JPS588951B2 - seam cover - Google Patents

Description

[Detailed description of the invention] This invention relates to a seam welding device.

In seam welding, as shown in Fig. 1, a plate-shaped material to be welded 2 is
, 2' are pressurized with disk-shaped welding electrodes 1, 1', and current is passed between 1 and 1' while rotating the welding electrodes 1 and 1'. The Joule heat generated by this current causes the material to be welded to melt. 2,2'
It has the feature that an airtight joint 6 can be obtained by continuously joining the parts.

However, with conventional seam welding equipment, as the welding speed increases, the energization time per unit length (the time during which welding current flows) becomes shorter.
The contact surface between the welding electrodes 1, 1' and the materials to be welded 2, 2l becomes very high temperature, and the materials to be welded 2, 2' finally melt, causing the welding electrodes 1, 1l and the materials to be welded 2, 2' to melt. Welding may occur, and dust may appear on the contact surface.

This is because as the welding speed increases, a larger welding current is required, and the current density at the contact surface between the welding electrodes 1, 1' and the parts to be welded 2, 2' increases, and as the welding speed increases, the welding This is because the welding electrodes 1, 1l cannot sufficiently cool the welding materials 2, 2' because the contact time between the electrodes 1, 1' and the materials to be welded 2, 2' becomes shorter. be.

As described above, in conventional seam welding equipment, the welding speed is restricted by the occurrence of welding or dust as described above, and this maximum speed decreases as the plate thickness increases.

This invention eliminates the drawbacks of the conventional seam welding equipment mentioned above,
The purpose is to increase welding speed.

FIG. 2 is a diagram showing the basic structure of the seam welding apparatus according to the present invention, and the disc-shaped welding electrodes 1, 1' are the same as those of the conventional apparatus.

Auxiliary electrodes 3, 3' and 4 are placed ahead of this (on the welding start side).
. Current is supplied by a welding transformer 5 connected to the auxiliary electrodes 3, 4.

Assuming that the current flows from the auxiliary electrode 3 to the auxiliary electrode 4, the current passes through the workpiece 2 to be welded, as shown by the broken line in FIG. It flows into the workpiece 2' through the section 6 and flows into the auxiliary electrode 4.

At this time, welding current is supplied between welding electrodes 1 and 1' in the same manner as in the past, so welding electrodes 1 and 1' are supplied to welding part 6.
The sum of the current supplied by ' and the current supplied by the auxiliary electrodes 3, 4 will flow.

In the conventional device, the current that melts the welding part 6 is supplied to the welding electrode 1.
, 1', when the welding speed increases and the welding current required for welding increases, the welding electrodes 1, 1'
The current density at the contact surface between the welding electrode 1' and the welding material 2, 2l increases, and the surface of the welding material 2, 2' melts (or welds), which increases the magnitude of the current that can be supplied from the welding electrode 1, 1l. There were restrictions on

However, in the device according to the present invention, a part of the necessary welding current is supplied from the auxiliary electrodes 3 and 4.
It is possible to increase the current density in the welding part 6 without increasing the current density at the contact surface between the welding electrodes 1, 1' and the parts to be welded 2, 2, and therefore seam welding can be performed at a higher speed than with conventional equipment. become.

It is better to use electrodes as wide as possible for the auxiliary electrodes 3, 3' and 4, 4' according to the present invention.
This is advantageous because the current density at the contact surface between the welding material 2, 2' and the welding material 2, 2' is reduced, and no current traces are left on the welding material 2, 2'.

It should be noted that increasing the width of the welding electrodes 1 and 1' seems to reduce the current density at the contact surface, but increasing the electrode width also increases the width of the weld 6, which reduces the current density in the weld 6. Since the density decreases and bonding (melting) becomes impossible, even if the width of the welding electrodes 1, 1' is increased, the current density at the contact surface cannot be reduced much.

Next, an example of the results obtained when carried out using the apparatus according to the present invention is not shown.

Part to be welded: SPCC 3.2mm, welding electrode: outer diameter 250φ, thickness 16mm, tip middle -7mm Auxiliary electrode: outer diameter 100φ, thickness 30mm, tip width -25
mm [For conventional equipment] At a welding speed of -2 m/min, pressurizing force = 1140 kg, and welding current of -2420 OA, the surface was melted and surface dust was generated, but the joint condition of the joint surface was insufficient. .

In the conventional method, the limit was 1 to 1.5 m/mih.

[Apparatus according to this invention]

At a welding speed of 4 m/miIX, a pressurizing force of 1140 kg, a welding current of 27000 A1, and an auxiliary current of 2100 OA, a beautiful appearance and sufficient joint strength were obtained.

Experiments have also revealed that the effect of the device according to the present invention is more pronounced when applied to thick plates of 1.6 mm or more than when applied to thin plates of 1.2 mm or less.

In the above embodiment, one pair of auxiliary electrodes was used, but a configuration in which many pairs of auxiliary electrodes are provided is also possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the basic configuration of a conventional seam welding device, and FIG. 2 is an explanatory diagram showing the basic configuration of a seam welding device according to the present invention. In the figure, 1 and 1' are disk electrodes for welding, 2 and 2' are materials to be welded, 3, 3', 4, and 4' are auxiliary electrodes, and 5 is a power supply device. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A pair of welding materials for welding the first and second materials to be welded by pressurizing the first and second materials to be welded, which are separated from each other and being transferred in the same direction, and applying electricity between the first and second materials to be welded. a disc electrode, a first auxiliary electrode for passing a current through the first material to be welded upstream of the disc electrode, a first auxiliary electrode provided in contact with the second material to be welded upstream of the disc electrode, and a second auxiliary electrode that receives a current flowing from the first auxiliary electrode through the part to be welded by the disc electrode; A seam welding device characterized in that the current flowing through the auxiliary electrode is added.