WO1986003442A1

WO1986003442A1 - Electric-resistance seam-welding method

Info

Publication number: WO1986003442A1
Application number: PCT/JP1984/000583
Authority: WO
Inventors: Makoto Kabasawa; Moriaki Ono
Original assignee: Nippon Kokan Kabushiki Kaisha
Priority date: 1983-06-10
Filing date: 1984-12-10
Publication date: 1986-06-19
Also published as: JPS59229290A; GB8612297D0; GB2178682A; DE3490793T1; CH668930A5; GB2178682B; JPS6324795B2

Abstract

This electric-resistance seam-welding method for welding difficult-to-weld steel plate suppresses the generation of burrs. The steel plate has coating layers of a metal harder than tin and an intermetallic compound. The thickness of the steel plate is not more than 0.5 mm. The overlap width of the steel plate is greater than 2.0 times the plate thickness, but is less than 2.4 times the plate thickness. The weldable current range of steel plate can be increased by this means.

Description

Specification

Electric resistance seam welding method

Technical field

The present invention relates to a welding method in which an electric current range for welding is expanded in electric resistance seam welding of a can body using a difficult-to-weld material, for example, tenfly steel. It is a thing.

Background technology

In recent years, due to the diversification of food container canning methods i, electric resistance seam welding, for example, copper wire resistance seam welding, has been remarkably developed as a method for manufacturing cans. ing .

As shown in Fig. 1, the copper wire resistance seam welding method is used to connect the copper wires ( ² ) wound around the upper and lower electrode electrodes ( ³ ). The longitudinal edge of the can body plate (1), which has been formed into a tubular shape in advance, is passed while being overlapped with a predetermined width, and the overlapping portion of the can body plate (1) is passed through the upper and lower roller electrodes (3). In this method, pressure and current are applied via the copper wire (2), and welding is performed continuously for 1 to 1 due to electric resistance heat generated at the overlapped portion.

Here, as shown in Fig. 2, the vertical edge of the can body (1) is connected to the guide groove using a Z-shaped guide bar ( ⁴ ).揷 People are superimposed on each other. This overlapping width is determined by the Z-shaped guide bar (4) where the vertical portions are overlapped, and the can body diameter determining hole disposed around the upper and lower electrodes (electrodes). ? It is determined .

The quality of the welds depends on the joint strength, airtightness and It is evaluated based on the appearance properties. Bonding strength and airtightness are problems related to leakage of the contents.To satisfy these characteristics, it is necessary that the heat generated by electric resistance at the bonding interface exceeds a certain limit. . From this, the minimum value of the welding current is determined. In addition, it is necessary that burrs exist as the appearance properties. Normally, after welding, the seam weld is covered with a protective paint.However, the presence of burrs can cause problems with paint application, ¾D, and exposed parts that are not covered with paint. When using a can body, the contents do not react with the burrs and change quality, and the burrs may peel off from the can body and be mixed into the contents. . In the burrs, molten metal scattered from the seam weld and adhered near the seam weld. In order for no pallets to exist, it is necessary that the heat generated at the junction interface be below a certain limit. From this, the maximum value of the welding current is determined. -If the minimum and maximum values of the welding current determined from the joint strength, airtightness, and appearance performance for evaluating the quality of this seam weld are defined as the lower limit current value and upper limit current value, respectively, The proper current value range for welding is a range where the value obtained by subtracting the lower limit current value from the upper limit current value is a positive value i, and the quality of the weldability of the container material depends on the width of this proper current value range. Is determined.

The steel material for containers used in this welding method is required to be excellent in various properties such as corrosion resistance, workability, paintability, etc. required for steel plates for containers, and also excellent in weldability. You. As a container steel material, soldering cans (tin adhesion of 2.8 f / rri or more) have been the mainstream, but new materials (steel materials) have been developed in recent years. When these materials are subjected to the electric resistance seam welding method, soldering cans and thinner cans are obtained! In some cases, the appropriate current value range is wide and the weldability is extremely good. However, a part of the thin solder and the tin-free steel have a narrower welding current range than the solder can and have poor weldability.

Tin-free steel is liable to generate burrs during welding, and if the welding current is reduced to suppress the formation of pallets, the joint strength and adhesion will not be sufficient. You.

Conventionally, the surface of the overlapped portion and the edge of the blank, which is to be overlapped, is exposed beforehand by exposing almost the entire iron surface by mechanical means such as a zipper. Electric resistance seam welding was being performed. However, these mechanical means increase the number of work steps, and further increase the number of work steps.9 The fine powder removed is not completely removed from the steel sheet surface and reattached, causing various inconveniences in the subsequent steps. Give rise. Moreover, the exposed surface of the iron after removing the surface coating has disadvantages such as lack of corrosion and impaired appearance. For this reason, tin-free steel is still in use in canned food cans.

The present invention solves the above-mentioned drawbacks, and performs any special pretreatment of a material for food containers, which is difficult to weld by electric resistance seam such as tin-free steel. Not easily It is intended to provide an electric resistance seam welding method that enables welding.

Disclosure of the invention

The present invention relates to an electric resistance seam welding method for a hard-to-weld steel plate! The steel sheet has a coating layer of a metal and an intermetallic compound harder than tin as a coating layer, and the thickness of the steel sheet is in a range usually used as a material for cans, that is, 0.5 or less. However, the overlapping width of the steel sheet is more than 2.0 times the sheet thickness and less than 2.4 times. As a result, the appropriate current range for welding the above steel sheet is expanded, the occurrence of burrs is suppressed, and the weldability is improved.

Brief explanation of drawings

Fig. 1 is an illustration of the copper wire resistance seam welding method, Fig. 2 is an illustration of the copper wire resistance seam welding method shown in Fig. 1, and Fig. 5 Fig. 4 is an explanatory view of the welding condition of the seam welded part of the tin free steel. Figs. 4 and 5 show the material plates for the tin free steel. FIG. 4 is a characteristic diagram showing a relationship between a ratio of a thickness to an overlap width and a welding current.

(1) can body plate, (2) copper wire, (3) roller electrode, (4) Z-shaped guide bar, (5) ground iron part, (6) ... Metal chromium layer, (7) hydrated chromium oxide layer, (8) welding current path, (9) molten metal,

(10)… Vari, (a)… Lower limit current value, (b)… Upper limit current value, (c)… Appropriate current value range.

BEST MODE FOR CARRYING OUT THE INVENTION ΟΙΛ * ---

"" The inventor of the present invention elucidated the weldability from the viewpoint of welding phenomena in order to solve the problem of welding difficult-to-weld materials. As a result, the following became clear.

In the case of soldering cans with good weldability, despite the fact that the hydrated oxide of the chemical conversion coating is an electrical insulator, the tin on the base is soft and the electrode The chemical conversion coating easily breaks and disperses, and a large energized area can be obtained. Therefore, electric resistance heat is generated uniformly at the joint interface, and a high-temperature softening region is obtained in a sufficiently wide range while molten metal is generated.Pressure welding is performed at the joint interface due to large plastic flow. And a good seam is obtained.

On the other hand, the tin free steel, which has poor weldability, is located under the chemical conversion coating ( ⁷ ), as shown in the schematic diagram of the seam weld formation in Fig. 3. Since the metal cup (6) is extremely hard compared to tin, the chemical conversion coating is not sufficiently ruptured by pressurization of the electrode.9 The current flows locally and unevenly during welding. become . Therefore, the molten metal (9) is formed at a relatively low current value. However, since the high-temperature softening region is not sufficiently formed, and the effect of confining the molten metal by plastic flow is weak, the molten metal is easily scattered and the barrier (10) Will form. However, it became clear that the joint strength and airtightness could be obtained relatively easily even by local joining.

As a measure to improve the weldability of difficult-to-weld materials, a conventional material list was used to prevent the generation of molten metal due to local heat generation. This is mainly due to the reduction in the amount of surface chemical conversion coating (the amount of chromium metal and chromium hydrate oxide).

As a result of elucidating the welding phenomena, the inventor of the present invention believes that it is effective to increase the force for suppressing the scattering of molten metal in order to improve the weldability of difficult-to-weld materials. Therefore, optimization of the seam welded shape (overlap width) was studied.

The superposition width that has been used conventionally is more than a4, observation and 0.8 Nada! The weldability when using these overlapping widths is described below! ). For example, when using a fin-free steel with a material thickness of 0.22 rinsing, if the overlapping width is 0.4 rinsing, the seam welded portion will overlap the material thickness. It's too small to fit together j? However, the effect of suppressing the scattering of the molten metal is weak, and the weldability is reduced. When the overlapping width is 0.0 baskets, the overlapping margin is large and the force per unit area decreases, so that the generation of molten metal due to local heat generation is promoted, and Good joints can be obtained because the ability to suppress the scattering of molten metal is weak.

It is presumed that there is a certain appropriate value for the overlap width, but in general, it is advisable to reduce the overlap allowance of the seam welded part in order to improve weldability. The overlap width tends to be smaller than the conventional 0.4 haze. As a result, reducing the overlapping width is not an effective measure to reduce the force for suppressing the scattering of the molten metal. In the present invention, it was found that the weldability was significantly improved by setting the ratio of the overlap width to the material thickness to be more than 2.0 times and less than 2.4 times.

In other words, the thickness of the material is 0.22, and the tin free steel (metal chrome amount: 150 / r hydrated oxidation) with temper T — 4 as the original plate is used. Using the copper wire resistance seam welding method, using the amount of the hole in the hole 30), the welding speed 45 / min, the electrode pressure 40 /, and the overlapping width 0.4. Welding was performed with a 0.45 0.5. 5 0.5. 50.0 rinse to examine weldability. As a result, the data shown in Fig. 4 was obtained. Fig. 4 shows the relationship between the overlap width and the material thickness, and the lower limit current a and the upper limit current b of the welding current. In FIG. 4, the region c surrounded by the lower limit current a and the upper limit current b is the appropriate current range.

This is it! In the case of tin free steel, which was previously considered to be non-weldable, the ratio of the overlap width to the material thickness was controlled to more than 2 times and less than 2.4 times! ) It was found that a sufficiently wide appropriate current range, that is, at least 500 A or more can be obtained in consideration of external factors.

In addition, welding occurs in the area where the deformation resistance decreases at high temperatures.) The quality of welding is considered to be affected by both the shape of the weld and the temperature distribution, and the temperature distribution depends on the material thickness. For this reason, Table 1 shows the results of an investigation on the adequacy of the applicable range of the material plate thickness with respect to the above-mentioned appropriate lamination width. table 1

In Table 1, the material TFS is tin-free steel of the chromium type, and the material LTS has a tin adhesion of 0.55 f / rri. The numbers in the table are the ratios of the overlap width to the material thickness, and the weldability evaluation results are indicated by で and X. 〇 indicates that the appropriate current range is 300 A or more and the weldability is good, は indicates that the appropriate current range is more than 0 A and less than 500 A, and X indicates the appropriate current range if the weldability is slightly better. Is negative

This is the case where the weldability is poor. '

(GMFI As a result, it has been found that the appropriate range of the material thickness to which the welding method of the present invention is applied is more than 0.2 mm and less than 0.25 lord.

Table 2 shows the welding test results when various materials were welded with a copper wire resistance seam welding method when the material thickness was 0.22 leakage and the electrode pressing force was 40 k. .

Table 2 Over

顶 Easy appropriate current overlap ^ * accuracy lower limit current

Material Wrap width

Rei A A A Material thickness

E 2.8 / 2.8 4 Π0 3100 1000

L T S 5250 2800 450

Ni Metsuki 5200 2050 550

丄 t> D 6 U 0 c n U O 1 U .nU b cr

E 2.8 / 2.8 4250 5200 Ί 050

L T S 5400 2850 550

0,50 2.27

N i Tsuki 3500 2750 550

T F S 27 U U 2260 440

E 2.8 / 2.8 4Ί 50 5550 800

L T S 2950 2900 50

0.55 2.50

N i Mekki 2800 2800 0

T F S 2500 2580 120

E 2.8 / 2.8 5500 5050 450

L T S

0.40 2700 2750 0

1.82

N i Mekki 2550 2000 0

T F S 2000 2250 0

E 2.8 / 2.8 5700 5400 300

L T S 2850 2950

0.60 0

2.75

N i Mekki 2800 2850 0

TFS 2550 2550 0 The material used for this welding was a tin can with a 2.8 W tin deposit! 2.8 ノ 2.8 鍚ぶぶぶぶぶぶぶぶぶぶぶぶぶぶぶぶぶぶぶ鍚ぶぶぶぶ鍚ぶぶぶぶぶぶぶぶぶ鍚鍚ぶ鍚ぶ. Here, when the ratio of the overlap width to the material thickness exceeds 2.0 times and is less than 2.4 times, all materials have a sufficiently wide welding appropriate current range.

Next, the quality of welding is considered to be affected by the shape of the seam weld, the electrode EE force, and the material thickness. Focusing on the fact that an increase in the electrode pressing force contributes significantly to the improvement of weldability, the electrode pressing force was increased from 40 / to 50 /, and a fin free with a material thickness of 0.1 mm was used. Fig. 5 shows the results of welding experiments using a steel stapling with an overlap width of 0.3, 0.55 inversion, 0.40 basket, 0.45 mm, and 0.50 haze. Shown in Fig. 5 shows the relationship between the ratio of the overlap width to the material thickness and the lower limit current a and the upper limit current b of the welding current, as in Fig. 4. The region c is the proper current range. In this case as well, if the overlap width exceeds 2.0 times, and if it is less than 2.4 times, a sufficiently wide welding appropriate current range can be obtained.

Next, welding experiments were conducted with a wide range of material thicknesses, and the applicable range of material thicknesses was examined. The results are shown in Table 3.

OMFI O 3¾98AViDd if /

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n

1 δ

In Table 5, the material TFS is a chrome-type tin-free steel. The numbers in the table are the ratios of the overlap width to the material plate thickness, and the results of the weldability evaluation are indicated by 〇; X. 〇 indicates that the appropriate current range is 500 mm or more and the weldability is good, indicates that the appropriate current range is more than 0 A and is less than 500 A, and that the weldability is somewhat good. Negative weldability is poor.

As a result, when the overlapping width of the steel sheets exceeds 2.0 times the material thickness and is less than 2.4 times, all the material thicknesses usually used as can materials, that is, the material thicknesses It was clarified that the weldability was improved for 0.5% or less. In other words, it was found that the improvement in weldability does not depend on the material thickness if the ratio of the overlap width of the steel sheet to the material thickness is within the above range.

Compared with soldering cans, container materials with localized and non-uniform electrical resistance heat generation are considered to have inferior weldability to soldering cans. For example, it is known that when the plating metal is harder than tin or when the chemical conversion coating is thick, the weldability is reduced, but the present invention is effective for all such materials. .

Table 4 shows the results when the material thickness is so-called, 0.25 leakage, 0.52 basket, and D-welding of various materials using the copper wire resistance seam welding method. The results of the welding test are shown. Table 4

The materials used for this welding were E 2.8 Z 2.8 for soldering cans with tin adhesion of 2.8 f / rri, and LTS and Ni for ignition with 0.55 f tin adhesion. This is a tin-free steel TFS of the same steel and chrome type. Here, if the ratio of the overlap width to the material thickness exceeds 2.0 times and less than 2.4 times, a sufficiently wide appropriate current range is obtained for all materials regardless of the material thickness. Have.

Industrial applications

As described above, the electric resistance seam welding method of the present invention is used. Is useful for extending the proper current range of difficult-to-weld materials! ), It is suitable for manufacturing welding cans using difficult-to-weld materials that have not been conventionally used for canned foods, such as tin-free steel.

Claims

The scope of the claims

In an electric resistance seam welding method for a hard-to-weld steel sheet having a coating layer of a metal and an intermetallic compound harder than tin, the thickness of the steel sheet is set to 0.5 rinse or less, and the overlapping width of the steel sheet is set. The electrical resistance seam welding method is characterized in that the thickness is more than 2.0 times and less than 2.4 times the sheet thickness.