JP5009175B2 - Splash adhesion preventing method and hot dip galvanizing equipment in hot dip galvanizing equipment - Google Patents

Description

  The present invention relates to a splash adhesion preventing method and a hot dip galvanizing facility in a hot dip galvanizing facility for preventing splashes wiped from a steel plate surface by a gas blown from a wiping nozzle from adhering to the steel plate again.

  In general, when continuously hot-dip galvanizing is applied to a steel plate, the steel plate is once drawn into a hot-dip zinc bath and then turned vertically by a sink roll disposed in the hot-dip zinc bath. And the surplus of the molten zinc adhering to the surface of the steel sheet is wiped off by blowing gas from a pair of wiping nozzles arranged opposite to the molten zinc bath to control the required thickness. However, at this time, there has been a problem that zinc wiped off from the surface of the steel sheet scatters and becomes splash and adheres again to the surface of the steel sheet after plating, which becomes splash wrinkles.

  In order to prevent the occurrence of such splash wrinkles, conventionally, as disclosed in Patent Document 1, for example, a seal box is provided above a pair of wiping nozzles, and a gas suction pipe and a seal box are provided directly above the wiping nozzles. Some have an upper pressurized gas tube. Then, the inert gas supplied from the pressurized gas pipe is sucked out from the lower gas suction pipe, thereby preventing the upward flow of the wiping gas and preventing splash splash. However, such a configuration has a problem that the wiping device becomes large and the cost is increased.

  Further, the wiping device shown in FIG. 8 is configured such that the splash scattered right above the wiping nozzle 2 is sucked by the blower 21 arranged in front of the gas pipe 1 and collected by the collection tank 22. Although this effect is excellent, it still has problems in terms of equipment costs.

  As one of the conventional methods, as shown in FIG. 9, there is one in which a metal net 3 for capturing a splash is disposed in the vicinity of the gas pipe 1. In this case, the metal mesh 3 can catch the splash scattered from the outside of the pipe toward the steel plate, but cannot catch the splash generated in the vicinity of the wiping nozzle 2. Further, there is a problem that it is not easy to attach and remove the wire mesh 3 and it takes time to remove zinc particles attached to the wire mesh 3.

As shown in FIG. 10, it is also conceivable that a gas blow nozzle 23 is arranged in the vicinity of the wiping nozzle 2 so that the splash splashed off is blown away. However, in this case, there is a problem that the equipment cost and the running cost are increased because the dedicated gas pipe 24 is required. As described above, none of the methods is satisfactory as a splash scatter prevention measure in terms of cost and effect.
JP-A-4-231448 JP-A-4-2756 JP 2000-328218 A

  In view of the above-described conventional problems, the present invention provides a splash scattering prevention method and a hot dip galvanizing facility in a hot dip galvanizing facility that can reliably catch scattered splashes and prevent the occurrence of splash flaws. It was made.

  In order to solve the above-mentioned problems, the inventors have conducted intensive research. That is, conventionally, it has not been possible to confirm a mechanism in which splashes that are wiped and scattered from the steel sheet surface adhere to the steel sheet again. Then, the following knowledge was acquired as a result of observing the scattering state of a splash with a CCD camera.

  In FIG. 1, the steel sheet that has passed through the molten zinc bath is raised upward, but a pair of wiping nozzles 2 are disposed opposite to each other with the steel sheet sandwiched immediately above the zinc bath, and the molten zinc adhered to the surface of the steel sheet. The excess is wiped off by blowing gas from the wiping nozzle 2 and controlled to a required thickness. Gas is supplied to the wiping nozzle 2 via the gas pipe 1.

  Here, an example of the occurrence of splash will be described. The pass line of the steel plate fluctuates left and right due to the waviness and undulation of the steel plate, and when the steel plate approaches the wiping nozzle 2, molten zinc particles are generated at the edge of the steel plate. When the pass line of the steel plate returns to the original normal position, the zinc particles generated at the edge portion are scattered from the edge portion and splash is generated (FIG. 2). Although not shown in the drawings, there is another estimation mechanism for the occurrence of splash, and an example of this is that the opposing gas collides at the edge of the steel plate and a violent turbulent flow may occur, so that the attached zinc may be blown off and generated. . The splashed splash collides with the base of the gas pipe 1 with the wiping nozzle 2 and bounces back above the wiping nozzle 2 (FIG. 3). The splash splashed upward falls onto the wiping nozzle 2, and the dropped splash rides on the gas flow in the vicinity of the wiping nozzle 2 and adheres again to the steel plate by the gas. Therefore, it has been found that the splash that has collided with the gas pipe 1 can be prevented from splashing above the wiping nozzle 2 and can be prevented from adhering again to the steel plate.

The splash adhesion prevention method in the hot dip galvanizing facility of the present invention completed by obtaining the above knowledge is that the splash splashed from the surface of the steel sheet by spraying the gas from the wiping nozzle onto the steel sheet pulled up from the zinc bath again is the steel sheet. A method for preventing splash adhesion in a hot dip galvanizing facility for preventing adhesion to a gas pipe, and a gas pipe for supplying gas to a wiping nozzle and / or a splash of fibrous or non-woven fabric having a melting point of 450 ° C. or less to the wiping nozzle By spraying gas onto the steel plate from the wiping nozzle after arranging the adsorbent , the scattered splash particles dissolve or burn the adsorbent fibers , entangle the adsorbent and entangle it and adsorb it. is there.

  In addition, in the above-described invention, when the adsorbing material of the splash is disposed in the gas pipe, the adsorbing material can be wound around a base portion with the wiping nozzle, and gas can be blown from the wiping nozzle to the steel plate. As the adsorbent, one or more of wool felt, rayon, polypropylene, nylon, polyester, m-aramid, tetrafluoroethylene, asbestos substitute flameproof fiber, and p-aramid can be used.

  Further, the hot dip galvanizing facility of the present invention is a hot dip galvanizing facility in which a pair of wiping nozzles for blowing gas onto a steel plate pulled up from a zinc bath is disposed above the zinc bath, and a gas pipe for supplying gas to the wiping nozzle and / or Alternatively, the wiping nozzle is provided with an adsorbent made of a fibrous or non-woven fabric having a melting point of 450 ° C. or less for adsorbing the splash scattered from the steel sheet surface.

  In the above-mentioned invention, the adsorbent of the splash can be wound around the base of the wiping nozzle of the gas pipe, and the adsorbent of the splash can be wool felt, rayon, polypropylene, nylon, polyester, m-aramid, One or more of tetrafluoroethylene, asbestos-substitute flame-resistant fiber, and p-aramid can be used.

  In the method for preventing splash adhesion in the hot dip galvanizing facility of the present invention, the splash adsorbent is disposed on the gas pipe for supplying the gas to the wiping nozzle and then the gas is blown from the wiping nozzle to the steel plate. Can be adsorbed. Therefore, it is possible to prevent the splash that has collided with the gas pipe from bouncing back and adhering to the steel plate again.

  In addition, since the hot dip galvanizing equipment of the present invention has the splash adsorbent disposed in the gas pipe that supplies gas to the wiping nozzle, the scattered splash is adsorbed by the adsorbent and prevented from adhering to the steel plate again. can do.

Hereinafter, the present invention will be described in detail with reference to the drawings.
5 and 6 are diagrams showing a hot dip galvanizing facility according to the present invention, and FIG. 5 shows a case where a fibrous or non-woven splash adsorbent 5 is wound around the root of the gas pipe 1 and the winding nozzle 2. FIG. 6 shows a case where a splash or adsorbent 5 made of fibrous or non-woven fabric is further attached to the surface of the wiping nozzle 2. This hot dip galvanizing equipment is not particularly different from that already described in the basic structure. That is, in FIGS. 5 and 6, the steel sheet fed into the molten zinc bath is changed in direction by the sink roll 4 and pulled up vertically. A pair of wiping nozzles 2 are arranged to face each other with a steel plate interposed therebetween, and a plurality of gas pipes 1 are connected to the upper surface of the wiping nozzle 2 by bending downward from an upper header pipe 11. For attaching the adsorbent 5, an appropriate fixing tool such as a wire or a clip can be used. 5 and 6, it is preferable to dispose the adsorbent in the gas pipe not only in the gas pipe 1 but also in the upper header pipe 11 and other pipes not shown in the figure. It is preferable to arrange in piping and other facilities within a radius of 1 m.

  In the structure constituted as described above, the steel sheet is once drawn into the molten zinc bath, and then the direction is changed by the sink roll 4 disposed in the molten zinc bath, and the steel sheet is pulled up vertically. And the surplus of the molten zinc adhering to the steel plate surface is wiped off by blowing gas from the pair of wiping nozzles 2. At this time, zinc wiped off from the surface of the steel sheet scatters and becomes splash. However, since this splash adheres to the adsorbent 5, it does not bounce off from the root of the gas pipe 1 with the wiping nozzle 2 and scatter upward. This can be estimated as follows. When the splash adsorbent is a ceramic fiber, the heat-resistant temperature is too high and the fiber does not melt or burn. For this reason, even if the splash splashed at or near the melting point of zinc collides with the adsorbent, the fiber does not melt or burn (actually, it burns slightly), and the splash grains melt or burn. It is presumed that the fiber is not entangled with the fiber. Therefore, since splash splash beyond this can be prevented, the occurrence of splash wrinkles can be prevented. For this reason, the upper limit of the melting point of the adsorbent of splash is 450 ° C. close to the melting point of zinc, and the lower limit is not particularly specified, but since it is in the vicinity of a molten zinc bath having a high atmospheric temperature, The melting point is preferably 30 ° C. or higher.

  In this manner, if the adsorbent is a splash adsorbent made of fibers or non-woven fabric having a melting point of 450 ° C. or lower, preferably 30 ° C. or higher, attachment to and removal from the gas pipe 1 is easy. Examples of materials suitable for the adsorbent include wool felt, rayon, polypropylene, nylon, polyester, m-aramid, tetrafluoroethylene, asbestos substitute flameproof fiber, and p-aramid. Moreover, since zinc particles adhering to the felt can be easily removed by blowing high-pressure air or sweeping them off with a brush or the like, resources are not wasted.

  Hereinafter, an embodiment of the present invention using wool felt as a splash adsorbent will be described in comparison with a conventional example without an adsorbent. That is, the reinspection rate by the splash flaw was compared using the conventional hot dip galvanizing equipment shown in FIG. 9 and the hot dip galvanizing equipment of the present invention shown in FIGS. The result is shown in FIG. 7, but the occurrence rate of splash soot was as high as 0.5% in the conventional equipment before the improvement, but in the case of FIG. 29%, a reduction of about 0.21%, and in the case of FIG. 6, a reduction of 0.24% and about 0.26% could be achieved.

  For materials other than wool felt, the zinc splash was skipped in a laboratory experiment and the state of trapping the splash particles was observed. The evaluation is ◎ that captured at least as much as in the above-mentioned examples of wool felt, ◎ that the adsorption amount is inferior to 20% less than wool felt is `` slightly inferior '' ○, other than the above ×, ◎, ○ was accepted. The results are shown in Table 1.

  As the melting point increases, the capture of splash grains tends to decrease, but it is generally good if the melting point is 450 ° C. or lower. The alumina fiber of the comparative example has little trapping of the splash grains and is about 20% of the wool felt, and the splash grains easily fall off when knocked. Cotton has a melting point (yellowing, decomposition temperature) close to that of wool felt, but the amount of splash captured is about 50 to 60% of wool felt, and it often smoldered and smoked compared to wool.

It is a principal part block diagram of the hot dip galvanization equipment which shows the state which the steel plate pass line changed to the right. It is a principal part block diagram of the hot dip galvanization equipment which shows the state which a splash scatters from a steel plate edge part. It is a principal part block diagram of the hot dip galvanization equipment which shows the state in which a splash bounces upwards from the base part of gas piping. It is a principal part block diagram of the hot dip galvanization equipment which shows the state in which the splashed splash adheres to a steel plate again. It is a schematic block diagram which shows the hot dip galvanization installation of this invention. It is a principal part enlarged view of FIG. It is a graph which shows the Example of this invention compared with a prior art example. It is a schematic block diagram of the conventional installation which attracts | sucks a splash with a blower. It is a schematic block diagram of the conventional installation which attaches a splash to a wire mesh. It is a schematic block diagram of the conventional installation which blows off a splash with a blow nozzle.

Explanation of symbols

1 Gas Pipe 2 Wiping Nozzle 4 Immersion Roll 5 Adsorbent 11 Header Pipe

Claims (6)

A splash adhesion prevention method in a hot dip galvanization facility for preventing splash of gas sprayed from a wiping nozzle on a steel plate pulled up from a zinc bath and splashing from the surface of the steel plate again to the steel plate. Dispersed splash particles are adsorbed by spraying gas from the wiping nozzle onto the steel sheet after disposing a fibrous or non-woven fabric splash adsorbent with a melting point of 450 ° C. or less on the gas piping and / or wiping nozzle for supplying gas. A method for preventing splash adhesion in a hot dip galvanizing facility , wherein fibers of a material are dissolved or burned , entangled in an adsorbent and entangled and adsorbed.   2. The hot dip galvanizing equipment according to claim 1, wherein when the splash adsorbent is disposed in the gas pipe, the adsorbent is wound around a base portion with the wiping nozzle, and gas is blown from the wiping nozzle to the steel plate. Splash adhesion prevention method.   One or more of wool felt, rayon, polypropylene, nylon, polyester, m-aramid, tetrafluoroethylene, asbestos substitute flameproof fiber, and p-aramid are used as the adsorbent for the splash. Item 3. A method for preventing splash adhesion in the hot dip galvanizing facility according to Item 1 or 2.   In a hot dip galvanizing facility in which a pair of wiping nozzles for blowing gas to the steel plate pulled up from the zinc bath is disposed above the zinc bath, the gas pipe for supplying gas to the wiping nozzle and / or the wiping nozzle is wiped from the steel plate surface. A hot dip galvanizing facility comprising a fibrous or non-woven adsorbent having a melting point of 450 ° C. or lower for adsorbing splashed splashes.   The hot dip galvanizing equipment according to claim 4, wherein the splash adsorbent is wound around a base portion of the gas pipe with a wiping nozzle.   The splash adsorbent is one or more of wool felt, rayon, polypropylene, nylon, polyester, m-aramid, tetrafluoroethylene, asbestos substitute flameproof fiber, and p-aramid. The hot dip galvanizing facility according to claim 4 or 5.

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