KR20000031415A - Arc welding method of zinc-plated steel sheet - Google Patents

Abstract

PURPOSE: An arc welding method of a zinc-plated steel sheet is provided to prevent a defect caused by the steam of zinc by removing a zinc plated layer of a zinc plated steel sheet and to discharge a bubble remaining inside a melted metal to the outside by vibrating a melted metal sheet when welding before the melted metal is solidified. CONSTITUTION: A lower member(10) is loaded on an upper part of a vibration body(70), and an upper member(20) is formed to be fillet-welded on the lower member. Then, the upper and lower members are fixed on the vibration body with a clamp(80), and the alloyed layers(11,12) of the surfaces of the upper and lower members are removed by grinding after operating a grinder magnet(60). Next, the vibration body is operated, and the upper and lower member are welded, keeping a slant angle of 45 to 60 degrees of a welding torch(50) and a distance with an overlapping fillet unit 12 to 20mm.

Description

Are Welding process of zink plated steel

The present invention relates to the arc welding method of the galvanized steel sheet in detail to remove the zinc vapor generated during the arc welding of the galvanized steel sheet to remove the bubbles generated by the zinc vapor to remove the defects generated in the weld It relates to an arc welding method of galvanized steel sheet.

In recent years, as the demand for demand is advanced and diversified according to the development of industrial technology and the standard of living, the use range of surface-treated steel sheet with beautiful surface is increasing. Especially, many galvanized steel sheet with excellent corrosion resistance and beautiful surface are among the surface-treated steel sheets. It is used.

Moreover, as automobiles are widely distributed due to the increase in income level, the scope of use is expanding for construction materials for automated steel sheet and home appliance case.

In order to make the galvanized steel sheet into the required shape, it is essential to cut and weld the steel sheet, and in particular, in the welding of steel products, the arc welding method that is economical and economically saves the high efficiency of welding is mainly used.

Arc welding means that two metal or carbon terminals in an electric circuit are brought into contact with each other to flow a current, and when a little is separated, arcs are generated and high heat is generated.

The terminal heats a small amount in a high heat to become a path for the current, and the current continues to flow.

The heat generated at this time is capable of melting the metal and the emitted light is hard to see directly with the naked eye. The incandescent portion of the arc is the hottest and is about 4000 ° C. for carbon arc and 3000 ° C. for metal arc.

The welding method that melts and joins the part to be bonded to the base metal by using the generated heat or welds another metal to the metal surface is called arc welding method. When welding while the welding part is blocked by air, the shielded gus Inert gas welding method, carbon dioxide gas arc welding method, etc. are classified according to the type, and carbon dioxide gas arc welding method is mainly used for steel welding.

However, when arc welding a galvanized steel sheet, zinc vapor is generated due to high heat, and the arc becomes unstable, so that a large amount of fume is generated. In particular, overlapped fillet welds cause defects such as pores, which makes the weld part vulnerable and surface conditions. Hurt. The main defect that makes the weld vulnerable is due to the gas generated in the weld during welding, which is generated inside the weld metal or on the surface of the weld bead, and the generated gas has a low temperature such as nitrogen and hydrogen, which are mixed during melting of the weld metal. Solubility decreases and gasifies more than saturated solubility (2H → H₂, 2N → N₂) to gasify, etc. When carbon in molten metal combines with oxygen to produce carbon monoxide

(C + O = CO) When impurities such as sulfur in molten metal react with hydrogen to gasify (S + 2H = H₂S) When components such as paint, oil and zinc plating are pyrolyzed and gasified (Zn → Zn Gas) Among the gases described above, the gas which has a great influence on welding of galvanized steel is caused by the mixing of the atmosphere, and the arc is scattered by the explosive combustion of zinc and the zinc vapor so that the atmosphere is mixed into the arc atmosphere and processing occurs. Hydrogen in the Zn + Fe alloy layer of the galvanized steel sheet is rapidly heated and melted by the welding arc to be dissolved in the molten metal, and solidification becomes unstable when the molten paper becomes thermally unstable due to melting. As a result, hydrogen is not stably released and pores are generated in the weld metal.

(2H → H₂) As a means for eliminating the defects of the weld by removing the causes such as the above, in Japanese Patent Laid-Open No. 6-142934, a preheating torch before and after the welding torch 50 is shown in FIG. 150) and the after-heat torch 160 is installed to burn zinc plated on the galvanized steel sheet using a preheating torch to prevent zinc vapor generation due to zinc to prevent defects and to prevent the after-heat torch 160. The method of eliminating the defects of the welded part by heating the deposited metal by discharging the residual zinc bubbles to the outside of the welded metal is described. However, this method increases the equipment by installing preheating and post-heating torch together with the welding torch. There was a problem that the work is cumbersome and the production cost increases.

In addition, Japanese Unexamined Patent Publication No. 6-320279 discloses that the first bead 140 is first formed on the overlapping surface as shown in FIG. 3B to re-release bubbles remaining inside the primary bead 130 to solve the defect. Although the method is described, this method has a problem that the secondary bead must be re-formed after forming the primary bead, which leads to waste of welding material and thermal deformation of the base material due to the double operation and an increase in production cost. .

Therefore, the technical problem to be achieved by the present invention is to remove the galvanized layer of the galvanized steel sheet before arc welding to solve the above problems, to prevent defects by zinc vapor during welding, and to vibrate the molten metal during welding to the inside of molten metal It is to provide a welding technique for releasing bubbles remaining in the molten metal to the outside before solidification.

Figure 1 is a side view showing the implementation of the present invention

2 is a front view showing an embodiment of the present invention.

Figure 3 A, B is a side view showing the prior art

Explanation of symbols on the main parts of the drawings

10: bottom material 11: galvanized layer

20: upper material 21: galvanized layer

30: weld bead 40: molten paper

50: welding torch 51: welding wire

60: grinder 70: vibrating body

80: crimp

In order to achieve the technical problem to be achieved the invention consists of removing the galvanized layer plated on the welded portion in arc welding galvanized steel sheet, and vibrating the molten paper during welding.

Hereinafter, described in detail with reference to the embodiment as follows.

Of course, the invention is not limited to the described embodiments.

Placing the lower material 10 on the upper part of the vibrator 70 and forming the upper material 20 to be fillet weldable on the lower material 10;

Fixing the upper material 20 and the lower material 10 to the vibrating body 70 with the clamp 80, and actuating the grinder bottom stone 60 to form a plating layer on the upper material 20 and the lower material 10 surface. (11) (21) to remove and grind the step of operating the vibrating body (70), to maintain the inclination angle of 45 to 60 degrees of the welding torch 50 to overlap the fillet portion and the distance 12 to 20 mm As a result of the step of holding and welding, the comparison results of Table 1 and Table 2 were obtained.

At this time, the welding method used was carbon dioxide gas welding. The welding wire was 1.2 mm in diameter, and the shielding gas was 100% CO2 gas.

In the pore evaluation, the weld bead length was 300mm and the number of pores and the pore size were examined through X-ray penetration test.

Table 1 Comparative Examples of the Invention Examples and General Examples

Plating Type Plate thickness (mm) Plating amount (g / ㎡) Pore generation water (ea / 10㎜) Pore size (mm) Example Electro zinc plating 1.6 20/20 0 - Hot dip galvanized 2.6 80/80 0 - Alloyed molten zinc 2.0 50/50 0 - Comparative example Electro zinc plating 1.6 20/20 3 0.7 Hot dip galvanized 2.6 80/80 5 1.0 Alloyed molten zinc 2.0 50/50 3 2.8

As shown in Table 1, three kinds of galvanized steel sheets were used and all conditions were the same except that the present invention was used and the present invention was not used, and the existing method was used. It can be seen that no porosity was generated at the welds used, and in the comparative example, 3 to 5 pore numbers were generated and the pore size was 0.7 to 2.8 mm.

In addition, in the X-ray photograph in Table 2, it can be seen that in the comparative example, many pores are visually observed in the comparative example.

Therefore, the welding method of the applied galvanized steel sheet of the present invention can be seen clearly to improve the quality of the weld by suppressing the bubble generation.

The effect of the present invention is to remove the galvanized layer before the arc welding to prevent defects caused by the zinc vapor generated in the galvanized layer during welding and to release the air bubbles to the outside without increasing the equipment and cumbersome double operation occurs in the weld It eliminates the defects and lowers the production cost and makes the welding spots of good quality.

Claims (1)

In arc welding of a galvanized steel sheet, the arc of the galvanized steel sheet, comprising the steps of removing the galvanized layer (11, 21) plated on the welded portion, and vibrating the molten pool (40) during welding. welding method.