JPS6082294A - Production of fused flux for submerged arc welding - Google Patents

Abstract

PURPOSE:To improve productivity of a flux by allowing a fused flux to flow downward by gravity and spraying gaseous material to the descending flow thereby solidifying the flux by air cooling to a powder and granular state while the fused flux flies in the form of particles. CONSTITUTION:Various conditions for production are set as follows in the stage of obtaining a flux F having an adequate grain size: The viscosity of a fused flux M is first set at <=10 poise. If the viscosity is higher than 10 poises, the flux flies like stringing to form fibrous fluxes which require regrinding. The flow rate of gas is set at 20-100m/sec. If the flow rate is <20m/sec., the flux does not fly and the lumped fluxes deposite in the falling position. If the flow rate exceeds 100m/sec., the flux is drifted to assume the fibrous state without flocculation. With flow rate molten metal amt. is regulated at 0.37-2.8m<3>/kg. If the wind flow rate for each 1kg of the molten metal is below 0.37, the particles are fused to each other again into a lump state. On the other hand, if the wind flow exceeds 2.8m<3>, cooling is excessive and the driving power of a blower 2 is wastefully consumed. An angle theta of injection is set at + or -40 deg. when viewed from a horizontal direction. If the angle exceeds +40 deg., the flux F scatters and is difficult to be recovered. If below -40 deg., substantial air cooling effect is not obtainable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention produces granular molten flux for latent arc welding (hereinafter sometimes simply referred to as flux) by blowing a gas flow such as air onto a molten flux raw material while flowing it down. The present invention relates to a method for producing 72x, in particular, a method for producing 72x that can produce 7ralex with a low hydrogen content through a simple production process.

Molten type 72x is manufactured by blending raw material ores into a predetermined composition, melting them in an arc furnace, etc., cooling them, solidifying and pulverizing them, and adjusting the particle size to an appropriate size. By the way, 7 is in a molten state.
Methods for cooling, solidifying, and pulverizing the laxative raw material (hereinafter referred to as melt) include the manual cooling method (transferring the melt to a container, cooling it in the air, and then pulverizing it with a show crusher, etc.) or the water cooling method (the method in which the melt is flowed down and crushed by a jet crusher). There is a method of spraying water), but the former has the disadvantage of poor productivity because it takes time to cool down, requires a separate pulverization process, and requires a double process, and also has the disadvantage of slow cooling, which causes crystallization. This has the disadvantage that it becomes easier to absorb moisture and water blisters are adsorbed during cooling, increasing the hydrogen content in the flux, resulting in frequent welding defects caused by the hydrogen in the flux. On the other hand, although the latter method has the advantage of being able to crush at the same time as cooling and solidification, it has the disadvantage of producing hydrates upon contact with water, which is beyond the air cooling method. An increase in the hydrogen content is unavoidable - Therefore, the inventors of the present invention believed that it was necessary to eliminate the above drawback, and developed a method in which rapid solidification and pulverization are simultaneously performed by blowing a gaseous body onto the melt while it is flowing down. I thought that all of the above drawbacks would be resolved by adopting the .

However, we learned that it is difficult to stably obtain the desired effect by simply injecting a gas into the flowing melt, and that it is necessary to add various improvements to the manufacturing conditions1.
The present invention has been made in view of these circumstances, and aims to efficiently produce 7lacs having an appropriate particle size and a low hydrogen content.

The method of the present invention, which achieved the above object, has a viscosity of 1O
Let the molten 7 lux below Boise flow down under its own weight,
For this downward flow, flow velocity: 20-100 m,/s
ec% air volume/'Molten metal volume: 0.37=2.8m'/kg
The gist is that the gas is blown from a direction within the range of +40° from the horizontal direction.

The basic concept of carrying out the method of the present invention is not shown in FIG.

Arc furnace
-M is caused to flow down from the spout 1a of the ladle 1 as shown in the figure by tilting the ladle 1.

Gas (generally air) is sprayed from the tip nozzle 3 of the blower 2 onto the melt) M flowing down in this way to crush the melt into imitative melt particles. It is blown in a direction and flies and falls in a parabolic pattern. During this time, the melt particles are air-cooled and solidified to 7 lux F. Note that 0 indicates the air injection angle.

By the way, in order to obtain 7 lux with an appropriate particle size, it is necessary to optimally set the various conditions of the manufacturing method shown in the above basic borrowing.
Explain the requirements for n formation.

(1) Melt viscosity: 10 boids or less If the viscosity is higher than 10 boids, the melt will not become granular but will fly like strings and become fibrous flux, which will be uneconomical as it will require re-grinding. . Incidentally, the viscosity of the tart depends on the flux components and the melt temperature, but the latter factor is particularly important, and if the temperature at which the tart is poured from the ladle 1 is low, the viscosity will naturally increase. When the viscosity is high, the fluidity of the melt deteriorates and the surface tension decreases, so when spraying, the melt particles that should be crushed by the impact force of the gas flow do not aggregate into granules and some of them When sprayed, it flies like a string in the airflow and becomes fibrous.

(2) Gas flow rate: 20 to 100 rH/sec flow rate is 2
If the groove is not set at 0 m/sec, the melt will not fly sufficiently and will concentrate in the vicinity of the point directly below the melt flow point, and will not be sufficiently cooled and solidified during the fall, resulting in lumpy flux being deposited at the falling position. On the other hand, when the flow rate exceeds 100 m/see, the flow rate of the gas flow during spraying is too fast, and the crushed melt particles cannot be coagulated, and are drawn like strings and become fibrous.

(3) Air volume/molten metal volume: 0.37-2.8 mX17k
g Molten metal (mel) 1kg own air volume is 0.37m'
If the amount is less than 1, the crushed melt will not solidify sufficiently due to the insufficient cooling power of the gas during spraying, and the melt particles will re-fuse with each other to form lumps. On the other hand, the air volume above is 2.8
If the amount exceeds m3, the cooling power of the gas will be excessive and the blower rotational power will be wasted.

(4) Injection angle 0: ±40'1!11' when viewed from the horizontal direction
If the angle of incidence exceeds +40° and the product is turned upside down, (1) the flight distance of the melt particles will become larger than necessary and the falling flux will be scattered, making it difficult to recover the product, or (2) the melt particles will reach the target. Since the height is too large, it becomes necessary to increase the height of the manufacturing equipment, and the scattering of flux becomes noticeable, making recovery difficult. On the other hand, if the injection angle is less than 140° (depression angle), air is blown in the direction of the flow of the melt, so the melt disintegration ability by the gas flow is insufficient, and the melt is not sufficiently disintegrated. The blower falls as if being chased down by the gas flow, and a sufficient air cooling effect cannot be obtained.

Since the present invention is constructed as described above, the melt is sufficiently crushed into melt particles, which are further air-cooled and solidified into powdery flux while flying. Therefore, it is possible to simplify the manufacturing process without requiring equipment for pulverization, which is required in the conventional cooling method, and also to enable continuous production and improve productivity. Also, since the melt is cooled by gas during spraying, no hydrates are formed during the water cooling method, and since the melt is efficiently cooled and quickly solidified while flying at high speed, there is almost no hydrogen adsorption. It is possible to obtain fusix with low hydrogen content by boiling.

1゜Experiment I The actual examples of the present invention will be explained below. Each K (material slack) of the component composition shown in Table 1 was melted in an arc furnace, and the melt was flowed outside the prefecture shown in Table 1. At the same time, empty gas was injected into this to produce fusix.The properties of the finished 7 lacs were as shown in Table 1.

Table 3 (p-voice) Note: Values in parentheses represent averages. As shown in Table 3, the method of the present invention can provide a flux with a lower hydrogen content than the air cooling method and the water cooling method. It is also possible to commercialize the products as shown in Table 4. In addition, the pulverization of the flux progresses considerably, and even if granulation is required, coarse pulverization is not required at all, and the pulverization process is reduced by several steps.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic concept of the present invention. 1...Ladle 2...Prower 3... Nozzle M... Melt F...Flux

Claims (1)

[Claims] A molten flux with a viscosity of 10 boids or less is allowed to flow down by its own weight, and a flow rate of 20 to 100 is applied to this downward flow.
m/see, air volume/molten metal volume 2037~2,8 m'/
A method for producing a molten flux for submerged arc welding, which comprises spraying a kg of gas from a direction within a range of ±40° from the horizontal direction.