JPH0240433B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an intermetallic compound used as one of the welding flux raw materials applied to coated arc welding rods, sintered fluxes for SAW, flux-cored wires, coated consumable nozzles, etc. In particular, it relates to intermetallic compounds with excellent water glass corrosion resistance. [Prior Art] The above-mentioned welding flux is manufactured by blending various flux raw materials such as arc stabilizers and slag forming agents, adding a fixing agent such as water glass, and granulating and sintering as necessary. ing. Ferroalloys (Fe-Si, Fe-Al, Fe-Si, Fe-Al,
Fe-Ti, etc.), Ca-Si, REM-Ca-Si, Al-Mg
Intermetallic compounds such as are used. By the way, when the above-mentioned intermetallic compound and water glass are mixed, the two react to generate H ₂ , and this H ₂ makes the inside of the kneaded flux void and causes a decrease in the fixing strength of the flux. It has been pointed out that the following problems have occurred. That is, in coated arc welding rods and coated consumable nozzles, the flux drop-off resistance deteriorates, resulting in a decrease in product yield. Furthermore, in the case of SAW flux, the pulverization rate of the flux increases, reducing the number of times it can be used repeatedly, leading to deterioration of product quality. Furthermore, in flux-cored wires, the pulverization of granulated flux causes non-uniform syntron properties during flux filling, causing segregation of flux components within the sheath, which in turn leads to deterioration of welding workability and deterioration of bead quality. Therefore, in order to solve these problems, the intermetallic compounds that are raw materials for the flakes are roasted to form an oxide film on the surface, and chemical treatments (dry or wet) are used.
Measures have been taken to form a protective film on the surface, and this surface film prevents the reaction between the intermetallic compound base and water glass. [Problems to be solved by the invention] However, the protective film formed by roasting and chemical treatment is often formed unevenly on the surface of the intermetallic compound, and in order to provide a sufficient protective function, it is necessary to take a long treatment time. There are inconveniences such as having to take a long time and using a large amount of chemicals. In addition, the protective film formed in this way does not necessarily have good adhesion to the underlying intermetallic compound base, and the protective film peels off due to friction between the flux raw materials during the kneading operation of the flux raw materials. It no longer functions as a film. That is, when the protective film peels off, the base material is exposed and its chemical activity increases, causing a reaction with water glass and water to generate H ₂ . As a result, the mixed flux expands due to the generated _H2 , and the contact area between the flux particles decreases, which is thought to lead to a decrease in the fixation strength of the flux after drying. The present invention has been made in view of these circumstances, and provides a metal as a raw material for a flux that eliminates the disadvantages such as non-uniform distribution and easy peelability of the protective film and has good corrosion resistance against water glass. The aim is to provide intermediate compounds. [Means for Solving the Problems] The intermetallic compound of the present invention that achieves the above object is characterized by containing 0.1 to 8% B (meaning % by weight, the same applies hereinafter). be. [Function] In the case of a protective film formed on the surface of an intermetallic compound by post-treatment such as roasting or chemical treatment, the above-mentioned drawbacks cannot be completely eliminated even if the treatment conditions are variously changed. Therefore, in order to form a uniform protective film on the surface of the intermetallic compound and with high adhesion to the substrate, the present inventors decided to use an Al ₂ O ₃ film on the surface of the metal Al, instead of using the above-mentioned forced means. I thought that it must be something that was naturally generated, like this. In other words, after conducting various studies, we came to the conclusion that a naturally occurring protective film would form uniformly and densely over the entire surface of the intermetallic compound, and would have a high degree of adhesion to the substrate. reached. That is, the B-containing intermetallic compound of the present invention naturally forms a B oxide film on its surface based on the oxidizability of B. As a result, the oxide film is formed in a manner that the distribution is uniform and dense, and the adhesion to the substrate is strong. In this way, the surface of the intermetallic compound is covered with a stable and homogeneous B oxide film and becomes inert, so it will not be corroded even when it comes into contact with water glass, and its corrosion resistance is improved by the flux mixture. It does not easily decrease due to friction due to time, etc. In order to effectively exhibit the above effects, it is necessary to contain 0.1 to 8% of B in the intermetallic compound.
If the amount of B is less than 0.1%, the thickness of the protective film will be insufficient because the amount of B added will be insufficient, and an intermetallic compound with good water glass corrosion resistance will not be obtained. On the other hand, if the amount of B exceeds 8%, the protective film formed on the surface of the intermetallic compound becomes too thick, which deteriorates the adhesion between the protective film and the substrate and causes it to peel off due to friction and collision when mixing the flux raw materials. It happens a lot. That is, water glass corrosion resistance deteriorates. The basic structure of the present invention is as described above, but the intermetallic compound according to the present invention has good heat resistance at high temperatures (high temperature oxidation resistance), and the oxide film thickness does not increase unnecessarily in a high temperature atmosphere. In addition, for example, a flux-cored wire filled with non-granulated flux has the advantage that intermetallic compounds are less likely to be oxidized when the wire sheath is annealed. Therefore, the intermetallic compound according to the present invention is also useful for welding fluxes that do not use water glass. In addition, in producing the B-containing intermetallic compound according to the present invention as described above, Fe-Si, Fe-Mn,
Metal B or a B compound (oxide, carbide, nitride, etc.) may be added as a raw material when melting Ca-Si or the like. Processing after melting is the usual method, that is, ingot formation →
Just follow the process of crushing → sieving. [Example] Example 1 Using Fe-Si with each B concentration shown in Table 2, the first
Coated arc welding rods having the flux composition shown in the table were manufactured according to a conventional method. However, the core wire used is 4mm.
φ×400ml, flux drying conditions are 400℃×30
It was a minute. The amount of water glass added was 14 ml per 100 g of raw material flux. In this experiment, the dry cracking conditions of the coating materials were compared, and the yield and shedding resistance of products without dry cracking were investigated, and the results shown in Table 2 were obtained.

【table】

【table】

【table】

[Table] As shown in Table 2, No. 1 and 2 have low B concentration, so
A protective film is not sufficiently formed on the Fe−Si surface and Fe−
This is an example of Si having insufficient water glass corrosion resistance, and both product yield and drop-off resistance were poor. No.9, 10
Because the B concentration is too high, the protective film is formed thickly, the adhesion between the protective film and the substrate becomes poor, and the protective film peels off due to frictional collisions between flux particles, resulting in water glass corrosion resistance of Fe-Si. My condition actually got worse. Moreover, both the product yield and the falling-off resistance performance of Experiment Nos. 9 and 10 were poor. On the contrary, Nos. 3 to 8, which are examples of the present invention, had good product yield and anti-dropping performance. Example 2 Coated arc welding rods having the flux compositions shown in Table 3 were manufactured in the same manner as in Example 1 using Fe-Mn of each B concentration shown in Table 4. In this experiment, the drying cracking of the coating materials was compared, and the yield and shedding resistance of products without drying cracking were investigated, and the results shown in Table 4 were obtained.

【table】

【table】

【table】

[Table] *1, *2, *3 Same as Table 2 As shown in Table 4, Nos. 1 and 2 have a low B concentration, so a protective film is not sufficiently formed on the ferromanganese surface, and the ferromanganese This is an example of insufficient corrosion resistance, and both product yield and drop-off resistance were poor. No. 8 is an example in which the B concentration is too high, and as in the case of Example 1, the adhesion between the thick protective film formed and the base is poor, so the friction and collision between flux particles during kneading prevents protection. The film peeled off, and the corrosion resistance of ferromanganese worsened. Moreover, the product yield and anti-dropping performance of No. 8 were poor. On the contrary, all Nos. 3 to 7 satisfied the conditions of the present invention, and good product yield and drop-off resistance were obtained. Example 3 Using Al-Mg with each B concentration shown in Table 6,
A filling flux for a flux-cored wire having the flux composition shown in the table was granulated and manufactured according to a conventional method. The amount of water glass added was 13ml per 100g of raw material flux, and the drying conditions for the granulated flux were 350℃
The particle size was 20×65 mesh for 1 hour. In this experiment, the rate at which the particle size-adjusted flux was pulverized before it was filled into the sheath, ie, the pulverization rate, was investigated, and the results shown in Table 6 were obtained. The higher the pulverization rate, the worse the syntron properties and the more likely flux segregation will occur.

【table】

[Table] As shown in Table 6, No. 1 and 2 have low B concentration.
This is an example of poor water glass corrosion resistance of Al-Mg and poor pulverization rate of granulated flux particles. No. 9 is an example in which the B concentration was too high, and the thick protective film that was formed had poor adhesion to the base, and as a result, the protective film could be peeled off due to friction and collision between flux particles during flux kneading. Happens, Al
- The corrosion resistance of Mg was not improved and the powdering rate was also poor. On the contrary, Nos. 3 to 8 all satisfied the conditions of the present invention, and B added to Al-Mg caused Al
- The water glass corrosion resistance of Mg was improved and showed a low level of powdering rate. Example 4 Using REM Ca-Si with each B concentration shown in Table 8,
Sintered fluxes for submerged arc welding having the flux composition shown in Table 7 were manufactured according to a conventional method. The amount of water glass added is per 100g of raw material flux.
The firing conditions for the 13 ml granulated flux were 450°C x 2 hours, and the particle size adjustment of the product flux was 12 x 65 mesh. In this experiment, the granulation yield and number of repeated uses of flux for submerged arc welding were investigated.
The results shown in Table 8 were obtained.

【table】

[Table] As shown in Table 8, in Nos. 1 and 2, due to the low B concentration, a protective film was not sufficiently formed on the REM Ca-Si surface, and the water glass corrosion resistance of REM Ca-Si was not improved. In this example, poor results were obtained in terms of product yield and number of repeated uses. No. 9 is an example in which the B concentration was too high, and Example 1
As in case 3, the protective film becomes thick due to the high B concentration, and the adhesion between the protective film and the base deteriorates.
The protective film peels off due to friction and collision between flux particles during kneading and granulation, and the water glass corrosion resistance of REM Ca-Si worsens, resulting in poor results in terms of granulation yield and number of repeated uses. Ta. On the contrary, Nos. 3 to 8 all satisfied the conditions of the present invention, and good results were obtained in terms of granulation yield and number of repeated uses. [Effects of the Invention] The present invention is configured as described above, and it is possible to provide an intermetallic compound for flux raw materials that has excellent water glass corrosion resistance, and as a result, provides various welding fluxes that have excellent bonding strength. I am now able to do this.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the groove shape in the experiment of Example 4.

Claims (1)

[Claims] 1. An intermetallic compound used as a raw material for welding flux, which is characterized by containing 0.1 to 8% by weight of B and having excellent water glass corrosion resistance.