Reducing material for gas pressure-welding, tool for processing the same and gas pressure-welding method

Abstract

To provide a reducing material for gas pressure-welding, which is enabled to be attached to tip parts of materials to be pressure-welded such as a steel rod to be fixed in a state where gaps of surfaces of tips of the materials to be pressure-welded are narrow, in attaching reducing materials for gas pressure-welding to the tip parts of the materials to be pressure welded, to reduce complicatedness in gap-adjustment work for setting the gaps of the surfaces of the tips wider, so as to be able to easily perform gas pressure-welding work.SOLUTION: A reducing material A1 for gas pressure-welding is made of thermoplastic resin and comprises a cap body 1a that can be externally fitted to a tip to be pressure-welded of a material to be pressure-welded. In a trunk part 10 of the cap body 1a is formed a cut edge 120 with a width sufficient to be fitted into the material to be pressure-welded in a circumferential direction with a predetermined thickness along a top plate 11 of the cap body 1a. Cut edges 122 and 123 leading to the cut edge 120 and extending at a nearly right angle up to an end part of a bottom with respect to the top plate 11 are formed in the other thick portions of the trunk part 10, which form a fitting-in port part 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reducing material for gas pressure welding, a processing tool thereof, and a gas pressure welding method, and more particularly, to a reducing material for gas pressure welding, a processing tool thereof, and a gas pressure welding method, which enable the reducing material for gas pressure welding to be attached to the tip end of the material to be pressure welded when the gap between the tip ends of the materials to be pressure welded is narrow, thereby reducing the complexity of the gap adjustment work that would be required when the gap between the tip ends must be set wide, and thereby facilitating the gas pressure welding work, [Background technology]

[0002] The process of pressure welding of steel materials such as rebar involves bringing two pieces of steel materials arranged vertically or horizontally into contact with each other, with their tip surfaces facing a common central axis, and then applying a predetermined pressure to the moving steel material. When the upper limit of pressure is reached, the area around the contact point is heated with a gas flame. When the temperature of the heated area reaches a temperature at which plastic deformation occurs, the pressure welded area deforms and becomes thicker, forming a so-called hump, and the process is completed.

[0003] In addition, in the pressure welding of steel materials, a reducing agent for gas pressure welding is often used to achieve stronger pressure welding. The reducing agent for gas pressure welding is used by sandwiching it between the end faces to be joined or by placing it near the end faces when two steel materials are opposed to each other and gas pressure welding is performed. For example, there is a "ring holding member with a built-in ring for gas pressure welding" as shown in Patent Document 1.

[0004] This ring holding member comprises a ring having approximately the same shape as the end face, formed from approximately the same material as the steel, and having a gas vent portion; a holding container made of synthetic resin having a protrusion on the bottom side having a ring installation space in which the ring is stored and a convex portion connected to the protrusion for contacting the outer shape of the steel for attachment; and a synthetic resin lid that fits over the ring installation space of the holding container and stops the rotation of the ring.

[0005] Conventional ring body holding members have this configuration, so that by stopping the rotation of the ring body with a lid inside the holding container, the position of the gas vent section can be reliably set at a predetermined position, making it extremely easy and safe to set the ring body on the end of the steel material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-177780 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, as shown in Fig. 1 etc., this ring-shaped holding member has a holding container formed of a thin sheet made of synthetic resin, and is therefore lightweight overall, so that when working outdoors, etc., it may come off from the tip of the steel material and be blown away by a sudden strong wind. Or, when a worker works around the contact part of the steel material, he or she may accidentally get his or her gloves caught on the ring-shaped holding member and come off.

[0008] Specifically, in the past, when using a ring-shaped holding member to press-weld steel materials, the gap between the tip faces of the fixed steel material and the movable steel material was first set to a gap equal to the height of the holding container of the ring-shaped holding member so that it could pass through. When setting the ring-shaped holding member, the ring-shaped holding member is inserted through the gap between the tip faces of the steel materials and attached to the tip of the fixed steel material, and the hydraulic cylinder of the pressing machine is used to bring the tip face of the movable steel material close to the tip face of the fixed steel material in order to clamp the bottom of the ring-shaped holding member.

[0009] However, if the wind blows strongly at this time, or if a worker touches it, the ring-holding member may come off the tip of the steel material and fall through the gap. In this case, even after the ring-holding member passes through the gap, the movable steel material moves toward the fixed steel material, so its tip surface hits the tip surface of the fixed steel material, leaving no gap between the tip surfaces.

[0010] In order to reattach the ring-holding member to the tip of the fixed steel material, the movable steel material must be returned from the position where it abuts the tip face of the fixed steel material to its original position again, so that the ring-holding member passes through the gap between the tip faces of the steel materials, and the steel materials must be temporarily fixed in that position. This task of ensuring gaps between the tip faces of the steel materials is a very time-consuming and tedious task, and the workload is particularly heavy when the gaps are large.

[0011] The present invention has been devised in consideration of the above points, and has as its object to provide a reducing material for gas pressure welding, a processing tool for the same, and a gas pressure welding method which, when attaching a reducing material for gas pressure welding (annular holding member) to the tip end of a material to be pressure welded (steel material), enables the material to be attached to the tip end when the gap between the tip faces of the materials to be pressure welded is narrow, thereby reducing the complexity of the gap adjustment work required when the gap between the tip faces must be set wide, thereby facilitating gas pressure welding work. [Means for solving the problem]

[0012] [1] In order to achieve the above object, the present invention provides a reducing material for gas pressure welding, which comprises a resin cap body that can be fitted onto the tip of the material to be pressure welded, and the body of the cap body has an insertion port portion that can be fitted into the material to be pressure welded from the side.

[0013] The resin cap body can be fitted onto the tip of the material to be pressure welded, such as steel. The cap body has a certain degree of deformability and flexibility, so it can be easily attached to the material to be pressure welded by fitting it onto the material, and if the dimensions are set appropriately, it is possible to maintain that state even after it is attached.

[0014] In addition, the body of the cap body is formed with an insertion opening that can be inserted into the pressure welded material from the side, so that even if the gap at the tip of the pressure welded material is narrow, the gas pressure welding reducing material can be inserted into the material from the side and attached to it. Even if the gap at the tip of the pressure welded material is wide, the reducing material can be attached to the tip and used as a reducing material.

[0015] [2] The reducing material for gas pressure welding of the present invention may be configured such that the fitting inlet portion has a cut edge along the top portion of the cap body with a predetermined thickness and a width that enables the fitting inlet portion to be fitted from the side into the material to be pressure welded, and a cut edge is provided in the remaining thickness portion of the body portion, continuing from the cut edge, at a predetermined angle to the top portion or in a predetermined shape, all the way to the bottom end.

[0016] In this case, if the leading end surface (pressure welding surface) of each pressure-welded material is open at least as wide as the thickness of the top part of the cap body, the gas pressure welding reducing material can be attached to the leading end of the pressure-welded material by inserting the thickness of the top part into the gap in the leading end surface of each pressure-welded material and fitting the fitting opening formed by the cutting edge and continuing from the part along the top part to the bottom end into the side of the leading end of the pressure-welded material. In this case, the gas pressure welding reducing material can be attached by simply expanding the gap to a width equal to the thickness of the top part of the cap body, which is significantly thinner than the thickness of the entire cap body.

[0017] [3] In order to achieve the above object, the present invention provides a reducing material for gas pressure welding, which comprises a resin cap body that can be fitted onto the tip of the material to be pressure welded, and a detachable weakened line is provided in the body of the cap body so as to form an insertion port that can be fitted into the material to be pressure welded from the side.

[0018] The resin cap body can be fitted onto the tip of the pressure-welding side of the material to be pressure-welded, such as steel material. The cap body has a certain degree of deformability and flexibility, so it can be easily attached to the material to be pressure-welded by fitting it onto the material, and if the dimensions are set appropriately, it is possible to maintain that state even after it is attached.

[0019] In addition, a breakable weakened line is provided in the body of the cap body so that an inlet part that can be fitted from the side of the pressure welded material can be formed, and the inlet part can be formed by cutting along the breakable line and removing the unnecessary part. As a result, the reducing material for gas pressure welding has an inlet part in the body part, unlike the original form, and can achieve the same effect as the reducing material for gas pressure welding described above in [1].

[0020] [4] The reducing material for gas pressure welding of the present invention may be configured so that the weakened line extends along the top of the cap body to a predetermined thickness, with a width that enables the cap body to be fitted circumferentially into the material to be pressure welded from the side, and continues from there to the bottom end of the remaining thickness of the body, at a predetermined angle to the top or in a predetermined shape.

[0021] In this case, the weakened line is provided along the top of the cap body, with a width that allows it to be fitted circumferentially into the material to be welded at a specified thickness, and is continuous with the remaining thickness of the body so that an insertion opening can be formed that is cut out to the bottom end at a specified angle or in a specified shape relative to the top.

[0022] In this way, by cutting off the portion of a specified thickness along the top of the weakened line from the remaining thickness of the body and removing the unnecessary portion, it is possible to form an inlet portion from the portion along the top to the bottom end of the body. As a result, the reducing material for gas pressure welding has an inlet portion in the body, unlike the original form, and can achieve the same effect as the reducing material for gas pressure welding described above in [1].

[0023] [5] The reducing material for gas pressure welding of the present invention may be configured such that the weakened line is approximately parallel to the top of the cap body, has a width that allows the cap body to be fitted from the side of the material to be pressure welded in the circumferential direction with a predetermined thickness, and is connected to the middle part and cut off to the bottom end to form an opening / closing portion that can open and close the body part.

[0024] In this case, the weakened line is arranged approximately parallel to the top of the cap body, with a width that allows it to be fitted circumferentially into the material to be welded at a predetermined thickness, and is connected to the middle part and cut off to the bottom end to form an opening and closing portion that can open and close the body part.

[0025] As a result, the reducing material for gas pressure welding of the present invention can be formed by separating a portion of a predetermined thickness parallel to the top part of the weakened line and a portion that is connected to the middle part and can be separated down to the bottom end, and by opening the two opening and closing pieces formed outward or inward, an opening and closing portion can be formed from the portion along the top part to the bottom end of the body, which differs from the original shape.

[0026] In the gas pressure welding method using this reducing material for gas pressure welding, the opening and closing piece is opened to form an opening and closing part in the cap body. Then, the thick part of the top part is inserted into the gap on the tip surface of the material to be pressure welded. As a result, the opening and closing part that continues from the part along the top part to the bottom end can be fitted into the side surface of the tip of the material to be pressure welded on the fixed side, so that the top part can be dropped into the tip of the material to be pressure welded to attach it.

[0027] [6] The reducing material for gas pressure welding of the present invention may also be configured to include a second cap body made of resin that can be fitted onto the tip of the material to be pressure welded, and the second cap body may be configured to be overlapped on the cap body in a state in which the body of the second cap body blocks at least a portion of the fitting opening.

[0028] In this case, the reducing material for gas pressure welding is provided with a second cap body made of resin that can be externally fitted onto the tip of the material to be pressure welded, and the second cap body is structured so as to be overlapped on the cap body in a state in which its body blocks at least a portion of the insertion opening portion.

[0029] First, the gas pressure welding reducing material is not used in a double structure when the end faces of the pressure-welded materials are narrower than the height of the cap body. When the gas pressure welding reducing material is placed on the end of the pressure-welded materials before the top part of the cap body of the gas pressure welding reducing material is sandwiched between the end faces of the pressure-welded materials, that is, when there is a wide gap between them, the gas pressure welding reducing material can be placed in a double structure. This makes it difficult for the gas pressure welding reducing material to come off the end of the pressure-welded materials due to the deep body of the second cap body, even if some wind blows before the top part of the cap body is sandwiched.

[0030] If the gas pressure welding reducing material does not come off before the top of the cap body of the gas pressure welding reducing material is sandwiched between the front end faces of the materials to be pressure welded, the sandwiched double-layered gas pressure welding reducing material can be used as a reducing material. In addition, since the top of the cap body of the gas pressure welding reducing material is also double-layered, a favorable effect as a reducing material can be expected.

[0031] Also, if the gas pressure welding reducing material comes off before the top part of the cap body of the gas pressure welding reducing material is sandwiched between the front end surface of each pressure welded material, the gas pressure welding reducing material having the fitting part in the cap body is removed from the second cap body of the removed gas pressure welding reducing material, and only this gas pressure welding reducing material is used as the reducing material. The action in this case is the same as the gas pressure welding reducing material described in [1] above, so it is used here by reference and the explanation is omitted.

[0032] Furthermore, the second cap body can be used as a single gas pressure welding reducing material even after the gas pressure welding reducing material having an insertion opening in the cap body is removed, and therefore can be reused, for example, as a normal bottomed cylindrical gas pressure welding reducing material or as a part of this double-structure gas pressure welding reducing material.

[0033] [7] The reducing material for gas pressure welding of the present invention may also be configured to include a resin or metal ring body provided on the top part of the cap body and melting at a higher temperature than the resin material constituting the top part.

[0034] In this case, a resin or metal ring body is provided on the top of the cap body and melts at a higher temperature than the resin material that makes up the top. During the crimping operation, the top of the resin cap body first melts and burns when heated by the gas flame.

[0035] Then, in the tiny gap between the tip surface of the material to be welded and the inside of the ring, which has not yet melted, the top part melts and burns in a very short time, and then vaporizes, causing a sudden increase in volume. As a result, the air in the gap inside the ring is pushed outward under high pressure, and the oxygen in the air combines with the carbon in the polymer to become carbon dioxide, suppressing oxidation around the welded area.

[0036] In addition, before the ring body melts, air is prevented from entering the gap inside the ring body, which in turn suppresses oxidation within the gap and prevents an oxide coating from forming on the tip surface on the pressure-welded side.

[0037] In this way, when using natural gas, propane gas, hydrogen gas, or the like, which have a lower heating power than acetylene gas, to perform gas pressure welding of the materials to be pressure-welded, the reducing material for gas pressure welding can suppress the formation of residues such as oxide coatings and metal residues on the pressure welding portion, even if heating is performed with a standard flame from the initial heating stage so as to obtain sufficient heating power, making it possible to perform pressure welding with sufficient strength.

[0038] [8] In order to achieve the above object, the present invention is a machining tool for processing the body of a resin cap body that can be fitted onto the tip of a material to be pressure-welded, and forming an insertion opening portion in the cap body that can be fitted from the side of the material to be pressure-welded, the machining tool comprising: a base member having a receiving device; a seesaw member that is swingably attached to the base member with one end biased by a spring so as to close toward the base member; a cutting blade of a predetermined shape that cuts out the insertion opening portion provided on the seesaw member; and a blade groove provided on the receiving device into which the cutting blade fits.

[0039] The processing tool of the present invention opens one end of the seesaw member on which the cutting blade is provided, and closes the body of the resin cap body by using the biasing force of a spring between the receiver of the base member inserted inside the cap body and the one end of the seesaw member outside the body, whereby the body of the cap body is cut by the cutting blade and fits into the cutting groove.

[0040] If the cutting of the body is not sufficient, the receiving tool of the base member and one end of the seesaw member are pressed toward each other, so that the cutting blade cuts the body and fits into the blade groove. This cuts the body of the cap body, and a reducing material for gas pressure welding having an insertion port in the body can be produced.

[0041] [9] In order to achieve the above object, the present invention is a gas pressure welding method comprising the steps of: attaching a resin cap body having a height greater than the gap to a tip end surface of one of the materials to be pressure welded, the tip end surface of the one of the materials to be pressure welded being arranged opposite to the tip end surface of the other material to be pressure welded with a predetermined gap therebetween, by fitting the resin cap body, which has a height greater than the gap, from the side of the one of the materials to be pressure welded, so as to fit the resin cap body onto the tip end surface of the one of the materials to be pressure welded; and, with the cap body attached, butting the tip ends of the one of the materials to be pressure welded and the other material to be pressure welded together and heating them.

[0042] According to the gas pressure welding method of the present invention, a resin cap body having a height greater than the gap is fitted from the side of one of the pressure-welded materials, which is arranged facing the tip face of the other pressure-welded material with a specified gap between them.Therefore, even if the gap is narrower than the height of the cap body, it can be attached by externally fitting it onto the tip face of the one of the pressure-welded materials.

[0043] As a result, for example, when re-attaching (re-attaching) the reducing material for gas pressure welding to the gaps in the tip faces of each pressure welded material, there is no need to significantly widen the gaps in the tip faces of each pressure welded material, such as steel, and it is possible to attach the reducing material for gas pressure welding from the side of the pressure welded material, which greatly reduces the complexity of the work and ultimately makes it easier to perform the gas pressure welding work.

[0044] By butting the leading edge of one material to be pressure-welded against the leading edge of the other material and heating them, it is possible to perform strong pressure welding while preventing the formation of an oxide film on the leading edge. That is, the top part of the resin cap melts and burns in a very short time in the small gap between the leading edges of the materials to be pressure-welded, and then vaporizes, causing a sudden increase in volume, which pushes the air out with high pressure and causes the oxygen in the air to combine with the carbon in the polymer to become carbon dioxide, thereby preventing oxidation around the pressure-welded area.

[0045]

[10] The gas pressure welding method of the present invention may include a step of forming an insertion port in the body of the cap body prior to the attachment step so that the cap body can be inserted from a side surface of one of the pressure-welded materials.

[0046] In this case, an insertion port is formed in the body of the cap body prior to the attachment process so that the cap body can be fitted from the side of one of the materials to be pressure-welded. Therefore, when the pressure welding operation is performed, it is possible to prepare a reducing material for gas pressure welding having a cap body which is equipped with an insertion port that is already adapted to the shape of the material to be pressure-welded, so that the pressure welding operation can be performed efficiently. Effect of the Invention

[0047] The present invention can provide a reducing material for gas pressure welding, a processing tool for the reducing material, and a gas pressure welding method, which enable the reducing material for gas pressure welding to be attached to the tip portion of the material to be pressure welded when the gap between the tip surfaces of the materials to be pressure welded is narrow, thereby reducing the complexity of the gap adjustment work that would be required when the gap between the tip surfaces must be set wide, and thereby making it easier to perform gas pressure welding work. [Brief description of the drawings]

[0048] [Figure 1] FIG. 2 is an explanatory diagram showing an embodiment of Type A of the reducing material for gas pressure welding according to the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing an embodiment of Type B of the reducing material for gas pressure welding according to the present invention. [Diagram 3]FIG. 2 is an explanatory diagram showing an embodiment of Type C of the reducing material for gas pressure welding according to the present invention. [Figure 4] FIG. 2 is an explanatory diagram showing one method of mounting the reducing material for gas pressure welding according to an embodiment of Type A. [Diagram 5] FIG. 4 is an explanatory diagram showing one method of mounting the reducing material for gas pressure welding according to an embodiment of Type B. [Figure 6] FIG. 11 is an explanatory diagram showing a method of mounting an embodiment of the reducing material for gas pressure welding of Type C. [Figure 7] FIG. 2 is an explanatory diagram showing a modified example of a reducing material for gas pressure welding, where (a) is a perspective view of the reducing material for gas pressure welding, and (b) is a sectional view of the reducing material for gas pressure welding taken along line AA. [Figure 8] 1A and 1B show an embodiment of a machining tool of the present invention, in which FIG. [Figure 9] 5A and 5B show a method of using the processing tool, where (a) is a cross-sectional explanatory view, and (b) is an explanatory view showing a cutting line in the cap body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] The embodiment of the present invention will be described in more detail with reference to Figures 1 to 9. In the following description of the reducing material for gas pressure welding, it will be divided into three types (A, B, C). Type A is a material with a pre-installed fitting portion, type B is a material with a weakened line so that the fitting portion and the opening and closing portion can be formed, and type C is a material with a pre-installed fitting portion and a bottomed cylindrical cap body stacked on top of it.

[0050] (Type A) The reducing material A1 for gas pressure welding shown in Fig. 1(a) has a cap body 1a. The cap body 1a is made of a sheet made of polystyrene resin, which is a thermoplastic resin. The body 10 (tubular part) of the cap body 1a is processed based on a cylindrical shape that is slightly flared at the bottom, and the upper end in Fig. 1(a) is closed by a circular top plate 11.

[0051] Furthermore, in the trunk 10, a cutting edge 120 is provided in the circumferential direction along the top plate 11 to a predetermined thickness, with a width that allows it to be fitted into a material to be pressure-welded 91 (see Figs. 4 to 6) described below. The thickened portion formed by the cutting edge 120 and the top plate 11 has a partially cylindrical shape, and this portion also serves as a fitting portion 121 that prevents the material to be pressure-welded 91 from falling off when it is fitted onto the tip of the material to be pressure-welded 91.

[0052] Continuing from both ends of the cut edge 120, cut edges 122, 123 are provided in the remaining thickness (height) portion of the body 10 in a direction approximately perpendicular to the top plate 11, forming a U-shaped fitting opening 12. A flange 13 with a slightly larger diameter is provided along the entire length of the bottom of the cap body 1a.

[0053] In the present embodiment, the central angle between the cutting edges 122 and 123 of the reducing material A1 in plan view (the opening angle of the fitting opening 12) is 150°, but is not limited to this. The central angle is sufficient if at least the cutting edge portion of the fitting opening 12 can be fitted into the material to be pressure welded 91, and is preferably an angle smaller than 180° so that the fitted state can be maintained after fitting (see FIG. 1(b)).

[0054] The gas pressure welding reducing material A2 shown in Fig. 1(c) has a cap body 1c. The cap body 1c is made of a sheet made of polystyrene resin, which is a thermoplastic resin. The body 10c of the cap body 1c is processed based on a cylindrical shape that is slightly flared at the bottom, and the upper end in Fig. 1(c) is closed by a circular top plate 11.

[0055] Furthermore, in the trunk portion 10c, a cutting edge 124 is provided in the circumferential direction along the top plate 11 to a predetermined thickness, with a width that allows it to be fitted into the pressure-welded material 91 described below. The thickened portion formed by the cutting edge 124 and the top plate 11 has a partially cylindrical shape, and this portion also serves as a fitting portion 125 that prevents the pressure-welded material 91 from falling off when it is fitted onto the tip of the pressure-welded material 91.

[0056] Then, continuing from both ends of the cut edge 124, approximately S-shaped cut edges 126, 127 are provided in the remaining thickness (height) portion of the body portion 10c, which are symmetrical with respect to the top plate 11, to form the fitting opening portion 12c. A flange portion 13 with a slightly larger diameter is provided along the entire length at the bottom of the cap body 1c. The approximately S-shaped cut edges 126, 127 are each structured so that the side closer to the bottom protrudes in a direction narrowing the fitting opening portion 12c, forming holding portions 128, 129.

[0057] (action) Here, with reference to FIG. 1(a) and FIG. 4, a gas pressure welding method using the above-mentioned reducing material A1 for gas pressure welding, which is one of the A types, and its action will be described.

[0058] The cap body 1a of the reducing material A1 for gas pressure welding can be fitted onto the tip of the pressure welding side (pressure welding surface 910 side) of the material to be pressure welded 91 such as a steel material. The cap body 1a is made of a thermoplastic resin and has a predetermined deformability and flexibility, so that it can be easily fitted onto the tip of the material to be pressure welded 91 and can maintain that state even after it is fitted.

[0059] The material to be welded 91 (and 92 described below) is made of steel such as deformed bars or round bars, and examples of such materials include deformed bars (SD295A, SD295B, SD345, SD390, SD490) specified in the steel bars for reinforced concrete (JIS G3112), round bars (SR235, SR295), or high-strength bars (USD385A, USD385B, USD980), as well as stainless steel bars (SUS316, SUS304, etc.) with improved durability and corrosion resistance.

[0060] When gas pressure welding the pressure-welded materials 91, 92, first, the fixed pressure-welded material 91 is held vertically at a specified height by a fixed clamp (not shown). The movable pressure-welded material 92 is held vertically by a movable clamp (not shown). The pressure-welded materials 91, 92 are adjusted so that their center lines are on the same line, and the pressure-welded surfaces 910, 920 of the pressure-welded materials 91, 92 are set at an appropriate distance. The pressure-welded materials 91, 92 may be held horizontally during the pressure welding operation.

[0061] The cap body 1a of the reducing material A1 for gas pressure welding has an insertion opening 12 formed at the cut edge of the body 10 from the portion along the top plate 11 to the bottom end, so that as long as the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92 are open at least to the same extent as the thickness of the top of the cap body 1a, it can be attached to the tip of the fixed side material to be pressure welded 91.

[0062] That is, first, the thickness of the top part is inserted horizontally into the gap between the pressure contact surfaces 910, 920 of the pressure-welded materials 91, 92. The top part may be inserted at an angle or in an inclined direction instead of horizontally. Accordingly, the fitting mouth part 12 continuing from the part along the top part to the bottom end is fitted into the side surface of the tip part of the pressure-welded material 91 on the fixed side, so that the top part can be attached to the tip part of the pressure-welded material 91 by dropping it into the pressure contact surface 910 (see FIG. 4(a)). Note that this fitting by dropping may be performed not only when the pressure contact surface 910 is located above the fitting mouth part 12 (closer to the top part than the fitting mouth part 12, or at the top part), but also when it is located below the fitting mouth part 12.

[0063] With the reducing material A1 for gas pressure welding attached as described above, the material to be pressure-welded 92 is lowered and the top plate 11 of the cap body 1a is sandwiched between the pressure-welded surfaces 910, 920. Then, by heating the materials to be pressure-welded 92 together with the materials to be pressure-welded 91, 92 by the gas flame, it is possible to perform strong pressure welding while preventing the formation of an oxide film on the pressure-welded surfaces 910, 920.

[0064] In other words, the top of the thermoplastic resin cap body melts and burns in a very short time in the small gap between the tip faces of the materials to be pressure-welded, and then vaporizes, causing a sudden increase in volume. As a result, the air is pushed outward at high pressure, and the oxygen in the air combines with the carbon in the polymer to become carbon dioxide, suppressing oxidation around the pressure-welded area.

[0065] Furthermore, with the reducing material A1 for gas pressure welding, if the reducing material A1 for gas pressure welding comes off before closing the pressure welding surfaces 910, 920 of the materials to be pressure welded, for example, it is necessary to reinstall the reducing material A1 for gas pressure welding. However, even in this case, there is no need to make complicated adjustments by greatly widening the gap between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92 (see FIG. 4(a)).

[0066] If the cap body does not have an inlet portion, as in the case of the reducing material D for gas pressure welding shown in Fig. 4(b), in order to insert the reducing material D for gas pressure welding into the gap, it must be adjusted to be at least a height h higher than the pressure welding surface 910 shown in Fig. 4(a). The task of ensuring a gap between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92 is a very time-consuming and tedious task, and the workload is particularly heavy, especially when the gap is large.

[0067] In contrast, the gas pressure welding reducing material A1 can be attached as described above by simply spreading it over a gap as wide as the thickness of the top of the cap body 1a, which is significantly thinner than the overall thickness of the cap body 1a. This significantly reduces the complexity of the work, and as a result, the gas pressure welding work can be performed easily.

[0068] When the reducing material A2 for gas pressure welding is attached to the material to be pressure welded 91, the holding parts 128, 129 grip the material to be pressure welded 91 in a slightly wraparound manner, providing excellent holding power to prevent the reducing material A2 for gas pressure welding from coming off. Other than that, the action of the reducing material A2 for gas pressure welding is the same as that of the reducing material A1 for gas pressure welding described above, and therefore a description thereof will be omitted here.

[0069] (Type B) The reducing material for gas pressure welding B1 shown in Fig. 2(a) has a cap body 2a. The cap body 2a is made of a sheet made of polystyrene resin, which is a thermoplastic resin. The body 20a of the cap body 2a has a cylindrical shape that is slightly flared at the bottom, and the upper end in Fig. 2(a) is closed by a circular top plate 21.

[0070] The body 20a is provided with a weakened line 22a that can be torn off. The weakened line 22a has perforations 220 of a width that allows the pressure-welded material 91 to be fitted into the pressure-welded material in the circumferential direction to a predetermined thickness along the top plate 21. The thick portion formed by the perforations 220 and the top plate 21 has a partially cylindrical shape, and this portion also becomes a fitting portion 221 that prevents the pressure-welded material 91 from falling off when it is fitted onto the tip of the pressure-welded material 91 after the separation piece 200 described later is separated.

[0071] Then, continuing from both ends of the perforation 220, perforations 222, 223 are formed in a U-shape in the remaining thickness (height) portion of the body portion 20a in a direction approximately perpendicular to the top plate 21 to the bottom end. Circular holes 229 are provided at both corners of the perforation 220 to prevent excessive cutting when separating. The holes 229 may be of other shapes, such as a rectangle.

[0072] In addition, a flange portion 23a having a slightly larger diameter is provided around the entire circumference of the bottom of the cap body 2a. By cutting along the perforations 220, 222, and 223, the cut-off piece 200 can be separated to form an inlet portion similar to the inlet portion 12 of the gas pressure welding reducing material A1.

[0073] The gas pressure welding reducing material B2 shown in Fig. 2(b) has a cap body 2b. The cap body 2b is made of a sheet of polystyrene resin, which is a thermoplastic resin. The body 20b of the cap body 2b has a cylindrical shape that is slightly flared at the bottom, and the upper end in Fig. 2(b) is closed by a circular top plate 21.

[0074] The body 20b is provided with a weakened line 22b that can be torn off. The weakened line 22b has a perforation 224 in the circumferential direction along the top plate 21 to a predetermined thickness, with a width that allows the pressure-welded material 91 to be fitted therein. A perforation 225 is provided in the remaining thickness (height) of the body 20b, continuing from the middle of the perforation 224, in a direction approximately perpendicular to the top plate 21 to the bottom end, forming an approximately T-shape.

[0075] Then, when it is cut apart at the perforations 224, 225, opening and closing pieces 226, 227 can be formed, and the thick portion formed by the perforations 224 and the top plate 21 has a partially cylindrical shape. This portion becomes a fitting portion 228 that prevents the pressure-welded material 91 from falling off when it is fitted onto the tip of the pressure-welded material 91.

[0076] In addition, a flange portion 23b having a slightly larger diameter is provided around the entire periphery of the bottom of the cap body 2b. By cutting along perforations 224 and 225, opening / closing pieces 226 and 227 can be made openable and closable, and an opening / closing portion (not shown) can be formed by opening the opening / closing pieces 226 and 227.

[0077] In this embodiment, perforations are used as the lines of weakness, but this is not limited to this and any other structure that can be easily torn by hand, such as a structure with short intermittent linear slits or a structure with a very thin sheet arranged in a linear pattern, will do.

[0078] (action) Here, with reference to FIG. 2(a) and FIG. 5, a gas pressure welding method using the above-mentioned reducing material for gas pressure welding B1, which is one of the B types, and its action will be described.

[0079] The cap body 2a of the reducing material for gas pressure welding B1 can be fitted onto the tip of the pressure welding side (pressure welding surface 910 side) of the material to be pressure welded 91 such as a steel material. The cap body 2a is made of a thermoplastic resin and has a predetermined deformability and flexibility, so that it can be easily fitted onto the tip of the material to be pressure welded 91 and can maintain that state even after it is fitted.

[0080] When gas pressure welding of the materials to be pressure-welded 91, 92 is performed, the fixed material to be pressure-welded 91 and the movable material to be pressure-welded 92 are set in the same manner as in the case of the pressure welding work using the reducing material for gas pressure welding A1. Then, for example, when it becomes necessary to attach the reducing material for gas pressure welding B1 again, the cap body 2a is cut along the perforations 220, 222, 223 to separate the cut-off piece 200, which is the unnecessary part, and the reducing material for gas pressure welding B11 having the fitting opening portion 24 (see FIG. 5) can be produced.

[0081] The method of use and action of the reducing material B11 for gas pressure welding after the fitting opening 24 is formed in the cap body 2a is the same as that of the reducing material A1 for gas pressure welding. Note that if the reducing material B1 for gas pressure welding comes off before closing the pressure welding surfaces 910, 920 of the pressure-welded materials, it is necessary to reattach the reducing material B1 for gas pressure welding.

[0082] In this case, there is no need to adjust the gap between the pressure-welded surfaces 910, 920 of the materials to be pressure-welded 91, 92 by widening it significantly. Just by widening the gap to a width equivalent to the thickness of the top part of the cap body 2a, which is significantly thinner than the overall thickness of the cap body 2a, the gas pressure welding reducing material B1 can be attached, just like the gas pressure welding reducing material A1 described above.

[0083] In the case of the reducing material for gas pressure welding B2, for example, when it becomes necessary to attach the reducing material for gas pressure welding B2 again after the materials to be pressure welded 91, 92 are set, the cap body 2b can be cut at the perforations 224, 225 to deform the opening and closing pieces 226, 227 inward and outward to make it openable and closable. This makes it possible to produce a reducing material for gas pressure welding (not shown) that can form an opening and closing portion (not shown) by opening the opening and closing pieces 226, 227.

[0084] In the gas pressure welding method using the reducing material B2 for gas pressure welding, the opening and closing pieces 226, 227 are opened to form an opening and closing portion in the cap body 2b. Then, the thick portion of the top part is inserted into the gap between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92. Accordingly, the opening and closing portion continuing from the portion along the top part to the bottom end is fitted into the side surface of the tip of the material to be pressure welded 91 on the fixed side, so that the top part can be attached to the tip of the material to be pressure welded 91 by dropping it into the pressure welding surface 910.

[0085] In addition, if the reducing material B2 for gas pressure welding comes off before closing the pressure welding surfaces 910, 920 of the pressure welded materials, it is necessary to reattach the reducing material B2 for gas pressure welding. In this case, there is no need to adjust the gap between the pressure welding surfaces 910, 920 of the pressure welded materials 91, 92 by significantly widening it, and the reducing material B2 for gas pressure welding can be attached just by widening the gap to a width equivalent to the thickness of the top part of the cap body 2b, which is significantly thinner than the thickness of the entire cap body 2b, just like the reducing material A1 for gas pressure welding.

[0086] (C type) The reducing material C for gas pressure welding shown in Fig. 3 is configured by combining a reducing material C11 for gas pressure welding having a structure similar to that of the reducing material A1 for gas pressure welding (the cap body has an inlet portion) and a reducing material C12 for gas pressure welding having a second cap body having a bottomed cylindrical shape and a structure substantially similar to that of the reducing material B1 for gas pressure welding and no weakened line 22a. Note that the respective structures of the reducing material C11 for gas pressure welding and the reducing material C12 for gas pressure welding are omitted here.

[0087] In this embodiment, the reducing material for gas pressure welding C has a double structure in which a reducing material for gas pressure welding C12 is covered with a reducing material for gas pressure welding C11. The reducing material for gas pressure welding C11 is processed from a material having the same shape as the reducing material for gas pressure welding C12, and is covered somewhat tightly with a flexible polystyrene resin sheet.

[0088] In addition, in the double-structure gas pressure welding reducing material C, the gas pressure welding reducing material C12 can be combined with the gas pressure welding reducing material C11 by covering it in the opposite manner to the above. When the gas pressure welding reducing material C12 is covered with the gas pressure welding reducing material C11, the gas pressure welding reducing material C11 is built into the gas pressure welding reducing material C12, which has the advantage that the gas pressure welding reducing material C11 is less likely to fall off due to unintended contact or the like.

[0089] (action) Here, a gas pressure welding method using the above-mentioned gas pressure welding reducing material C of type C and its action will be described with reference to Figs.

[0090] The reducing material for gas pressure welding C has a structure in which a reducing material for gas pressure welding C11 having an inlet portion is layered on the outside of a reducing material for gas pressure welding C12 which is a bottomed cylindrical body.

[0091] First, before the top part of the cap body of the reducing material C for gas pressure welding is sandwiched between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92, that is, when the gap is wide, the reducing material C for gas pressure welding is placed over the tip part of the fixed-side material to be pressure welded 91 while keeping the double structure. As a result, even if some wind blows before the top part of the cap body is sandwiched, the reducing material C for gas pressure welding is unlikely to come off the tip part of the material to be pressure welded 91 due to the action of the deep body of the cylindrical gas pressure welding reducing material C12 with a bottom.

[0092] If the gas pressure welding reducing material C does not come off before the top of the cap body of the gas pressure welding reducing material C is sandwiched between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92, the sandwiched double-layered gas pressure welding reducing material C is used as a reducing material. Note that since the top of the cap body of the gas pressure welding reducing material C is also double-layered, a favorable effect as a reducing material can be expected.

[0093] Furthermore, if the reducing material C for gas pressure welding comes off before the top part of the cap body of the reducing material C for gas pressure welding is clamped between the pressure welding surfaces 910, 920 of each of the materials to be pressure welded 91, 92, the reducing material C11 for gas pressure welding having the fitting opening part 24 on the cap body is removed from the reducing material C12 for gas pressure welding in the detached state, and only this reducing material C11 for gas pressure welding is used as the reducing material.

[0094] The action of the reducing material C11 for gas pressure welding when used is the same as that of the reducing material A1 for gas pressure welding, and when re-attaching the reducing material C11 for gas pressure welding, there is no need to adjust the gap between the pressure welding surfaces 910, 920 of the materials to be pressure-welded 91, 92 by significantly widening it. The reducing material C11 for gas pressure welding can be attached simply by widening the gap to a width equal to the thickness of the top part of the cap body, which is significantly thinner than the thickness of the entire cap body.

[0095] The reducing material for gas pressure welding according to the present invention can be combined with an air blocking ring and a reducing sheet in order to more reliably prevent the formation of an oxide film on the pressure welding surfaces 910, 920 when pressure welding the materials 91, 92. The reducing material for gas pressure welding B3 shown in Fig. 7 is one embodiment of the B type.

[0096] The reducing material for gas pressure welding B3 has a cap body 3. The cap body 3 is made of a sheet of polystyrene resin, which is a thermoplastic resin. The body 30 of the cap body 3 has a cylindrical shape that is slightly flared at the bottom, and the upper end is closed by a circular top plate 31.

[0097] The body 30 is provided with vertical reinforcing parts 32 that bulge outward at a predetermined interval in the circumferential direction. The body 30 is also provided with weakened lines 35 that can be torn apart to separate it. The weakened lines 35 are provided in the circumferential direction along the top plate 31 to a predetermined thickness, and have perforations 350 of a width that allows them to be fitted into the material 91 to be pressure welded.

[0098] The thick portion formed by the perforations 350 and the top plate 31 has a partially cylindrical shape, and this portion also becomes a fitting portion 351 that prevents the pressure welding material 91 from falling off when it is fitted onto the tip of the pressure welding material 91 after the separation piece 300 is cut off. The reducing material B3 for gas pressure welding has strength due to the vertical reinforcing portion 32, and has a good grip on the pressure welding material 91.

[0099] Then, continuing from both ends of the perforation 350, perforations 352, 353 are formed in a U-shape in the remaining thickness (height) portion of the body portion 30 in a direction approximately perpendicular to the top plate 31 to the bottom end. A flange portion 36 having a slightly larger diameter is provided around the entire circumference of the bottom portion of the cap body 3. By cutting along the perforations 352, 353, the separation piece 300 can be separated to form an insertion port similar to the insertion port portion 12 of the gas pressure welding reducing material A1 described above.

[0100] An air blocking ring 33 made of polyimide resin, which is a thermosetting resin, is disposed on the inner surface (lower surface) of the top plate 31, and a circular reduction sheet 34 made of polystyrene resin and slightly larger in diameter than the air blocking ring 33 is welded to the top plate 31 at its center, sandwiching the air blocking ring 33 between the inner surface of the top plate 31 and the reduction sheet 34. The reduction sheet 34 is thermally deformed so as to conform to the outer shape of the air blocking ring 33, and cooperates with the inner surface to enclose the air blocking ring 33 (see the enlarged view of FIG. 7).

[0101] When gas pressure welding of the materials to be pressure-welded 91, 92 is performed using the reducing material for gas pressure welding B3, the fixed material to be pressure-welded 91 and the movable material to be pressure-welded 92 are set in the same manner as in the case of pressure welding work using the reducing material for gas pressure welding A1. Then, for example, when it becomes necessary to attach the reducing material for gas pressure welding B3 again, the cap body 3 can be cut along the perforations 350, 352, 353 to separate the cut-off piece 300, which is the unnecessary part, and a reducing material for gas pressure welding (not shown) having an insertion opening portion (not shown) can be produced.

[0102] The method of use and action of the reducing material for gas pressure welding after the fitting opening is formed in the cap body 3 is the same as that of the reducing material for gas pressure welding A1 described above, except that the air blocking ring 33 and the reducing sheet 34 are added, which produces an action due to them.

[0103] In this case, in the pressure welding operation, the reducing material B3 for gas pressure welding is heated by the gas flame together with the materials to be pressure welded 91, 92, so that first the reducing sheet 34 and the top plate 31 melt and burn. Then, in a very short time, the reducing sheet 34 melts and burns in the small gap between the pressure welding surfaces 910, 920 of the materials to be pressure welded 91, 92 inside the air blocking ring 33, which is made of thermosetting resin and has not yet melted.

[0104] Furthermore, as a result of the combustion causing vaporization and a sudden increase in volume, the air in the gap inside the air shutoff ring 33 is pushed outward under high pressure, and the oxygen in the air combines with the polymeric carbon to become carbon dioxide gas, suppressing oxidation around the pressure-welded area.

[0105] Furthermore, before the air blocking ring 33 melts, air is prevented from entering the gap inside the air blocking ring 33, which in turn suppresses oxidation within the gap and prevents an oxide coating from forming on the tip surface on the pressure-welded side.

[0106] In this way, when using natural gas, propane gas, hydrogen gas, or the like, which have a lower thermal power than acetylene gas, when performing gas pressure welding, the reducing material B3 for gas pressure welding can suppress the generation of residues such as oxide coatings and metal residues on the pressure welding surfaces 910, 920 even if heating is performed with a standard flame from the initial heating stage so as to obtain sufficient thermal power, making it possible to perform pressure welding with sufficient strength.

[0107] In addition, if the reducing material B3 for gas pressure welding comes off before closing the pressure welding surfaces 910, 920 of the pressure welded materials, it is necessary to reattach the reducing material B3 for gas pressure welding. At that time, there is no need to adjust the gap between the pressure welding surfaces 910, 920 of the pressure welded materials 91, 92 by significantly widening it, and the reducing material B3 for gas pressure welding can be attached simply by widening the gap to a width equivalent to the thickness of the top part of the cap body 3, which is significantly thinner than the thickness of the entire cap body 3.

[0108] Please refer to Figures 8(a) and 8(b). The processing tool 8 is a tool for forming a fitting opening in a cap body E that does not have a fitting opening. The processing tool 8 has a base member 80. Support members 81 are provided on both sides in the width direction of one surface (the upper surface in FIG. 8) of the base member 80. A receiving leg 82 is provided at the tip of the base member 80, and a receiving tool 83 is provided extending from the support member 81 to the receiving leg 82, slanting slightly downward toward the tip.

[0109] A seesaw member 84 is placed on the support member 81 so as to be able to swing in the direction of the arrow via a fulcrum part 840. A tip member 841 (left side in FIG. 8(b)) of the seesaw member 84 has a shape curved in the width direction toward the base member 80 side. A cutting blade 843 that is U-shaped in a plan view is attached to a concave surface 842 of the tip member 841 on the base member 80 side along the curved shape. Also, as shown in FIG. 8, the seesaw member 84 is formed in a shape that is curved slightly upwards with the fulcrum part 840 as a boundary, and a pressing piece 844 is provided at the tip and an operating part 845 is formed on the base side.

[0110] The seesaw member 84 is biased by a C-shaped leaf spring 85 in a direction in which the tip of the seesaw member 84 and the receiver 83 of the base member 80 are sandwiched at both ends and come into close contact with each other. In a normal state, the seesaw member 84 is closed and the cutting blade 843 is housed in a blade groove 830 provided in the receiver 83. The cutting blade is not limited to being U-shaped, and may be formed, for example, in a U-shape, with the fitting opening also being U-shaped.

[0111] The seesaw member 84 can be swung in the direction of the arrow by pushing back the operation part 845. The distance between the tip of the base 83 and the cutting blade 843 when the seesaw member 84 is closed is set to the same as the height of the fitting part 121 in the thickness direction.

[0112] A method of using the machining tool 8 will be described with reference to FIGS. 9(a) and 9(b). The cap body E to be processed here is a type that does not have a flange portion around the opening 100.

[0113] First, the operating portion 845 is pressed to open the tip member 841 of the seesaw member 84 having the cutting blade 843, and the tip portion of the base member 80 is inserted through the opening 100 of the cap body E. At this time, the body portion 101 of the cap body E is inserted between the tip portion of the base member 80 and the tip member 841 of the seesaw member 84.

[0114] Then, when the tip of the base member 80 is brought into contact with the top plate 102, the operating portion 845 is loosened, and the leaf spring 85 is returned to its normal state, the tip member 841 closes. As a result, the pressing piece 844 comes into contact with the top plate 102 of the cap body E and pinches the top plate 102, determining the position of the cutting blade 843, and at the same time, the cutting blade 843 cuts the body part 101 of the cap body E into a U-shape and fits into the blade groove 830 (see the shapes shown by dotted lines in Figures 8(b), 9(a), and 9(b)).

[0115] One end of the seesaw member 84 has a shape that is curved roughly like a gutter toward the base member 80, the receiving device 83 on the base member 80 side is curved to roughly follow the curved surface of the seesaw member 84, and the cutting blade 843 provided on the seesaw member 84 has a curved cutting edge that roughly follows the curved surface of the body 101 of the cap body E to be processed.

[0116] As a result, the cutting edge of the cutting blade 843 is near the curved surface of the body 101 of the cap body E over substantially the entire length before it moves in the cutting direction, so the movement of the cutting blade 843 until cutting is completed is reduced. Accordingly, deformation of the cap body E caused by the cutting blade 843 during cutting is kept small, so that the cap body E can be prevented from being cut in a distorted manner.

[0117] In addition, if the biasing force of the leaf spring 85 alone is not enough to allow the cutting blade 843 to sufficiently cut the body portion 101, the body portion 101 of the cap body E can be reliably pushed through by pinching the tip of the base member 80 and the tip member 841 of the seesaw member 84 with the hands from inside and outside the cap body E.

[0118] The processing tool 8 can also process a cap body having a flange portion. In this case, if the cap body is cut in a state where it is appropriately deformed so that the flange portion does not get in the way, a reducing material for gas pressure welding that is substantially the same as the reducing material for gas pressure welding A1 described above can be formed.

[0119] The terms and expressions used in the present specification and claims are merely for explanatory purposes and are not limiting in any way, and are not intended to exclude terms and expressions equivalent to the features described in the present specification and claims and parts thereof. In addition, it goes without saying that various modifications are possible within the scope of the technical idea of ​​the present invention. [Explanation of symbols]

[0120] A1 Reducing agent for gas pressure welding 1a Cap body 10. Torso 11 Tabletop 12. Insertion port 120 Cutting Edge 121 Fitting part 122, 123 Cutting edge 13 Flange 91, 92 Pressure welded material A2 Reducing agent for gas pressure welding 1c Cap body 10c Torso 12c Insertion opening 124 Cutting Edge 125 Fitting part 126, 127 Cutting edge 128, 129 Holding part B1 Reducing agent for gas pressure welding 2a Cap body 20a Torso 21 Tabletop 22a Line of weakness 220 Perforation 221 Fitting part 222, 223 Perforation 229 holes 200 section 23a Flange B2 Reducing agent for gas pressure welding 2b Cap body 20b Torso 22b Line of weakness 224, 225 Perforations 226, 227 Opening / closing piece 228 Fitting part 23b Flange part C Reducing agent for gas pressure welding C11 Reducing agent for gas pressure welding C12 Reducing agent for gas pressure welding B3 Reducing agent for gas pressure welding 3 Cap body 30 Torso 31 Tabletop 32 Vertical reinforcement 33 Air cutoff ring 34 Rebate Sheet 35 Weakened Lines 350 perforations 351 Fitting part 352, 353 Perforation 300 section 36 Flange section 8 Processing tools 80 Base material 81 Support member 82 Socket 83 Receiver 830 Cutting groove 84 Seesaw member 840 Support part 841 Tip material 842 Concave 843 Cutting blade 844 Clamp 845 Operation section 85 Leaf Spring

Claims

1. A resin cap body is provided which can be fitted onto the tip of the material to be pressure-welded, and a fitting opening is formed in the body of the cap body so that the material to be pressure-welded can be fitted into the cap from the side. A reducing material for gas pressure welding.

2. The fitting opening is formed by providing a cut edge along the top of the cap body with a predetermined thickness and a width that allows the cap body to be fitted from the side into the material to be welded in the circumferential direction, and a cut edge is provided in the remaining thickness of the body part, at a predetermined angle to the top or in a predetermined shape, up to the bottom end. The reducing material for gas pressure welding according to claim 1.

3. A resin cap body is provided which can be fitted onto the tip of the material to be pressure-welded, and a breakable weakened line is provided on the body of the cap body so that an insertion opening part which can be fitted into the material to be pressure-welded from the side can be formed. A reducing material for gas pressure welding.

4. The weakened line is provided along the top of the cap body to a predetermined thickness, with a width that allows the cap body to be fitted into the workpiece from the side, and continues from the top to the bottom end of the remaining thickness of the body at a predetermined angle or in a predetermined shape relative to the top. The reducing material for gas pressure welding according to claim 3.

5. The weakened line is provided in a substantially parallel manner to the top of the cap body, with a predetermined thickness and a width that allows the cap body to be fitted from the side of the material to be welded in the circumferential direction, and is connected to the middle part and cut off to the bottom end to form an opening and closing part that allows the body part to be opened and closed. The reducing material for gas pressure welding according to claim 3.

6. A second cap body made of resin is provided which can be fitted onto the tip of the material to be pressure welded, and the second cap body is placed on the cap body in a state where the body of the second cap body closes at least a part of the fitting opening. The reducing material for gas pressure welding according to claim 1 or 2.

7. a ring body made of resin or metal that is provided on the top part of the cap body and melts at a higher temperature than the resin material that constitutes the top part; The reducing material for gas pressure welding according to claim 2, 4 or 5.

8. A processing tool for processing a body of a resin cap body that can be fitted onto a tip of a material to be pressure-welded, and forming an insertion opening portion on the cap body that can be fitted into a side surface of the material to be pressure-welded, A base member having a receiving tool; a seesaw member attached to the base member so as to be swingable with one end biased by a spring so as to close toward the base member; a cutting blade having a predetermined shape for cutting out the fitting opening portion provided on the seesaw member; A cutting groove is provided in the receiving tool and into which the cutting blade is fitted. Processing tools.

9. a step of fitting a resin cap body having a height greater than the gap to one of the pressure-welded materials, the resin cap body being fitted from the side of the one of the pressure-welded materials, the resin cap body having a height greater than the gap, onto the tip of the one of the pressure-welded materials, the resin cap body being fitted from the outside to the tip of the one of the pressure-welded materials, the resin cap body having a height greater than the gap being fitted to the side of the one of the pressure-welded materials, the resin cap body being fitted from the outside to the tip of the one of the pressure-welded materials, the resin cap body being fitted from the side of the one of the pressure-welded materials, the resin cap body being fitted from the outside to the tip of the one of the pressure-welded materials, and a step of butting the tip surfaces of the one material to be pressure-welded and the other material to be pressure-welded together and heating them while the cap body is attached. Gas pressure welding method.

10. The cap body can be fitted onto the one of the workpieces from a side surface thereof, The method includes a step of forming a fitting opening in the body of the cap body prior to the step of attaching the cap body. The gas pressure welding method according to claim 9.

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