines in FIG.

In addition to these, there are other welding conditions such as welding speed and energization cycle, but these are determined by the required performance of the joint, and the conditions may be selected each time to suit the purpose.

Resistance heating type solid phase seam welding, which is carried out at a high pressure and at a sufficiently low welding current so that nuggets are not formed, is performed by sandwiching the materials 1, 1 to be joined, as shown in FIG. It is composed of a pair of disc electrodes 2, 2, a welding power source 3 that supplies welding current to these disc electrodes 2.2, and a pressure R barrel (not shown).
A cooling R structure, such as a water immersion type, is provided to cool the joints.

In this way, if resistance heating type solid phase seam welding is carried out in a range where the pressurizing force is high and the welding current is sufficiently low in a range where nuggets are not formed, it is possible to No melt nuggets are formed at the joint;
Resistance heat is generated due to the application of welding current, and at the same time, a high pressure is applied, and a diffusion phenomenon of atoms occurs between the bonding surfaces, resulting in a type of diffusion bonding. Become.

After bonding, the bonded portion is rapidly cooled to maintain the bonded state.

This quenching method includes cooling the materials to be joined by immersing them in water, or by spraying them with water from a nozzle or the like.

As shown in the cut surface of the jointed parts 1 and 1 joined in this way, no molten nuggets are formed at the joint, and atomic diffusion occurs as in diffusion bonding. It can be seen that joining occurs due to this phenomenon, and it is seen that this is greatly different from the case shown in FIG. 3(b), which shows the joining surface when a molten nugget is formed and joined by conventional resistance seam welding.

The welding conditions in the case of FIG. 3(a) were selected as follows.

■ Material to be joined = 3 masks Mask plate: 5US304 with plate thickness of 0.81111m Intermediate plate: plate thickness of 0.4111m, upper layer is nickel, lower layer is 5
Clad material of US304, mask grade: 5US304■ with plate thickness 0.81111
Welding current: 1600Amp, ■Applying force: 227kg/cd, ■Welding speed: 30 an/l! n.

In order to confirm the strength of the joint joined by such resistance heating type solid phase seam joining, as shown in Fig. 4,
After seam-joining the periphery of the two materials 1.1 to be joined using this joining method, compressed air (7 kg/ai) was supplied inside and the presence or absence of leakage from the surroundings was confirmed underwater.

As a result, it was confirmed that there was no leakage and that the state was completely airtight.
It was confirmed that there was no deformation caused by , 2.

[Effects of the Invention] As described above in detail with one embodiment, according to the resistance heating type solid phase seam joining method of the present invention, the welding conditions are such that the welding current flowing between the electrodes is low and the pressing force is low. Since we set the welding conditions such that nuggets are not formed during resistance seam welding and are energized, the welding surface is heated by resistance heat and melting occurs due to the diffusion phenomenon of atoms at the welding surface. It is now possible to join the materials in a solid state without causing any damage.

Therefore, deformation due to solidification shrinkage of the molten nugget can be eliminated, and the surface of the welded material can be kept flat.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of welding conditions and a schematic configuration diagram of a joining device in an embodiment of the resistance heating type solid phase seam joining method of the present invention, and Figure 3 is a sectional view of the joint. Figure 4 (a) shows the case according to the method of this invention, and Figure 4 (b) shows the case according to the conventional method. Fig. 4 is an explanatory diagram of the experimental method for the joint. 1: Materials to be joined, 2: disk electrode, 3: welding power source, A: range of welding conditions of this invention, N: range of welding conditions of conventional resistance seam welding.

Claims (1)

[Claims] When seam joining multiple materials to be welded by stacking them and using resistance heating while pressing them with electrodes, the welding current applied between the electrodes is kept low and the pressure is increased to maintain resistance seam welding conditions where no nuggets are formed. , a resistance heating type solid phase seam welding method characterized in that the materials to be joined are prevented from being deformed by the diffusion phenomenon of atoms occurring in the joint portion.