JPH02255282A - Wire for seam welding and seam welding method - Google Patents

Abstract

PURPOSE:To prevent the local heat generation and the occurrence of dusting in the vicinity of the contact surfaces between steel plates and wires by using the wires forming unevennesses on the contact surfaces of materials to be welded to lap the chrome plated steel plates forming unevennesses on the surfaces and subjecting the lapped parts to seam welding. CONSTITUTION:The unevennesses 3 are formed on the contact surfaces between the wires 1 and 1a for seam welding and the chrome plated steel plates 2. These wires 1 and 1a are used to lap the steel plates 2 forming unevennesses on the surfaces and the lapped parts are subjected to seam welding. The unevennesses of the wire 1 and 1a are formed to about 0.01-10mum diameter and about 0.001-0.1mum height and the unevennesses distribution is desirable to be about 0.1-50% at the area rate. The unevennesses of the steel plate 2 surfaces are desirable to be formed almost uniformly as the projecting part diameter of about 30-300mm and the number of projecting parts of about 1.2X10<4>-1.0X10<17>-pieces/m<2>. By this method, stable and smooth seam welding is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a seam welding wire and a seam welding method.

[Prior Art] When welding can bodies such as beverage cans, the well-known seam welding is used.

However, in chrome-plated steel sheets, the chromium oxide that forms on the upper layer of metal chromium inhibits current flow and deteriorates weldability. It is known that by applying pressure, the oxide is broken at the convex portion, and by bringing the electrode into direct contact with metal chromium, the conduction of electricity is ensured and weldability is improved (Japanese Patent Application Laid-open No. 281899/1989).

In welding, as shown in Fig. 1, wire 1, la
There is contact between the steel plate 2 and the chromium-plated steel plate 2 (hereinafter abbreviated as steel plate), and contact between the steel plate 2 and the steel plate 2. In the former contact, the surface of the steel plate 2 has minute irregularities, but the material to be welded by the wire 1 The surface that comes into contact with a certain steel plate 2 is flat. The contact surface between the latter steel plate 2 and the steel plate 2 has uneven surfaces in contact with each other, so the former has a large contact resistance, and the latter has a small contact resistance, and local heat generation occurs near the steel plate-wire contact surface. The reason for the high contact resistance at the contact surface between the flat electrode surface and the steel plate surface with fine irregularities is due to the destruction of the chromium oxide layer due to the fine irregularities. This is considered to be insufficient.

[Problem M to be Solved by the Invention] The present invention has been made to advantageously solve these difficulties.

[Means and effects for solving the problems] The present invention is characterized by a seam welding wire in which irregularities are formed on the surface of the seam welding wire that contacts the material to be welded,
Seam welding is also characterized in that a chrome-plated steel plate with an uneven surface is wrapped using a wire with an uneven surface in contact with the material to be welded, and the lapped portions are joined. It is about the method.

In the present invention, as described above, unevenness is formed on the surface of the seam welding wire (electrode) that contacts the material to be welded, and the contact surfaces of the wire 1 and the steel plate 2 as shown in FIG. 2 are also uneven. By bringing the surfaces into contact, the overall contact resistance is reduced and weldability is improved. That is, the welding is performed by forming irregularities 3 on the surfaces of the wires 1 and 1a that come into contact with the steel plate 2. However, when it comes to forming irregularities on a wire, the diameter is 0. OL”10μm, height 0.0
It is sufficient to form a convex portion of 0.01-0.1 μm, and this convexity is caused by the convexity and convexity formed on the surface of a chromium-plated steel plate as described below.
This range is preferable for welding (reducing current resistance).

Further, the distribution of the unevenness is preferably 0.1 to 50% in terms of area ratio.

For example, in general, seam welding wire is made by passing a copper wire with a circular cross section between rollers and flattening it to ensure contact at the welded area. At this time, the wire is flattened using a roller with slight irregularities formed on its surface, and at the same time, irregularities are formed on the surface of the wire that comes into contact with the material to be welded.

Next, the unevenness to be formed on the surface of the chrome-plated steel plate is as follows: The diameter of the protrusions is 30 to 300+im, and the number of protrusions is 1.2 x 10'.
1, OX 10" pieces 7 m 2 may be formed uniformly.

As a forming method, for example, a chromium-plated steel plate is formed using Cry,
By anodizing the upper layer using chromium as the main agent, removing a part of the chromium oxide on the upper layer, and then electrolyzing the chromium-plated steel plate as a cathode to apply chromium plating on the upper layer, or Cr plating using Cry as the main agent. The unevenness is formed on the metal chromium surface by repeated intermittent energization in the air.

Next, the amount of chrome plating is 30 for a steel plate for one can.
~200mg/m'', with 3~20mg/m of oxide on top layer
m2 (as the amount of chromium) is sufficient and can be used as is as a steel sheet for cans. However, for example, chromium oxides generated during chromium plating can be removed by immersion in a plating solution or drag-out tank bath, or by washing with water. ,Cry
It is also possible to generate new homogeneous chromium oxide on metal chromium by electrolysis or the like in a separate bath containing chromium as the main ingredient.

[Example] Next, examples of the present invention will be listed together with comparative examples.

The chromium-plated steel sheets and wires are shown in Table 1.

Note 1: The original plated plate is made of ordinary steel and has a thickness of 0.19mm.

Note 2: Wire composition is copper.

The welding conditions and weldability are shown in Table 2.

Note 3: The appropriate welding current range is a welding current of 2000 to 30
Welding is performed by changing the value in sequence within the range of 00A, and the lower limit is the welding strength.
The upper limit was determined based on dust generation. What is the welding strength?

The welded portion was processed using a DuPont impact tester, and the presence or absence of peeling cracks was evaluated, and the occurrence of dust was evaluated based on the presence or absence of dust visually observed.

Note 4: Two stacked test steel plates are loaded with 50kgf from above and below using an electrode shaft wrapped with a copper wire that has been flattened in a specified manner.
Pressurize with 1. A small current of OA is applied to the plate ~ plate and plate ~
The voltage between the electrodes (copper wire) was measured and the contact resistance was calculated. (The buckle resistance of the I plate and copper wire is small compared to the contact resistance and can be ignored.) As seen in Table 2, the embodiments of the present invention have a wide range of appropriate welding current, and the contact resistance between the electrode and the plate is also small. small.

[Effects of the Invention] When the seam welding wire and seam welding method of the present invention are used, local heat generation and dust generation near the steel plate-wire contact surface can be improved, and stable and smooth seam welding can be performed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional seam welding method using a wire, and FIG. 2 is an explanatory diagram showing a seam welding method using a wire according to the present invention. Patent applicant Nippon Steel Corporation

Claims (4)

[Claims] (1) A seam welding wire with unevenness formed on the contact surface of the seam welding wire to the material to be welded. (2) A seam characterized by wrapping a chromium-plated steel plate with an uneven surface using a wire with an uneven surface in contact with the material to be welded, and joining the lapped parts. Welding method. (3) The unevenness has a diameter of 0.01 to 10 μm and a depth of 0.00
The seam welding wire according to claim 1, wherein the unevenness is formed by forming convex portions of 1 to 0.1 μm in an area ratio of 0.1 to 50%. (4) The wire that formed the unevenness has a diameter of 0.01~
The seam welding method according to claim 2, wherein the wire is a wire having convex portions of 10 μm and a depth of 0.001 to 0.1 μm with an area ratio of 0.1 to 50%.