KR100860556B1 - Activating flux powder to be used for welding structural materials stainless steel, carbon steel and producing method thereof - Google Patents

Abstract

An environmental friendly activating flux having satisfactory mechanical properties and welding characteristics for welding stainless steel and carbon steel is provided to be economically applied to related welding industries requiring high reliability and advanced safety, and a preparation method of the activating flux is provided. An activating flux for welding stainless steel and carbon steel comprises rutile, chromium oxide, titanium-magnetite, fluorite, carnallite, and quartz sand. The activating flux comprises 5 to 30% by weight of rutile, 5 to 15% by weight of chromium oxide, 5 to 15% by weight of titanium-magnetite, 15 to 70% by weight of fluorite, 1 to 10% by weight of carnallite, and the balance of quartz sand. A preparation method of an activating flux for welding stainless steel and carbon steel comprises the steps of: mixing rutile, chromium oxide, titanium-magnetite, fluorite, carnallite, and quartz sand to obtain a mixture; charging a liquid phase material and the mixture obtained in the step into a ball-mill, sealing the liquid phase material and the mixture, and applying mechanical energy to the liquid phase material and the mixture by ball milling to obtain a powder; and calcining the powder obtained in the step.

Description

Activating flux powder to be used for welding structural materials stainless steel, carbon steel and producing method

Figure 1 is a photograph showing the X-ray diffraction results of the pore defects of the welding joint TIG welded SUS316L stainless steel plate when the active flux of the present invention and the active flux is not used.

Figure 2 shows the penetration of a welding joint welded to a single pass (1 pass) of SUS304 stainless steel material having a thickness of 6 mm when the active flux of the present invention is used (right picture) and the active flux is not used (left picture). This is a photograph comparing the cross-sectional appearance (Morphology) comparing the depth (Penetration depth).

3 shows the penetration depth of the welding joint in which TIG welding of SUS316L material having a thickness of 10 mm (two passes) with the active flux of the present invention (right photo) and without using the active flux (left photo) It is a photograph comparing the morphology of cross section comparing Penetration depth.

Figure 4 is the depth of penetration of the welding joint welding TIG welded SUS316L stainless steel having a thickness of 7mm (1 pass) when using the active flux of the present invention (Fig. 4b) and without using the active flux (Fig. 4a) This is a picture comparing Morphology comparing the (Penetration depth).

5 is a welding joint welded to the TIG welded carbon steel having a thickness of 6 mm (1 pass) in the case of using the active flux of the present invention (Fig. 5b) and without using the active flux (Fig. 5a). It is a photograph comparing the cross-sectional appearance (Morphology) comparing Penetration depth.

6 is a penetration depth of a welding joint welded to a single (1 pass) MIG welded SUS316L stainless steel having a thickness of 6 mm when using the active flux of the present invention (Fig. 6b) and without using the active flux (Fig. 6a). This is a picture comparing Morphology comparing the (Penetration depth).

7 is a schematic view showing a welded portion when welding stainless steel, where B is a width of the top side of the weld, b is a width of the weld root, and H is a height of the weld portion. Height of the top side of the weld, h, represents the height of the weld root.

The present invention relates to an active flux for welding stainless steel and carbon steel and a method for manufacturing the same, more specifically rutile, chromium oxide, titanium-magnetite, fluorite, Structural stainless steel and / or using welding techniques that are widely used today, including Canallite and Quartz sand, including TIG welding, MIG welding, Plasma welding, and CO ₂ Laser welding. Or it relates to an active flux (welding flux) and a method for manufacturing the same that can weld carbon steel (Carbon Steel) very effectively.

The arc welding method (Arc-welding, GTAW, GMAW, etc.) and other special welding methods such as laser welding and plasma welding have been developed and commercialized so as to more effectively weld the above-described welding structural materials. Activating flux for welding can be classified as follows.

(1) Activating flux developed mainly from Cr ₂ O ₃ and SiO ₂ has the technical disadvantage that it is difficult to obtain uniform and stable penetration depth.

(2) Active fluxes having a composition of 23.1 wt% TiO, 23.1 wt% TiO _2, 23.1 wt% Ti ₂ O _3, 23.1 wt% NiO and 7.5 wt% Mn ₁₅ Si ₂₆ compared to TIG welding without flux. This is advantageous in that the welding depth is increased by about 2 times. However, the formed depth is largely dependent on the thickness of the flux layer applied to the welded portion. In addition to the technical problem of having a weld surface property, it also contains toxic harmful nickel oxides (Nickel Oxide), which is disadvantageous to humans and the environment.

(3) Activation fluxes developed based on 50% by weight of TiO or TiO ₂ , 40% by weight of Cr ₂ O ₃ and 10% by weight of SiO ₂ have the characteristics of sufficient penetration depth. Non-metallic inclusions are incorporated into the welded metal, which deteriorates the mechanical properties of the weld.

In other words, by using the arc welding method and other special welding methods such as laser welding, plasma welding, etc., the main welding structural materials such as stainless steel and carbon steel are welded using conventional welding techniques, or the active flux for welding which has been developed and commercialized so far In the case of welding by welding, in addition to the above-mentioned technical problems, welding defects such as incorporation of oxide inclusions in welded joints are generated, which causes a large decrease in operational properties during use. I have a problem.

As described above, conventional welding active fluxes, which have been developed and commercially used to effectively weld major welding structural materials such as stainless steel and carbon steel by using arc welding and other special welding methods such as laser welding and plasma welding, The situation is accompanied by technical problems that adversely affect the disadvantages of the composition or welding properties, as well as the expensive manufacturing can be seen that both economic and commercial lack.

Thus, while solving these problems and drawbacks of conventional active fluxes, the development of new environmentally friendly active fluxes for stainless steel and carbon steel welding, together with industrially satisfactory mechanical and welding properties, There is an urgent need.

The present invention has been made in order to solve the problems of the prior art and to have improved welding and mechanical properties. As described above, the conventional welding activity utilized for welding of major welding structures such as stainless steel and carbon steel. Solve the problems with fluxes to produce new environmentally friendly stainless steel and carbon steel active fluxes for the automotive, aviation, aerospace, shipbuilding, machinery, chemical and nuclear industries with satisfactory mechanical and welding properties. It is an object of the present invention to provide an active flux that can be economically provided to the welding industry that requires high reliability and high safety, and a method of manufacturing the same.

The activating flux of the present invention can be used as an active flux paste prepared by uniformly mixing the active flux powder in powder form or the active flux in powder form with a volatile solvent.

In particular, in order to improve the convenience and work efficiency of the active flux paste of the present invention in the use of welding application (Painting brush, Aerosol can Spray, Felt-tip pen applicator) The welding may be carried out after uniformly coating on the surface of stainless steel and / or carbon steel to be welded before welding.

The present invention for solving the above-mentioned object is rutile (Chrodium Oxide), chromium oxide (Chromium Oxide), titanium-Magnetite (Fluorite), Canallite (Carnallite) and quartz sand (Quartz sand) Represents an active flux for welding stainless steel and carbon steel comprising a.

The active flux of the present invention is 5-30% by weight of rutile, 5-15% by weight of chromium oxide, 5-15% by weight of titanium-magnetite, 15-70% by weight of fluorite, 1-10% by weight of canriteite and the remaining silica sand. Include.

The chromium oxide may be any one or more selected from chromium oxide, chromium oxide, chromium trioxide.

The active flux of the present invention can be shown in powder form.

The active flux of the present invention can be presented in the form of a suspension or paste by mixing the solvent in powder form.

The solvent may be any one or more selected from ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone.

Among the components of the active flux of the present invention, rutile, chromium oxide, titanium-magnetite and silica sand promote the increase of penetration depth in welding stainless steel and / or carbon steel, and also improve the overall welding properties of the flux. Play a role.

Among the components of the active flux of the present invention, fluorite not only reduces the high melting point oxide contained in the weld slag, but also increases the penetration depth and is free of defects such as pores and oxides. It forms a welded joint, and also serves to induce a large Kp value and a small Δh value to stably form a good surface shape of the welded portion.

In addition, the active flux of the present invention plays an important role of reducing the effect of the flux layer coating thickness on the nonuniformity of the penetration depth by mixing and adding cannalite and silica sand.

In the active flux for welding stainless steel and carbon steel of the present invention, the active flux for welding stainless steel and carbon steel is applied in various components and contents, in order to achieve the object of the present invention, the active flux for welding stainless steel and carbon steel under the above-mentioned conditions. It turned out that it is preferable.

The active flux of the present invention can be in the form of a powder, suspension or paste in order to maximize the convenience and efficiency of work in the welding application, the active flux is a paint brush (Painting brush), spray spray (Aerosol can Spray) It may be commercialized by a method such as a felt-tip pen applicator, a polyurethane roller, or the like.

In addition, the present invention uses an active flux commercialized by the method of the paint brush, aerosol can spray, felt-tip pen applicator, polyurethane roller, etc., and TIG. Welding, MIG welding, Plasma welding, and CO ₂ Laser welding technology, including the method of welding to structural stainless steel (Carbon Steel), including the welding method.

The present invention includes a method for producing an active flux for welding stainless steel and carbon steel of the present invention.

Method for producing an active flux for welding stainless steel and carbon steel of the present invention is (1) rutile, chromium oxide, titanium-magnetite, fluorite, canalite and silica sand by mixing rutile, chromium oxide, titanium-magnetite, fluorite, cannite And obtaining a mixture in which silica is mixed,

(2) charging the mixture and liquid substance obtained in the step (1) to a ball-mill and sealing, and then obtaining mechanical powder by applying the ball-mill to obtain a powder,

(3) calcining (Calcination) the powder obtained in step (2).

Among the active fluxes for welding stainless steel and carbon steel of the present invention, chromium oxide may be any one or more selected from chromium oxide, chromium oxide, and chromium trioxide.

In the preparation of the active flux for welding stainless steel and carbon steel of the present invention, the liquid substance in step (2) is ethyl alcohol, ethyl alcohol, isopropyl alcohol, acetone. Any one or more selected may be used.

In the preparation of the active flux for welding stainless steel and carbon steel of the present invention, the liquid material of step (2) may be used in an amount of 50 to 200 parts by weight based on 100 parts by weight of the mixture obtained in step (1).

In the preparation of the active flux for welding stainless steel and carbon steel of the present invention, the mixture and liquid material obtained in the above (2) to (1) are charged together in a ball-mill and sealed to prevent air from penetrating. In this state, when the ball-mill is operated at room temperature, the powder becomes an optimal nano size having a predetermined size by mechanical energy, and then the resulting powder is collected.

On the other hand, the time for completing the ball-mill described above will vary depending on the weight ratio of the powder and the ball, the rotational speed of the ball-mill, the size of the ball, the amount of use of the liquid material, and the ball-mill treatment to obtain the optimal fine nanostructures. The time will depend on the individual equipment and process conditions.

For example, in the preparation of the active flux for welding stainless steel and carbon steel of the present invention, the mixture and the liquid material obtained in the above step (2) to (1) are placed in a ball mill and the particle size is 5 to 100 nm by the mechanical energy of the ball mill. Phosphorous nanostructured powder can be obtained.

In the preparation of the active flux for welding stainless steel and carbon steel of the present invention, the calcination in step (3) may be performed at 100 to 200 ° C. for 30 minutes to 2 hours.

In the manufacture of the active flux for welding stainless steel and carbon steel of the present invention, the calcination in step (3) may be performed at 150 ° C. for 1 hour.

The method for producing the active flux for welding stainless steel and carbon steel of the present invention may further include the step of mixing the calcined powder in step (3) with a volatile solvent to prepare an active flux in the form of a suspension or paste.

The volatile solvent may be any one or more selected from ethyl alcohol, ethyl alcohol, isopropyl alcohol, acetone.

When the powder calcined in step (3) is mixed with the volatile solvent, the powder calcined in step (3) and the volatile solvent may be mixed in a weight ratio of 1: 9 to 9: 1.

When the powder calcined in step (3) is mixed with the volatile solvent, the powder calcined in step (3) and the volatile solvent may be mixed in a weight ratio of 1: 1.

The active flux of the present invention prepared by the above-mentioned method may be in the form of powder, suspension or paste in order to maximize the convenience and efficiency of operation in the use of welding application, and the active flux may be used as a paint brush. ), An aerosol can spray, a felt-tip pen applicator, and a polyurethane roller.

In addition, the present invention manufactured by the above-mentioned method and commercialized in the manner of a paint brush, aerosol can spray, felt-tip pen applicator, polyurethane roller, etc. It can be applied to structural stainless steel and carbon steel using TIG welding, MIG welding, Plasma welding and CO ₂ Laser welding technology.

Hereinafter, the content of the present invention will be described in detail through examples and test examples. However, these are intended to explain the present invention in more detail, and the scope of the present invention is not limited thereto.

<Example 1-4>

After mixing the components of the content shown in Table 1 to obtain a mixture, the mixture and methyl alcohol in a ball-mill (Ball-mill) charged and sealed, the mechanical energy by the ball-mill was added to the particle size A nanostructured powder having 50 ± 5 nm was obtained.

The nanostructured powder was calcined for 1 hour at 150 ° C. to prepare an active flux for welding stainless steel and carbon steel.

<Comparative Example 1-2>

After mixing the components of the content shown in Table 1 to obtain a mixture, the mixture was calcined at 150 ℃ for 1 hour to prepare an active flux for welding stainless steel and carbon steel.

 Table 1. Flux Components and Composition (wt%)

<Test Example 1>

Flux paste mixed with each active flux powder prepared in Examples and Comparative Examples in a weight ratio of 1: 1 by the spray method before the welding surface of the stainless steel (SUS316L stainless steel) It was uniformly coated with a width of 5 mm and a thickness of 0.25 mm at the edges, and welded using TIG, MIG welding techniques, and the like.

The use of the active flux of the present invention in TIG and MIG welding, plasma welding, CO ₂ laser welding, etc. can significantly reduce the size and quantity of pores formed in the weld metal.

The large porosity mainly present in the oxidation inclusions in the TIG welded weld can be completely removed by using the active flux of the present invention. The reason why the large pores formed in the weld metal is removed may be explained by the fact that the active flux of the present invention completely removes an oxide film that adsorbs moisture, which is the main cause of the pores. .

When TIG welding SUS316L structural material, the number of pores in 100mm length of weld metal according to the thickness of the structural material is divided into the case of using the active flux of the present invention and the case of not using the active flux of the present invention. It showed an excellent effect in the entire thickness range of the welded structure of the test object, and also the parameter for the relative extent of oxides ΣL _o / L _j (where ΣL _o = total oxide) , L _j = length of welded metal) The use of the active flux according to the present invention was much less, and the welding effect was very excellent.

The excellent effect on the removal of pores and oxidation inclusions in the welded area by using the active flux of the present invention is that the pores of the welded joint in which TIG-welded SUS316L stainless steel sheet is used when the active flux of the present invention is used and the active flux is not used. X-ray diffraction results for (Pores) defects are clearly confirmed in the photograph of FIG. 1.

The removal of pores and oxidation inclusions in the welded joint by the use of the active flux of the present invention showed an excellent effect on the carbon steel welded structural members.

The parameter of the shape Kp = b / h, the value of the interfacial gradient between the weld root and the bottom of the parent metal, is a measure of its mechanical properties when the joint is subjected to dynamic loads. As an index giving value, the larger the Kp value, the more gentle the interface forms the curved line, so that the joint has a good weld shape that can withstand a larger load. In Kp = b / h, b is the width of weld root and h is the height of weld root (see FIG. 7).

Δh = h _max -h _min, the difference between the maximum and minimum heights of the weld root, is a parameter for the uniformity of the weld geometry that determines the uniformity of the weld surface and the surface roughness. Is an important welding characteristic factor.

When TIG welding the SUS316L structural member, the Kp value and Δh value of the welded portion according to the thickness of the structural member are divided into the case where the active flux of the present invention is used and the case where the active flux of the present invention is not used. The large Kp value gives the interfacial curve of the welded joint a very good weld shape, and the good welded shape of the welded joint gives the welded joint the ability to withstand higher loads.

However, when the active flux of the present invention is not used, a very steep interface curve is formed by a small Kp value, thereby forming a bad weld shape, thereby deteriorating the operational properties of the wet metal. There are disadvantages. In addition, it can be seen from the examples that the case where the thickness of the welded structural material is thin has a larger Kp value than the case where the welded structure material is thick to form a good weld shape.

On the other hand, the smaller the Δh value is, the better the uniformity of the penetration depth becomes, thereby resulting in a weld surface characteristic with a small surface roughness.

In the case of using the active flux according to the present invention it was confirmed through the examples that the effect of obtaining a welded joint having a smoother surface characteristics and a uniform penetration depth by a small Δh value. In addition, the Δh value showed an effect that the penetration depth was uniform and smooth surface characteristics by the Δh value stable in the entire thickness range when the active flux of the present invention is used, but the active flux of the present invention is not used The larger the thickness of the welded structure, the larger the Δh value, and the welded depth of the welded structure with irregular penetration depth.

The effect of using the active flux of the present invention on the parameter of the shape Kp and the parameter for the uniformity of the weld geometry Δh described above by using the active flux of the present invention is carbon steel ( Carbon Steel) also showed an excellent effect on welded structural materials (see Table 2).

All samples of Examples 1, 2, 3, and 4 showing the active flux according to the present invention increased the penetration depth, formed a good appearance, and removed oxides of high melting point. Although excellent welding properties were shown, the sample of Comparative Example 5 having a composition deviating from the target composition did not show a stable penetration depth, and the sample of Comparative Example 6 showed poor welding characteristics.

Table 2. Main welding characteristic values of activated flux (Stainless steel)

* 1, 2, 3, 4, ratio 1, and ratio 2 show Example 1, Example 2, Example 3, Example 3, Example 4, Comparative Example 1, and Comparative Example 2, respectively.

** ○: Good, △: Satisfactory, ×: Bad

<Test Example 2>

Flux paste of the active flux powder prepared in Example 3 and ethyl alcohol in a weight ratio of 2: 8 was sprayed to the width of the weld surface edge before welding of SUS316L stainless steel. 5mm, 0.25mm thickness uniformly, welded using TIG, MIG welding technology, etc., and experimental tool, welded using SUS316L stainless steel TIG, MIG welding technology, etc. without applying active flux. As a control, the results for the experimental and control groups are shown in FIGS. 2 to 6.

2 is a welding joint welded to a single pass (1 pass) of SUS304 stainless steel material having a thickness of 6 mm when using the active flux of the present invention (right picture) and without using the active flux (left picture). It is a photograph comparing the cross-sectional appearance (Morphology) comparing Penetration depth.

3 shows the penetration depth of the welding joint in which TIG welding of SUS316L material having a thickness of 10 mm (two passes) with the active flux of the present invention (right photo) and without using the active flux (left photo) It is a photograph comparing the morphology of cross section comparing Penetration depth.

Figure 4 is the depth of penetration of the welding joint welding TIG welded SUS316L stainless steel having a thickness of 7mm (1 pass) when using the active flux of the present invention (Fig. 4b) and without using the active flux (Fig. 4a) This is a picture comparing Morphology comparing the (Penetration depth).

5 is a welding joint welded to the TIG welded carbon steel having a thickness of 6 mm (1 pass) in the case of using the active flux of the present invention (FIG. 5B) and without using the active flux (FIG. 5A). It is a photograph comparing the cross-sectional appearance (Morphology) comparing Penetration depth.

6 is a penetration depth of a welding joint welded to a single (1 pass) MIG welded SUS316L stainless steel having a thickness of 6 mm when using the active flux of the present invention (Fig. 6b) and without using the active flux (Fig. 6a). This is a picture comparing Morphology comparing the (Penetration depth).

It can be seen that the experimental zone using the active flux of Example 1 of the present invention when welding stainless steel as shown in the results of FIGS. 2 to 6 has superior welding properties as compared to the control without using the active flux of the present invention.

<Test Example 3>

Using the active flux of the present invention prepared in Example 1 shown in Table 3, the hazardous component discharge component, its measured value and the standard maximum allowable value after welding of stainless steel (SUS316L stainless steel).

Table 3. Hazardous Emissions Components and Measured Values (mg / m ³ )

Hazardous Substances Measured value (mg / m ³ ) Permissible value (mg / m ³ )  Welding dust at filter <1.79 4 Iron at filter <0.11 4 Fluorine <0.16 0.5 Chloride <0.89 5

As shown in Table 3 above, the active flux for welding stainless steel and / or carbon steel of the present invention has been proved to be an environmentally friendly active flux that is safe for humans and the environment as a result of measuring toxic substance emission components and the numerical values thereof, so that the welding flux is separate from the welding industry. It is environmentally friendly and safe for anyone to use without special protective equipment.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

As can be seen from the above description, the active flux according to the present invention is applied to the conventional welding technology that is widely used at present, such as TIG welding method, MIG welding method, Plasma welding method and CO ₂ Laser welding method, etc. , In case of welding carbon steel, increase penetration depth, omit pretreatment such as Groove, shorten overall welding time, high productivity and labor cost, save required welding materials and electricity, back-gouging It has the effect of showing excellent welding characteristics such as reduction, reduction of welding defects and improvement of mechanical properties of the weld, reduction of welding heat affected zone (HAZ-Heat Affected Zone) and welding deformation by welding heat.

Therefore, the active flux of the present invention can be very economically useful for welding structural materials in industries requiring high reliability and high safety, such as automotive, aviation, aerospace, shipbuilding, machinery, chemical and nuclear industries. Since the active flux of the present invention does not contain any toxic oxides or additives that are harmful to human body and environment, it can be widely used as an environmentally friendly invention that can be conveniently and safely used by welders anytime and anywhere.

Claims (7)

For welding stainless steels and carbon steels, including rutile, chromium oxide, titanium-magnetite, fluorite, canallite and quartz sand Active flux. The method according to claim 1, wherein rutile 5-30 wt%, chromium oxide 5-15 wt%, titanium-magnetite 5-15 wt%, fluorite 15-70 wt%, canalite 1-10 wt% and the remaining silica sand Activated flux for welding stainless steel and carbon steel, comprising. (1) mixing rutile, chromium oxide, titanium-magnetite, fluorite, cannite and silica sand to obtain a mixture of rutile, chromium oxide, titanium-magnetite, fluorite, cannite and silica sand, (2) charging the mixture and liquid substance obtained in the step (1) to a ball-mill and sealing, and then obtaining mechanical powder by applying the ball-mill to obtain a powder, (3) a method of producing an active flux for welding stainless steel and carbon steel, comprising calcining the powder obtained in step (2). The liquid material of claim 3, wherein the liquid material of step (2) is any one or more selected from ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, and the (2) A method for producing an active flux for welding stainless steel and carbon steel, characterized in that 50 to 200 parts by weight of the liquid material of step) is charged in a ball mill with respect to 100 parts by weight of the mixture obtained in step (1). The method of claim 3, wherein the calcination in step (3) is performed at 100 to 200 ° C for 30 minutes to 2 hours. The method of claim 3, further comprising mixing the calcined powder in step (3) with a volatile solvent to obtain an active flux in the form of a paste, wherein the active flux for welding stainless steel and carbon steel is obtained. The method of claim 6, wherein the volatile solvent is any one or more selected from ethyl alcohol, methyl alcohol, isopropyl alcohol, acetone, and the like. Method of producing flux.

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