JPS6186074A - Butt welding method of dead thin plate material - Google Patents

Abstract

PURPOSE:To widen a width of a welding condition for executing an appropriate welding, and to obtain a weld zone of a high quality by giving a stretch of a specified quantity of a weld line direction, to a butt part, when welding a butt part which is butted each dead thin plate material being a base metal. CONSTITUTION:Dead thin plate materials 10, 10 being base metals are butted, and thereafter, a stretch as indicated with an arrow is given to their butt part 12. Subsequently, welding is executed along the butt part 12 by a prescribed welding means 14 such as an arc welding, etc., under the condition that its stretch quantity (tensile strain) : Q satisfies an expression [alpha : a coefficient of linear expansion (1/ deg.C) of the base metal, T : a temperature ( deg.C) at which a deformation resistance of the base metal scarcely comes to exist by heating executed immediately before welding]. In this way, a deformation caused by a free thermal expansion of the plate material 10 is absorbed effectively by the stretch quantity : Q, a deformation of the butt part 12 caused by the free thermal expansion is softened, and the purpose can be attained.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a method of abutting extremely thin plate materials serving as base materials and performing fusion welding along the abutted portions, in particular, by preventing deformation of the abutting portions due to heating. The present invention relates to a method for performing good butt welding.

BACKGROUND TECHNIQUES AND THEIR PROBLEMS Traditionally, when ultra-thin plates with a thickness of about 0.4+n or less are butted together and fusion welded, the vicinity of the butt is mechanically moved, for example using an appropriate positioning jig. However, the butt part itself along the welding line could not be restrained, and as a result, there was a problem that the butt part would be deformed by heating from the welding heat source, such as an arc. .

In the direction perpendicular to the welding direction, as is clear from Figure 2, this appears as deformation in which the edges of the base metal mainly overlap due to free thermal expansion of the base metal (2) due to heating, and also during welding. In the direction, as shown in Fig. 3, the free thermal expansion part (A) of the base metal (2) along the welding direction causes tensile stress in the part (B) in a non-thermal manner, and the free thermal expansion part (A) Expanded part (
When A) receives compressive stress from the non-heat affected zone (B), it mainly appears as waving deformation.

Due to such deformation caused by the heating of the welding heat source, the abutting portion cannot be stably restrained, thus causing welding defects. Furthermore, since the butt portions are easily deformed by heating, it is extremely difficult to set appropriate welding conditions, and conventionally, butt welding of extremely thin plate materials has been difficult.

Solution The present invention has been made to solve such conventional problems, and its feature is that when butt welding extremely thin plate materials that are base materials, the butt part is stretched. The reason for this is that welding is performed under conditions in which the amount of stretch Q in the direction of the welding line satisfies the following formula (1): % formula % (1).

That is, as shown in FIG.
0.10, a stretch (tensile stress) is applied to the abutted portion 12 as shown by the arrow, and arc welding is performed under the condition that the amount of stretch (tensile strain) Q satisfies the above equation (1). Predetermined welding means 14 such as
Welding is performed along the butt portion 12 at the step.

Here, the ultra-thin plate material 10 usually has a plate thickness of 0.4
Various metal plates with a size of about 1 or less are used,
Various methods can be used to stretch the abutting part 12, such as clamping and pulling both ends of the abutting part 12, for example.

In addition, as the welding means 14, various welding methods such as not only ordinary arc welding but also plasma arc, bipulse arc (direct current arc superimposed with high frequency current), laser, etc. can be adopted, but If a heat source with a high energy density is used, the width of the heat affected zone becomes narrower, which is more convenient in preventing deformation due to heating.

Then, if the butt portion 12 is welded in this way,
Since the deformation due to free thermal expansion of the ultra-thin plate material 10 due to heating is effectively absorbed by the stretch amount Q, the deformation of the butt portion 12 due to the free thermal expansion is alleviated,
The range of welding conditions under which appropriate welding can be performed is widened, and high-quality welded parts without weld defects such as welding and waving can be obtained.

Note that if the stretch amount Q is too small, the deformation due to free thermal expansion of the ultra-thin plate material 10 due to heating cannot be sufficiently absorbed, resulting in deformation of the butt portion 12. ) must be set to satisfy the formula.

Next, one embodiment of the present invention will be shown, but this is merely an illustration, and it goes without saying that the present invention should not be interpreted in the same limited manner as the following description.

Example A titanium plate having a thickness of 0.2 mm was used as the base material, and butt welding was performed under the welding conditions shown in Table 1. Note that the coefficient of linear expansion of the titanium plate is approximately 1 x 10-'(1/'c),
The heating temperature at which the base metal is easily deformed by heating immediately before welding is about 700 to 800 ('C).

Table 1*: Arc welding using high-frequency current superimposed on DC-TIC arc Butt welding of extremely thin titanium plates like this was nearly impossible in the past, but as a result of the present invention, the distortion A good welded joint with little was obtained.

In addition, a titanium plate with a plate thickness of 0.2 mm was used, welding method: high pulse arc welding, welding current: 3OA.

When butt welding was performed under the welding conditions of a welding speed of 1.9 m/min and a stretch of 120, burn-through, poor fusion, and insufficient fusion occurred intermittently in the weld, making it impossible to obtain a good weld. There wasn't.

Effects of the Invention As detailed above, if the welding method of the present invention is followed, the deformation due to free thermal expansion caused by heating during welding is absorbed by the amount of stretch, so the deformation of the butt part is alleviated, which is different from conventional methods. Butt welding of extremely thin plate materials, which had been considered difficult, became possible, and it was possible to obtain high-quality welds.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram conceptually showing a specific embodiment of the method of the present invention, and FIGS. 2 and 3 are diagrams for explaining the generation mechanism of deformation that occurs in the abutting portion in the conventional method, respectively. It is. 10: Ultra-thin plate material 12: Butt part 14: Welding means

Claims (1)

[Claims] A method in which ultra-thin plate materials serving as base materials are butted against each other and welding is performed along the butt portions, the butt portions are given stretch, and the amount of stretch in the welding line direction: Q is determined by the following formula: Q≧αT/10 However, α: linear expansion coefficient of the base metal (1/℃) T: temperature (℃) at which the deformation resistance of the base metal is almost eliminated by heating immediately before welding. A unique butt welding method for ultra-thin plate materials.