JPH01215492A - Backing flux for one side arc welding - Google Patents

Abstract

PURPOSE:To improve the shape quality of a back bead and to reduce the welding cost by contg. the nickel slag of specified wt.% in the backing flux for one side arc welding. CONSTITUTION:A backing flux is formed by adding a coking binder, deoxidizer melt flux, etc., so as to attain at 30-90wt.% for the total flux by adjusting the grain size by crushing a nickel slag by mechanical crushing, etc. The nickel slag contains the components of SiO2 and MgO at the rate of about 6:4 in the components composition to lower the m. p. The melting in welding thus becomes smooth and the smoothness of a back bead shape and the conformability of an end part are improved. The MgO component improves the refractoriness of the flux and SiO2 betters the viscosity of a melting slag. The shape quality of the back bead is thus synthetically improved and the welding cost is reduced because of the nickel slag being inexpensive.

Description

[Detailed Description of the Invention] (Field of Industrial Application) - The present invention relates to backing bracks for single-sided arc welding used in the construction of steel structures such as ships, offshore structures, storage tanks, steel frames and bridges, and further relates to This article relates to an improvement in the composition of a granular backing material for single-sided arc welding that is pressed against the back surface of a groove of a material to be welded to form a back bead.

(Prior art) Single-sided arc welding refers to backing blacks 2 housed in a fire-resistant canvas cloth on the back surfaces of the grooves of the materials to be welded 1a and lb that are butted together as shown in m1Q (a) and (b). Alternatively, the backing 7 hooks 2 spread in a layer on the copper dowel 4 are pressed down with an air hose 3, etc., and the welding wire 5 is applied to the welding wire 5 only from the front side to form a bead 6 on the front and back sides of the material to be welded. , is a high-efficiency welding method for completing joints, the former being called the 7-foot welding method and the latter the 7-foot copper joining method. In addition, in the normal single-sided 7-layer welding method, single-width welding is performed on a workpiece with a plate thickness of 10 to 40 s+m using 2 to 3 electrode welding, so the heat input is large compared to normal double-sided multilayer welding. This will be welding. .

In order to obtain a sound back bead in such high heat input single-sided 7-way welding, the backing device, welding conditions, and 7-way welding performance are important factors, as shown in Figure 51. The back bead is formed by the backing 7 luffs,
Characteristics of backing 7 lux for single-sided arc welding method,
In other words, the composition, physical properties, etc. are extremely important.
That is, in the case of single-sided arc contact, it is required to produce a smooth back bead with good conformability at the end, but for this purpose, it is necessary to create a smooth back bead with good conformability at the end. It is necessary to generate blowfish, and fire resistance is also required to uniformly control the back bead even in high heat input welding. On the other hand, the bulk density and particle size distribution are important physical properties, and these are related to the adhesion of the backing upcus to the groove bottom and the amount of slag generated, and the remaining 11
9. It is related to the amount and shape of excess buildup, gas defects, and the occurrence of stiffness.

Traditionally, in such single-sided arc welding, Ca
Nord 7 FAX, which is mainly composed of oxides such as OlMgO%5iOz and Altos, Pond 7 FAX, which is granulated by adding metal powder such as a deoxidizing agent to the raw materials of these components, or simply mechanically mixing the raw materials. 7 faxes are used, and furthermore, 7 fax backings in which the particle surfaces are coated with an organic binder are used. Here, the organic binder refers to resins or carbohydrates, etc. During welding, these binders melt due to welding heat and exhibit caking properties, which solidifies the backing black and strengthens its puffing effect, resulting in uniform uniformity. Demonstrates excellent effect on back and one-do formation.

Many proposals have been made regarding the above-mentioned Ura-A-7 Futsukus, but one of the most representative ones is the
There are 7 lacs on the back disclosed in Japanese Patent Publication No. 68744, Japanese Patent Publication No. 49-27497, and Japanese Patent Publication No. 13248-1988.

However, all of these urata blacks have advantages and disadvantages, and do not have satisfactory performance in all respects. However, in the case of meltbucks, it is necessary to melt them once during the manufacturing process, and large amounts of high melting point oxides such as MgOlAllow and CaO cannot be added, resulting in high heat input welding. cannot obtain the high fire resistance required for
Publication No. 7 discloses the use of bonded arapex, which is made by granulating raw material powder with water, but bonded arapex has a small bulk density, and therefore has the disadvantage that the amount of slag produced is small and the back bead tends to be excessively large. In addition, since it is easily powdered, its quality deteriorates once it is used, making it impossible to recycle it and making it economically disadvantageous. Furthermore, Japanese Patent Publication No. 44-13248 discloses a machine-mixed raw material powder with a base of 7 lux, but when raw material powders are simply mixed, the particle size structure of common raw materials inevitably becomes fine, and S Afterlife〃・
A major problem is that gas escape is poor and gas defects are likely to occur.

(Issues to be Solved by the Invention 1) The present invention solves the problems of the conventional single-sided arc S welding method as described above, namely, lack of fire resistance, excessive bulk density, or 1.
To provide a backing 7 hooks that can completely solve defects and the like and obtain an excellent back bead free of defects.

(Means for Solving the Problems) The main point of the present invention is that in a single-sided arc S bale backing 7fukus mixed with raw materials, 3 nickel slags are added to the total weight.
Single-sided arc S characterized by containing 0-95 t%
Back for m 7? It's Tsukusu.

(Function) The inventors of the present invention previously disclosed in Japanese Patent Application No. 62-33197 that the present invention contains 30 to 98% by weight of nickel slag for the purpose of improving the bead shape in low heat input welding, high speed welding, or fillet welding. 7 for submerged arc welding characterized by
I suggested Lux.

The present invention was made after further investigation into the effects of nickel slag, and it was discovered that nickel slag has a great effect on improving back bead r in high heat input single-sided arc welding.

Nickel slag in the present invention means slag discharged during the Ni manufacturing process. Jllll, Ni
Bullion is produced by melting and reducing Ni-containing ore in an electric furnace or the like and recovering Ni. Nickel slag is the slag after Ni is removed from nickel ore. The composition is SiO*50"66w
t%, MgO30=40wt% as the main component, and A
It is composed of 5 wt% or less of ItOs, 5 wt% or less of Ca, etc.

This composition comprehensively shows the composition of general nickel slag, and in actual use, the composition can be controlled within a narrower range.

In the present invention, the above-mentioned nickel slag is used which has been granulated by suitable pulverization means such as mechanical pulverization or air pulverization.

In the present invention, nickel slag is the main component and 30 to 95 t% is added to the entire 7Fax.
This is because s and its content ratio are extremely effective as a composition of backing upx.

First of all, MgO improves the fire resistance of Aufukus whose melting point is < (2800℃), and even in high heat input welding such as single-sided, single-layer arc welding, it can completely control back bead formation and obtain a uniform back bead. I can do it. On the other hand, the melting temperature of S i 01 is not very high at 1700°C, but it is extremely useful for increasing the viscosity of the molten slag and obtaining a smooth and well-fitting back bead.

Furthermore, the compositional advantage of nickel slag is that the ratio of Si02 to MgO in nickel slag is approximately 6:4, which is almost the same as the eutectic composition formed in the Si01-MgO system. , which lowers the actual melting point and
The melting during welding becomes smooth, and this is extremely effective in improving the smoothness of the back bead shape and the conformability of the gong end.

Furthermore, nickel slag is a strong crystalline compound, −
Once adjusted to an appropriate particle size range, it can be used as is without any special granulation. The particle size of the nickel slag can be adjusted to the same particle size as the normal backing 7 lux, and it is usually preferable to set the particle size to about 100 to 2400 μ-.If the particle size is in this range, gas release during welding will be prevented. The material is also good, and there is no fear of gas defects unlike the conventional raw material mixed type backing 7x.

In addition, since the particles are strong, they will not turn into powder during use.
The parts that do not turn into slag during welding can be recovered and used as many times as needed.

The effects of the present invention as described above can be obtained when the amount of nickel slag added to the 7-fucks is 30 wt% or more, but if it exceeds 95 wt%, it is necessary to add other components necessary for the backing 7-fucks. Therefore, it is necessary to reduce the 95 Wisdom to 1% or less.

As for the other components of the lining and sourdough of the present invention, a caking binder, a deoxidizing agent, a granular raw material, a melt 7x, an assorted bond 7x, etc. are added as appropriate depending on the purpose.

Caking binder means a substance that melts with heat and solidifies 7 fax, such as synthetic resins such as phenol resin and epoxy resin, natural resins such as cachet nut a liquid, starch, and carbohydrates such as dextrin. By adding an appropriate amount of one of these substances, it is melted by welding heat in the area in front of the arc in the direction of welding progress, solidifying the powdery backing 7 hooks, and turning the backing 7 hooks into a groove. It prevents the back surface from moving or being blown away by arc force or space pressure, and also improves the puffing action itself. The appropriate amount of the caking binder added to the total backing black is 2 to 10 wt%.

Next is the deoxidizing agent.This can be a normal deoxidizing agent such as Si%Mn or AI, but as for the particle size, fine powder tends to cause segregation, so the particle size is 7 lux! It is necessary that the granularity is about the same as I.

As the particle size raw material, available materials such as silica sand, zircon sand, rutile, etc. having a particle size comparable to that of 7x are used as appropriate. Nord 7 Lux and Bond 7 Lux may be added in amounts that do not impair the advantages of the present invention.
I can do things.

In the form of the backing 7 lacs of the present invention, the above-mentioned raw materials are blended into an appropriate composition and mixed using a machine. However, since the caking binder is not necessarily available in granular form, it is necessary to prepare a suitable solvent in advance. The caking binder is prepared as a bath liquid by dissolving it in a bath liquid, and is stirred and mixed with the mixed backing alax to coat or adhere the caking binder to the particle surface.

The application of Melt 7 Hooks and Bond 7 Hooks in the present invention means that they can be added either purely or as an auxiliary addition, but in the case of Melt 7 Hooks, the particle strength is sufficiently strong, and from a compositional point of view. If permissible, it may be used in a slightly larger amount without impairing the effects of the present invention.

It is preferable that the backing material of the present invention has a particle size in the same range as the nickel slag particle size, that is, in the range of about 100 to 2400 μm, in order to ensure good slag removal properties.

(Example) First, eight types of A-back blanks F1 to F8 as shown in Table 1 were produced. Among Fl to F8, F1 to F6 are examples, and F7 and F8 are comparative examples.

Among these backing blanks, all except F6 had phenol resin or dextrin added as a caking binder.

Urato blanks! The manufacturing method is to first mechanically mix the raw materials other than caking bangu, then dissolve the phenolic resin in ethyl alcohol, and the dextrin in hot water.
After making it into a liquid, mix it with other raw materials and stir.
It was dried at ℃ to obtain a backing blank.

The raw materials used to make these backing blanks are shown in Table 2. Nickel slag is 21! JI! [Later was used, but it has the same composition, and the particle size range is $2.As shown in the table, there are two types: coarse particles and relatively fine particles. In addition, the other raw materials used were relatively coarse in particle size. This is a consideration to improve the leakage. Further, the nickel slag was not mechanically pulverized, but molten slag was pulverized by air and then sized and used.

Next, the secret number 7 on the first table? Tsukusu as police officer 1 and 7? One-sided arc f# welding method using Tsukusunozufuking and black-suction copper backing method was carried out, but the test steel plate in this case,
The test wire and Table 7 facsimile are shown in Tables 3 and 4, respectively.
Omote t! Table 5 shows the welding conditions for single-sided arc ff# contact, and Table 6 shows the groove shape.

The combinations of these test materials and welding conditions are shown in the left column of Table 7, and the observation results of the back bead appearance after single-sided arc welding are shown in the right column of Table 1117.
Regarding 6, it is Xiaomi that obtains a satisfactory back bead without defects such as leakage or casting. Jj%No, 7,
Regarding No. 8, the effect of the present invention could not be obtained due to too little or too much nickel slag, and the back bead shape, smoothness, etc. were deteriorated.

(Effects of the Invention) As described above with respect to the embodiments of the present invention, the present invention makes it possible to obtain a stable and excellent back bead shape in high heat input single-sided 7-tS rolling.

[Brief explanation of the drawing]

Figures 1 (a) and 1 (b) are front views for explaining the single-sided arc welding method, and Figure 1 (a) is a diagram showing the 7-lux packing method, and Figure 1 (b) is a diagram showing the 7-rack packing method. Fig. tPJ2 is a front view showing the groove shape used in the example. 1a, lb... material to be welded? ... K To Blacks,
3... Air hose, 4... Copper dowel, 5... Welding wire, 6... Bead, 7... Fireproof canvas.

Claims (1)

[Claims] (1) In backing flux for single-sided arc welding mixed with raw materials, nickel slag is 30 to 95w relative to the total weight.
A backing flux for single-sided arc welding characterized by containing t%.