JPS61262488A - Backing strip for one-side welding - Google Patents

Abstract

PURPOSE:To improve the quality of one-side welding by sticking a treating agent consisting of Te, Se, etc. alone or contg. the compd. thereof onto the surface of an inorg. fiber layer and providing a penetration bead forming layer. CONSTITUTION:A ceramic fiber tape consisting of SiO2, Al2O3, etc. is immersed into water suspended with powdery TeO2 and is then pulled up and dried. The treating agent contg. Te, Se, REM or Sb alone or 1 or >=2 kinds of the compds. thereof is stuck onto the surface of the inorg. fiber layer by such method. A groove is formed to steel plates 1, 1 and the penetration bead forming layer 2 stuck with such treating agent is disposed on the rear side thereof, then the steel plates are subjected to one-side welding. The surface active agent element such as Te or Se plays the role of decreasing the surface tension of a molten steel and decreasing the fluidization thereof thereby contributing to the improvement of the fluidity of the molten steel. The wettability between the molten steel and the non-melted part of the base metal is thus improved and the quality of welding is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention Industrial Field of Application The present invention relates to a backing material for single-sided welding in welding metal materials.

Specifically, it relates to a backing material for welding only from one side of the material to be welded, which makes it possible to omit reversing and back lifting of parts in order to streamline the assembly process, and also to omit back welding in an upward position. be.

Conventional technology Conventionally, powdered flux, solid flux obtained by solidifying the flux with water glass, inorganic fibers such as glass fibers, or composite materials combining these have been used as the back bead forming layer of the backing material. There is.

Among these, the backing material with inorganic fiber as the back bead forming layer is
Special Publication No. 45-5133, Special Publication No. 40-27168
As is known from Japanese Patent Publication No. 33-1110, it has good flexibility and can be easily applied to single-sided welding of grooves with misalignment or curved welding such as welding of steel pipes. It has the following advantages.

However, raw materials and material components for inorganic fibers are severely limited from the viewpoint of productivity, and raw materials with good productivity generally contain components that melt into the weld metal and adversely affect the quality of the welded part. This often results in deterioration of physical properties and appearance.

For example, inorganic fibers whose main raw materials are S i 01 and A I, 03, etc. increase the viscosity of molten slag during welding, which in turn inhibits the fluidity of molten steel and causes unevenness, undercuts, and overlaps on the back bead. It has the disadvantage of causing In order to solve this problem, if a large amount of B2O3 is mixed in as a component to lower the viscosity of the molten slag, cracks will easily occur in the back bead.
35488), and it could not be said to be practically satisfactory.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned drawbacks.In order to improve the appearance of the back bead, it is necessary to reduce the surface tension and viscosity of molten steel. We believed that it was necessary to take concrete measures to improve the wettability between molten steel and the non-molten part of the base metal, and we have been conducting research on the effect of adding a third component.

The present invention was completed as a result of such research, and its purpose is to provide a beautiful and metallurgically sound back bead appearance and undercut without losing the usefulness of the inorganic fiber as a back bead forming layer. , no overlap etc.
That is, the object is to provide a backing material that is optimal for single-sided welding and is inexpensive.

Structure and operation of the invention The structure of the present invention is a cloth-like fabric that has been generally manufactured in the past.
The main component is an inorganic fiber layer in the form of a mat or tape, and at least on the surface thereof, Te, Se, REM,
The gist of the present invention is a backing material for single-sided welding characterized by having a back bead forming layer to which a treatment agent containing one or more of Sb alone or a compound is adhered.

Means to Solve the Problem Te, Se, REM (
By using as a backing material for single-sided welding a single substance of sb (rare earth metal) or one or more compounds containing either of these substances, it is possible to remove these substances during welding. The deposits move into the molten steel, lowering the surface tension of the molten steel and promoting its fluidity and wettability with the unfused parts of the base metal.

The inorganic fibers constituting the back bead forming layer of the present invention include mineral fibers, natural fibers such as asbestos, metallic fibers such as steel fibers and tungsten fibers, and ceramic fibers such as rock wool, glass fibers, ceramic fibers, and slag wool. The main component is inorganic components such as quality fibers, carbonaceous fibers, and various whisker fibers, and if necessary, additives such as appropriate organic fibers and adhesives are also included.

1 of Te, Se, RE M, Sb in the present invention
As a treatment agent containing one or more species, the above-mentioned substances alone or compounds containing them may be used as the main component, and appropriate additives such as water, solvents, adhesives, dispersion aids, etc. may be added as necessary. It's also good.

The common effect of Te, Se, REM, and Sb is to lower the surface tension of molten steel. In other words, these are surface-active elements that improve the fluidity of molten steel during single-sided welding and improve the bond between molten steel and base metal. This improves the wettability with the molten part and makes the appearance of the back bead smooth, making it possible to obtain a beautiful back bead without undercuts or overlaps.

The backing material for single-sided welding according to the present invention is produced by dispersing the treatment agent to be attached to the inorganic fibers in water or a solvent, and adding appropriate dispersion aids, adhesives, and penetrants as necessary. Making it cloudy and dipping an inorganic fiber layer in the form of cloth, mat, tape, etc., or conversely, adhering it by a method such as spraying the suspension with a spray gun, etc., or applying it with a spatula, etc. It is also possible. In addition, it can also be obtained by mixing and molding the above-mentioned processing agent together with the inorganic fibers when forming and bonding the inorganic fibers into cloth, mat, tape, etc.

In addition, by cutting the backing material for single-sided welding in the present invention into a continuous size and installing it at the bead starting end, it can also be used as an end tab for welding, and the tab and bead starting end can be used like conventional iron tabs. This eliminates the need for gas cutting or grinding at the bead starting end.

Further, in the backing material for single-sided welding of the present invention, the back bead forming layer obtained by the above-mentioned treatment can be used alone, but it can also be used in combination with a fire-resistant solid or granular material.

Various application examples will be explained with reference to FIGS. 1 to 4.
The method shown in the drawings is only one example, and any method using the back bead forming layer of the present invention may be used, and the method is not limited to these drawings.

FIG. 1 shows a method according to the present invention in which only the back bead forming layer is used alone as a backing material for single-sided welding.

FIG. 2 shows a method suitable for submerged arc welding or a welding method using a large current, and is a method in which a pad made of copper or other heat-resistant material is used in combination under the back bead forming layer in the present invention.

FIG. 3 shows a method of combining solid refractory materials such as silica, zirconia, magnesia, etc.

FIG. 4 shows a method of using it in combination with powdery refractory materials made of silica, zirconia, magnesia, etc.

(For the instruction numbers in these drawings, refer to the brief description section of the drawings.) Example 1 Ceramic fiber tape (thickness 3.Osm, width 4.0
0 mm, length 600 mm) was immersed in water in which powdered TeO2 was suspended, and then pulled up and dried.

In this case, the amount of T e 02 deposited was 4 g/♂ based on the surface area of the ceramic fiber.

Next, a backing material was prepared using this tape as a back bead forming layer, and single-sided welding was performed as shown in FIG. 1 under the following conditions.

Welding conditions Welding wire: Solid wire for carbon dioxide gas diameter.
1.2m intestinal base material...5M50A (25mmt) Bevel angle...
60 degrees V Shielding gas: 100% carbon dioxide gas, 2017 minutes Other conditions - 24OA, 26V, 20 cm/min As a result, the back bead shape of the resulting joint was uniform in both height and width, and had good gloss. There was no undercut or overlap.

Comparative Example 1 Using a ceramic fiber tape having the same chemical composition and shape as in Example 1, single-sided welding was performed under the same welding conditions without the above treatment.

The shape of the back bead of the resulting joint was highly uneven, with undercuts and overlaps occurring, and the appearance was clearly poor.

Example 2 Chemical components S i Oa 40%, AI, 0.20%, C
a030%, Mg07%, FeA2%, MnO1%
Rock wool paper (thickness 4.0mm, width 6mm)
0■, length 800 Wm1), 5eO1, monazite (
They were each immersed in water in which Sb (containing 45% CeO and 24% LaO), Sb, and O were suspended separately, and then pulled up and dried.

In this case, the amount of each treatment agent deposited was 8 g/male based on the surface area of the rock wool paper.

Next, three sheets of the same type of paper were stacked to form backing materials each serving as a back bead forming layer, and single-sided welding was performed under the same welding conditions as in Example 1.

As a result, the shape of the back bead of the joint obtained is as follows.

In all cases, as in Example 1, the height and width were uniform, the gloss was good, and there were no undercuts or overlaps.

Comparative Example 2 Three layers of rock wool paper having the same chemical composition and shape as in Example 2 were used, and single-sided welding was performed under the same welding conditions without the above treatment.

The shape of the back bead of the resulting joint was highly uneven, with undercuts and overlaps occurring, and the appearance was clearly poor.

Example 3 Chemical components S i Oz 72%, AI 20.2%, Ca
Glass fiber mat (thickness 2II11, width 50mm, length 6
00 mm), Te, FeSe, monazite (La0
A suspension obtained by adding 1,1,1-trichloroethane to a mixed powder of (24% CeO, 45% CeO, 5bLs) was dried by spraying with an i-spray gun.

In this case, the adhesion amount of the mixed powder was 2 g/m with respect to the surface area of the glass fiber.

Next, we stacked three of these mats to create a back bead forming layer, and as shown in Figure 2, we laid a 61111-thick copper pad under it, and applied them from below to the back of the steel plate. single-sided welding was performed under the following conditions.

Welding conditions Welding wire: Wire for submerged arc welding Diameter: 6.4 mm Base material: 5M50A (18+5lt) Bevel angle:
・50 degree V flux... Sintered type flux and other conditions ・1100 A, 36 V, 35 cm/min As a result, the back bead shape of the resulting joint has a smooth surface,
It was also defect-free and in very good condition.

Comparative Example 3 Using a glass fiber mat having the same chemical composition and shape as in Example 3, single-sided welding was performed under the same welding conditions without the above treatment.

As a result, the shape of the back bead of the resulting joint was extremely uneven, with undercuts and overlaps occurring, and the appearance was poor.

C. Effects of the Invention As explained in detail above, the present invention is a backing material for single-sided welding in which the back bead forming layer is made of an inorganic fiber layer with a surface-active element attached as a single substance or a compound. Active elements are effective in lowering the surface tension and viscosity of molten steel, improving the fluidity of molten steel, smoothing the surface of molten steel, and improving wetting between molten steel and the non-molten parts of the base metal. This has excellent effects in that it does not cause undercuts or overlaps, and does not impair the advantages of the inorganic fiber layer, such as flexibility.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are schematic vertical cross-sectional views showing how one-sided welding is performed by various methods using the bracing material of the present invention. (1) Steel plate (2) Back bead type tL layer in the present invention (3)
...Filling made of copper or other heat-resistant material (4)...Solid refractory material made of silica, zirconia, magnesia, etc. (5)...Powdered refractory material made of silica, zirconia, magnesia, etc. (6)- ... Campus (7) ... Air hose (8) ... Gutter

Claims (1)

[Claims] 1. Te at least on the surface of the inorganic fiber layer
, Se, REM, Sb alone or one or two of their compounds
A backing material for single-sided welding, characterized in that it has a back bead forming layer formed by adhering a treatment agent containing at least one species.