JPS63212093A - Production of flux cored wire for welding - Google Patents

Abstract

PURPOSE:To improve the flow property of the flux filled in a steel wire sheath and to improve the quality and production efficiency of a wire by adding 1 or >=2 kinds of fatty acids and fatty acid salts into the filled flux. CONSTITUTION:The particulate flux prepd. by pelletizing flux raw material powder with a binder, then adding and mixing 1 or >=2 kinds of the fatty acids and fatty acid salts further to and with the same is filled into the steel wire sheath. The flow property of the filled flux is thereby enhanced and the fluctuation in the filling density is decreased. The wire having the stable quality is thus obtd.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing flux-cored wire for welding used for mild steel, high-strength steel, low-alloy steel, etc. The present invention relates to a method for producing a black-cored wire for welding, which greatly improves wire quality and production efficiency by increasing fluidity.

(Prior Art) Currently, flux-cored wires for automatic or semi-automatic welding include (A) normal flux-cored wire having a W40 part and (B) so-called so-called flux-cored wire manufactured by the technology described in Japanese Patent Publication No. 45-30937. Seamless flux-cored wires are roughly divided into two types, and both contain deoxidizing agents, denitrifying agents,
A flux made of a slag forming agent, iron powder, etc. is filled into a steel shell made of a steel band or pipe. In this case, the flux-cored wire (A) is filled with 7 gamma fluxes supplied from a hopper during the continuous shaping of a steel strip such as mild steel. The seamless flux-cored wire (B) is filled with black by supplying flux into a spirally wound pipe of a predetermined diameter, such as mild steel, and simultaneously applying vibration.

At this time, the filling property of blacks is 72
It greatly depends on the falling conditions of the tsukus and the movement of flux inside the pipe.

Therefore, in both cases (A) and (B), the quality and production efficiency of the flux-cored wire are determined by how the flux is filled in as targeted and uniformly.

Especially these days, very strict performance is required depending on the bulk used, and it is no longer possible to allow the maximum value of puffiness of the filling rate to be ±(2 to 3)% of the target value as in the past. , is required to be controlled within ±1%.

Furthermore, in view of improving productivity, it is common to draw and draw wires at high speeds, and as a result, it has become necessary to shorten the flux filling time. However, blanks have subtle differences in particle size, specific gravity, shape, etc., and it is often difficult to fill them according to the target, let alone shorten the filling time.Therefore, there are large variations in the filling rate, and as a result, the required welding performance cannot be achieved. This has resulted in a high number of defective products and a decline in production efficiency.

Therefore, in order to deal with such problems,
Methods for adjusting the particle size of 7faxes proposed in Publications No. 158697 and Japanese Patent Publication No. 17637/1980, ■Methods for adjusting the feed speed and vibration frequency of flux feeders, ■Methods for improving fluidity of blanks, etc. is proposed.

(Problems to be Solved by the Invention) However, in the above method (2), there is a problem that the fluidity of the 72 px deteriorates or the production efficiency decreases due to a decrease in the yield of flux. In addition, the above method (2) does not provide sufficient effects when the filling rate is low or when a so-called metal cored wire contains a large amount of metal powder.

Next, method (1) above is the most effective method for preventing puffiness in blank filling rate and stabilizing quality. In particular, the method using silicone oil proposed in JP-A No. 61-216892 is very effective for increasing the fluidity of 7FAX, but When welding is carried out using wire, the Si content in the weld metal is extremely high, resulting in a decrease in toughness and cracking resistance, making it impossible to obtain sufficient performance as a weld metal.

The present invention was made with attention to these problems, and the present invention is a welding black that reduces the buffiness of the flux filling rate by increasing the fluidity of the filling flux, and significantly improves the quality of the wire and the production efficiency. It is an object of the present invention to provide a method for manufacturing a cored wire.

(Means for Solving the Problems) That is, the gist of the present invention is to reduce the buffiness of the filling rate by increasing the fluidity of the filling 7 fax, thereby providing a wire with stable quality. However, flux-containing for welding is characterized by granulating the flux raw material powder with a binder, then adding IM or two or more of fatty acids and fatty acid salts, and filling the inside of the steel wire with a mixed powdery flux. This is a method for manufacturing wire.

(Function) Possible causes related to the fluidity of blanks include (i) particle shape, (11) particle size, (ii) hygroscopicity, (ii) surface resistance between particles, and (,) sinterability.

(1) The rounder the particle shape, the better the fluidity.
It is practically impossible to control the shape of blanks during granulation. (ii) fIL1! The coarser the t, the better it is, but if only coarse particles are used, the filling rate will be limited, raw material powder with poor granulation properties cannot be used, and production efficiency will be affected due to non-uniformity of ingredients due to fine particle removal. is less well-dressed. (ii
Although the hygroscopicity of ) and the sinterability of (ma) are affected by the binder used during granulation or the firing conditions,
It may not be possible to use it depending on the required 'f# welding dissimilar metal ability or raw material powder.

Therefore, the present inventors conducted various studies focusing on (ii) as the most practical method for increasing fluidity.

First of all, it was found that lowering the surface resistance of the particles themselves is not realistic because it is greatly influenced by the type of raw material powder and manufacturing conditions. Therefore, we experimented with adding a substance that acts as a buffer material as a means of reducing the surface resistance between particles. In this case, it goes without saying that the following conditions must be met for this substance: ■ It must have excellent moisture absorption resistance; ■ It must not contain harmful components to the weld metal; ■ It must not react with Arax particles. It is desirable to be effective with as little amount as possible.

As a result, it was found that fatty acids and fatty acid salts satisfy the above conditions (1), (2), and (3), and that the surface resistance between particles is reduced, making them extremely effective in improving the fluidity of flux.

FIG. 1 shows the influence of the amount of sodium stearate added on the fluidity of a filled 7-fax (measured according to JIS Z 2502; the same applies hereinafter). Two types of flux were tested with the same formulation: 72 px (A), which has a particle size of 32 to 150 meshes, and flux (B), which has a particle size of 100 meshes or less. If sodium stearate is not added, the flowability is approximately 40 to 45 seconds 15 degrees, and the fluidity is poor. However, with the addition of sodium stearate, the fluidity improves, and even if 0.01% (wt%; the same applies below)
It has been found that even a small amount of addition has a sufficient effect.

Figure 2 shows the effect of the amount of calcium stearate added on puffiness at a 7x filling rate.
Fill the pipe with 2 prescriptions of 72x, and make the diameter 1.2cm.
80 samples were taken and the filling rate was measured. The method for drawing the wire and the method for collecting the sample are the same as in the examples described later.

Here, the filling rate is a value expressed by the following formula.

Blacks filling rate (%) Wire weight = (Steel shell + 7x filling) Weight According to Figure 2, if calcium stearate is not added, both formulations (A) and (B) have ±( 2-3)
% variation occurred. On the other hand, when calcium stearate is added to the filled blacks, the variation in the filling rate is very small and stable at about ±0.5% even when added at 0.01%. Note that the method of adding sodium stearate and lucifum stearate in Figures #&1 and Figure 2 is to granulate the flux raw material powder with a binder, and then add and mix. If raw powder is added to the steel shell as it is, it will cause vibrations, especially in seamless wires.
When filling Tsukusu, the raw material powder is separated into high-density raw material powder and low-density raw material powder, causing segregation in the longitudinal direction of the wire, making it impossible to produce a uniform wire, which is the objective of the present invention.
Further, even in the case of a conventional flux-cored wire in which flux is supplied from a hopper while forming a steel strip, a phenomenon occurs in which light raw material powder with low density does not fall from the hopper, and production is often interrupted.

Therefore, in the present invention, the black raw material powder is granulated in advance with a binder. The binder in this case includes water lass, alumina sol, silica sol, amine silicate, lithium silicate, colloidal T# liquid, methyl cellulose, carboxymethyl cellulose, alginate, guam gum, gum arabic, and the like.

By the way, the fatty acid or fatty acid salt covers the surface of the granulated flux or is inserted between the particles.
As a result, the surface resistance between particles is reduced, and fluidity is improved. This is the OH group of fatty acids or the 0 of fatty acid salts.
This is thought to be due to the surface active effect of the M group (M represents a metal element).

In this case, the amount of one or more fatty acids and fatty acid salts added to the Arax will be determined depending on the type of Arax and the filling rate, but it is preferably within 15%.
If the wire is too thick, the Arax filling rate will be extremely high, and wire breakage will occur more easily, which will actually reduce productivity.

Furthermore, in the production of normal S-branched wire, annealing treatment (approximately 650° C.) is performed one or more times in order to prevent wire breakage due to hardening of the steel outer sheath. Therefore, since the boiling point of fatty acids and fatty acid salts is low (approximately 300°C or less), they sublimate within the steel shell during the final wire drawing process.
It has no effect on the actual weld metal.

The fatty acids or fatty acid salts used in the present invention include stearic acid, calcium stearate, sodium stearate, magnesium stearate, barium stearate, valmitic acid, calcium palmitate,
sodium palmitate, magnesium valmitate,
Barium palmitate, oleic acid, calcium oleate, sodium oleate, magnesium oleate, barium oleate, etc. are used.

In this case, the fluidity of the flux is improved by adding fatty acids and fatty acid salts.Flux is supplied from a hopper into a normal flux-cored wire or pipe, which is filled with flux while forming the steel strip, and is filled by vibration. Any type of seamlessly inserted wire is effective.

(Example) Table 1 shows the test results of the variation in the fluidity and filling rate of the filled 7 FAX when the addition amount of one or more types of fatty acids and fatty acid salts in the filled up gas was changed. The fluidity was measured in accordance with JIS Z2502.

In addition, the wire for measuring the variation in the filling rate has a filling rate target of 12%, and No. 1-7 and No. 10 have a diameter of 3.2 mm after filling a pipe with a diameter of 13.81 mm with flux.
The wire was drawn to a diameter of 1.21 mm, heat treated at 650° C. for 4 hours, and finished to a length of 800 m. Also, N
8.9 is a steel band with a thickness of 0.8 am and a width of 11.0 ma+, filled with 72 tx, formed to a diameter of 3.21 mm, drawn to a diameter of 1.20 mm, and finished to a length of 800 m. Eighty samples each having a length of 2,001,611 mm were collected from each 10 samples, and the filling rate was measured. Here, the filling rate buffiness indicates the maximum deviation of (actual value - target value).

Nos. 2 to 9 had good fluidity and filling rate buffiness of the filled blacks.

However, No. 1 without the addition of fatty acids or fatty acid salts was significantly poor in both the fluidity of the blacks and the buffiness of the filling rate. In addition, No. 10 had good results with small variations in fluidity and filling rate compared to 77x, but the addition of too much fatty acid and fatty acid salt in 7x was insufficient in other alloy components.

(Effects of the Invention) As stated above, the present invention reduces the variation in the filling rate by improving the fluidity of the #X flux when manufacturing flux-cored wire for welding, and as a result, the quality is stabilized. This provides a method for dispensing 7-fax wire for welding that dramatically improves production efficiency.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the influence of sodium stearate on the fluidity of filled JJE blacks, and FIG. 2 is a diagram showing the influence of calcium stearate on the buffiness of the filling rate.

Claims (1)

[Claims] (1) A welding flux characterized by granulating flux raw material powder with a binder, then adding one or more of fatty acids and fatty acid salts, and filling the steel wire outer sheath with a mixed powdery flux. Method of manufacturing cored wire.