JP4447261B2 - Joining method for press fittings - Google Patents

Description

The present invention relates to a press-type pipe that is press- bonded by pressing with a press tool in a state in which a connection pipe made of thin metal such as thin stainless steel is inserted into a pipe joint body formed of thin metal such as thin stainless steel The present invention relates to a joint joining method .

  Conventionally, there is a press-type pipe joint as one of joints for connecting stainless steel pipes applied to water supply, hot water supply, and cold / hot water. For example, as shown in Patent Document 1, an airtight material (rubber ring) is built into a receptacle of a thin joint, and the outer periphery of the press-type pipe joint is inserted into the joint by a press machine. By pressing and reducing the diameter of the connecting part from the joint end part, which is the pipe insertion part, to the vicinity of the center, the pipe and the joint are joined to seal the pressure fluid. Press-type pipe joints are widely used in piping equipment such as building equipment because they can be kept at a low cost compared to pipe joints that are joined by screwing pipes into the joints. ing.

At the time of joining the joint and the pipe, the pipe is inserted into the connection part of the joint, and the whole connection part is pressed by a press from the outer peripheral surface side to reduce the diameter. When the diameter of the annular groove portion containing the airtight material is reduced, if the compressive force is applied to the outer peripheral surface of the annular groove portion substantially uniformly, the internal airtight material is compressed and deformed as a whole, and the airtight material is pressed against the outer wall surface of the pipe. In this manner, deformation and pressure bonding are attempted to prevent leakage of fluid after joining.
Further, at this time, the pipe insertion side pipe end surface of the annular groove portion containing the airtight material is deformed so as to bite into the outer peripheral surface of the pipe, and by this deformation, the sealing performance and the pipe pull-out resistance force are increased.

  The joint has a shape in which an annular groove bulges out in order to incorporate an airtight material in the receiving port of the pipe connection portion, and the annular groove is composed of a combination of round-shaped elements. On the other hand, the pipe diameter of the pipe is set to such a dimension as to come into contact with the airtight material of the annular groove when inserted into the joint.

When the diameter of the joint is reduced by a press, a certain range in the vicinity of the receiving port of the connecting portion is radially compressed, and the joint connecting portion and the pipe fitted to the connecting portion are integrated in a polygonal cross section. The shape is plastically deformed and joined, and this polygonal shape is preferably a hexagonal shape.
JP-A-53-70072

However, when pressing a press-type pipe joint, the portion of the pipe joint in contact with the die may extend due to the ductility of the material when pressed by a press die, which causes tensile residual stress around the press part. There are many things. When such tensile residual stress is generated, the strength as a material is lowered, and there is a problem that stress corrosion cracking occurs when the pipe joint is exposed to a corrosive environment.
Further, when the groove-like portion in which the airtight material is accommodated is pressed, tensile residual stress is generated in the groove-like portion along with the pressing, and furthermore, the end portion of the joint (end portion of the annular groove portion) Since tensile residual stress is also generated by biting into the outer periphery of the pipe, the strength also decreases at the groove-like part and the pipe side, and stress corrosion cracking may occur when the pipe joint is exposed to a corrosive environment.

  For example, at the time of joining a joint and a pipe in Patent Document 1, a uniform compressive force is applied from the outer peripheral direction to an annular groove portion containing an airtight material when pressed by a press, and this compressive force is strongly applied to the entire annular groove portion. There is a risk that tensile residual stress may occur due to the work, and when a large compressive force is applied to the annular groove, the annular groove is composed of a combination of R-shaped elements. There is a possibility that tensile residual stress is generated intensively due to the stress concentrated on the extremely small round-shaped region connecting the two.

In addition, the hermetic material is deformed into a shape that causes the annular groove to be crushed as a result of the pressure applied to the annular groove, which may adversely affect the sealing performance, and the wear will be severe and maintain long-term sealing performance. It was difficult to do.
The hermetic material is usually provided with a tightening allowance that is normally deformed when pressed, and it is necessary to increase the tightening allowance in order to improve the sealing performance between the joint and the pipe after joining. In order to increase the tightening allowance, it is necessary to increase the pipe outer diameter relative to the inner diameter of the airtight material. In this case, the pipe outer peripheral surface and the airtight material come into contact with each other when the pipe is inserted into the annular groove. Since the force to do so increases, the airtight material may be damaged. Furthermore, if this tightening margin is large, a strong pressing force is applied to the airtight material during pressing, and the airtight material is deformed so as to be crushed into a shape that bulges from the annular groove after the airtight material is deformed. This also had an adverse effect on the durability of the airtight material.
In addition, there is also a problem that the joint distal end side and the pipe outer peripheral surface are liable to be cracked when the tip end side of the annular groove portion for storing the airtight material bites into the pipe outer peripheral surface.

On the other hand, when plastically deforming a certain range of the connecting portion into a polygonal cross-section, if this shape is hexagonal, the amount of deformation in the axial direction increases, and if this amount of deformation increases, tensile residual stress increases. There was a problem that it was easy. When the amount of deformation is large, the ductility of stainless steel, which is a material, acts strongly, and a work-induced martensite structure is likely to occur in a structure that originally consists of an austenite structure. The material became brittle and easily cracked.
In addition, there is a problem in that the degree of biting into the pipe varies depending on the deformation location due to the amount of deformation.

  It should be noted that press-type fittings are prone to material embrittlement even when external stress is applied after processing. For example, stress caused by vibration from a pump or chlorine contained in a fluid such as water in a hot water supply line Corrosion is likely to proceed due to ions, and corrosion cracking may occur. For this reason, it has been difficult to maintain high sealing performance for a long period of time.

  The present invention was developed in view of the conventional problems, and the object of the present invention is to provide stress corrosion cracking in a press-type pipe joint for connecting pipes for supplying water, hot water, cold / hot water, etc. An object of the present invention is to provide a press-type pipe joint that can prevent and maintain high sealing performance over a long period of time.

In order to achieve the above object, the invention according to claim 1 is a method of joining a press-type pipe joint for joining a connection pipe made of a thin metal pipe to a joint body made of a thin metal pipe, the end of the joint body With a large rounded surface including a taper portion formed in a connecting portion between the bulging curved surface of the receiving portion and the outer peripheral surface of the joint body, an airtight material such as an O-ring is accommodated in the receiving portion bulging on the portion side. Connect, insert the connection pipe into the joint body up to the insertion end, surround the outer peripheral surface of the joint body with the die of the press tool, and insert the recess for pressing the receiving portion of the joint body and the round surface for pressing the round surface. By pressing with the pressing surface of the die having, the taper portion is pressed with the pressing surface of the die, and the receiving portion is pressed to tilt toward the pipe insertion side with the round surface as a fulcrum, Outlet edge and outside connection pipe To have a gap between the surface, and further, a method of bonding press type pipe joint so as to compression bonding with bonding surface provided with the connection pipe and the outer peripheral surface of the fitting body to said die.

The invention according to claim 2 is a method for joining press-type pipe joints , wherein the pressure-bonding surface of the die has an octagonal cross section .

According to the present invention, a tensile residual stress after pressing is not generated, stress corrosion cracking can be prevented, and high sealing performance can be maintained over a long period of time . In particular, when the outer peripheral surface of the joint body is pressed by the pressing surface of the die, the taper portion of the joint body comes into contact with the taper surface of the round surface portion of the die, so that the taper portion is pressed and the round surface is used as a fulcrum. Since the part is pressed so as to incline toward the pipe insertion side, there is no occurrence of tensile residual stress in the entire receiving part that is the press part, or in the part that connects the receiving part and the enlarged diameter part of the joint body, Since it has compressive residual stress after joining, the strength of the pipe joint can be improved by the characteristic of this compressive residual stress, and embrittlement of the material can be prevented for a long time. By abutting against, it is possible to prevent the diameter of the receiving portion from expanding and the gap with the pipe from expanding, and therefore it is possible to ensure an appropriate sealing performance by the airtight material.

It is possible to maintain a high pulling prevention force while suppressing the amount of deformation in the axial direction at each deformation point, and of course, the pulling prevention force is not inferior when compared with a pressure-bonded portion having a hexagonal cross section, Generation of tensile residual stress can also be suppressed.

It is possible to prevent stress corrosion cracking when a pipe joint is formed of an anti-corrosion material and a fluid such as warm water flows.

It prevents embrittlement of the pipe crimping portion after pressure wear, it is possible to obtain a high pipe pulling stopping power.

Contact without pipe outer peripheral surface and the mouth part edge being damaged after bonding time and bonding the connection pipe, prolonged over stress corrosion cracking by suppressing the occurrence of corrosion of the connection pipe outer peripheral surface and the socket portion edge Can be prevented.

Contact reliably when compression bonding the connection pipe can be joined in a state of holding the connection pipe, the bonding position can be joined with high dimensional accuracy without or deviation, also can be provided by the anti-corrosion material having high It is a press-type pipe joint.

Oh or using the processing tool rata, without processing steps or more, higher while maintaining the pull-out blocking force, easily form sustainable press type pipe joint with high sealability to prevent stress corrosion cracking It is the joining method of the press-type pipe joint which can do.

While crimped securely fitting body and the connecting pipe, Ru can press the airtight material in appropriate pressing force.

Without pipes outer peripheral surface and the mouth part end edge or damaged, suppressing the occurrence of corrosion of the connection pipe outer peripheral surface and the socket portion edge for a long time even after the bonding, can prevent the stress corrosion cracking It is a joining method of a press-type pipe joint.

An embodiment of a press-type pipe joint according to the present invention will be described with reference to the drawings. The press-type pipe joint of the present invention is formed by pressing a joint body made of thin-walled stainless steel in a state where the pipe is inserted, and crimping and joining the joint body and the pipe.
FIG. 1 is a cross-sectional view showing a state before joining of a press-type pipe joint according to the present invention. In the figure, reference numeral 1 denotes a joint body. A joint pipe 6 is joined to the joint body 1 to provide a pipe joint. I have to. The joint body 1 and the connection pipe 6 are made of a metal material having corrosion resistance, for example, Cr—Ni—Si—Cu-based stainless steel.
In the joint body 1, the diameter-expanded step portion 2 is formed by molding means such as bulge molding so that the smallest inner diameter portion is smaller than the outer diameter of the connection pipe 6, and the diameter of the end portion side of the joint body 1 is increased. When the connecting pipe 6 is inserted into the inner peripheral surface 1b of the enlarged diameter portion 1c, the rear end portion of the tapered enlarged diameter step portion 2 is used as the abutting portion 2a of the connecting pipe 6 so that the connecting pipe 6 is locked. It can be held in a state.

  Reference numeral 3 denotes a receiving portion for storing an airtight material 5 such as an O-ring. The bulge is formed. The airtight member 5 seals the outer peripheral surface 6a of the connection pipe 6 inserted into the joint body 1, and when the outer peripheral surface 1a of the joint body 1 is crimped, the connection pipe 6 can be crimped and joined. A connecting portion between the bulging curved surface 3 a and the outer peripheral surface 1 a of the joint body 1 is connected by a large round surface 12 including the tapered portion 4. In the case of a joint nominal diameter of 13 to 25 Su, the radius surface 12 preferably has a curvature radius of 3.0 to 5.0 mm. If it is smaller than 3.0 mm, stress concentration tends to occur. On the other hand, if it is larger than 5.0 mm, the taper portion 4 is reduced and the space of the receiving portion 3 is widened so that the O-ring is easily moved. This is because the sealing performance may be lowered. The tapered portion 4 may be formed at an appropriate angle, but is preferably 42 to 46 °, more preferably about 45 ° with respect to the outer peripheral surface 1a of the joint body 1. When the angle is smaller than 42 °, the space 3c of the receiving portion 3 is widened and the O-ring is likely to move, and the sealing performance may be deteriorated. This is because the tilt of 3 is increased, and the O-ring may be overcompressed.

In FIG. 3, reference numeral 11 denotes a crimping part for crimping and joining the joint body 1 and the connection pipe 6. The crimping part 11 is formed so as to crimp the outer peripheral surface 1 a of the joint body 1 into a substantially octagonal cross section. 11 is formed in a predetermined length C in which the pulling-in preventing force of the connecting pipe can be configured with the direction toward the axial direction. As a dimension of the length C, for example, in the case of a nominal diameter of 25 Su, about 5 mm is desirable. At the time of pressure bonding, the pressure-bonding portion 11 is pressure-bonded so that the metal structure becomes an austenite structure.
As shown in FIG. 6, a gap D is formed between the outer peripheral surface 6 a of the connection pipe 6 connected to the edge 3 b of the receiving port 3 formed on the end side of the joint body 1.

  The airtight material 5 is provided with heat-resistant butyl rubber as a material, for example, but may be made of ethylene propylene rubber (EDPM) or other materials generally used as heat-resistant seal materials. The inner diameter of the airtight material 5 is provided to be larger than the outer diameter of the connection pipe 6 before the connection pipe 6 is joined, and the connection pipe 6 does not contact the airtight material 5 when the connection pipe 6 is inserted. It is provided as follows.

Next, the operation of the embodiment will be described.
The press-type pipe joint of the present invention has a receiving part 3 bulging and formed on the distal end side of the enlarged diameter part 1 c of the joint body 1, and a connecting pipe 6 with an airtight material 5 such as an O-ring housed in the receiving part 3. The outer peripheral surface 6a of the joint body 1 is crimped and the connection pipe 6 is crimped and joined, so that the bulging curved surface 3a of the receiving port 3 and the outer peripheral surface 1a of the joint main body 1 are joined. Since the connecting portion is connected by the large rounded surface 12 including the taper portion 4, there is a tensile residue on the entire receiving portion 3 that is a press portion or a portion that connects the receiving portion 3 and the enlarged diameter portion 1 c of the joint body 1. Not only does it cause stress, but also has compressive residual stress after joining, so the strength of the pipe joint can be improved by the characteristics of this compressive residual stress, and material embrittlement can be prevented for a long time. it can.

Since the airtight member 5 is deformed into a substantially wedge-shaped cross section along the tapered portion 4 when the receiving port 3 is pressed, a suitable seal is obtained by an appropriate pressing force using the elastic force of the airtight member 5. In addition, the airtight material 5 is not easily damaged because it does not receive a strong pressing force, and is excellent in durability.
Moreover, since the clearance gap D is formed between the edge 3b of the receptacle part 3 of the coupling main body 1, and the outer peripheral surface 6a of the connection pipe 6, the end edge 3b and the outer peripheral surface 6a contact and corrode. There is nothing.

A connection pipe 6 inserted into the joint body 1 is crimped and joined by a crimping part 11 in which the outer peripheral surface 1a of the joint body 1 is crimped into a substantially octagonal cross section, and the connection pipe 6 is pulled out with the crimping part 11 directed in the axial direction. Since the blocking force is formed so as to have a predetermined length C that can be configured, each of the press-bonded portions 11 in the axial direction is more dispersed by dispersing the press portions as compared with the case of a substantially hexagonal cross section. The amount of deformation can be reduced. For this reason, generation | occurrence | production of a process induction martensite structure | tissue can be suppressed, the structure | tissue which consists only of an austenite structure | tissue can be maintained, and there is no possibility that material may become embrittled. Further, the difference in the degree of biting of each crimping part 11 into the connection pipe 6 is reduced, and the lengths of the crimping parts 11 in the axial direction can be made substantially uniform.
The crimping force when the crimping part 11 is provided in an octagonal shape can be adjusted by changing the length C, and the minimum deformation amount of the crimping part 11 can be adjusted by setting the length C to an appropriate value. The maximum pull-out prevention force can be obtained.

Then, the joining method and press tool of a press-type pipe joint are demonstrated.
First, the connection pipe 6 is inserted into the joint body 1 until the end of the connection pipe 6 comes into contact with the abutting portion 2 a of the joint body 1. At the time of insertion, the inner diameter of the airtight member 5 attached to the joint main body 1 and the inner diameter of the enlarged diameter portion 1c of the joint main body 1 are larger than the outer diameter of the connection pipe 6 as described above. Can be inserted into the joint body 1 without being in contact with the airtight member 5 or the enlarged diameter portion 1c. Thereby, in addition to the airtight material 5 not being damaged by the insertion of the connection pipe 6, it is also possible to visually confirm that the seal by the airtight material 5 is insufficient when the press bonding with the connection pipe 6 is insufficient. it can.
In this state, as shown in FIGS. 2, 5A and 6A, the outer peripheral surface 1a of the joint body 1 is surrounded by a die 7 including an upper die 7a and a lower die 7b of the press tool body 20. set. At the time of setting, the joint body 1 is placed on the lower mold 7b, and the upper mold 7a is set in a state where it can be pressed onto the joint body 1.

The press tool main body 20 presses the joint main body 1 and the connection pipe 6 in the above-described state and is bonded by pressure bonding. In the die 7 of the press tool main body 20, the pressing of the upper die 7 a and the lower die 7 b is performed. The surface 7 c is a cross-sectional view for crimping the receiving portion 3 pressing recess 7 d surrounding the receiving portion 3 of the joint body 1, the round surface 12 pressing radius surface portion 8, and the outer peripheral surface 1 a of the joint body 1. An octagonal pressure-bonding surface 9 is formed, and the pressing surface 7c is configured to be annular when the upper die 7a and the lower die 7b come into contact with each other by pressing.
Further, at the rounded surface portion 8, the tapered portion 4 on the rounded surface 12, which is a connecting portion between the outer peripheral surface 1 a and the bulging curved surface 3 a on the outer peripheral side of the receiving port portion 3 of the joint body 1, is pressed. Is formed at a position connected to the recess 7d.

At the time of pressing, when pressing the upper die 7a to start pressing, the outer peripheral surface 1a of the joint body 1 is surrounded by the die 7 of the press tool body 20 as shown in FIGS. 5 (b) and 6 (b). When the pressing surface 7c of the die 7 is pressed, the tapered portion 4 of the joint body 1 first comes into contact with the tapered surface 9 in the rounded surface portion 8 of the die 7, so that the tapered portion 4 is pressed and the rounded surface 12 is moved. The receiving port 3 is pressed as a fulcrum so as to tilt toward the pipe insertion side.
In this way, the die 7 comes into contact with the receiving portion 3 first, so that the receiving portion 3 that may be generated when the die 7 comes into contact with the crimping portion 11 first, that is, the phenomenon that the receiving portion 3 tries to float up. The phenomenon that the diameter of the part 3 expands and the gap with the pipe 6 expands is prevented, and an appropriate sealing property by the airtight material 5 is ensured.

When pressed further, the bulging curved surface 3a of the receiving port 3 comes into contact with the concave portion 7d of the die 7 by deforming the receiving port 3 while tilting, and the contact surface pressure between the bulging curved surface 3a and the concave portion 7d at this time Is smaller than the contact surface pressure between the taper surface 9 and the taper portion 4, so that when the pressing by the die 7 is continued, the mouthpiece portion 3 is pushed from the taper portion 4 side, and the inclination of the mouthpiece portion 3 is deformed. The receiving part 3 is not compressed perpendicularly to the axial direction of the tube by the recess 7d, and the receiving part 3 is tilted while being guided along the recess 7d.
The shape in the vicinity of the receiving port 3 after deformation is formed in a shape substantially similar to the shape from the rounded surface 8 of the die 7 to the recess 7d.

  When the pressing is further continued, as shown in FIGS. 5 (d) and 6 (d), the crimp surface 10 having a substantially octagonal cross section of the die 7 comes into contact with the outer peripheral surface 1 a of the joint body 1. When the main body 1 is pressed, the joint main body 1 and the connection pipe 6 are pressure-bonded at the pressure-bonding portion 11 as shown in FIG.

When the pressing of the die 7 to the joint body 1 is completed, the airtight material 5 accommodated in the receiving port 3 is pressed to the outer periphery of the connection pipe 6 by an appropriate pressing force, and the inner peripheral side of the joint body 1 and the connection pipe 6 are The outer peripheral side can be sealed liquid-tight.
Further, when the press is completed, a gap D is formed between the end edge 3b and the outer peripheral surface 6a of the connection pipe 6, and this gap D is, for example, in a range of about 0.5 to 0.8 mm at a nominal diameter 25Su. Therefore, the gap D after pressing can be provided to a minimum.

As described above, the receiving portion 3, particularly the substantially semi-annular section formed by the recess 7 d, is not subjected to a strong compressive force by the die 7 in the course of the press, and the end 3 b of the joint body 1. Does not bite into the outer periphery of the connection pipe 6, and is a press-type pipe joint joining method that does not generate tensile residual stress that causes stress corrosion cracking.
Moreover, since the connection pipe 6 is unevenly fitted to the inner surface of the joint body 1 in the crimping portion 11 after pressing, the connection pipe 6 can be appropriately joined.

  Austenitic stainless steels such as SUS304 and SUS316 are common as materials for pipe joints for supplying cold and hot water, as specified in the Japan Water Works Association Standard JWWA G116-2001 “Stainless Steel Pipe Fittings for Water Supply”. However, these austenitic stainless steels have a problem that a stress corrosion cracking phenomenon is particularly likely to occur when a tensile stress is applied in a corrosive environment. In addition, when these are used as materials, especially when tap water of 50 ° C or higher is passed through pipes and joints where tensile stress during processing remains, a corrosive environment is formed by the temperature of the liquid and chlorine contained in the tap water. There is a risk of stress corrosion cracking in pipes and joints.

  Therefore, in this example, the joint body was formed using SUS315J2 having a composition of 0.04C-18.5Cr-12Ni-3Si-2Cu-0.8Mo-0.4Mn-N as a material. Since SUS315J2 contains copper and silicon, the material becomes sticky, and the proof stress can be increased as compared with SUS304 and SUS316. In addition, the hardness is reduced by reducing the content ratio of molybdenum and manganese so that the material has a certain degree of elasticity.

  On the other hand, the joint body material as a comparative example is SUS304, and the pipe joints of the present invention and the comparative example are changed in the shape and size of each pipe crimping part, and the residual stress and structure of the crimping part are analyzed, and the joint performance of As an evaluation test, an evaluation test of the pulling low strength of the connection pipe, the time cracking, and the stress corrosion cracking was performed. The results are shown in Tables 1 and 2. The nominal diameter of the joint used in the evaluation test is 25Su.

According to the results of Table 1, in the case of the press-type pipe joint according to the present invention, all of the residual stress became a compressive residual stress by using a material called SUS315J2 in addition to the device of the shape surface. Therefore, it was confirmed that all the specimens were pipe joints that did not cause stress corrosion cracking.
The specimen (No. 1 and 2) in which the side shape of the pipe crimping part is an arc, and the specimen (No. 3) in which the hexagonal side part is a straight line and the length C of the crimping part is 3 mm, Although a slight martensite structure was confirmed in the pipe crimping portion, the pulling resistance was able to ensure about 4500N. In addition, in the specimen (No. 4) in which the crimping part has a substantially hexagonal cross section and the side part is a straight line and the length C of the crimping part is 5 mm, the pipe crimping part has an austenite structure, and the connection pipe The pulling resistance is also No. It improved about 1.2 times compared with the test sample of 1-3. Further, in the specimens (Nos. 5 to 6) in which the crimping part has a substantially octagonal cross section and the side part is straight, the pipe crimping part has an austenite structure, and the pulling resistance of the connecting pipe is No. It improved about 1.5 times compared with the test sample of 1-3.

  According to the result of Table 2, No. which is a comparative example. In all the specimens 7 to 12, tensile residual stress was confirmed in the pipe crimping portion, and stress corrosion cracking occurred. In all specimens, a martensite structure was confirmed, and the pulling resistance was not stabilized accordingly.

  The present invention is suitable for a press-type joint for connecting stainless steel pipes applied to water supply, hot water supply and cold / hot water. Stainless steel pipes can be easily, quickly and reliably joined by using a caulking dedicated tool. Can be applied to various joints such as sockets, elbows, tees, reducers, etc.

It is sectional drawing which showed the state before joining of the press-type pipe joint in this invention. It is the sectional view on the AA line of FIG. It is sectional drawing which showed the state after joining of the press-type pipe joint of this invention. It is the BB sectional view taken on the line of FIG. (A) thru | or (d) is explanatory drawing which showed the joining process of the press-type pipe joint in this invention. (A) thru | or (d) are the partially expanded views of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint main body 1a Outer peripheral surface 1c Expanded part 2a Abutting part 3 Receiving part 3a Swelling curved surface 3b End edge 4 Tapered part 5 Airtight material 6 Connection pipe 6a Outer peripheral surface 7 Die 7c Pressing surface 7d Recessed part 8 Round surface part 9 Tapered surface 10 Crimping surface 11 Crimping part 12 Round surface 20 Press tool body C Length D Clearance

Claims (2)

A press-type pipe joint joining method for joining a connection pipe made of a thin-walled metal pipe to a joint body made of a thin-walled metal pipe, wherein an air-tight such as an O-ring is formed in a receiving portion bulged on the end side of the joint body The material is stored and connected with a large rounded surface including a tapered portion formed at the connecting portion between the swollen curved surface of the receiving part and the outer peripheral surface of the joint body, and the connection pipe is inserted into the joint body to the insertion end. surrounds the outer peripheral surface of the joint main body at a die of the press tool, by pressing with the pressing surface of the die having a rounded surface of the recess and the curved surface pressed for socket portion pressing of the joint body, the front Symbol tapered portion It is pressed by the pressing surface of the die, and the socket portion of the curved surface as a fulcrum is pressed so as to tilt the pipe insertion side Rutotomoni, between the outer peripheral surface of the socket portion edge and the connecting pipe of the fitting body to have a gap, and further, fitting the Method of joining a press type pipe joint being characterized in that as an outer peripheral surface and the connecting pipe to compression bonding with bonding surface provided on the die. The method for joining press-type pipe joints according to claim 1, wherein the pressure-bonding surface of the die has an octagonal cross section .

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