JP5467693B2 - Narrowing nozzle and TIG welding torch using the same - Google Patents

Description

  The present invention mainly relates to a narrowing nozzle attached to a TIG welding torch used in TIG welding in which ends of metal thin plates such as stainless steel plate and electromagnetic steel plate are butt welded to each other, and a TIG welding torch using the same. In particular, an electromagnetic force and a magnetic field acting on the arc are accelerated by disposing a constricting nozzle around the tip of the tungsten electrode rod and flowing a high-speed rectifying gas from the constricting nozzle around the arc, thereby accelerating the flow of the plasma air flow. Enhance the arc energy density, arc directivity and rigidity to enable high-speed welding, and improve the shielding effect of the welded part with shielding gas such as argon gas or helium. In addition, the tungsten electrode rod can be easily and accurately attached to the original position when replacing the tungsten electrode rod. Rukoto relates TIG welding torch using the constricting nozzle and the same to thereby improving the reproducibility and workability can.

  In general, in the TIG welding method, an arc (arc plasma) is generated between a tungsten electrode rod and a base material which is an object to be welded by flowing a shielding gas such as argon gas around the tungsten electrode rod, and the heat of the arc is generated. The base material is melted at the same time, and is widely used as an important joining technique in manufacturing sites using metal materials.

However, the TIG welding method has the following problems (1) to (5) as compared with other welding methods (for example, a plasma welding method, a laser welding method, and an electron beam welding method).
(1) The TIG welding method is inferior in welding ability and welding strength as compared with other welding methods such as a plasma welding method.
(2) In the TIG welding method, the tungsten electrode rod and the argon gas used as the shielding gas are relatively expensive, and the cost increases.
(3) In the TIG welding method, the shielding gas is easily affected by wind during welding, and the shielding effect is poor. If the shielding effect is poor, the second part of the weld (the heat-affected zone that occurs in the base metal due to welding heat, which is the part where the base metal structure has changed due to rapid heating / cooling due to welding heat) is burnt darkly. And an oxide film is generated on the bead surface.
(4) In the TIG welding method, if the arc length is not shortened when welding is performed with a small current, the arc becomes unstable.
(5) When the welding speed is increased in the TIG welding method, an undercut (dent) is generated in the second weld portion.

  On the other hand, as the TIG welding torch used in the TIG welding method, for example, a TIG welding torch (Patent Document 1) using a cylindrical shield nozzle for releasing a shielding gas such as argon gas, the shield nozzle and the like A TIG welding torch (Patent Document 2) using a constricting nozzle for increasing the energy density of an arc is known.

  FIG. 12 shows an example of a conventional TIG welding torch using a shield nozzle. The TIG welding torch is inserted with an electrode collet 22 for holding and fixing a tungsten electrode rod 21 in the torch body 20. The torch body 20 has a structure in which a ceramic shield nozzle 23 for releasing a shield gas G such as argon gas is attached to the tip of the torch body 20, and the shield gas G that has flowed in through the torch body 20 is supplied to the torch body 20. The laminar flow is performed by a gas lens 24 comprising a filter or the like provided at the tip of the gas, and the laminar flow of the shield gas G flows from the shield nozzle 23 toward the base material to be welded. An arc (arc plasma) is generated between the tungsten electrode rod 21 and the base material, and the base material is melted by the heat of the arc. It is obtained by way.

  FIG. 13 shows an example of a conventional TIG welding torch using a shield nozzle 23 and a constricting nozzle 25. The TIG welding torch holds a tungsten electrode rod 21 in a torch body (not shown). A fixed electrode collet (not shown) is inserted, and a ceramic shield nozzle 23 for flowing a shield gas G such as argon gas is attached to the tip of the torch body. Further, a shield nozzle 23 is attached to the tip of the shield nozzle 23 from the shield nozzle 23. Also, a constricted nozzle 25 having a small diameter is attached, and a shielding gas is formed around the arc (arc plasma) generated between the tungsten electrode rod 21 and the base material from the constricted nozzle 25. G is concentrated and the energy density of the arc is increased by the thermal pinch effect of the shielding gas G Those were Unishi.

  However, even with the conventional TIG welding torch using the shield nozzle 23 and the constricting nozzle 25, it is impossible to solve all of the above problems in TIG welding. I have it.

  For example, since the TIG welding torch using the shield nozzle 23 only diffuses and releases the shield gas G from the tip of the shield nozzle 23 having a relatively large inner diameter, the concentration of the shield gas G around the arc decreases, and the energy A high-density arc was not obtained, and the arc was unstable. For this reason, there is a problem that the welding speed must be slow and the directivity of the arc is poor.

Further, the TIG welding torch using the shield nozzle 23 and the constriction nozzle 25 causes the shield gas G to flow intensively from the constriction nozzle 25 to the periphery of the arc, so that the energy density of the arc is TIG welding using only the shield nozzle 23. Because the welding speed can be increased and the directivity of the arc can be improved because it is increased compared with the torch for the use, but the discharge range of the shielding gas G is narrowed and the shielding effect is deteriorated, and the quality of welding is reduced. There was a problem.
Moreover, when the tungsten electrode rod 21 is replaced, it is difficult to set the tungsten electrode rod 21 to the original position (the center position of the constriction nozzle 25), and there is a problem that the reproducibility and workability are poor.

  Therefore, in the TIG welding torch used in the TIG welding method, it is desired to develop a welding torch using a new nozzle that solves all the problems in the TIG welding method described above.

Japanese Patent No. 3163559 Japanese Patent No. 4327153

  The present invention has been made in view of such problems, and its purpose is to accelerate the flow of a plasma air flow by flowing a high-speed rectifying gas around the arc, and to generate an electromagnetic force and a magnetic field acting on the arc. Enhance the arc energy density, arc directivity and rigidity to enable high-speed welding, and improve the shielding effect of the welded part with shielding gas such as argon gas or helium. In addition, a narrowed nozzle that enables easy welding and can be easily and accurately attached to the original position when replacing the tungsten electrode rod, thereby improving reproducibility and workability. It is to provide a torch for IG welding.

In order to achieve the above object, according to the first aspect of the present invention, the shield gas flowing in through the inside of the torch body is laminarized by a gas lens disposed at the tip of the torch body. The laminar shield gas is discharged from the cylindrical shield nozzle disposed at the tip of the torch body toward the base material W, which is the workpiece, and is placed at the center of the shield nozzle in the atmosphere of the shield gas. to generate an arc between the set tungsten electrode rod and the base material, in the constriction nozzle attached to the TIG welding torch so as to melt the base material in the heat of the arc, the constriction nozzle gas lens the distal end surface center detachably attached to the ring between the a tip portion around the tungsten electrode rod disposed tungsten electrode rod concentrically tip outer peripheral surface of the tungsten electrode rod A cylindrical nozzle body that forms a high-speed gas passage, and a nozzle body that is formed on the inner circumferential surface of the nozzle body so as to protrude at a predetermined interval in the circumferential direction and holds the tungsten electrode rod at the center position of the nozzle body. A plurality of positioning ridges along the longitudinal direction and a plurality of gas rectifying grooves formed between the plurality of positioning ridges and extending parallel to the longitudinal direction of the nozzle body and rectifying the shield gas flowing in the high-speed gas passage The positioning protrusion and the gas rectifying groove are formed at positions away from the tip of the nozzle body, and a high-speed gas passage located between the tip of the nozzle body and the positioning ridge and the gas rectifying groove is formed. An inner diameter is formed larger than the inner diameter of the high-speed gas passage upstream of the positioning protrusion and the gas rectifying groove, and a part of the shield gas discharged from the torch body is part of the high-speed gas passage and each gas rectifier. The high-speed rectification gas that is faster than the laminar shield gas discharged from the shield nozzle and stabilized, and the flow of the high-speed rectification gas that has passed through the gas rectification groove is stabilized at the downstream portion of the high-speed gas passage. It is characterized in that the converted high-speed rectified gas flows from the tip opening of the nozzle body around the arc.

According to a second aspect of the present invention, in the first aspect of the present invention, the gas rectifying grooves are formed on the inner peripheral surface of the nozzle body so as to cause the high-speed rectified gas to flow evenly around the arc from the tip opening of the nozzle body. It is characterized by the arrangement .

According to a third aspect of the present invention, in the first aspect of the present invention , in each gas rectifying groove, the high-speed rectified gas is allowed to flow in a large amount from the opening at the tip of the nozzle main body to the opposite positions around the arc. It is characterized by being arranged on the peripheral surface .

According to a fourth aspect of the present invention, there is provided a cylindrical torch body, an electrode collet that is screwed into the torch body so as to move up and down and rotate, and holds the tungsten electrode rod detachably, and an upper end of the electrode collet A collet handle that is attached to the body and rotates the electrode collet forward and backward relative to the torch body, and detachably attached to the lower end of the torch body. A gas lens that is uniformly diffused and stratified, and a gas lens or torch body that is detachably attached in a state surrounding the tip of the tungsten electrode rod, and a shield gas that is stratified by the gas lens around the arc A cylindrical shield nozzle that discharges, and a detachable attachment at the center position of the tip of the gas lens. Especially it consisted either of constriction nozzle according to claims 1 to 3 which is disposed around the end portion is characterized.

The constricting nozzle according to claim 1 of the present invention is a cylinder which is arranged concentrically with the tungsten electrode rod around the tip portion of the tungsten electrode rod and forms an annular high-speed gas passage between the outer peripheral surface of the tip portion of the tungsten electrode rod. And a plurality of positioning members along the longitudinal direction of the nozzle body, which are formed on the inner peripheral surface of the nozzle body so as to protrude at a predetermined interval in the circumferential direction and hold the tungsten electrode rod at the center position of the nozzle body It is formed between a ridge and a plurality of gas rectifying grooves formed between a plurality of positioning ridges and extending parallel to the longitudinal direction of the nozzle body to rectify the shield gas flowing in the high-speed gas passage. A part of the shield gas to be flowed through the high-speed gas passage is used as a high-speed rectification gas faster than the laminarized shield gas discharged from the shield nozzle, and the high-speed rectification gas is used as the nozzle Because you are configured to flow from the body of the tip opening around the arc, it is possible to achieve excellent effects as follows.
(1) That is, the narrowing nozzle of claim 1 of the present invention uses a part of the shielding gas as a high-speed rectifying gas faster than the laminarized shielding gas discharged from the shielding nozzle, and this high-speed rectifying gas is used around the arc. Therefore, the speed of the plasma airflow flowing from the tungsten electrode rod side toward the base material side to be welded is twice to three times the conventional speed (about 100 m / sec) ( About 200 to 300 m / sec), the electromagnetic force and the magnetic field acting on the arc are strengthened, and the arc energy density, the arc directivity and the rigidity are increased, and a stable arc is obtained.
As a result, the constriction nozzle according to claim 1 of the present invention can increase the welding speed 5 to 20 times faster than the conventional welding speed (1000 mm / min to 7000 mm / min) and can perform high-speed welding. In addition, the bead width is uniform on both the front and back surfaces, and the bead waveform is equally spaced, so that high-quality and stable welding can be performed.
(2) The constricting nozzle according to claim 1 of the present invention allows the shield gas to flow with a high-speed rectifying gas and allows high-speed welding, so that the shield gas is not affected by wind during welding, and heat Rapid heating / cooling of the affected area suppresses crystal coarsening and improves the bending ductility of the weld metal.
(3) The constricting nozzle according to claim 1 of the present invention can prevent re-adhesion / mixing of metal vapor (impurities) generated in the molten metal into the molten metal by a high-speed plasma stream, and can perform high-quality welding.
(4) Since the constricted nozzle according to claim 1 of the present invention squeezes the shielding gas from the nozzle body and discharges it as a high-speed rectified gas, the amount of shielding gas used is small, and the cost can be reduced.
(5) The narrowing nozzle according to claim 1 of the present invention has a plurality of positioning protrusions protruding from the inner peripheral surface of the nozzle body to hold the tungsten electrode bar at the center position of the nozzle body. At the time of replacement, the tungsten electrode rod can be accurately and reliably set to the original position (center position of the narrowing nozzle), the reproducibility of the attachment position of the tungsten electrode rod can be improved, and the workability is also improved.

The narrowing nozzle according to claim 1 of the present invention is such that the positioning protrusion and the gas rectifying groove are formed at positions away from the tip of the nozzle body, and the tip of the nozzle body, the positioning protrusion and the gas rectifying groove, Because the inner diameter of the high-speed gas passage located between them is larger than the inner diameter of the high-speed gas passage on the upstream side of the positioning protrusion and the gas rectification groove, the flow of the high-speed rectification gas passing through the gas rectification groove is high-speed Stabilization occurs in the downstream portion of the gas passage, and turbulence is prevented.
As a result, high-quality and stable welding can be performed reliably and satisfactorily.

Furthermore, the invention of claim 2 of the present invention is configured such that each gas rectifying groove is arranged on the inner peripheral surface of the nozzle body so that the high-speed rectifying gas flows evenly around the arc from the tip opening of the nozzle body. The plasma airflow that flows from the tungsten electrode rod side to the base metal side will flow evenly, a circular shape with a high roundness cross section can be formed, and the arc during welding will be stable Become.

Furthermore, the invention of claim 3 of the present invention is configured such that each gas rectifying groove is arranged on the inner peripheral surface of the nozzle body so that a large amount of the high-speed rectifying gas flows from the opening at the tip of the nozzle body to the opposite positions around the arc. Therefore, it is possible to form an arc having an elliptical cross section and a high energy density.
As described above, when an arc having an elliptical cross-sectional shape is formed, the preheating effect is increased, the penetration is increased, and a back wave is easily generated.

Since the TIG welding torch according to the fourth aspect of the present invention includes the above-described narrowing nozzle, the above-described effects can be achieved.
Moreover, this TIG welding torch is designed to double seal with a high-speed rectifying gas that flows from the constriction nozzle around the arc and a laminarized shielding gas that flows from the shielding nozzle to the outside of the TIG welding torch. As a result, the ingress of air into the molten pool can be surely blocked, the surface bead has less oxide film, glossy welding can be performed on the bead surface, and the life of the tungsten electrode rod is extended.

Further, the TIG welding torch according to claim 4 of the present invention is configured so that the stenosis nozzle is detachably attached to the center position of the front end surface of the gas lens, so that the stenosis nozzle burns out or the tungsten electrode rod has a different diameter. Even when the electrode is replaced with a tungsten electrode rod, the constricting nozzle can be easily replaced, which is extremely convenient.

The external appearance shape of the torch for TIG welding using the constriction nozzle which concerns on the 1st Embodiment of this invention is shown, (A) is a front view of the torch for TIG welding, (B) is a side view of the torch for TIG welding. . It is a longitudinal cross-sectional view of the torch for TIG welding similarly. It is an enlarged vertical sectional view of the principal part of the torch for TIG welding similarly. FIG. 4 is a cross-sectional view taken along the line II in FIG. 3. It is an expansion longitudinal cross-sectional view of a constriction nozzle. FIG. 6 is a cross-sectional view taken along the line of FIG. It is explanatory drawing which shows the force which acts on an arc. A stainless steel plate was butt welded under the same welding conditions using a conventional TIG welding torch using a constricting nozzle and a TIG welding torch using a constricting nozzle of the present invention, and the welded part was subjected to an Ericksen test. (A) is an expansion perspective view of the welding part of the stainless steel plate welded using the conventional narrowing nozzle, (B) is an expansion perspective view of the welding part of the stainless steel plate welded using the narrowing nozzle of this invention. It is an expanded longitudinal cross-sectional view of the principal part of the torch for TIG welding using the constriction nozzle which concerns on the 2nd Embodiment of this invention. FIG. 10 is a sectional view taken along the line ha-ha in FIG. 9. It is explanatory drawing which shows the principle of the constriction nozzle shown to FIG.9 and FIG.10, (A) is explanatory drawing of the state in which the strong plasma airflow is flowing, (B) is explanatory drawing of the state in which the weak plasma airflow is flowing, (C) is explanatory drawing which shows the cross-sectional shape of the arc at the time of using the constriction nozzle shown in FIG.9 and FIG.10. It is an expanded longitudinal cross-sectional view of the principal part of the conventional TIG welding torch using only a shield nozzle. It is an expanded longitudinal cross-sectional view of the principal part of the torch for TIG welding using a shield nozzle and the conventional constriction nozzle.

  1 to 6 show a constricting nozzle according to a first embodiment of the present invention and a TIG welding torch using the same, and the TIG welding torch is mainly an end of a thin metal plate such as a stainless steel plate or an electromagnetic steel plate. Used when butt welding the parts, a cylindrical torch body 1 through which a shielding gas G such as argon gas or helium is passed, and a screw that is vertically movable and rotatable from above into the torch body 1 An electrode collet 3 that is inserted and holds the tungsten electrode rod 2 in a detachable manner, and a collet handle 4 that is attached to the upper end of the electrode collet 3 and moves the electrode collet 3 up and down relative to the torch body 1 by rotating forward and backward. And a gas that is detachably attached to the lower end of the torch body 1 and diffuses the shield gas G flowing in through the inside of the torch body 1 into a laminar flow. The gas 5 and the torch body 1 are removably attached to the tip of the tungsten electrode rod 2 so as to surround the tip of the tungsten electrode rod 2, and the shield gas G laminarized by the gas lens 5 is discharged around the arc a. It is composed of a cylindrical shield nozzle 6 and a constricting nozzle 7 disposed around the tip of the tungsten electrode rod 2.

  1 and 2, 8 is formed on the outer peripheral surface of the upper end portion of the torch body 1, a screw scale indicating the lifting amount of the electrode collet 3, and 9 is formed on the outer peripheral surface of the lower end portion of the collet handle 4. A screw scale 10 indicating the amount of rotation of the collet handle 4 is provided on the torch body 1, a pressure adjusting screw for applying an appropriate rotation resistance to the electrode collet 3 to hold the electrode collet 3 in an adjustment position, and 11 a torch body. 1 is an electrode / main gas pipe fitting fixed to 1, 12 is an O-ring for sealing between the torch body 1 and the collet handle 4, and 13 is for gas sealing interposed between the torch body 1 and the gas lens 5. The rubber ring 14 is a plastic adjustment ring interposed between the torch body 1 and the shield nozzle 6.

As shown in FIGS. 1 and 2, the torch body 1 includes a rectangular tube portion formed of a metal material such as an aluminum alloy and a cylindrical portion continuously provided at the upper end of the rectangular tube portion, and a peripheral wall of the rectangular tube portion. The electrode / main gas pipe connection fitting 11 and the pressure adjusting screw 10 are inserted and fixed.
Further, a female screw 1a into which an electrode collet 3 holding the tungsten electrode rod 2 is screwed up and down is formed on the inner peripheral surface of the upper end opening of the torch body 1. On the peripheral surface, a female screw 1b is formed on which a gas lens 5 for laminating the shield gas G is detachably screwed.
The electrode / main gas pipe connection fitting 11 is connected to a main gas supply pipe and a power cable, which are not shown.

As shown in FIG. 2, the electrode collet 3 is formed in a long and narrow cylindrical shape having a halved chuck portion at the tip, and the upper and lower female screws 1a on the upper end portion side of the torch body 1 are vertically A copper collet body 3 ′ having a male screw 3 a that is movably screwed, and tungsten that is detachably screwed to the chuck portion of the collet body 3 ′, and is inserted into the collet body 3 ′ by tightening the chuck portion. It is comprised from the copper cylindrical fixing tool 3 '' which fixes the electrode rod 2. As shown in FIG.
The electrode collet 3 is screwed into the torch body 1 from above, and moves up and down in the torch body 1 by rotating the collet handle 4 fixed to the upper end of the collet body 3 '. Yes.

  The gas lens 5 includes a holder 5 'having a cylindrical structure made of copper and detachably attached to the lower end of the torch body 1, and a metal filter 5 "attached to the holder 5'.

Specifically, as shown in FIGS. 2 and 3, the holder 5 ′ is formed in a cylindrical body in which a gas passage 5 a is formed at the center, and the lower end portion of the torch body 1 is formed on the outer peripheral surface of the upper end portion. A male screw 5b that is detachably screwed to the female screw 1b on the side is formed, and a cylindrical screw having a male screw 5c that is detachably screwed to the outer peripheral surface is formed at the lower end portion. A holding cylinder part 5d and a supporting cylinder part 5f formed with an internal thread 5e, which is positioned at the center of the holding cylinder part 5d and in which the narrowing nozzle 7 is detachably screwed, are formed.
Further, the space between the holding cylinder part 5d and the support cylinder part 5f of the holder 5 'is an annular gas chamber 5g, and a plurality of gas flow holes 5h formed in the vicinity of the base end part of the support cylinder part 5f. And communicated with the inside of the torch body 1 through the gas passage 5a of the holder 5 '.

On the other hand, the filter 5 ″ is formed by laminating a plurality of annularly punched wire meshes, and its inner peripheral edge is the support cylinder 5f of the holder 5 ′ and its outer peripheral is the holder 5 ′. It is attached to the holder 5 'by being fitted into the holding cylinder portion 5d.
The filter 5 ″ is a combination of three 600 mesh stainless steel wire meshes and two 300 mesh stainless steel wire meshes.

As shown in FIGS. 2 and 3, the shield nozzle 6 is formed in a cylindrical shape whose tip is narrowed by a ceramic material, and a holding cylindrical portion 5d of the gas lens 5 is formed on a part of the inner peripheral surface thereof. A female screw 6a that is detachably screwed to the male screw 5c is formed.
The shield nozzle 6 is attached to the outer peripheral surface of the gas lens 5 by screwing the female screw 6a into the male screw 5c of the holding cylinder portion 5d of the gas lens 5, and passes through the filter 5 ″ of the gas lens 5. A laminar shield gas G is discharged around the tip of the tungsten electrode rod 2.

  2 and 3, the narrowing nozzle 7 is disposed around the tip of the tungsten electrode rod 2 and forms an annular high-speed gas passage 7d between the tip of the tungsten electrode rod 2. As shown in FIG. Yes, a part of the shield gas G flowing from the torch body 1 into the gas passage 5a of the holder 5 'of the gas lens 5 flows into the high-speed gas passage 7d and flows from the shield nozzle 6 around the constriction nozzle 7 The high-speed rectifying gas G3 is faster than the shield gas G, and the high-speed rectifying gas G3 flows around the arc a.

  That is, the constriction nozzle 7 is formed in a cylindrical body from a copper material (beryllium copper) excellent in electrical conductivity and strength. As shown in FIGS. 2 to 6, the periphery of the tip of the tungsten electrode rod 2 is formed. Are arranged concentrically with the tungsten electrode rod 2 and form an annular high-speed gas passage 7d between the tip end outer peripheral surface of the tungsten electrode rod 2 and an inner peripheral surface of the nozzle main body 7a. A plurality of positioning protrusions 7b along the longitudinal direction of the nozzle body 7a, which are formed to protrude in the circumferential direction at predetermined intervals and hold the tungsten electrode rod 2 at the center position of the nozzle body 7a, and a plurality of positioning protrusions It consists of a plurality of gas rectifying grooves 7c formed between the strips 7b and extending parallel to the longitudinal direction of the nozzle body 7a to rectify the shield gas G flowing in the high-speed gas passage 7d.

Specifically, the nozzle body 7a has a distal end (lower end) outer peripheral surface tapered, and a base end (upper end) outer peripheral surface has a support tube for the holder 5 'of the gas lens 5. A male screw 7e that is detachably screwed to the portion 5f is formed.
The nozzle body 7a is attached to the center position of the front end surface of the gas lens 5 by screwing the male screw 7e into the support cylinder portion 5f. At this time, the nozzle main body 7a is arranged concentrically with the tungsten electrode rod 2 and the shield nozzle 6 around the tip portion of the tungsten electrode rod 2, and is an annular high-speed gas passage between the tip electrode outer peripheral surface. 7d is formed.

  Further, the positioning protrusions 7b and the gas rectifying grooves 7c are arranged at equal angles in the circumferential direction of the inner peripheral surface of the nozzle body 7a, respectively, and the high-speed rectified gas G3 is supplied to the arc a from the tip opening of the nozzle body 7a. It can be made to flow evenly around.

Further, the positioning protrusion 7b and the gas rectifying groove 7c are formed at positions away from the tip of the nozzle body 7a, and are positioned between the tip of the nozzle body 7a and the positioning ridge 7b and the gas rectifying groove 7c. The inner diameter of the high-speed gas passage 7d is larger than the inner diameter of the high-speed gas passage 7d on the upstream side of the positioning protrusion 7b and the gas rectifying groove 7c.
As a result, the shield gas G that has flowed into the high-speed gas passage 7d passes through the gas rectifying groove 7c and is rectified to become the high-speed rectified gas G3. After stabilization at the downstream portion of the high-speed gas passage 7d, the nozzle body 7a It is discharged from the tip opening.

In this embodiment, the diameter of the tungsten electrode rod 2 to be used is set to 1.6 mm.
Further, as shown in FIGS. 4 and 6, six positioning protrusions 7b and gas rectifying grooves 7c are formed on the inner peripheral surface of the nozzle body 7a every sixty degrees, and cross the positioning protrusions 7b. The surface shape is formed in a substantially trapezoidal shape in which the top surface of the positioning protrusion 7b is arcuate, and the cross-sectional shape of the gas rectifying groove 7c is formed in a U shape.
Further, the total length of the constricting nozzle 7 is 18 mm, the outer diameter of the largest diameter portion is 6 mm, the inner diameter of the nozzle body 7 a on the proximal end side is 2.7 mm, and the inner diameter of the nozzle body 7 a on the distal end side is 3 mm. The length of the positioning protrusion 7b and the gas rectifying groove 7c is about 2 mm, the width of the gas rectifying groove 7c is 0.5 mm, and the depth of the gas rectifying groove 7c is 0.75 mm. The passing distance between the two positioning protrusions 7b is set to 1.7 mm, and the formation positions of the positioning protrusions 7b and the gas rectifying grooves 7c are set to be 3 mm from the tip of the nozzle body 7a.
The distance between the two opposing positioning protrusions 7b is set to be 0.1 mm larger than the outer diameter of the tungsten electrode rod 2 so that the tungsten electrode rod 2 can be slidably held.

Next, the effect | action of the torch for TIG welding using the narrowing nozzle 7 mentioned above is demonstrated.
First, the electrode collet 3 holding and fixing the tungsten electrode rod 2 is inserted into the torch body 1, and the tungsten electrode rod 2 is in a state of slightly protruding from the tip of the constriction nozzle 7. The protruding length of the bar 2 is set.

  Next, the base material W, which is the set workpiece, is positioned below the tungsten electrode rod 2 of the TIG welding torch, or the holding device (not shown) for holding the TIG welding torch is adjusted to adjust the tungsten. After the tip of the electrode rod 2 is positioned in the vicinity of the welding location of the base material W, the collet handle 4 is rotated to adjust the distance between the tip of the tungsten electrode rod 2 and the base material W to a set value.

  The welding conditions such as the welding current, the length of the arc a, the welding speed, the supply amount of the shielding gas G, and the tip shape of the tungsten electrode rod 2 are optimum conditions depending on the material of the base material W, the plate thickness, etc. Of course, it is set to.

When the setting of the TIG welding torch and the base material W is completed, a power source (not shown) is supplied while flowing a shielding gas G such as argon gas from the shielding nozzle 6 and the narrowing nozzle 7 of the TIG welding torch toward the base material W. Is applied to apply a voltage between the tungsten electrode bar 2 and the base material W to generate an arc a between the tip of the tungsten electrode bar 2 and the base material W in the atmosphere of the shield gas G.
In this embodiment, the welding has a positive polarity (rod minus) in which direct current is used as a power source and welding is performed by connecting the tungsten electrode rod 2 to the negative electrode of the direct current welding machine.

  The shield gas G supplied into the torch body 1 flows down in the gas passage 5a of the holder 5 'of the gas lens 5, and a part thereof flows into the annular gas chamber 5g from the plurality of gas flow holes 5h. The remainder flows from the gas passage 5a into the high-speed gas passage 7d of the constriction nozzle 7.

The shield gas G that has flowed into the annular gas chamber 5g passes through the filter 5 ″, is homogeneously diffused, becomes a laminar gas G1, and is discharged from the shield nozzle 6 around the arc a.
The shield gas G that has flowed into the high-speed gas passage 7d is increased in speed to become the high-speed gas G2, and is rectified by passing through the plurality of gas rectification grooves 7c to become the high-speed rectification gas G3. Is emitted from the front end opening to the periphery of the arc a.

  The high-speed rectified gas G3 that has passed through the gas rectifying groove 7c is located downstream of the high-speed gas passage 7d because the positioning protrusion 7b and the plurality of gas rectifying grooves 7c are formed at positions away from the tip of the nozzle body 7a. It stabilizes at the side part and is discharged from the tip opening of the nozzle body 7a in a stable state.

Then, since the arc a generated between the tip of the tungsten electrode rod 2 and the base material W spreads from the tungsten electrode rod 2 toward the base material W as shown in FIG. 7, the internal pressure of the arc a is The tungsten electrode rod 2 is higher than the base material W.
As a result, part of the shield gas G is drawn into the arc a, and a high-speed gas flow called a plasma airflow P is generated. This plasma air flow P has a great influence on the penetration formation of the base material W, and also affects the directivity and rigidity of the arc a (the property that the arc a retains its shape), and its velocity is As the speed increases, the directivity and rigidity of the arc a can be increased.
Further, the generated arc a is narrowed down by a thermal pinch effect by the high-speed rectifying gas G3 discharged from the constricting nozzle 7, and becomes a stable arc a having a high energy density.

  When the stable arc a is generated, the TIG welding torch is moved and moved along the welded portion of the base material W at a predetermined speed. Then, the welded portion of the base material W is melted and joined by the heat of the arc a generated between the tip of the tungsten electrode rod 2 and the base material W.

The TIG welding torch using the stenosis nozzle 7 described above converts a part of the shield gas G by the stenosis nozzle 7 into a high-speed rectifying gas G3 that is faster than the laminarized shield gas G discharged from the shield nozzle 6. Since the rectifying gas G3 is configured to flow around the arc a, the speed of the plasma airflow P flowing from the tungsten electrode rod 2 side toward the base material W side to be welded is the conventional speed (about 100 m / sec). ) To twice as fast as 3 times (about 200 to 300 m / sec). Further, the magnetic field acting on the arc a and the electromagnetic force in the central axis direction are strengthened, and the energy density of the arc a, the directivity and the rigidity of the arc a can be increased, and a stable arc a can be obtained.
As a result, if the TIG welding torch is used, the welding speed can be increased to 5 to 20 times faster than the conventional welding speed (1000 mm / min to 7000 mm / min), and high-speed welding can be performed. In addition, the bead width is uniform on both sides and the bead corrugation is formed at equal intervals, so that high-quality and stable welding can be performed.

Further, the TIG welding torch allows the shield gas G to flow from the constriction nozzle 7 as a high-speed rectifying gas G3 and enables high-speed welding, so that the shield gas G is not affected by wind during welding, and heat Rapid heating / cooling of the affected area suppresses crystal coarsening and improves the bending ductility of the weld metal.
Furthermore, the TIG welding torch can prevent re-adhesion / mixing of metal vapor (impurities) generated in the molten metal by the high-speed plasma airflow P into the molten metal, and can perform high-quality welding.
In addition, since the TIG welding torch is sealed twice by the high-speed rectifying gas G3 flowing around the arc a and the laminarized shielding gas G flowing outside the arc a, the shielding effect is enhanced. Thus, the ingress of air into the molten pool can be reliably blocked, the surface bead has a small oxide film, glossy welding can be performed on the bead surface, and the life of the tungsten electrode rod 2 is extended.
In addition, since this TIG welding torch squeezes the shielding gas G by the constricting nozzle 7 and discharges it as the high-speed rectifying gas G3, the amount of the shielding gas G used is small, and the cost can be reduced.
Further, in this TIG welding torch, the positioning protrusion 7b and the gas rectifying groove 7c are arranged at equal angles in the circumferential direction of the inner peripheral surface of the nozzle body 7a, respectively, and the high-speed rectifying gas G3 is provided from the tip of the nozzle body 7a. Since the plasma air flow P flowing from the tungsten electrode rod 2 toward the base material W flows uniformly, the cross-sectional shape having a high roundness is a circular arc. a can be formed, and the arc a during welding is stabilized.

Table 1 below uses the conventional TIG welding torch using only the shield nozzle 23 described at the beginning, the conventional TIG welding torch using the shield nozzle 23 and the narrowing nozzle 25, and the narrowing nozzle 7 of the present invention. It is the table | surface which compared the effect of the torch for TIG welding which had.
As can be seen from Table 1, the TIG welding torch using the constricting nozzle 7 of the present invention has a conventional shield nozzle 23 or the like in the directivity of arc a, welding speed, shielding effect, welding quality, etc. Compared with the TIG welding torch using the constricting nozzle 25, it is possible to exhibit excellent effects in all aspects.

FIG. 8 shows a butt welding of a stainless steel plate under the same welding conditions using a conventional TIG welding torch using a narrowing nozzle 25 and a TIG welding torch using a narrowing nozzle 7 of the present invention. FIG. 8A shows a welded portion of a stainless steel plate butt welded using a TIG welding torch using a conventional constricting nozzle 7, and FIG. 8B shows this part. The welding part of the stainless steel plate butt-welded using the torch for TIG welding using the constriction nozzle 7 of invention is shown.
As apparent from the photograph of FIG. 8, in the TIG welding torch using the conventional constricting nozzle 25, cracks are formed in the welded portion, but the TIG welding torch using the constricting nozzle 7 of the present invention. In this case, it can be seen that there is no crack, and that butt welding superior in strength to the conventional one can be performed.

  9 and 10 show the main part of a TIG welding torch using the constricting nozzle 7 according to the second embodiment of the present invention, and the constricting nozzle 7 defines each gas rectifying groove 7c with a nozzle body 7a. The high-speed rectified gas G3 is arranged on the inner peripheral surface of the nozzle body 7a so that a large amount of the high-speed rectified gas G3 can flow from the front end opening to the opposite positions around the arc a.

  That is, as shown in FIG. 10, the constricting nozzle 7 has two positioning protrusions 7b and gas rectifying grooves 7c arranged at 180 ° intervals in the circumferential direction of the inner peripheral surface of the nozzle body 7a. A large amount of the high-speed rectification gas G3 is allowed to flow from the tip of the gas to the opposite positions around the arc a, and a small amount of the high-speed rectification gas G3 is allowed to flow to other locations.

As shown in FIGS. 11A to 11C, the TIG welding torch using the constricting nozzle 7 alternately forms strong and weak portions of the plasma air flow P every 90 ° in the circumferential direction of the arc a. Therefore, it is possible to form an arc a having an elliptical cross section and a high energy density.
As described above, when the arc a having an elliptical cross-sectional shape is formed, the preheating effect is improved, the penetration is increased, and a back wave is easily generated. However, good welding can be performed even if the current is increased.

  Note that the number, the cross-sectional shape, the size, the positional relationship, etc. of the positioning protrusions 7b and the gas rectifying grooves 7c of the constricting nozzle 7 are not limited to those of the above embodiments, but around the arc a. Of course, the number, the cross-sectional shape, the size, the positional relationship, and the like can be changed as appropriate as long as the high-speed rectified gas G3 can be flown through.

  1 is a torch body, 2 is a tungsten electrode rod, 3 is an electrode collet, 4 is a collet handle, 5 is a gas lens, 6 is a shield nozzle, 7 is a constricting nozzle, 7a is a nozzle body, 7b is a positioning protrusion, 7c is Gas rectifying groove, 7d is a high-speed gas passage, a is an arc, G is a shielding gas, G1 is a laminar flow gas, G2 is a high-speed gas, G3 is a high-speed rectifying gas, and W is a base material.

Claims (4)

The shield gas (G) flowing in through the inside of the torch body (1) is stratified by the gas lens (5) disposed at the tip of the torch body (1), and the stratified shield is formed. The gas (G) is discharged from the cylindrical shield nozzle (6) disposed at the tip of the torch body (1) toward the base material W as the work piece, and shielded in the atmosphere of the shield gas (G). An arc (a) is generated between the tungsten electrode rod (2) disposed at the center position of the nozzle (6) and the base material (W), and the base material (W) is melted by the heat of the arc (a). In the stenosis nozzle (7) attached to the TIG welding torch configured as described above, the stenosis nozzle (7) is detachably attached to the center position of the front end surface of the gas lens (5), and the tungsten electrode rod (2 ) Around the tip of the tungsten electrode rod (2) A tubular nozzle body forming an annular high-speed gas passage (7d) between the concentrically disposed tip outer peripheral surface of the tungsten electrode rod (2) (7a), the inner circumference of the nozzle body (7a) A plurality of positioning protrusions along the longitudinal direction of the nozzle body (7a) that are formed on the surface so as to protrude at a predetermined interval in the circumferential direction and hold the tungsten electrode rod (2) at the center position of the nozzle body (7a). (7b) and a plurality of positioning protrusions (7b), and rectifies the shield gas (G) that flows parallel to the longitudinal direction of the nozzle body (7a) and flows in the high-speed gas passage (7d). The positioning ridge (7b) and the gas rectifying groove (7c) are formed at positions away from the tip of the nozzle body (7a). Tip and positioning ridge (7b) and The inner diameter of the high-speed gas passage (7d) located between the gas rectifying groove (7c) is larger than the inner diameter of the high-speed gas passage (7d) on the upstream side of the positioning ridge (7b) and the gas rectifying groove (7c). A part of the shield gas (G) that is formed and discharged from the torch body (1) flows through the high-speed gas passage (7d) and the gas rectifying grooves (7c) and is discharged from the shield nozzle (6). High-speed rectifying gas (G3) that is faster than the shield gas (G), and the flow of the high-speed rectifying gas (G3) that has passed through the gas rectifying groove (7c) is stabilized in the downstream portion of the high-speed gas passage (7d) The constricted nozzle is characterized in that the stabilized high-speed rectifying gas (G3) flows from the tip opening of the nozzle body (7a) around the arc (a). The fact that each gas rectifying groove (7c) is arranged on the inner peripheral surface of the nozzle body (7a) so that the high-speed rectifying gas (G3) flows evenly around the arc (a) from the opening at the tip of the nozzle body (7a). The constriction nozzle according to claim 1 , wherein The gas rectifying grooves (7c) are arranged on the inner peripheral surface of the nozzle body (7a) so that the high-speed rectified gas (G3) flows from the opening at the front end of the nozzle body (7a) to the opposite positions around the arc (a). The constriction nozzle according to claim 1 , wherein A cylindrical torch body (1), an electrode collet (3) that is screwed into and inserted into the torch body (1) so as to be movable up and down and rotatable, and detachably holds the tungsten electrode rod (2), and an electrode collet A collet handle (4) attached to the upper end of (3) and rotating up and down with respect to the torch body (1) by rotating the electrode collet (3) forward and backward, and detachably attached to the lower end of the torch body (1) Attached to the gas lens (5) for uniformly diffusing the shield gas (G) flowing in through the inside of the torch body (1) into a laminar flow, and the gas lens (5) or the torch body (1) A cylindrical shield that is detachably attached in a state surrounding the tip of the tungsten electrode rod (2), and discharges the shield gas (G) laminarized by the gas lens (5) around the arc (a). The slip (6) and any one of claims 1 to 3, wherein the gas lens (5) is detachably attached to the center of the tip surface of the gas lens (5) and disposed around the tip of the tungsten electrode rod (2). TIG welding torch characterized by comprising a narrowing nozzle (7).