JP2020073286A - Plating removing method, welding method, welded product, structure - Google Patents

Abstract

To make it possible to easily and reliably obtain a plating removal part with respect to chiefly a steel material plated part on a face on which plural steel materials with a plated surface are overlapped.SOLUTION: According to the present invention, with respect to a plated part 18 of a steel material 19 with the plated part 18 on a face on which plural steel materials 19 are overlapped, the plated part 18 is partially removed or oxidized by heating so as to form a plating removal part 21.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a plating removal method, a welding method, a welded product, and a structure.

  For example, welding of a steel material having a plated surface is performed. Note that it is also known to remove plating as a pretreatment for welding a steel material having a plated surface (see, for example, Patent Documents 1 to 8).

JP 62-179869 A JP, 6-262362, A JP, 7-236984, A JP 2005-40806 A JP-A-2-310399 JP-A-4-99123 JP, 2003-112217, A JP, 9-141238, A

  However, first, when a steel material having a plated surface is directly welded, internal defects such as blowholes and surface defects such as pits are likely to occur at the welded portion due to mixing of the plated material. Therefore, it takes a lot of trouble to repair these defective welding points. Further, it is necessary to cut or re-weld the welded portion of the steel material for repair, and the dimensional accuracy of the steel material deteriorates.

  In addition, when molten plating adheres to the welding electrode, the contact area between the welding electrode and the steel material increases and the welding strength decreases, as well as the welding current to reduce the welding strength due to the increase in the contact area. There was a problem that it was necessary to raise it.

  Further, there is a problem that the welding electrode is apt to be damaged due to the sticking of the plating on the welding electrode, and that it is necessary to use an expensive welding electrode which is strong in sticking the plating in order to prevent the welding electrode from being damaged. Was.

  Therefore, in the above-mentioned Patent Document 1, a protrusion is used in the welded portion to provide a gap to prevent the entrainment of plating. However, in this case, a protrusion is required to provide a gap in the welded portion, which causes a restriction on the design of the welding target. Further, a change in the size of the gap causes a difference in the effect of preventing the entrainment of plating, which also affects the dimensional accuracy of the welding target and the way the welding target is deformed during welding. Furthermore, only lap welding can be performed to provide the above-mentioned gap. In addition, if a gap is provided, the gap tends to shrink when the welded part cools, and the other part of the gap unintentionally opens due to the gap shrinking (that is, the gap cannot be kept constant). Problems also occur.

  Further, in the case of Patent Document 2, a large amount of oxygen is mixed into the shield gas during welding so that the plating is burned with a large amount of oxygen. However, in such a case, a special shield gas containing a large amount of oxygen is required, resulting in cost increase, and the oxygen contained in the shield gas in a large amount melts into the welding target to be welded. There is a risk of changing the physical characteristics.

  In Patent Documents 3 and 4, the laser heat source is used to remove the plating. However, since the laser device is expensive, using the laser device makes it impossible to achieve the purpose of cost reduction. Further, since the laser beam has a narrow heating range, it is necessary to perform weaving and the like, and it is not easy to obtain a uniform and stable plating removal portion, and it is difficult to improve product quality.

In Patent Document 5, titanium or a titanium alloy is subjected to electrolytic treatment or the like to remove oxide scale. In Patent Document 6, the oxide layer is reduced with a high-temperature gas containing a required concentration of hydrogen radicals. In Patent Document 7, only the polygonal particles or the metal particles in which the polygonal particles and the substantially spherical particles are mixed at an appropriate mixing ratio are sprayed onto the surface of the metal material to form an oxide film on the surface of the metal material. I am trying to remove it. In Patent Document 8, a steel piece on which a plating layer containing Zn is formed is charged together with a hard material into a rotary kiln having a cross-sectional diameter of 20 cm or more, and then the rotary kiln is rotated at a rotation speed of 0.1 rpm or more. By doing so, the plating layer is removed. However, since all of Patent Documents 5 to 8 require special equipment, it is difficult to perform pretreatment on site and it is difficult to perform partial treatment.
Further, in JP-T-2014-53324, the laser beam is radiated so as to penetrate into the joint toward the joints of a plurality of overlapped workpieces. Since the workpiece is melted to form a laser weld bead having some porosity, it was not possible to successfully remove only the plating layer of the overlapped portion without melting the steel portion of the workpiece.

  Therefore, the present invention mainly aims to solve the above-mentioned problems.

  In order to solve the above problems, the present invention forms a plating removal part by partially removing or oxidizing the plating part by heating, with respect to the plating part of the surface of the steel material having the plating part where a plurality of steel materials are superposed. It is characterized by a method of removing plating.

  According to the present invention, with the above configuration, it is possible to easily and surely obtain the plating removal portion with respect to the plated portion of the surface of the steel material having the plated portion on the surface of which a plurality of steel materials are superposed.

It is a perspective view of a unit building concerning an example. It is a perspective view of the building unit used for the unit building of FIG. FIG. 3 is a partially enlarged view of an upper joint portion of the building unit of FIG. 2. FIG. 3 is a partially enlarged view of a lower joint portion of the building unit of FIG. 2. It is a longitudinal cross-sectional view which partially enlarged the joining part of the steel material which has a plating part on the surface. It is a longitudinal cross-sectional view similar to FIG. 5 which shows the plating removal method using arc energy. It is a longitudinal cross-sectional view similar to FIG. 5 which shows the plating removal method using high frequency induction heating. It is a longitudinal cross-sectional view similar to FIG. 5 which shows the steel material in which the plating removal part was formed. It is a side view of a tungsten electrode at the time of performing TIG arc welding. It is a side view of a tungsten electrode when performing a plating removal method. It is a side view which shows spot welding with respect to the steel material in which the plating removal part was formed. FIG. 6 is a side view similar to FIG. 5, showing a case where welding (for example, TIG arc welding or carbon dioxide gas arc welding) is performed on the steel material on which the plating removal portion is formed. It is a side view similar to FIG. 5 which shows the welding defect which arises when welding (for example, TIG arc welding, carbon dioxide gas arc welding, etc.) is performed with respect to the steel material which does not form the plating removal part. FIG. 12 is a side view similar to FIG. 11, showing a state where welding is performed on a steel material on which a plating removal portion is not formed. FIG. 12 is a side view similar to FIG. 11, showing a state immediately after welding is performed on a steel material having no plating removed portion. It is a perspective view showing a state of a tip of a welding electrode when welding is performed without forming a plating removal part. It is a perspective view which shows the state of the front-end | tip of a welding electrode at the time of performing welding after forming a plating removal part. It is a graph which shows the relationship between the strength of welding and the number of hit points.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
1 to 17 are for explaining this embodiment.

  <Structure> The structure will be described below.

  FIG. 1 shows a unit building 1. This unit building 1 conveys a plurality of building units 2 manufactured in a factory in advance to a construction site, and arranges the plurality of building units 2 in the horizontal direction or stacks the building units 2 in the construction site in a short period of time. It is a building that can be built. In addition, in the figure, a roof formed by attaching a roof panel provided with a solar cell panel 4 is installed on an upper portion of a building body configured by the building unit 2.

  In the building unit 2 described above, for example, as shown in FIG. 2, the upper ends of four steel unit columns 5 are connected in a rectangular shape by four steel ceiling beams 6, and The unit frame 8 has a box-ramen structure in which the lower ends of the steel unit columns 5 are connected in a rectangular shape by four steel floor beams 7.

  Then, as shown in FIG. 3, the unit pillar 5 and the ceiling beam 6 described above are joined by using a joint piece 11 made of steel. The unit pillar 5 and the ceiling beam 6 are integrated by welding (welded portion 12 (for example, arc welded portion 12a, spot welded portion 12b)). Further, a steel plate 13 having a positioning hole for positioning another building unit 2 installed on the upper side is attached to the upper end of the unit pillar 5 by welding (welding part 12 (for example, Arc weld 12a))). The welded portion 12 is a joint portion or a fixed portion having an integrated structure structure in which mutual structures are mixed and continuous by softening / melting of the interface due to heating.

  Similarly, as shown in FIG. 4, the unit pillar 5 and the floor beam 7 are joined by a steel joint piece 14. The unit pillar 5 and the floor beam 7 are integrated by welding (welded portion 12 (for example, arc welded portion 12a, spot welded portion 12b, etc.)). A steel plate (not shown) having a positioning hole for positioning the foundation of the building or another building unit 2 installed on the lower side is attached to the lower end of the unit pillar 5 by welding. ing.

  The surface of each of the unit pillars 5, the ceiling beams 6, the floor beams 7, the joint pieces 11 and 14, the plate 13 and the like has a plated portion 18 on the surface as shown in FIG. Steel material 19 is used.

  In addition to the basic or overall structure as described above, this embodiment has the following structure.

  (1) In the plating removal method of this embodiment, as shown in FIGS. 6 to 8, the surface of the steel material 19 having the plated portion 18 is partially heated by heating (see FIG. 6 or 7). To remove or oxidize to form the plating removal portion 21 (see FIG. 8).

Here, the material of the steel material 19 and the material of the plated portion 18 may be any material, but preferably, the steel material 19 has a higher melting point than the plated portion 18. For example, when the steel material 19 is made of iron, the melting point of the steel material 19 is about 1500 °. When the plated portion 18 is galvanized, the melting point of the plated portion 18 is approximately 420 ° and the boiling point of the plated portion 18 is approximately 900 °. Therefore, in order to vaporize or oxidize and remove the plated portion 18 without melting the steel material 19, it is necessary to heat at a temperature within the range of 330 ° to 1500 °.
The plating removal portion 21 may be formed by combining a plurality of steel materials 19 to be welded with each other in advance as shown in FIG. 6, or as shown in FIG. The plating removal portion 21 may be individually formed for the steel material 19 to be welded, and then a plurality of steel materials 19 to be welded may be combined together as shown in FIG.

  (2) The steel material 19 may have a three-dimensional shape (three-dimensional object).

  Here, any three-dimensional shape may be used as long as it has a more complicated shape than a simple bar or face material. It is sufficient that at least one three-dimensionally shaped steel material 19 is provided. For example, in the case of FIGS. 3 and 4, one steel material 19 (the unit pillar 5, the joint pieces 11 and 14, etc.) has a three-dimensional shape such as a rectangular tube shape or a C cross section.

  (3) As shown in FIGS. 6 and 7, the plating removal portion 21 is preferably formed by heating means 31 and 32 which perform either heating by arc energy or high frequency induction heating. ..

  Here, the heating means 31 for heating with arc energy can be, for example, a TIG welding torch 40 as shown in FIG. Then, the TIG welding torch 40 is used so as to generate the arc 41 without supplying the welding wire and with the applied current dropped (than the welding current when performing the TIG arc welding). ..

  The TIG welding torch 40 is provided so as to surround a welding electrode 42 such as a tungsten electrode, a cylindrical collet body 43 (electrode guide) that sends the welding electrode 42 toward the welding portion 12, and an outer periphery of the collet body 43. And a nozzle 45 for injecting a shield gas 44 such as argon gas toward the welded portion 12. Then, the welding current from the welding power source 46 is applied between the collet body 43 and the steel material 19. The TIG welding torch 40 may be operated by hand, or may be operated by using a welding robot whose moving path is taught in advance.

  When performing TIG arc welding, the welding electrode 42 such as a tungsten electrode is used with its tip (left end) sharpened and sharpened as shown in FIG. In the case of heating for forming, it is not necessary to sharpen the tip end of the tungsten electrode, and as shown in FIG. 10, it can be used without being sharpened. However, the heating means 31 for heating with arc energy is not limited to the TIG welding torch 40.

  The heating means 32 for heating by high frequency induction heating is, for example, a high frequency induction heating device 47 as shown in FIG. 7. The high frequency induction heating device 47 is a device in which a high frequency power supply device 49 is connected to the induction coil 48. As the induction coil 48, an optimum one is prepared in advance according to the shape of the steel material 19 and the size and shape of the plating removal portion 21 to be formed on the steel material 19.

  It is needless to say that the heating means 32 for heating by high frequency induction heating may be used in the case of FIG. 6 and the heating means 31 for heating by arc energy may be used in the case of FIG. Further, the TIG welding torch 40 and the high frequency induction heating device 47 described above, needless to say, detect the temperature with a temperature sensor and perform control.

(4) Then, as shown in FIGS. 11 and 12A, a welding method of welding the steel material 19 having the plated portion 18 by arc welding or spot welding is performed.
At this time, a partial plating removal portion 21 is previously formed (as a pretreatment) on the surface of the steel material 19 having the plating portion 18 by the above-described plating removal method (plating removal step), and then as shown in FIG. Then, the plating removal portion 21 of the steel material 19 is welded (welding process). Note that FIG. 11 shows an example of spot welding.

Here, if necessary, a step (steel material combination step) of combining the steel materials 19 in which the plating removal portions 21 are individually formed in the plating removal step as shown in FIG. 7 as shown in FIG. 8 is performed before the welding step. You can put it in.
The plating removal portion 21 as a pretreatment for welding is formed to be larger than the welding portion 12 by about one size with respect to the periphery of the welding portion 12. The arc welding can be performed, for example, by using the TIG welding torch 40 shown in FIG. 6 as it is (TIG arc welding, see FIG. 12A). Alternatively, carbon dioxide gas arc welding or other types of arc welding can be performed.

  For spot welding, for example, a spot welding machine 51 having a pair of welding electrodes 42 sandwiching two superposed steel materials 19 as shown in FIG. 11 is used.

  (5) By the welding method described above, the welded product 61 having the welded portion 12 (structural structure by welding) is formed in the plating removal portion 21 (which is partially provided on the surface of the steel material 19 having the plated portion 18) ( See FIG. 2).

In this case, the weldment 61 may be the unit frame 8 of the building unit 2 described above or the like. However, the weldment 61 is not limited to the unit frame 8.
In other words, this welded product 61 softens the interface between the plating removal parts 21 partially provided for the plurality of steel materials 19 having the plating parts 18 on the surface due to heating. A plurality of steel materials 19 are integrated by providing the welded portion 12 which is a joint portion or a fixed portion having a structure structure in which mutual structures are mixed and continuous by melting.
Alternatively, the welded material 61 is provided between the plurality of steel materials 19 having the plating parts 18 on the surface, the plating removing parts 21 partially provided for each steel material 19, and the plating removing parts 21. A plurality of steel materials 19 are integrated with each other, and a welded portion 12 having a joint structure or a fixed portion having a structure structure in which mutual structures are mixed and mixed by softening / melting of an interface due to heating. Will be things.

  (6) The structure 71 is constructed by the welded object 61 (see FIG. 1).

  In this case, the structure 71 may be the unit building 1 or the like described above. However, the structure 71 is not limited to the unit building 1.

  <Effect> According to this embodiment, the following effects can be obtained.

  (Function and Effect 1) The plating removal portion 21 is formed by heating the surface of the steel material 19 having the plating portion 18. Thereby, the unnecessary plating part 18 (plating) on the surface of the steel material 19 can be partially removed. Since the partial removal of the plating part 18 by heating can be easily performed on site, the plating removal part 21 necessary for the required part can be freely set on the spot when it is needed during site work. Can be provided in the. The plated portion 18 is removed by being evaporated or oxidized by heating. The removal of the plated portion 18 can be confirmed by, for example, measuring the surface temperature of the steel material 19 with a radiation thermometer or measuring the temperature of the heating range of the steel material 19 with a thermal image measuring device.

  By performing the above-described plating removal method, an oxide film is formed on the plating removal portion 21 of the steel material 19, but the oxide film (oxidation film formed by heating at a temperature for removing the plating portion 18 (oxidation) is formed. The analysis confirmed that iron, zinc oxide, etc., are such that they have no particular effect on the subsequent work (eg welding).

  (Function and Effect 2) The steel material 19 has a three-dimensional shape. Then, a partial plating removal portion 21 is formed by heating the plating portion 18 on the surface of the steel material 19 having a three-dimensional shape. As a result, the plating removal portion 21 can be formed even on the plating portion 18 formed on the surface of the three-dimensionally shaped steel material 19. Therefore, the applicable range of the plating removal method can be expanded.

  (Function and Effect 3) The plating removal portion 21 is formed by the heating means 31 and 32 that perform either heating by arc energy or high frequency induction heating. Both the heating by arc energy and the high frequency induction heating have a high calorific value, and the heating conditions (caloric amount, location, etc.) can be electrically set arbitrarily, so both can be performed only in an instantly required place. Can be heated to the required temperature. Therefore, the plating removal portion 21 can be formed easily and in a short time while suppressing the thermal strain applied to the steel material 19 without melting the steel material 19, so that heating by arc energy or high frequency induction heating is It is particularly advantageous and most ideal as compared with the case of using the heating method of.

  Moreover, in the case of heating by arc energy or high frequency induction heating, the range that can be heated at one time (heating range) is wide, and since temperature control is easy, it is possible to stably heat all necessary parts to the required temperature. it can. Therefore, it is possible to easily and surely obtain the uniform and uniform plating removal portion 21 in a short time. Moreover, it is also suitable for treating the three-dimensionally shaped steel material 19 as described above.

  For example, it is conceivable to perform heating with a laser in order to obtain the plating removal portion 21, but since the laser device is expensive, cost reduction cannot be achieved. In addition, since the laser beam has a narrow heating range (small beam diameter), weaving or the like must be performed in order to heat the laser beam widely, and it is not easy to obtain the plating removal portion 21 as desired, thus improving product quality. It is difficult to connect to.

  On the other hand, the above-described heating by arc energy and high-frequency induction heating are significantly cheaper than the laser device (TIG welding torch 40 and high-frequency induction heating device 47), and the heating range is relatively wide. So there is no need to weave. Therefore, it is possible to surely obtain cost reduction, quality improvement, and processing efficiency. Further, it is not necessary to change the shape of the welded portion 12, and it is possible to flexibly deal with the steel material 19 and the welded portion 12 regardless of the shape of the welding because the processing can be performed while changing the heating posture. Further, for example, a special and expensive shield gas such as one containing a high concentration of oxygen is not required.

  (Function and Effect 4) The portion of the plating removal portion 21 formed as a pretreatment on the steel material 19 is welded by arc welding or spot welding. As a result, as in the case where welding is performed without forming the plating removal portion 21 (see FIG. 12B), internal defects such as blowholes 81 and pits 82 due to (plating) of the plating portion 18 in the welding portion 12. It is possible to prevent the occurrence of surface defects such as, and it is possible to eliminate the trouble of repairing these defective welding points.

  Further, as shown in FIG. 13, when the molten plating portion 18 (of the plating) adheres to the welding electrode 42, the contact area between the welding electrode 42 and the steel material 19 increases (S1 in FIG. 11 <FIG. 13). S2) The problem that the welding strength decreases, the problem that the welding current needs to be increased in order to cope with the decrease in the welding strength due to the increase in the contact area, and the plating part 18 (plating) on the welding electrode 42 As shown in FIGS. 14 and 15, the problem that the welding electrode 42 is easily damaged (damaged portion 83) and the welding electrode 42 are prevented from being damaged by the sticking are expensive welding that is strong against sticking of plating. There arises a problem that it is necessary to use the electrode 42.

  However, if the plating removal portion 21 is provided in advance on the steel material 19 and the portion of the plating removal portion 21 is welded, all of the above problems can be solved at once, so that the welding strength is improved and the welding current is suppressed. In addition, the life of the welding electrode 42 can be extended and the inexpensive welding electrode 42 can be used at the same time (see FIG. 16). Therefore, it is possible to reliably obtain a high-quality welded portion 12 with low energy consumption and low cost with high yield.

  Then, as a result of actually performing the welding after the plating removal portion 21 was provided, it was confirmed that in the case of arc welding, the blow hole 81, the pit 82, and the like were not generated. Therefore, the frequency of repair is also reduced. It has become possible. Therefore, the number of man-hours for welding has been significantly reduced. Further, since it is not necessary to cut or re-weld the welded portion 12 of the steel material 19 for repair, deterioration of the dimensional accuracy of the steel material 19 was prevented. Moreover, by using the TIG welding torch 40, it becomes possible to continuously perform the formation of the plating removal portion 21 and the arc welding.

  Further, in the case of spot welding as shown in FIG. 11, the damage of the welding electrode 42 due to (the plating of) the plated portion 18 was slight (see FIG. 16). Further, as shown in FIG. 17, the decrease in welding strength due to repeated welding was reduced (in the figure, the line X has the plating removal portion 21 formed, and the line Y has the plating removal portion 21 not formed). .. Therefore, it is not necessary to increase the welding current in order to eliminate the decrease in welding strength, and the heat generation of the welding electrode 42 can be suppressed. Therefore, the life of the welding electrode 42 is further extended and the cost of the welding electrode 42 is also suppressed. Was given. In addition, the number of times the factory line is stopped to replace the welding electrode 42 has been reduced, resulting in a significant improvement in production efficiency.

  (Function and Effect 5) The steel material 19 having the plated portion 18 is provided with the partial plating removal portion 21 in advance, and the plating removal portion 21 is welded to form the welded product 61 having the welding portion 12 in the plating removal portion 21. did. As a result, it is possible to stably obtain a high-quality weldment 61 having the welded portion 12 without defects. Alternatively, the quality of the welded product 61 can be improved.

  (Operation and Effect 6) A structure 71 was constructed using the welded product 61. This makes it possible to obtain a high-quality structure 71 including the high-quality weldment 61. Alternatively, the quality of the structure 71 can be improved.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the embodiments are merely examples of the present invention. Therefore, the present invention is not limited to the configuration of the embodiment, and it goes without saying that the present invention includes modifications of the design within the scope not departing from the gist of the present invention. Further, for example, in the case where each embodiment includes a plurality of configurations, it is needless to say that possible combinations of these configurations are included even if not particularly described. Further, in the case where a plurality of examples and modified examples are disclosed as embodiments of the present invention in the embodiments, possible combinations among configurations that extend across these are included, even if not particularly described. Of course it will be done. Further, it is needless to say that the configurations depicted in the drawings are included even if not particularly described. Further, when the term “etc.” is used, it is used in the meaning of including the equivalent. In addition, when there are terms such as “almost”, “about”, and “degree”, they are used in the sense of including a range and accuracy that are commonly accepted.

18 plating part 19 steel material 21 plating removal part 31 heating means 32 heating means 40 welding torch 47 high frequency induction heating device 51 spot welding machine 61 welded material 71 structure

Claims (6)

  A method for removing plating, characterized in that a plating removal portion is formed by partially removing or oxidizing a plating portion on a surface of a steel material having a plating portion on which a plurality of steel materials are superposed, by heating. The plating removal method according to claim 1, wherein
The method for removing plating, wherein the steel material has a three-dimensional shape. The plating removal method according to claim 1 or 2, wherein
The plating removal method is characterized in that the plating removal portion is formed by a heating unit that performs either heating by arc energy or high frequency induction heating. A welding method of welding a steel material having a plated portion by arc welding or spot welding,
A partial plating removal portion is formed in advance on a plating portion of a surface of a steel material having a plating portion on which a plurality of steel materials are superposed by the plating removal method according to any one of claims 1 to 3, and then, A welding method, which comprises welding a plating removal portion of a steel material.   A welded product comprising a welded portion at a plating removal portion provided on a plated portion of a surface of a steel material having a plated portion, the plurality of steel materials being superposed on each other.   A structure constructed by the welded product according to claim 5.