JPS62212096A - Production of flux cored wire for welding - Google Patents

Abstract

PURPOSE:To produce a flux cored wire for welding which satisfies welding workability by blowing gas of any among Ar, Ar+CO2, etc., into a pipe to substitute the air in an open pipe with said gas before the butt part of the pipe is welded. CONSTITUTION:Both ends of a long-sized strip 1 are bend and formed to a U shape and a flux 2 is packed into a U groove, then the strip is formed to a pipe shape and the butt part of such metallic strip 1 is welded. The gas of any among Ar, CO2 and Ar+CO2 is ejected from a gas blow port 5 at the time when the U-shaped metallic strip 1 is transferred to below a hood 3. The air in the U groove is substd. with the gas and thereafter, the flux 2 is packed into the groove from a flux feed port 4. The flux cored wire for welding which satisfies welding workability and mechanical properties is obtd.

Description

[Detailed description of the invention] Engoku 9” The present invention applies to CO of mild steel, high tensile strength steel, low alloy steel, etc.

The present invention relates to a method for producing a flux-cored wire suitable for use in gas arc automatic and semi-automatic welding.

Conventionally, one method for manufacturing flux-cored wire as described above has been to fill the center hole of a seamless pipe with flux powder and then draw the wire, but automatic welding Alternatively, since the composite wire used for semi-automatic welding is extremely long, filling the center hole of the pipe with flux powder requires extremely complicated work, and it is difficult to fill the entire long pipe with the filling made of the powder. It was extremely difficult to uniformly fill the entire area. Another method for manufacturing flux-cored wire is to bend a long metal strip, fill the bending part with flux, then bend the metal strip further to form a pipe shape, and form the pipe butt part. This is generally done by welding and wire drawing. However, when manufacturing flux-cored wire from such a metal strip, the process of bending the metal strip, filling it with flux, and forming it into a pipe shape is performed in the atmosphere, so air remains inside the pipe. This air is brought into the welding flux-cored wire obtained through butt welding and wire drawing in subsequent steps, and the wire contains high concentrations of nitrogen and oxygen. When welding work is performed using such a welding flux-cored wire, there are problems in that welding workability deteriorates and the mechanical properties of the weld metal are impaired.

The present invention improves the problems with composite wires formed from long metal strips as described above.

The object of the present invention is to provide a method for manufacturing a flux-cored wire for welding that has good welding workability and does not cause deterioration of the mechanical properties of the weld metal.

In the present invention, a long metal strip is sequentially bent from both ends thereof, flux is filled in the middle of the bending, and then the metal strip is further bent to form a pipe shape. In a method of manufacturing a flux-cored wire for welding by welding pipe butts, at least before the butt welding process, Ar, Ar+GO2, or CO2 gas is blown into the open pipe to remove the air in the open pipe. It is characterized by replacing it with gas.

The invention will now be described with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing the manufacturing process of a welding flux-cored wire according to the method of the present invention.

In Fig. 1, a long metal strip 1 (Fig. a) is bent at both ends to form a U-shape as shown in Fig. B, and flux 2 is filled into this U-shaped groove (Fig. figure).

Then, the metal strip 1 is further bent and formed into a pipe shape filled with flux 2 (Figure d). obtained (Fig. e). A product (Figure f) is obtained by drawing this to a desired size.

In the present invention, A r is applied before the process of filling the metal strip with the flux 2, for example, from the step (b) in FIG. 1 to the step (e) of butt welding.

A r + Either gas of CO2 or CO7 is blown into the gas. FIG. 2 is a schematic explanatory diagram showing an example of carrying out the method of the present invention. In FIG. 3, and this hood 3 is provided with a flux injector 4 for filling the flux 2, and a gas outlet 5 before and after the injector 4. In addition, in Fig. 2, b '' e indicates the state of the cross-sectional view of the metal strip and flux-cored metal strip shown in Fig. 1.As shown in Fig. 2, the U-shaped When the metal strip 1 is moved below the hood 3, A r , A r + CQ are released from the gas outlet 5.
, and CO2 are ejected, and after the air in the U-shaped groove is replaced by these gases, a predetermined amount of flux 2 is filled into the U-shaped groove from the flux injection device 4. The filled metal strip is further bent at both ends by forming rolls (not shown) and while the metal strip moves, the gas is ejected from the gas outlet 5 provided on the downstream side of the flux injector 4, and the gas is ejected into the flux 2. After replacing the remaining air with these gases, immediately after coming out of the hood 3, the abutting portions of the metal strips 1 are welded by TIG welding or high frequency welding using a welding machine 6.

Welded by known means such as resistance welding, a composite wire is obtained which is filled with air, i.e. a nitrogen- and oxygen-free flux 2, which wire is then drawn to the desired dimensions.

It is considered a product.

In addition, in the present invention, the intended purpose can be achieved even if Ar, Ar+C○2, or CO2 is used as the gas to replace air as described above.
It will be readily appreciated that other inert gases may also be used in conjunction with r or CO2.

Inert gases other than Ar are not practical for economic reasons. Furthermore, CQ gas is a cheaper gas than Ar gas, and is also used as a shielding gas when welding the resulting composite wire, so even if CO2 gas remains within the composite wire, It has no adverse effect on welding and can be said to be extremely practical.

In this way, in the present invention, the process atmosphere is set to A from before filling the fluff during bending of the metal strip to butt welding.
To create a gas atmosphere of either r, Ar + CO2t CO2, the air in the U-shaped groove or pipe until the end of the open pipe, i.e., butt welding work, is replaced with these gases, and the air, that is, nitrogen and oxygen, is replaced with these gases. This results in a composite wire that does not contain any of the following.

Examples are shown below.

Soft 11I (Spcc) with a thickness of 1.21ffl and a width of 28.0R11 was used as the metal band, and the first
The composition shown in the table was used.

Table 1 Gold H as shown above! A L band is formed into a U-shape, and the above-mentioned flux is filled into the U-shaped groove as shown in FIG. 2, and various gases are applied in the vicinity thereof to an extent that the flux powder does not scatter (gas flow rate: 5. After replacing the metal strips with air, the butt parts of the metal strips were TIG welded (250A
A composite wire of 10.0 mmφ was made. This wire was drawn to a wire diameter of 1 to 2 mm to obtain a flux-cored wire for welding.

Using the obtained flux-cored wire for welding.

Welding tests were conducted under the following conditions, and the welding workability and mechanical properties of the weld metals were investigated. The results are shown in Table 2.

Welding current: 300A Arc voltage: 31v Welding speed: 30cm/min Shielding gas: Co, , 20Q/m1n (the following margins) As described above, according to the present invention, a composite wire containing flags is produced from a metal strip. A flux-cored wire for welding that satisfies both welding workability and mechanical properties of the weld metal because nitrogen and oxygen in the wire are replaced with Ar, Ar+GO, and CO2 gases. This has the effect of being obtained by a relatively simple method.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing the manufacturing process of a welding flux-cored wire according to the method of the present invention. FIG. 2 is a schematic explanatory diagram showing an example of implementing the method of the present invention.

Claims (1)

[Claims] 1. Bend a long metal strip sequentially from both ends, fill in flux in the middle of the bending, then bend the metal strip further to form a pipe shape, and weld the butt parts of the pipes. A method for manufacturing a flux-cored wire for welding, characterized in that at least before the butt welding process, any one of Ar, Ar+CO_2, and CO_2 gases is blown into the open pipe to replace the air in the open pipe with these gases. A method for manufacturing flux-cored wire for welding.