JPH069757B2 - A wire with a seamless flux for arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a seamless flux-cored wire for arc welding applied to all-position welding of shipbuilding, bridges, steel frames, industrial machines and the like.

[Conventional technology]

A so-called seamless flux cored wire for arc welding (hereinafter referred to as a seamless wire), which does not have an opening on the outside, represented by JP-B-45-30937, has no moisture absorption of the filling flux, and an extremely low hydrogen weld metal can be obtained. In addition, since the wire surface is copper-plated, it has excellent electrical conductivity during welding, so the arc is stable and the consumption of parts such as chips and liners is small, so the usage rate is increasing year by year. .

At present, the seamless wire according to Japanese Examined Patent Publication No. 45-30937 uses a transportation method by vibration from the pipe end when filling the flux, so that water glass is generally added as a fixing agent before the filling for the purpose of preventing segregation. Granulation is performed (Japanese Patent Laid-Open No. 58-2359).
(See Japanese Patent Publication No. 5).

However, when a seamless wire filled with flux that is granulated by adding water glass is welded by increasing the current, the outer shell melts earlier than the filling flux, and the filling flux remains unmelted and is larger than the wire diameter. The phenomenon of sticking out into the arc for a considerably long time may occur. The protrusion of such unmelted flux is a factor causing frequent spatter during welding. Further, when the welding speed is high such as vertical down welding, there is a problem that the flux enters the molten pool as it is unmelted and is slag entrainment without being floated and separated.

The reason for this is that the water glass coats the flux particles almost completely, which causes an insulating action between the filling flux and the outer skin, and the electric current supplied from the outside of the outer skin by the welding tip mainly flows to the outer skin. As a result, it is considered that the unmelted flux protrudes into the arc because the outer shell melts before the filled flux.

As a measure for preventing the unmelted flux from sticking out, the inventors of the present invention investigated various fixing agents other than water glass and used carboxymethyl cellulose, thereby suppressing sticking out of the unmelted flux and almost the same fixing force as water glass. Based on the finding that it can be obtained, a patent application was filed (Japanese Patent Laid-Open No. 60-111795).

However, even with the above seamless wire, there were insufficient points to be improved in the protrusion length of unmelted flux, the amount of spatter generation, slag inclusion, and the like.

[Problems to be solved by the invention]

In view of the above problems, the present invention provides a seamless wire in which the protrusion of unmelted flux is suppressed, the amount of spatter generated is small, and slag is not involved by using carboxymethylcellulose having an appropriate composition of C content as a binder. With the goal.

[Means for solving problems]

The gist of the seamless wire according to the present invention is C
Carboxymethylcellulose containing 20 to 50% by weight as a binder is used in an amount of 0.3 to
It is contained at 6.0 wt%, and the flux is filled at 8 to 25 wt% (hereinafter referred to as%) with respect to the total weight of the wire. The present invention will be described in detail below.

[Work]

The present inventors have found that the C content is 10, 15, 20, 25, 3
0, 35, 40, 45, 50, 55, 60% by weight of carboxymethylcellulose was added to TiO ₂ 30%, SiO ₂ 4%,
ZrO ₂ 5%, MgO 4%, NaF 1%, Bi 0.2%, K ₂ TiO ₃ 1
%, Fe-Si 7%, Fe-Mn 15%, Fe-Al 3%, iron powder 28.
1.0% of total weight of flux with 8% flux
%, Added with water, wet-mixed, and further dried and granulated through a rotary drier set to a furnace atmosphere temperature of 250 ° C., using the technique described in Japanese Examined Patent Publication No. 45-30937 to 15 to the total weight of the wire. %, And a 1.2 mmφ seamless wire was prototyped. Using this trial wire, the V-groove groove was vertical-advanced welded at 250A-26V, and the protrusion length of unmelted flux and the amount of spatter were measured.
The protruding length of the unmelted flux was determined by photographing with a high-speed camera, and the amount of spatter was collected by enclosing it in a copper container and welding, and evaluated as the amount generated per minute.

According to FIG. 1 showing the investigation result, the protruding length of the unmelted flux is more than twice the wire diameter when C% in the carboxymethylcellulose composition is 10%, but it decreases to about 20% at the wire diameter and further 25%. It is understood that the wire diameter decreases to 1/2 of the wire diameter. This tendency does not change even when C% in the carboxymethyl cellulose composition is 60%. When the C% was 10%, the amount of spatter was 4.5 g per minute, which was extremely high, and when the C% was 20%, it was reduced by about 60%, and when it was 25%, it was decreased by 70% or more. But,
If the C% exceeds 50%, the amount of spatter generated increases, and 6
At 0%, 5.0 g or more was generated per minute. It is considered that this is because the C + O → CO reaction occurs violently, so that spatter frequently occurs.

That is, the C% in the carboxymethyl cellulose composition is 20.
If it is less than%, the protrusion of unmelted flux is considerably long,
Therefore, spatter frequently occurs. Further, when it exceeds 50%, it has been found that the protrusion of unmelted flux is short but the amount of spatter generated is extremely large.

That is, the protrusion length of the unmelted flux is remarkably reduced by C% in the composition of carboxymethyl cellulose because the granulation results in a mold in which C is uniformly dispersed in the flux particles, the conductivity of the flux is improved, and When an electric current is passed, the arc, which had been generated only from the outer metal until now, is also generated from the inside of the wire cross section, which promotes the melting of the filling flux and prevents the unmelted flux from sticking to the arc property. To be

However, the C% in the carboxymethyl cellulose composition is 2
If it is less than 0%, the electrical conductivity of the flux is poor and the protrusion of the unmelted flux becomes long, resulting in frequent spattering. Also C
When the C content exceeds 50%, the C + O → CO reaction occurs violently, and it is considered that the spatter generation amount increases. Thus, the C% in the carbomethylcellulose composition is preferably in the range of 20 to 50%. The amount of carboxymethyl cellulose added is preferably in the range of 0.3 to 6.0% with respect to the total weight of the flux. If it is less than 0.3%, the granulation property of the flux is poor, and the protrusion of the unmelted flux cannot be prevented.
If it is contained in excess of%, spatter frequently occurs due to the effect of C.

As a specific method for producing a filling flux containing carboxymethyl cellulose, carboxymethyl cellulose is added to the flux, water is further added and wet mixed, a method of drying through a rotary kiln or a rotary dryer, or a carboxymethyl cellulose aqueous solution is added to the flux. There is a method of adding, wet mixing and drying. Whichever method is used, 0.3 to 6.0% of carboxymethyl cellulose may be contained.

The flux contained in carboxymethyl cellulose produced by the above method is preferably filled in the range of 8 to 25% to form a seamless wire. If the filling amount is less than 8%, it is difficult to obtain a sound weld metal because the flux as the welding wire is insufficient, and if the addition amount exceeds 25%, the outer metal becomes too thin to make the wire.

The effects of the present invention will be described more specifically by way of examples.

〔Example〕

1.2 mm filled with flux having the composition shown in Table 1
Φ seamless wires No. 1 to No. 20 were prototyped, vertical downward welding was automatically performed under the welding conditions shown below, the protrusion length of unmelted flux was measured, and slag inclusion was checked.
Also, the amount of spatter generated was measured.

The presence or absence of slag inclusion was determined by an X-ray test.

Welding conditions Welding current: 280A DC (+) Welding voltage: 30V Welding speed: 60cm / min Shielding gas: CO ₂ , 20 / min Base material: Round V groove groove (groove angle: 90 ° root R: 2) Chip-base material distance: 20 mm Table 2 shows the measurement results.

Seamless wires No. 1 and No. 2 are comparative examples in which the C content in the carboxymethyl cellulose composition is less than 20%,
The protrusion of the unmelted flux is more than twice the wire diameter, and slag entrainment occurs and the amount of spatter is large.

The seamless wires No. 3 and No. 4 are comparative examples in which the C content in the carboxymethyl cellulose composition exceeds 50%. The protrusion of unmelted flux was short and slag entrainment did not occur, but spatter frequently occurred. Seamless wire
No. 5 and No. 6 are comparative examples in which the amount of carboxymethyl cellulose added with respect to the total weight of the flux is outside the scope of the present invention. Since No. 5 is less than the lower limit, the protrusion of unmelted flux is 2 wire diameters. It was twice as much, and slag was involved and spatter frequently occurred. Also, since No. 6 exceeds the upper limit, the amount of spatter generated is large.

No. 7 to No. 17 are examples of the present invention satisfying the requirements of the present invention, the unmelted flux protrusion is shorter than the wire diameter, no slag entrainment occurs, and the amount of spatter generation is small.

Seamless wires No. 18 and No. 19 are comparative examples in which the flux filling rate is out of the range of the present invention. No. 18 is less than the lower limit, so the arc is unstable and the slag hardly covers the beads. Was not implemented. Also No. 19
Since the value exceeds the upper limit, the test could not be conducted because the wire was broken several times during wire drawing.

The seamless wire No. 20 was filled with a flux that was granulated using water glass, and the protrusion of unmelted flux was extremely long, slag entrainment occurred, and spatter frequently occurred.

[Effects of the Invention] As described above, according to the present invention, since the protrusion of the unmelted flux during welding can be significantly reduced, it is possible to reduce the amount of spatter generation, prevent the inclusion of slag, and the like. However, it greatly contributes to the development of industry.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the C content in the carboxymethyl cellulose composition, the protrusion length of the unmelted flux, and the spatter generation amount.

Claims (1)

[Claims] 1. Carboxymethylcellulose containing 20 to 50% by weight of C is used as an adhesive agent in an amount of 0.3 to 6.0% by weight based on the total weight of the flux, and the flux is contained in an amount of 8 to 25% by weight based on the total weight of the wire. % Welded seam flux cored wire for arc welding.