Double-side-arranged type double-layer inner side bent nozzle device and narrow gap welding method thereof

Abstract

The invention discloses a double-side-arranged type double-layer inner side bent nozzle device and a narrow gap welding method thereof.The nozzle device is composed of an outer-layer front nozzle pipe and an inner-layer front nozzle pipe which are arranged in the vertical direction, and each nozzle pipe is formed by connecting an upper connecting section, a middle vertical section and a lower bent section; wherein the middle vertical section and the lower bent section both extend into the narrow-gap welding groove and can be used in the full groove depth; the lower bent sections of the inner-layer front nozzle pipe and the inner-layer rear nozzle pipe are both bent towards the inner side and are respectively aligned with the lower section of the contact tube of the welding torch from the front side and the rear side, and the lower bent sections of the outer-layer front nozzle pipe and the outer-layer rear nozzle pipe are both bent towards the inner side and are respectively aligned with a welding arc area in the groove obliquely downwards from the front side and the rear side; and the inner / outer layer nozzle air flow is vectorized and adjusted to protect a welding high-temperature area, meanwhile, the contact tube is directly cooled, and the contact tube and the lower end face of the welding torch body are prevented from being impacted by welding high-temperature hot air, so that the narrow-gap welding quality is improved, and the service life of the welding torch contact tube is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of high-efficiency welding and automatic welding, and in particular relates to a nozzle device suitable for narrow-gap gas shielded consumable arc welding and a welding method thereof. Background Art

[0002] Narrow gap gas shielded consumable arc welding, referred to as narrow gap GMAW, is an efficient arc welding method suitable for thick plates, which is generally welded in an automated manner. In narrow gap GMAW, I-shaped or U-shaped narrow gap grooves are often used, and the groove gap is generally 8-16mm. In ultra-narrow gap welding, the groove gap can be reduced to 4-5mm. In order to solve the problem of poor fusion of the side wall of the narrow gap groove, the ultra-narrow gap GMAW process, the shaking / swinging arc GMAW process, the rotating arc narrow gap GMAW process, and the narrow gap GMAW process with double passes per layer have been developed.

[0003] In narrow gap GMAW, the groove gap is narrow, the welding operation space is small, and the problems of welding conductive nozzle cooling and welding gas protection are particularly prominent. In fact, the narrow gap welding conductive nozzle is a consumable part, which needs to be replaced frequently and cannot be directly water-cooled; especially in the case of shaking arc / rotating arc narrow gap welding, because the conductive rod and the conductive nozzle have shaking / rotating motion relative to the welding torch body, the conductive rod and the conductive nozzle cannot be water-cooled. Accordingly, in order to increase the service life of the conductive nozzle, air cooling of the conductive nozzle is the only possible effective cooling method, and this conductive nozzle air cooling needs to be achieved through nozzle structure design. On the other hand, in order to solve the problem of narrow gap welding gas protection, an external nozzle device and an extended nozzle device have been developed. When the groove is shallow, such as the groove depth is 30mm or less, an external sleeve-shaped welding protective gas nozzle can be used; when the groove is deep, such as the groove depth exceeds 30mm, an extended welding protective gas nozzle is required to provide effective gas protection for the arc welding area deep in the narrow gap groove.

[0004] The insertion nozzle includes two forms, one is a sleeve nozzle and the other is a side nozzle. The invention patent with Chinese patent application number 202010914110.4 and the name "Sleeve-shaped flat nozzle device for narrow gap welding and its use method" discloses a sleeve-shaped flat nozzle device that can be inserted into a narrow gap welding groove. The flat nozzle is mounted on the periphery of the conductive rod, and the welding shielding gas flow ejected by it can provide direct gas cooling for the conductive nozzle connected to the lower end of the conductive rod, thereby increasing the service life of the conductive nozzle. The disadvantage is that the sleeve-shaped flat nozzle needs to be mounted on the outside of the conductive rod for use, which increases the thickness of the nozzle, increases the allowable groove gap accordingly, and significantly reduces the efficiency of narrow gap welding.

[0005] The invention patent with Chinese patent application number 200610038184.6 and name "A rotating arc narrow gap welding gas protection device" discloses a side-mounted nozzle device that can be extended into a narrow gap welding groove. A flat nozzle with an inward bend is symmetrically arranged on both sides of the welding torch conductive rod to form a double-sided single-layer nozzle device. The nozzle thickness may not be greater than the diameter of the welding torch conductive rod. It is suitable for narrow grooves of 12mm and below, and has a high welding efficiency. Its disadvantages are: the two welding shielding air flows sprayed from the double-sided inwardly bent flat nozzles will generate an upward high-temperature hot air flow after meeting in the welding high-temperature zone, directly impacting the lower end face of the welding torch body and the conductive nozzle connected to the lower end of the conductive rod of the welding torch, resulting in: ① the conductive nozzle is softened by heat under the impact of continuous high-temperature hot air flow, which will significantly shorten the service life of the conductive nozzle and reduce practicality; ② the lower end face of the welding torch body is severely heated, and strong water cooling is required, which increases the complexity of the welding torch structure and reduces practicality; ③ the welding smoke entrained in the upward high-temperature hot air flow is easy to enter the interior of the welding torch body, which will increase the failure rate of the welding torch.

[0006] Chinese patent application number 202011546613.7, entitled "A Narrow Gap Welding Gun", discloses a narrow gap welding gun comprising a primary air intake mechanism and a secondary air intake mechanism, wherein the secondary air intake mechanism comprises a protective gas hood for protecting several layers of surface welds, and the primary air intake mechanism comprises two sets of inner and outer air blowing pipes located on both sides of the conductive nozzle for protecting welds deep in the narrow gap groove, wherein the end cutout of the inner air blowing pipe faces inward for protecting the intermediate arc and the molten pool, and the end cutout of the outer air blowing pipe faces outward for preventing the outside air from being drawn in and protecting the surface of the welded high-temperature weld. Its disadvantages include: ① The inner air blowing pipe is a straight pipe, and the gas blown out generally flows downward, which cannot directly cool the conductive nozzle. It will also cause the two airflows on both sides of the conductive nozzle to meet in the arc and molten pool area, generating an upward high-temperature hot air flow, which directly impacts the conductive nozzle and the secondary protective gas hood, affecting the service life of the conductive nozzle and the protective gas hood; ② An oblique cut facing inward is provided at the end of the inner air blowing pipe, so that the two inner airflows are easier to flow inward after reaching the bottom of the groove, thereby promoting the formation of an upward high-temperature hot air flow; ③ The inner and outer air blowing pipes share the same air chamber, so that the outlet gas flow rates of the inner and outer air blowing pipes are the same and cannot be adjusted independently ④ An oblique cut is provided at the end of the air blow pipe, which is equivalent to increasing the cross-sectional area of ​​the air blow pipe outlet, thereby reducing the outlet flow velocity and stiffness of the welding shielding air flow and reducing the welding gas protection effect; ⑤ It is necessary to indirectly provide cooling for the conductive nozzle through water cooling of the conductive rod. This indirect cooling not only has poor cooling effect, but also complicates the welding torch mechanism and reduces practicality.

[0007] In short, when the nozzle is inserted into the narrow gap groove for use, the sleeve nozzle is mounted on the outside of the conductive rod, which can provide direct air cooling for the conductive nozzle and extend the service life of the conductive nozzle. However, because the nozzle thickness is significantly greater than the conductive rod diameter, the allowable groove gap becomes larger and the welding efficiency is reduced. The existing single-layer or double-layer side-mounted nozzles may have a nozzle thickness no greater than the conductive rod diameter, which is suitable for narrower grooves and has high welding efficiency. However, the two welding shielding air flows ejected from the nozzles on both sides cannot directly cool the conductive nozzle, and will also generate an upward high-temperature hot air flow after meeting in the high-temperature welding zone, directly impacting the welding torch conductive nozzle, thereby significantly shortening the service life of the conductive nozzle. In other words, the existing technology has failed to effectively solve the problem of the mutual constraints between the efficiency of narrow gap arc welding and the service life of the conductive nozzle. Summary of the invention

[0008] The purpose of the present invention is to address the prominent problems of the low practicality of the prior art and the mutual restriction between the efficiency of narrow gap GMAW welding and the service life of the welding torch conductive nozzle, and to propose a double-side-mounted double-layer inner-bend nozzle device for narrow gap GMAW welding, which is suitable for narrow grooves, has good conductive nozzle cooling effect and is highly practical, and a narrow gap welding method thereof, so as to improve the narrow gap welding efficiency while improving the narrow gap welding quality and the service life of the welding torch conductive nozzle.

[0009] In order to achieve the above-mentioned purpose of the invention, the narrow gap welding method of the present invention is implemented by adopting the following technical scheme:

[0010] A narrow gap welding method, the welding torch used comprises a welding torch body, a welding torch conductive rod mechanism, and a nozzle device, wherein the nozzle device comprises an outer layer rear nozzle tube and an outer layer front nozzle tube, and an inner layer rear nozzle tube and an inner layer front nozzle tube, comprising the following steps:

[0011] ① Setting the nozzle device: the upper ends of the four nozzle tubes, namely the outer layer rear nozzle tube, the outer layer front nozzle tube, the inner layer rear nozzle tube and the inner layer front nozzle tube, are fixed on the welding torch body, wherein each nozzle tube is formed by connecting an upper connecting section, a middle vertical section and a lower curved section; the lower parts of the inner layer front nozzle tube and the inner layer rear nozzle tube are bent inwards and respectively aligned with the lower section of the conductive nozzle at the lower part of the inner part of the welding torch conductive rod mechanism from the front and rear sides, and the lower parts of the outer layer front nozzle tube and the outer layer rear nozzle tube are bent inwards and respectively aligned obliquely downwards from the front and rear sides with the welding arc zone in the narrow gap welding groove;

[0012] ② Setting the welding shielding gas flow rate: connecting each nozzle tube to the gas chamber or directly to the gas source, so that the outlet gas flow rate of the inner layer rear nozzle tube is not less than the outlet gas flow rate of the outer layer rear nozzle tube, and the outlet gas flow rate of the inner layer front nozzle tube is not less than the outlet gas flow rate of the outer layer front nozzle tube; or, further comprising making the outlet gas flow rate of the inner layer rear nozzle tube not less than the outlet gas flow rate of the inner layer front nozzle tube, and / or the outlet gas flow rate of the outer layer rear nozzle tube not less than the outlet gas flow rate of the outer layer front nozzle tube;

[0013] ③ Each layer welding method: the welding wire is sent out obliquely from the welding torch conductive rod mechanism, and the rotating motion mechanism in the welding torch body drives the welding torch conductive rod mechanism, driving the arc at the end of the welding wire to rotate or swing in a circular arc in the narrow gap welding groove, or the welding wire is sent out from the welding torch conductive rod mechanism straight downward along the center line of the welding torch, and the prefabricated welding wire drives the arc at its end to rotate or swing left and right in the narrow gap welding groove, and at the same time, the welding torch and the arc move relative to the workpiece in the welding direction; the middle vertical section and the lower curved section of each nozzle tube are correspondingly extended into the narrow gap welding groove, so that a narrow gap weld is formed under the action of the welding shielding gas sprayed from the four nozzle tubes;

[0014] ④ Multi-layer welding method: As the number of narrow gap weld layers increases, the welding torch moves upward together with the four nozzle tubes to maintain a constant distance from the lower ends of the four nozzle tubes to the bottom of the groove, until the gas outlets on either side of the inner rear nozzle tube and the inner front nozzle tube are exposed to the upper surface of the narrow gap welding groove, or by arranging a gas storage groove above the narrow gap welding groove so that the nozzle device is used until the narrow gap welding groove is fully welded, thereby achieving multi-layer narrow gap welding.

[0015] Preferably, in step ①, when the lower curved sections of the inner layer rear nozzle tube and the inner layer front nozzle tube are aligned with the lower section of the conductive nozzle from the front and rear sides respectively, the center line of the lower curved section of the inner layer rear nozzle tube and the center line of the lower curved section of the inner layer front nozzle tube 302 intersect at a point on the center line of the lower section of the conductive nozzle, and at this time, the center line of the lower curved section of the nozzle tube and the center line of the lower section of the conductive nozzle are in the same plane;

[0016] Alternatively, it also includes making the intersection of the center lines of the lower curved sections of the inner layer rear nozzle tube and the inner layer front nozzle tube coincide with the center point of the end of the conductive nozzle; or, it also includes making the distance from the center of the end of the lower curved section of the inner layer rear nozzle tube to the center point of the end of the conductive nozzle equal to the distance from the center of the end of the lower curved section of the inner layer front nozzle tube to the center point of the end of the conductive nozzle.

[0017] Preferably, in the steps ① and ③, when the lower curved sections of the outer left nozzle tube and the outer right nozzle tube are respectively directed obliquely downward from the front and rear sides to the welding arc area in the narrow gap welding groove, the center line of the lower curved section of the outer rear nozzle tube and the center line of the lower curved section of the outer front nozzle tube intersect at a point on the workpiece surface, and the intersection is located on the center line of the welding torch, or on the center line of the dry extension section of the welding wire when it is obliquely fed in front of or behind the welding direction. At this time, the center line of the lower curved section of the nozzle tube is in the same longitudinal plane as the center line of the welding torch or the center line of the dry extension section of the welding wire; or, it also includes making the distance from the center of the end of the lower curved section of the outer rear nozzle tube to the intersection equal to the distance from the center of the end of the lower curved section of the outer front nozzle tube to the intersection;

[0018] Among them, when the intersection is located on the center line of the welding torch, the welding wire is fed out obliquely and the arc at the end of the welding wire rotates, or the welding wire is fed straight downward along the center line of the welding torch and the prefabricated welding wire drives the arc at its end to rotate or swing left and right; or, when the intersection is located on the center line of the dry extension section of the obliquely fed welding wire, the arc at the end of the welding wire shakes in a circular arc shape.

[0019] Preferably, in step ④, once the gas outlets on either side of the inner layer rear nozzle tube and the inner layer front nozzle tube in the inner layer nozzle are exposed to the upper surface of the narrow gap welding groove, a left process plate and a right process plate are respectively placed on the upper surface of the left wall and the right wall of the narrow gap welding groove before welding, so that the left process plate and the right process plate surround a gas storage groove, and the depth of the gas storage groove is h 3 Not less than (h 1 +(h 2 -h 1 )), where h 1 is the nozzle height, h 2 is the height of the upper end of the inner nozzle, (h 2 -h 1 ) is the height difference between the inner layer nozzle and the outer layer nozzle, so that the nozzle device is used until the narrow gap welding groove 7 is fully welded, thereby realizing the full groove depth use of the nozzle device.

[0020] In order to achieve the above-mentioned purpose of the invention, the double-side-mounted double-layer inner-bend nozzle device of the narrow gap welding method of the present invention adopts the following technical solutions to achieve it:

[0021] The device is composed of four nozzle tubes, namely, an outer layer rear nozzle tube, an outer layer front nozzle tube, an inner layer rear nozzle tube and an inner layer front nozzle tube, which are arranged in the up-down direction. The center plane of each nozzle tube is on the same longitudinal center plane as the center plane of the welding torch conductive rod mechanism; the outer layer rear nozzle tube and the inner layer rear nozzle tube are both located at the rear side of the welding torch conductive rod mechanism, the outer layer front nozzle tube and the inner layer front nozzle tube are both located at the front side of the welding torch conductive rod mechanism, the inner layer rear nozzle tube is on the inner side of the outer layer rear nozzle tube, and the inner layer front nozzle tube is on the inner side of the outer layer front nozzle tube;

[0022] Each nozzle tube is connected by an upper connecting section, a middle vertical section and a lower curved section. The upper ends of the upper connecting sections of the four nozzle tubes are fixedly connected to the welding torch body through nozzle connectors. The middle vertical sections of the outer front nozzle tube and the outer rear nozzle tube are symmetrical with respect to the center line structure of the welding torch. The middle vertical sections of the inner front nozzle tube and the inner rear nozzle tube are symmetrical with respect to the center line structure of the welding torch. The lower curved sections of the inner front nozzle tube and the inner rear nozzle tube are bent inward and are respectively aligned with the lower section of the conductive nozzle at the lower part of the conductive rod mechanism of the welding torch from the front and rear sides. The lower curved sections of the outer front nozzle tube and the outer rear nozzle tube are bent inward and are respectively aligned obliquely downward from the front and rear sides with the welding arc zone in the narrow gap welding groove.

[0023] Preferably, the cross-sections of the inner layer rear nozzle tube and the inner layer front nozzle tube are smaller than the cross-sections of the outer layer rear nozzle tube and the outer layer front nozzle tube.

[0024] Preferably, the upper connecting sections of the outer layer rear nozzle tube and the outer layer front nozzle tube are flat tubular bodies or upper round and lower flat transition bodies, and the middle vertical section and the lower curved section are flat tubular bodies.

[0025] Preferably, the upper connecting sections of the inner layer rear nozzle tube and the inner layer front nozzle tube are circular tubular bodies or flat tubular bodies or upper circular and lower flat transition bodies, and the middle vertical section and the lower curved section are circular tubular bodies or flat tubular bodies.

[0026] Furthermore, the thickness of the flat tubular body or the outer diameter of the circular tubular body is not greater than the outer diameter of the conductive rod at the upper inner portion of the conductive rod mechanism of the welding torch.

[0027] Optionally, the inner side surface of the outer rear nozzle tube is connected to the outer side surface of the inner rear nozzle tube to form an integrated dual-gas path rear nozzle body, and the inner side surface of the outer front nozzle tube is connected to the outer side surface of the inner front nozzle tube to form an integrated dual-gas path front nozzle body.

[0028] Compared with the existing similar technologies, the main advantages and beneficial effects of the present invention are:

[0029] 1) The nozzle device of the present invention is an inner and outer layer of two groups of inner curved nozzles arranged on both sides of the conductive rod of the welding torch, wherein the outer layer nozzle is bent toward the welding arc area and is used to protect the high temperature area of ​​narrow gap welding, and the inner layer nozzle is bent toward the conductive nozzle and is used to directly cool the conductive nozzle and suppress the upward rush of high temperature airflow in the welding area. Through the vector adjustment of the airflow of the inner / outer nozzle, the welding shielding gas flow rate before and after the arc is reasonably distributed, so as to improve the narrow gap welding efficiency while improving the narrow gap welding quality and the service life of the conductive nozzle of the welding torch.

[0030] Therefore, compared with the double-sided single-layer nozzle used in the invention patent with Chinese patent application number 200610038184.6 and name "A rotating arc narrow gap welding gas protection device", the two groups of inner and outer layers of the present invention are not necessarily symmetrically distributed on both sides of the arc, but are arranged for the welding arc and the conductive nozzle respectively, which protects the welding arc and the conductive nozzle at the same time, so that the conductive nozzle and the lower end face of the welding torch body can be avoided from being impacted by continuous high-temperature hot air flow. Therefore, the present invention not only improves the service life of the conductive nozzle, but also avoids the high-temperature heat damage of the welding torch body.

[0031] In addition, in the invention patent of Chinese patent application No. 202011546613.7, entitled "A Narrow Gap Welding Gun", the inner and outer blowing pipes used are both vertical straight pipe structures, and the end of the inner blowing pipe is higher than the end of the outer blowing pipe to avoid welding spatter causing blockage of the outlet of the inner blowing pipe. The end cutout of the inner blowing pipe is facing inward only to widely protect the intermediate arc and the molten pool, and the end cutout of the outer blowing pipe is facing outward only to prevent the outside air from being drawn in and to protect the surface of the welded high-temperature weld. Compared with the nozzle structure of the inner and outer blowing pipes, the inner and outer layers of the two sets of nozzles in the present invention adopt a lower section inner bend structure, and the inner bends are aimed at different objects and have different working principles, so they have different effects.

[0032] 2) The present invention provides direct gas cooling for the welding torch conductive nozzle through the side-mounted inner layer inner curved nozzle airflow, and suppresses the high-temperature airflow that mainly comes from the welding arc and molten pool area by making the inner layer nozzle airflow velocity not less than the outer layer nozzle airflow velocity, which can effectively reduce the working temperature of the conductive nozzle end and the bottom end face of the welding torch body, and significantly improve the service life of the narrow gap welding conductive nozzle and the welding torch; and by making the thickness of the side-mounted inner layer nozzle and the outer layer nozzle not greater than the conductive rod diameter, a narrow welding groove is adopted to obtain high welding efficiency. Therefore, while improving the narrow gap welding efficiency through the side-mounted nozzle, the service life of the narrow gap welding conductive nozzle and the welding torch can be effectively improved through the direct air cooling effect of the inner layer nozzle airflow, creatively solving the problem of the mutual restriction between the narrow gap arc welding efficiency and the conductive nozzle service life, and improving the practicality of the nozzle.

[0033] 3) The present invention makes the inner cavity cross-section of the nozzle tube of the inner nozzle smaller than the inner cavity cross-section of the nozzle tube of the outer nozzle, which is beneficial for the inner nozzle to obtain a faster outlet gas flow rate without increasing the gas flow consumption of the inner nozzle, so as to more effectively suppress the upward rush of high-temperature airflow in the welding area; the nozzle tube of the inner nozzle can also be set as a circular tubular body without increasing the groove gap, so as to facilitate the manufacture and installation of the inner nozzle.

[0034] 4) The present invention increases the gas flow of the inner and / or outer nozzles behind the arc, thereby improving the shielding gas flow rate behind the arc, and can vector-adjust the welding shielding gas flow distribution between the front and rear of the arc, so that more shielding gas flows in the welding direction. While improving the gas protection effect in the welding arc area, more welding smoke is directed to the front of the welding, thereby obtaining a high-quality weld with a bright weld surface and improving the welding quality.

[0035] 5) The present invention arranges an air storage groove on the upper surface of the narrow gap groove, so that the side-mounted nozzle can be used until the bottom end of the nozzle is exposed from the upper surface of the two side walls of the narrow gap groove, thereby realizing the use of the side-mounted nozzle at the full groove depth in the narrow gap welding groove, thereby eliminating the need for an external protective gas hood or an external sleeve-shaped nozzle for protecting several layers of welds near the groove surface, simplifying the nozzle mechanism design and improving the practicality of the side-mounted nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of a double-side mounted double-layer inner curved nozzle device for narrow gap welding according to the present invention. Figure 1 In the figure, 1 is the welding torch body; 201 is the outer layer rear nozzle tube; 202 is the outer layer front nozzle tube; 301 is the inner layer rear nozzle tube; 302 is the inner layer front nozzle tube; 4 is the welding torch conductive rod mechanism; 5 is the welding wire; 6 is the arc; 9 is the welding torch center line; V 2a —Outer layer rear nozzle outlet gas flow velocity; V 2b —Outer layer front nozzle outlet gas flow velocity; V 3a —Air flow velocity at the outlet of the inner rear nozzle; V 3b —Air flow velocity at the outlet of the inner front nozzle tube.

[0037] Figure 2 Schematic diagram of arc shaking / rotation motion. Figure 2 In the figure, 10 is rotational motion; 11 is circular arc shaking; 12 is the center line of the arc motion trajectory; 13 is welding direction; r is the arc shaking / rotation radius; O is the projection point of the welding torch center line 9 on the workpiece surface; M is the midpoint of the arc shaking.

[0038] Figure 3 This is a schematic diagram of the position relationship of the outer nozzle tube of outer nozzle embodiment 1. Figure 3In the figure, 201a is the center line of the lower curved section of the outer layer rear nozzle tube; 202a is the center line of the lower curved section of the outer layer front nozzle tube; 704 is the workpiece surface; 4 —The center of the end of the lower curved section of the outer rear nozzle tube; O 5 —The center of the end of the lower curved section of the outer front nozzle tube.

[0039] Figure 4 This is a schematic diagram of the position relationship of the outer nozzle tube of outer nozzle embodiment 2. Figure 4 In, O 1 —The intersection of the center line of the welding wire extending obliquely in front or behind the welding direction and the workpiece surface.

[0040] Figure 5 This is a schematic diagram of the position relationship of the inner layer nozzle tube of inner layer nozzle embodiment 1. Figure 5 In the figure, 401 is the first conductive rod; 402 is the first conductive nozzle; d 1 —Outer diameter of the conductive rod; d 2 —Outer diameter of the circular nozzle tube; O 2 —The center point of the first conductive tip end; O 6 —The center of the end of the lower curved section of the inner rear nozzle tube; O 7 —The center of the end of the lower curved section of the inner front nozzle tube.

[0041] Figure 6 This is a schematic diagram of the position relationship of the inner layer nozzle tube of inner layer nozzle embodiment 2. Figure 6 In the figure, 403 is the second conductive rod; 404 is the second conductive nozzle; 3 —Centre point of the end of the second conductive nozzle.

[0042] Figure 7 This is a photo of the nozzle device of the present invention in a working state. Figure 7 In the figure, 403a is a bent conductive rod; 404a is a center hole conductive nozzle.

[0043] Figure 8 It is a schematic diagram of the cross section when the outer nozzle and the inner nozzle extend into the narrow gap welding groove. Figure 8 In the figure, 7 is the narrow gap welding groove; 701 is the left wall; 702 is the right wall; 703 is the weld; 8 is the gas storage groove; 801 is the left process plate; 802 is the right process plate; d is the thickness of the flat tubular nozzle tube.

[0044] Fig. 9 for Figure 8 A schematic diagram of a right-side longitudinal section when the outer layer nozzle and the inner layer nozzle extend into a narrow gap welding groove. Fig. 9 In, h 1 —Nozzle height; h 2 —Height of the upper end of the inner nozzle; h 3 —Deepness of gas storage groove. DETAILED DESCRIPTION

[0045] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0046] The orientation of the nozzle device of the present invention is as follows: Figure 8 and Fig. 9 As shown, the position of the left wall 701 on the cross section of the narrow gap welding groove 7 is “left”, and the position of the opposite right wall 702 is “right”; the position of the arc 6 is “bottom”, and the position of the welding torch conductive rod mechanism 4 is “top”; the position of the outer layer rear nozzle tube 201 on the longitudinal section of the narrow gap welding groove 7 is “rear”, and the position of the outer layer front nozzle tube 202 forward along the welding direction 13 is “front”; the welding torch center line 9 is the middle, the direction close to the welding torch center line 9 is “inside”, and the direction away from the welding torch center line 9 is “outside”.

[0047] like Figure 1 As shown, the double-sided double-layer inner-bend nozzle device for narrow gap welding of the present invention is composed of four nozzle tubes, and the four nozzle tubes are arranged in the up and down direction. The upper ends of the four nozzle tubes are fixedly connected to the welding torch body 1 for narrow gap welding, and the lower sections of the four nozzle tubes are bent inwards. The four nozzle tubes are respectively an outer layer rear nozzle tube 201, an outer layer front nozzle tube 202, an inner layer rear nozzle tube 301 and an inner layer front nozzle tube 302, wherein the outer layer rear nozzle tube 201 and the inner layer rear nozzle tube 301 are both located at the rear side of the welding torch conductive rod mechanism 4, the outer layer front nozzle tube 202 and the inner layer front nozzle tube 302 are both located at the front side of the welding torch conductive rod mechanism 4, the inner layer rear nozzle tube 301 is on the inner side of the outer layer rear nozzle tube 201, and the inner layer front nozzle tube 302 is on the inner side of the outer layer front nozzle tube 202; the inner layer nozzle is composed of the inner layer front nozzle tube 302 and the inner layer rear nozzle tube 301, and the outer layer nozzle is composed of the outer layer front nozzle tube 202 and the outer layer rear nozzle tube 201. The center planes of the four nozzles and the center plane of the welding torch conductive rod mechanism 4 are on the same longitudinal center plane.

[0048] The four nozzle tubes are all hollow tubular bodies. Each nozzle tube is formed by the upper connecting section, the middle vertical section and the lower curved section being continuously connected. They can be made as a whole or connected in sections. The upper ends of the upper connecting sections of the four nozzle tubes are connected by nozzle connectors ( Figure 1 The middle vertical section and the lower curved section of each nozzle tube can be extended into the narrow gap welding groove 7 (see Figure 8 and Fig. 9 ).

[0049] The four nozzle tubes are used in conjunction with the welding torch body 1 and the welding torch conductive rod mechanism 4 to form a narrow gap welding torch. The welding torch conductive rod mechanism 4 includes a conductive rod and a conductive nozzle. The upper end of the conductive rod is connected to the welding torch body 1 along the welding torch center line 9, and the lower end is connected to the conductive nozzle. The conductive rod can be a straight conductive rod or a curved conductive rod, and the conductive nozzle can be a center hole conductive nozzle, an eccentric conductive nozzle, or a bent conductive nozzle. When the straight conductive rod is equipped with an eccentric conductive nozzle or a bent conductive nozzle, or when the curved conductive rod is equipped with a center hole conductive nozzle, the welding wire 5 extends obliquely downward from the welding torch conductive rod mechanism 4, as shown in FIG. Figure 1 When the straight conductive rod is equipped with a center hole conductive nozzle, the welding wire 5 is sent straight down along the center line 9 of the welding torch ( Figure 1 (omitted and not drawn).

[0050] The upper connecting sections of the outer layer rear nozzle tube 201 and the outer layer front nozzle tube 202 are flat tubular bodies or upper round and lower flat transition bodies, and the middle vertical section and the lower curved section are flat tubular bodies; the upper connecting sections of the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 are round tubular bodies or flat tubular bodies or upper round and lower flat transition bodies, and the middle vertical section and the lower curved section are round tubular bodies or flat tubular bodies. The lower curved section of the inner layer rear nozzle tube 301 and the lower curved section of the inner layer front nozzle tube 302 are both bent inward, and are respectively aligned with the lower section of the conductive nozzle at the lower part of the inner part of the welding torch conductive rod mechanism 4 from the front and rear sides, so as to directly cool the conductive nozzle and suppress the high-temperature airflow from the welding center area (including the arc area and the molten pool area) to rush upward. The lower bending section of the outer rear nozzle tube 201 and the lower bending section of the outer front nozzle tube 202 are both bent inward, and are respectively aimed obliquely downward from the front and rear sides at the welding arc zone in the narrow gap welding groove 7, so as to protect the narrow gap welding high temperature area including the arc, molten pool and solidified high temperature weld, forming a double-sided double-layer inner side bent nozzle device.

[0051] Preferably, the middle vertical sections of the outer nozzle and the inner nozzle are symmetrically arranged on both sides of the welding torch center line 9, that is, the middle vertical sections of the outer front nozzle tube 202 and the outer rear nozzle tube 201 are structurally symmetrical relative to the welding torch center line 9, and the middle vertical sections of the inner front nozzle tube 302 and the inner rear nozzle tube 301 are structurally symmetrical relative to the welding torch center line 9.

[0052] Optionally, the inner side surface of the outer layer rear nozzle tube 201 is connected to the outer side surface of the inner layer rear nozzle tube 301 to form an integrated dual-path rear nozzle body; similarly, the inner side surface of the outer layer front nozzle tube 202 is connected to the outer side surface of the inner layer front nozzle tube 302 to form an integrated dual-path front nozzle body; the dual-path front nozzle body and the dual-path rear nozzle body can each be formed by bending a dual-channel hollow tubular body.

[0053] Preferably, the inner layer nozzle has a smaller inner cavity cross section than the outer layer nozzle. Thus, the inner layer nozzle can obtain a faster outlet gas flow rate V without increasing the gas flow consumption of the inner layer nozzle. 3a and V 3b , in order to suppress the upward rush of high-temperature airflow mainly coming from the welding arc and the molten pool area. The nozzle tube of the inner nozzle can also be set to a circular tubular body without increasing the groove gap, so as to facilitate the production and installation of the inner nozzle.

[0054] Preferably, the thickness of the flat tubular body of each nozzle tube is not greater than the outer diameter of the conductive rod in the upper part of the welding torch conductive rod mechanism 4; when the inner layer nozzle tube is a round tubular body, the outer diameter of the round tubular body is not greater than the outer diameter of the conductive rod. For example, when the diameter of the conductive rod is 8 mm, the thickness of the flat tubular body and the outer diameter of the round tubular body of each nozzle tube can be no greater than 8 mm. Thus, a narrow groove gap is used as much as possible, for example, the groove gap of the narrow gap welding can be narrowed to 10-13 mm to improve the welding efficiency.

[0055] Optionally, the nozzle device of the present invention also includes an air chamber, an air screen may be provided in the air chamber, an air chamber is provided between the nozzle connector and the welding torch body 1, the air chamber is fixedly connected to the welding torch body 1 through the nozzle connector, and is connected and communicated with each nozzle tube; the air chamber includes a rear air chamber connected to the upper connecting sections of the outer rear nozzle tube 201 and the inner rear nozzle tube 301 at the same time, and a front air chamber connected to the upper connecting sections of the outer front nozzle tube 202 and the inner front nozzle tube 302 at the same time; or, the air chamber includes a rear outer air chamber connected to the upper connecting section of the outer rear nozzle tube 201, a rear inner air chamber connected to the upper connecting section of the inner rear nozzle tube 301, and a front outer air chamber connected to the upper connecting section of the outer front nozzle tube 202, and a front inner air chamber connected to the upper connecting section of the inner front nozzle tube 302. By setting up the air chamber, the welding shielding gas connected from the external gas source (gas pipe) can be calmed and rectified, so that the airflow ejected from each nozzle tube is more stable and orderly, so as to improve the welding protection effect.

[0056] The nozzle device of the present invention is suitable for shaking arc or rotating arc narrow gap welding in which the welding wire 5 is sent obliquely downward from the conductive rod mechanism 4 of the welding torch, or for rotating arc or left-right swinging arc narrow gap welding of prefabricated shaped welding wire in which the welding wire 5 is sent straight downward along the center line 9 of the welding torch, or for narrow gap welding in which the welding wire 5 is sent straight downward along the center line 9 of the welding torch or sent obliquely downward from the conductive rod mechanism 4 of the welding torch without shaking, swinging or rotating arc, and the prefabricated shaped welding wire includes cable welding wire, twisted welding wire, bent welding wire or wavy welding wire.

[0057] When in use, the welding wire 5 extends obliquely downward from the welding torch conductive rod mechanism 4 (see Figure 1), or extends straight down along the center line 9 of the welding torch (not shown). When the welding wire 5 extends straight down along the center line 9 of the welding torch from the welding torch conductive rod mechanism 4, the welding wire 5 is a straight welding wire or a prefabricated formed welding wire, and the prefabricated formed welding wire can drive the arc at the end of the welding wire to rotate unidirectionally or swing back and forth between the two side walls of the narrow gap welding groove to increase the penetration depth of the groove side wall, thereby realizing the prefabricated formed welding wire rotating arc or swinging arc narrow gap welding of each single weld layer under the protection of the welding gas provided by the nozzle device. When the welding wire 5 extends obliquely downward from the welding torch conductive rod mechanism 4, as shown in FIG. Figure 1 and Figure 2 As shown, the rotary motion mechanism in the welding torch body 1 can drive the welding torch conductive rod mechanism 4, driving the arc 6 at the end of the welding wire 5 to perform a unidirectional rotational motion 10 around the welding torch center line 9, or to perform a reciprocating circular arc swing 11 around the swing midpoint M relative to the welding torch center line 9. At this time, the arc swing or rotation radius is r, and the projection point O of the welding torch center line 9 on the arc motion trajectory plane and the swing midpoint M are located on the arc motion trajectory center line 12. When the welding torch and the arc 6 move relative to the workpiece along the welding direction 13, the swing arc or rotating arc narrow gap welding of each single weld layer can be achieved in the narrow gap welding groove 7 under the protection of the welding gas provided by the nozzle tube, wherein the arc rotation direction can be clockwise or counterclockwise. When the welding wire 5 extends obliquely from the welding torch conductive rod mechanism 4, the welding wire 5 can also be biased toward one side of the narrow gap welding groove, so that under the protection of the welding gas provided by the nozzle pipe, a narrow gap welding without shaking, swinging or rotating arc is achieved for each layer of double-pass weld. The welding shielding gas can be CO 2 gas or argon or argon-rich mixed gas.

[0058] In the nozzle device of the present invention, the inner layer nozzle provides direct gas cooling for the conductive nozzle in the lower part of the conductive rod mechanism 4 of the welding torch, and suppresses the upward rush of high-temperature airflow mainly from the welding arc and the molten pool area, which can effectively reduce the working temperature of the end of the welding conductive nozzle and the bottom end face of the welding torch body 1, and improve the service life of the conductive nozzle and the working reliability of the welding torch; by making the thickness of the side-mounted inner layer nozzle and the outer layer nozzle not greater than the diameter of the conductive rod, a narrow groove gap can be used to obtain high welding efficiency. Therefore, while improving the narrow gap welding efficiency, the service life of the conductive nozzle and the working reliability of the narrow gap welding torch can be effectively improved, solving the problem of the mutual restriction between the narrow gap arc welding efficiency and the conductive nozzle life, and improving practicality.

[0059] See also Figure 3In the structure of the embodiment 1 of the outer layer nozzle shown, the center line 201a of the lower curved section of the outer layer rear nozzle tube 201 and the center line 202a of the lower curved section of the outer layer front nozzle tube 202 intersect at the same point, namely, point O, on the workpiece surface 704 in the narrow gap welding groove 7. Point O is also the projection point of the welding torch center line 9 on the workpiece surface 704. At this time, the center lines 201a and 202a of the lower curved section of the outer layer nozzle tube and the welding torch center line 9 are in the same longitudinal plane. Preferably, the center line O of the lower curved section end of the outer layer rear nozzle tube 201 is 4 The distance from the intersection point O to the center O of the lower curved section end of the outer front nozzle tube 202 5 The distances to the intersection O are equal, so that two welding shielding gas flows symmetrically about the center line 9 of the welding torch can be obtained to improve the arc stability. Embodiment 1 of the outer layer nozzle is suitable for rotating arc narrow gap welding when the welding wire 5 extends obliquely downward (see Figure 3 ), or is suitable for straight welding wire or prefabricated forming welding wire narrow gap welding (omitted and not drawn) when the welding wire 5 is fed straight downward along the center line 9 of the welding torch; wherein, when the prefabricated forming welding wire is used, rotating arc narrow gap welding through cable welding wire or twisted welding wire, or left and right swinging arc narrow gap welding through bent welding wire or wavy welding wire can be achieved.

[0060] See also Figure 4 In the structure of the embodiment 2 of the outer layer nozzle shown in FIG. 1 , the center line 201a of the lower curved section of the outer layer rear nozzle tube 201 and the center line 202a of the lower curved section of the outer layer front nozzle tube 202 intersect at O ​​on the workpiece surface 704 in the narrow gap welding groove. 1 point, while its O 1 The point is located in front of the welding direction 13 (see Figure 4 ) or directly behind (not shown), the center line of the extended section of the welding wire 5 when it is extended obliquely. At this time, the center lines 201a and 202a of the lower curved section of the nozzle tube are in the same longitudinal plane as the center line 9 of the welding torch and the center line of the extended section of the welding wire 5 extended obliquely. Preferably, the center line O of the lower curved section end of the outer layer rear nozzle tube 201 is 4 To the intersection O 1 The distance between the center O of the lower curved section end of the outer front nozzle tube 202 is 5 To the intersection O 1 The distance between the two ends of the welding arc is equal, so that the narrow gap welding arc can obtain two welding shielding gas flows that are basically symmetrical on both sides, so as to improve the arc stability. The embodiment 2 of the outer layer nozzle is suitable for shaking arc narrow gap welding when the welding wire 5 extends obliquely downward. At this time, the welding wire 5 drives the welding arc to shake symmetrically on both sides about the welding direction 13 (see Figure 2); or, for narrow gap welding in which the arc does not shake, swing or rotate when the welding wire 5 extends obliquely downward, the welding wire 5 does not shake, swing or rotate, and the welding wire 5 is preferably biased toward one side of the narrow gap welding groove.

[0061] See also Figure 5 The structure of the embodiment 1 of the inner layer nozzle shown in the figure, the welding torch conductive rod mechanism 4 includes a first conductive rod 401 at the top and a first conductive nozzle 402 at the bottom, the first conductive rod 401 is a straight conductive rod, the first conductive nozzle 402 is an eccentric conductive nozzle or a center hole conductive nozzle, and the center lines of the first conductive rod 401 and the first conductive nozzle 402 are both on the welding torch center line 9. Among them, the upper end of the first conductive rod 401 is connected to the welding torch body 1, and the lower end is connected to the first conductive nozzle 402. After the welding wire 5 passes through the center hole of the first conductive rod 401, it is sent out obliquely downward from the eccentric hole of the eccentric conductive nozzle (see Figure 5 ), or send it straight down from the center hole of the conductive nozzle ( Figure 5 The center line 301a of the lower curved section of the inner layer rear nozzle tube 301 intersects with the center line 302a of the lower curved section of the inner layer front nozzle tube 302 at a point, and this point of intersection is located on the center line of the lower section of the first conductive nozzle 402. At this time, the center lines 301a and 302a of the lower curved sections of the two nozzle tubes of the inner layer nozzle are in the same longitudinal plane as the center line 9 of the welding torch.

[0062] Preferably, the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 are both circular nozzle tubes, and the outer diameter d of the circular nozzle tubes is 2 Not larger than the outer diameter d of the conductive rod 1 In addition, the intersection of the center lines 301a and 302a of the lower curved section and the center point O of the end of the first conductive nozzle 402 can be made to be equal to each other. 2 or the center O of the lower curved section end of the inner rear nozzle tube 301 is also overlapped. 6 To the center point O of the end of the first conductive tip 402 2 The distance between the inner front nozzle tube 302 and the lower curved section end center O 7 To the center point O of the end of the first conductive tip 402 2 The inner layer nozzle embodiment 1 is suitable for swing arc or rotating arc narrow gap welding when the welding wire 5 extends obliquely downward, or when the welding wire 5 is fed straight downward along the center line 9 of the welding torch ( Figure 5 Narrow gap welding with straight welding wire or preformed welding wire (omitted and not shown).

[0063] See also Figure 6The structure of the embodiment 2 of the inner layer nozzle shown in the figure, the welding torch conductive rod mechanism 4 includes a second conductive rod 403 and a second conductive tip 404, the second conductive rod 403 is a curved conductive rod or a straight conductive rod, and the second conductive tip 404 is a center hole conductive tip or a curved conductive tip. The upper end of the second conductive rod 403 is connected to the welding torch body 1, and the lower end is connected to the second conductive tip 404. After the welding wire 5 passes through the center hole of the second conductive rod 403, it is sent out obliquely downward from the center hole of the second conductive tip 404; the center line 301a of the lower curved section of the inner layer rear nozzle tube 301 and the center line 302a of the lower curved section of the inner layer front nozzle tube 302 intersect at one point, and when the center lines 301a and 302a of the lower curved sections of the two nozzle tubes of the inner layer nozzle and the center line of the second conductive tip 404 are in the same longitudinal plane, the intersection point is just located on the center line of the lower section of the second conductive tip 404.

[0064] Preferably, the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 are both circular nozzle tubes, and the outer diameter d of the circular nozzle tubes is 2 Not larger than the outer diameter d of the conductive rod 1 In addition, when the center lines 301a and 302a of the lower curved sections of the two inner nozzle tubes and the center line of the second conductive nozzle 404 are in the same plane, the intersection of the center lines 301a and 302a of the lower curved sections and the center point O of the end of the second conductive nozzle 404 can be made to be equal to each other. 3 Alternatively, the inner layer of the nozzle tube 301 after the lower bending section of the end center O 6 To the center point O of the end of the second conductive tip 404 3 The distance between the inner front nozzle tube 302 and the lower curved section end center O 7 To the center point O of the end of the second conductive tip 404 3 The inner layer nozzle embodiment 2 is suitable for oscillating arc narrow gap welding when the welding wire 5 extends obliquely downward, or for narrow gap welding without oscillating, swinging or rotating arc when the welding wire 5 extends obliquely downward.

[0065] like Figure 7As shown, in the nozzle device of the present invention, the welding torch conductive rod mechanism 4 is composed of a bent conductive rod 403a and a center hole conductive nozzle 404a, the outer layer rear nozzle tube 201 and the outer layer front nozzle tube 202 are both formed by bending and pressing a round tube, and the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 are both formed by bending a round tube; during welding, the front and rear nozzle tubes of the inner layer are obliquely downwardly aligned with the lower section of the center hole conductive nozzle 404a from the front and rear sides of the bent conductive rod 403a, and the front and rear nozzle tubes of the outer layer 202 and 201 are obliquely downwardly aligned with the arc at the end of the welding wire 5 from the two sides of the bent conductive rod 403a. Among them, the cross-section of the two inner nozzle tubes 301 and 302 is smaller than the cross-section of the two outer nozzle tubes 201 and 202. The middle vertical sections of the inner and outer front and rear nozzle tubes are symmetrically arranged on both sides of the welding torch center line 9, while the bent section of the lower nozzle tube is asymmetrical front and back, and the bent section of the inner nozzle tube is not parallel to the bent section of the outer nozzle tube on the same side. It is suitable for shaking arc or non-shaking arc narrow gap welding when the welding wire 5 is fed obliquely downward.

[0066] like Figure 8 , Fig. 9 and Figure 1 As shown, taking the application of shaking arc / rotating arc narrow gap welding as an example, when the nozzle device of the present invention is used, Figure 8 It is a schematic cross-sectional view of the outer layer nozzle and the inner layer nozzle extending into the narrow gap welding groove 7, Fig. 9 It is a right longitudinal section schematic diagram of the outer layer nozzle and the inner layer nozzle extending into the narrow gap welding groove 7. Preferably, the welding torch centerline 9 is perpendicular to the workpiece surface 704, and the thickness d of the flat tubular nozzle of the outer layer nozzle is the same as the outer diameter of the conductive rod in the welding torch conductive rod mechanism 4.

[0067] Before welding, the welding shielding gas flow rate of the four nozzle tubes of the outer layer nozzle and the inner layer nozzle of the nozzle device is set. When the four nozzle tubes of the outer layer nozzle and the inner layer nozzle are extended into the narrow gap welding groove 7 for use, such as Figure 8 and Fig. 9 As shown, the welding wire 5 is sent out obliquely downward from the welding torch conductive rod mechanism 4, and the rotary motion mechanism in the welding torch body 1 drives the welding torch conductive rod mechanism 4, driving the arc 6 at the end of the welding wire 5 to perform a unidirectional rotational motion 10 or a reciprocating circular arc shaking 11 in the narrow gap welding groove 7. At the same time, the welding torch together with the arc 6 moves relative to the workpiece along the welding direction 13, thereby forming a narrow gap weld 703 under the protection of the welding gas sprayed from the four nozzle tubes of the outer nozzle and the inner nozzle.

[0068] As the number of layers of the narrow gap weld 703 increases, the welding torch moves upward together with the nozzle assembly to maintain a constant distance from the lower end of the nozzle assembly to the bottom of the groove 7 (also the workpiece surface 704), that is, the nozzle height h 1 Keep constant, such as Fig. 9During the welding process, the nozzle device can be used until the gas outlets on either side of the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 in the inner layer nozzle are exposed to the upper surface of the narrow gap welding groove 7, and then the external sleeve nozzle can be used until the narrow gap welding groove 7 is fully welded.

[0069] Alternatively, once the gas outlets on either side of the inner layer rear nozzle tube 301 and the inner layer front nozzle tube 302 in the inner layer nozzle are exposed to the upper surface of the narrow gap welding groove 7, before welding, a process plate is placed on the upper surface of the left wall 701 and the right wall 702 of the narrow gap welding groove 7, that is, the left process plate 801 and the right process plate 802 are placed correspondingly, so that the left process plate 801 and the right process plate 802 surround a gas storage groove 8 (see Figure 8 ), the depth h of the gas storage groove 8 3 (See Fig. 9 ) is not less than (h 1 +(h 2 -h 1 )), where h 1 is the nozzle height, h 2 is the height of the upper end of the inner nozzle, (h 2 -h 1 ) is the height difference between the inner layer nozzle and the outer layer nozzle. At this time, due to the depth h of the gas storage groove 8 3 Not less than nozzle height h 1 and the height difference between the inner nozzle and the outer nozzle (h 2 -h 1 ), so that the nozzle device is used until the narrow gap welding groove 7 is fully welded, thereby realizing the full groove depth use of the nozzle device.

[0070] Optionally, before welding, the welding shielding gas flow rate is set so that the outlet gas flow rate V 3a Not less than the outlet gas flow velocity V of the outer rear nozzle tube 201 2a , so that the outlet gas flow velocity V of the inner front nozzle tube 302 3b Not less than the outlet gas flow velocity V of the outer front nozzle tube 202 2b ,like Figure 1 As shown. Thus, the inner nozzle airflow can provide direct gas cooling for the welding torch contact tip while more effectively suppressing the high-temperature airflow that mainly comes from the welding arc and molten pool area, so as to reduce the operating temperature of the welding contact tip end and the bottom end face of the welding torch body, thereby increasing the service life of the contact tip and the reliability of the welding torch.

[0071] Optionally, before welding, the welding shielding gas flow rate is set so that the outlet gas flow rate V 3a Not less than the outlet gas flow velocity V of the inner front nozzle tube 3023b , and / or make the outlet gas flow velocity V of the outer rear nozzle tube 201 2a Not less than the outlet gas velocity V of the outer front nozzle tube 202 2b , see Figure 1 Thus, the shielding gas flow rate behind the arc can be increased by increasing the gas flow rate of the inner and / or outer nozzles behind the arc, and the shielding gas flow rate behind the arc can be vector-adjusted between the front and rear of the arc to make more shielding gas flow in the welding direction 13 (see Fig. 9 ), while improving the welding gas protection effect, it directs more welding smoke to the front of welding, so as to obtain high-quality welding joints with bright weld surface, so as to improve welding quality.

[0072] In addition, there are many specific implementation methods and approaches of the present invention, and the above is only a preferred implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several equivalents, improvements and modifications can be made, and these equivalents, improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in the embodiments of the present invention can be implemented by existing technologies.

Claims

1. A narrow gap welding method, characterized in that The following steps are involved: ① The upper ends of the outer front and rear nozzle tubes (202, 201) and the outer front nozzle tube (202) and the inner front and rear nozzle tubes (302, 301) are all fixed on the welding torch body, and each nozzle tube is formed by connecting an upper connecting section, a middle vertical section and a lower curved section; the lower parts of the inner front and rear nozzle tubes (302, 301) are bent inward and respectively aligned with the lower section of the conductive nozzle at the lower part of the welding torch conductive rod mechanism from the front and rear sides, and the lower parts of the outer front and rear nozzle tubes (202, 201) are bent inward and respectively aligned obliquely downward from the front and rear sides with the welding arc zone in the narrow gap welding groove; ② Each nozzle tube is connected to an air chamber or an air source, the outlet air velocity of the inner layer rear nozzle tube (301) is not less than the outlet air velocity of the outer layer rear nozzle tube (201), and the outlet air velocity of the inner layer front nozzle tube (302) is not less than the outlet air velocity of the outer layer front nozzle tube (202); or, the outlet air velocity of the inner layer rear nozzle tube (301) is not less than the outlet air velocity of the inner layer front nozzle tube (302), and / or the outlet air velocity of the outer layer rear nozzle tube (201) is not less than the outlet air velocity of the outer layer front nozzle tube (202); ③ The welding wire is fed obliquely, and the arc at the end of the welding wire rotates or shakes in a circular arc in the narrow gap welding groove, or the welding wire is fed straight downward along the center line of the welding torch, and the prefabricated welding wire drives the arc at its end to rotate or swing left and right in the narrow gap welding groove, and at the same time, the welding torch and the arc move relative to the workpiece in the welding direction; the middle vertical section and the lower curved section of each nozzle tube are extended into the narrow gap welding groove, and a narrow gap weld is formed under the action of the welding shielding gas; ④ As the number of narrow gap weld layers increases, the welding torch and the four nozzle tubes move upward together, maintaining a constant distance from the lower end of each nozzle tube to the bottom of the groove, until the gas outlets on either side of the front and rear nozzle tubes (302, 301) of the inner layer are exposed before the upper surface of the narrow gap welding groove, thereby achieving multi-layer narrow gap welding.

2. The narrow gap welding method according to claim 1, characterized in that: In the step ①, when the lower curved sections of the inner layer rear nozzle tube (301) and the inner layer front nozzle tube (302) are aligned with the lower section of the conductive nozzle from the front and rear sides respectively, the center line (301a) of the lower curved section of the inner layer rear nozzle tube (301) and the center line (302a) of the lower curved section of the inner layer front nozzle tube (302) intersect at a point on the center line of the lower section of the conductive nozzle, and at this time, the center line (301a, 302a) of the lower curved section of the nozzle tube and the center line of the lower section of the conductive nozzle are in the same plane; Alternatively, it also includes making the intersection of the center lines (301a, 302a) of the lower curved sections of the inner layer rear nozzle tube (301) and the inner layer front nozzle tube (302) coincide with the center point of the end of the conductive nozzle; or, it also includes making the distance from the center of the end of the lower curved section of the inner layer rear nozzle tube (301) to the center point of the end of the conductive nozzle equal to the distance from the center of the end of the lower curved section of the inner layer front nozzle tube (302) to the center point of the end of the conductive nozzle.

3. The narrow gap welding method according to claim 1, characterized in that: In the steps ① and ③, when the lower curved sections of the outer left nozzle tube (201) and the outer right nozzle tube (202) are respectively directed obliquely downward from the front and rear sides to the welding arc area in the narrow gap welding groove, the center line (201a) of the lower curved section of the outer rear nozzle tube (201) and the center line (202a) of the lower curved section of the outer front nozzle tube (202) intersect at a point on the surface of the workpiece, and the intersection point is located on the center line (9) of the welding torch or at a point along the welding direction. On the center line of the dry extension section of the welding wire (5) when it is sent out obliquely from the front or rear, at this time, the center line (201a, 202a) of the lower curved section of the nozzle tube and the center line (9) of the welding torch or the center line of the dry extension section of the welding wire (5) are in the same longitudinal plane; or, it also includes making the distance from the center of the lower curved section end of the outer layer rear nozzle tube (201) to the intersection equal to the distance from the center of the lower curved section end of the outer layer front nozzle tube (202) to the intersection; When the intersection is located on the center line (9) of the welding torch, the welding wire (5) is fed out obliquely and the arc at the end of the welding wire (5) rotates, or the welding wire (5) is fed straight downward along the center line (9) of the welding torch and the prefabricated welding wire (5) drives the arc at its end to rotate or swing left and right; or, when the intersection is located on the center line of the dry extension section of the obliquely fed welding wire (5), the arc at the end of the welding wire (5) swings in a circular arc shape.

4. The narrow gap welding method according to claim 1, characterized in that: In step ④, once the gas outlets on either side of the inner layer rear nozzle tube (301) and the inner layer front nozzle tube (302) in the inner layer nozzle are exposed to the upper surface of the narrow gap welding groove (7), before welding, a left process plate (801) and a right process plate (802) are respectively placed on the upper surface of the left wall (701) and the right wall (702) of the narrow gap welding groove (7), so that the left process plate (801) and the right process plate (802) form a gas storage groove (8), and the depth h3 of the gas storage groove is not less than (h1+(h2-h1)), wherein h1 is the nozzle height, h2 is the height of the upper end of the inner layer nozzle, and (h2-h1) is the height difference between the inner layer nozzle and the outer layer nozzle, so that the nozzle device is used until the narrow gap welding groove (7) is fully welded, thereby realizing the full groove depth use of the nozzle device.

5. A double-side mounted double-layer inner curved nozzle device for implementing the narrow gap welding method according to any one of claims 1 to 4, characterized in that: The device is composed of four nozzle tubes, namely an outer layer rear nozzle tube (201), an outer layer front nozzle tube (202), an inner layer rear nozzle tube (301) and an inner layer front nozzle tube (302), which are arranged in the up-down direction. The center plane of each nozzle tube is on the same longitudinal center plane as the center plane of the welding torch conductive rod mechanism (4); the outer layer rear nozzle tube (201) and the inner layer rear nozzle tube (301) are both located at the rear side of the welding torch conductive rod mechanism (4), the outer layer front nozzle tube (202) and the inner layer front nozzle tube (302) are both located at the front side of the welding torch conductive rod mechanism (4), the inner layer rear nozzle tube (301) is on the inner side of the outer layer rear nozzle tube (201), and the inner layer front nozzle tube (302) is on the inner side of the outer layer front nozzle tube (202); Each nozzle tube is formed by connecting an upper connecting section, a middle vertical section and a lower curved section. The upper ends of the upper connecting sections of the four nozzle tubes are fixedly connected to the welding torch body (1) through nozzle connectors. The middle vertical sections of the outer front nozzle tube (202) and the outer rear nozzle tube (201) are symmetrical in structure relative to the welding torch centerline (9). The middle vertical sections of the inner front nozzle tube (302) and the inner rear nozzle tube (301) are symmetrical in structure relative to the welding torch centerline (9). The lower curved sections of the inner front nozzle tube (302) and the inner rear nozzle tube (301) are bent inward and are respectively aligned with the lower section of the conductive nozzle at the inner lower part of the welding torch conductive rod mechanism (4) from the front and rear sides. The lower curved sections of the outer front nozzle tube (202) and the outer rear nozzle tube (201) are bent inward and are respectively aligned obliquely downward from the front and rear sides to the welding arc zone in the narrow gap welding groove.

6. The double-side-mounted double-layer inner curved nozzle device according to claim 5, characterized in that: The cross-sections of the inner layer rear nozzle tube (301) and the inner layer front nozzle tube (302) are smaller than the cross-sections of the outer layer rear nozzle tube (201) and the outer layer front nozzle tube (202).

7. The double-side-mounted double-layer inner curved nozzle device according to claim 5, characterized in that: The upper connecting sections of the outer layer rear nozzle tube (201) and the outer layer front nozzle tube (202) are flat tubular bodies or upper round and lower flat transition bodies, and the middle vertical section and the lower curved section are flat tubular bodies.

8. The double-side-mounted double-layer inner curved nozzle device according to claim 5, characterized in that: The upper connecting sections of the inner layer rear nozzle tube (301) and the inner layer front nozzle tube (302) are circular tubular bodies or flat tubular bodies or upper circular and lower flat transition bodies, and the middle vertical section and the lower curved section are circular tubular bodies or flat tubular bodies.

9. The double-side mounted double-layer inner curved nozzle device according to claim 7 or 8, characterized in that: The thickness of the flat tubular body or the outer diameter of the circular tubular body is not greater than the outer diameter of the conductive rod at the inner upper part of the welding torch conductive rod mechanism (4).

10. The double-side-mounted double-layer inner curved nozzle device according to claim 5, characterized in that: The inner side surface of the outer layer rear nozzle tube (201) is connected to the outer side surface of the inner layer rear nozzle tube (301) to form an integrated dual-gas path rear nozzle body, and the inner side surface of the outer layer front nozzle tube (202) is connected to the outer side surface of the inner layer front nozzle tube (302) to form an integrated dual-gas path front nozzle body.

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