Welding device and process for local repair of dummy bar head

Abstract

The invention discloses a welding device and process for local repair of a dummy bar head, the dummy bar head is integrally formed by a head part and a flat connecting part, and a first inclined plane, a second inclined plane and a bottom plane are respectively arranged at the front part, the rear part and the bottom of the lower parts of the two sides of the head part of the dummy bar head; the welding device is used for supporting a dummy bar head and comprises a base frame, two front supporting rods with the tops matched with the bottom plane are arranged on the front side of the base frame in a spaced mode, and two rear supporting rods with the tops matched with the second inclined face are arranged on the rear side of the base frame in a spaced mode. A first side supporting rod and a second side supporting rod of which the tops are matched with the two first inclined surfaces are arranged on the left side and the right side respectively; the tops of the first side supporting rod and the second side supporting rod are used for supporting the two first inclined faces respectively, the tops of the two rear supporting rods are used for supporting the two second inclined faces respectively, the tops of the two front supporting rods are used for supporting the front sides of the two bottom planes respectively, and the dummy bar head is made to be in a vertical state together. By applying the method, welding repair of the dummy bar head deformation position can be effectively achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a welding device and process for local repair of a dummy bar ingot head, and is suitable for the butt welding field of high-strength steel. Background Art

[0002] The dummy bar is a key device in metallurgical continuous casting machines. It is mainly used to guide and support the initial solidification of the billet to ensure the smooth progress of the continuous casting process. Figure 6 The photo of the dummy rod is shown. The dummy rod is mainly composed of various dummy heads, transition sections, chain links, tail sections and pins. The molten steel solidifies and condenses together with the dummy heads. The dummy head of the dummy rod is pulled by the straightening machine for a long time, which will cause deformation at the traction part of the dummy head. If it continues to be used, there will not only be major equipment safety hazards, but also seriously affect the production rhythm.

[0003] If the ingot head is deformed at the ingot head traction position, if it is replaced as a whole, the processing time of the parts will be long and the procurement cost of the parts will be high. The current solution is generally to locally cut the deformed part, replace the traction structure, and then fix it by welding. However, since the ingot rod is made of 42CrMo high-strength steel, there are the following main problems during welding: (1) The local cutting and replacement part must be placed in a flat welding position, and the ingot head is a special-shaped structure, so it is difficult to place the deformed part in a flat welding position. (2) Welding cracks (hot cracks, cold cracks): Hot cracks, the crystallization temperature zone is large when the weld metal solidifies and crystallizes, and segregation is prone to occur; cold cracks, high-carbon martensite is easily generated in the weld and heat-affected zone, and the welding stress generated during welding increases the tendency of cold cracks. (3) Heat-affected zone embrittlement, due to the high carbon content and many alloy elements, the steel has a strong tendency to harden, so a large amount of high-carbon martensite with high hardness and brittleness is generated in the quenching zone, resulting in severe embrittlement. (4) Softening of the heat-affected zone. When the heat-affected zone is heated to a temperature exceeding the tempering temperature of the quenching and tempering treatment, a softening zone with lower strength and hardness than the parent material will appear. Therefore, it is necessary to design a welding device and process for local repair of the dummy bar head. And the following requirements need to be met after the local welding repair of the dummy bar head: (1) Through manual self-repair and fine grinding, the overall effect meets the inspection of technical specifications and reaches the size required for use. (2) Low investment cost, convenient on-site operation and maintenance, and short welding time. (3) The metallurgical bonding welding layer is suitable for periodic use. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present invention provides a welding device and process for local repair of a dummy bar ingot head, which effectively solves the problem of welding and repairing the deformed part of the dummy bar ingot head.

[0005] The technical solution of the present invention to solve the technical problem is as follows:

[0006] According to one aspect of the present invention, a welding device for local repair of a starter rod ingot head is provided, wherein the starter rod ingot head is formed by an ingot head head and a flat connecting part being integrally formed, and the front, rear and bottom of the lower parts of both sides of the ingot head head are respectively provided with a first inclined surface, a second inclined surface and a bottom plane, and the characteristic is that: the welding device is used to support the starter rod ingot head, and it includes a base frame, two front support rods whose tops are adapted to the bottom plane are arranged at intervals on the front side of the base frame, and two rear support rods whose tops are adapted to the second inclined surfaces are arranged at intervals on the rear side of the base frame, and a first side support rod and a second side support rod whose tops are adapted to the two first inclined surfaces are respectively arranged on the left and right sides; wherein: the tops of the first side support rod and the second side support rod are respectively used to support the two first inclined surfaces, the tops of the two rear support rods are respectively used to support the two second inclined surfaces, and the tops of the two front support rods are respectively used to support the front sides of the two bottom planes, and together make the starter rod ingot head in a vertical state.

[0007] Furthermore, top ends are respectively provided at the tops of the rear support rods.

[0008] Furthermore, the base frame includes a rectangular bottom plate and side plates respectively fixed on the edges of the upper surface of the bottom plate, and the spacing between the front and rear side plates is not less than the length of the flat connecting portion, and the front support rod, the rear support rod, the first side support rod and the second side support rod are respectively fixed on the bottom plate.

[0009] Furthermore, the front support rod and the rear support rod are respectively vertically arranged on the base frame, and the first side support rod and / or the second side support rod are obliquely arranged on the base frame.

[0010] Furthermore, the base frame is formed by welding steel plates and channel steels, and the front support rod, the rear support rod, the first side support rod and the second side support rod are formed by machining square steels.

[0011] According to another aspect of the present invention, a process for repairing a dummy bar ingot head is provided, wherein the dummy bar ingot head is formed by an ingot head head and a flat connecting portion being integrally formed, and the front, rear and bottom of the lower parts of both sides of the ingot head head are respectively provided with a first inclined surface, a second inclined surface and a bottom plane, and the center of the end portion is an ingot head traction position and is provided with a traction position notch, and the steps are as follows:

[0012] S1. Production of welding device and setting of dummy bar head;

[0013] 1.1) According to the specifications of the dummy bar head to be repaired, a base frame of the welding device according to the above claim is manufactured, and the base frame is placed horizontally;

[0014] 1.2) Place the dummy rod head vertically on the base frame, with the head and the flat connection part facing upward and downward respectively. According to the positional relationship between the first inclined surface, the second inclined surface and the bottom plane of the head and the base frame, and the specifications of the flat connection part, determine the sizes of the front support rod, the rear support rod, the first side support rod and the second side support rod and make them respectively;

[0015] 1.3) Weld and fix each front support rod, rear support rod, first side support rod and second side support rod on the base frame, so that the top of each front support rod, rear support rod, first side support rod and second side support rod supports the bottom plane, the second inclined plane and the first inclined plane respectively;

[0016] 1.4) Cut and grind the deformed position of the notch at the traction part of the head of the ingot;

[0017] 1.5) According to the size of the notch at the traction location, a hat-shaped traction structure that can be set inside the notch at the traction location for traction is machined through an alloy steel plate, and welding grooves are respectively opened at the top of the hat-shaped traction structure and the welding position of the notch at the traction location;

[0018] S2. Preparation before welding:

[0019] 2.1) Welding equipment: manual carbon dioxide gas shielded welding machine; welding materials: ER120S-G welding wire, gas shielded welding wire φ1.2mm;

[0020] 2.2) Heating device: heat treatment temperature control box, crawler type heating plate;

[0021] 2.3) Welding material: 42CrMo high-strength steel;

[0022] 2.4) Welding position: horizontal fixed welding 1G;

[0023] 2.5) Auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, sample, thermometer, magnifying glass, thermal insulation cotton;

[0024] 2.6) Requirements before welding: The welding area and welding materials must be free of oil, oxide layer and moisture, and the metallic luster must be exposed;

[0025] 2.7) Welding technical requirements: single-sided welding and double-sided forming, the weld cladding layer fuses the parent material, the weld has no welding defects and meets the design dimensions;

[0026] 2.8) Welding process parameters: Welding parameters are determined according to welding equipment, welding materials and welding requirements;

[0027] S3, welding implementation;

[0028] 3.1) The hat-shaped traction structure is arranged in pairs at the notch of the traction part, and the areas on both sides of each welding groove are cleaned, and the notch of the traction part and the hat-shaped traction structure are preheated to a temperature range of 250-300°C by a crawler-type heating plate of a heat treatment temperature control box;

[0029] 3.2) After the preheating temperature is reached, the bottom layer welding is performed on each welding groove by the manual carbon dioxide gas shielded welding machine and the 1.2mm ER120S-G welding wire. The horizontal angle between the welding gun and the weldment is 85-95°. The straight line wire method is used. The bottom layer is welded on one side and formed on both sides. After welding, the weld surface is cleaned and confirmed to be free of any welding defects and the weld is flat.

[0030] 3.3) Keep the interlayer temperature not lower than the preheating temperature range, use the manual carbon dioxide gas shielded welding machine and φ1.2mm ER120S-G welding wire to weld the filling layer and the cover layer, use the crescent-shaped wire feeding method, clean the weld surface layer by layer, and the weld layer reaches 10mm. Use hammering to further eliminate local welding stress. After ensuring that there are no welding defects, weld the next layer. Ensure that the cover layer is higher than the base material, and both sides of the weld maintain a smooth transition with the base material;

[0031] 3.4) After all welding is completed, continue to use the heat treatment temperature control box crawler heating plate to track and heat the weld area to 300℃ and keep it horizontal for 10 hours, then wrap it with insulation cotton and slowly cool it to room temperature. After passing UT flaw detection and fully meeting the requirements, it can be delivered for use.

[0032] Furthermore, the welding equipment is a Panasonic YD-350FR2 manual carbon dioxide gas shielded welding machine, and the heat treatment temperature control box is a ZWK-180KW heat treatment temperature control box.

[0033] Furthermore, when welding the base layer, the welding current is 160-180A, the arc voltage is 22-24V, the welding speed is 4.3-6.6mm / s, and the heat input is 0.6-0.9kJ / mm; when welding the filling layer, the welding current is 240-260A, the arc voltage is 26-32V, the welding speed is 5.0-7.0mm / s, and the heat input is 1.0-1.1kJ / mm; when welding the cover layer, the welding current is 240-260A, the arc voltage is 26-32V, the welding speed is 5.0-7.0mm / s, and the heat input is 0.9-1.1kJ / mm.

[0034] Furthermore, when the cover layer is welded, the cover layer is not higher than the base material by 3 mm.

[0035] Compared with the prior art, the welding device and process for local repair of the ingot head of the ingot bar described in the present invention effectively ensure that the repaired part of the ingot head is horizontally upward by setting a welding device. The welding device has low investment cost, convenient on-site operation and maintenance, short repair time, and can be reused. By adopting a manual carbon dioxide gas shielded welding machine, selecting ER120S-G, ф1.2 welding wire, and uniformly adopting manual carbon dioxide gas shielded welding bottom layer, filling and cover welding methods, the requirements of the welding process are met. At the same time, through the optimization of preheating temperature, interlayer temperature and welding parameters, attention is paid to filling the arc pit in the welding process, and preheating, slow cooling and post-heating are coordinated to prevent the occurrence of defects such as hot cracks, cold cracks, embrittlement of the heat-affected zone, and softening of the heat-affected zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 and Figure 2 The schematic diagram of the structure of the dummy bar head from different angles (the traction deformation part has been cut);

[0037] Figure 3 and Figure 4 Schematic diagram of placing the dummy bar head on the welding device from different angles;

[0038] Figure 5 It is a structural schematic diagram of the dummy bar ingot head being placed on the welding device for welding repair;

[0039] Figure 6 This is an on-site photo of the existing dummy rod.

[0040] In the figure: 1. base frame; 11. bottom plate; 12. side plate; 21. front support rod; 22. rear support rod; 221. top stop; 23. first side support rod; 24. second side support rod; 3. ingot head of ingot guide rod; 31. ingot head head; 32. flat connecting part; 33. connecting hole; 34. traction notch; 35. first inclined surface; 36. second inclined surface; 37. bottom plane; 4. hat-shaped traction structure; 41. welding groove. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention 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, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the usual meanings understood by people with general skills in the field to which the present disclosure belongs. "Up", "down", "left", "right", "front", "back" and the like used in the patent application specification and claims of the present disclosure are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly; "connected" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The parts not described in detail in the present invention are all known technologies of technicians in the field of this technology.

[0042] Embodiment 1:

[0043] like Figure 1 and Figure 2 The ingot bar head 3 shown is a special-shaped structure, which is formed by an ingot head 31 and a flat connecting part 32 in one piece. The front, rear and bottom of the lower part of both sides of the ingot head 31 are symmetrically provided with a first inclined surface 35, a second inclined surface 36 and a bottom plane 37, respectively. A traction notch 34 is provided at the center of the end of the ingot head 31, and the ingot head traction is provided at the position of the traction notch 34. The flat connecting part 32 is provided with a plurality of connection holes 33 for connection. When the ingot head 31 is used for a long time and the ingot head traction is deformed, the corresponding traction structure needs to be cut and welded. During welding repair, the traction notch 34 needs to be in a flat welding position, and the structure of the ingot bar head 3 itself makes it impossible for it to be in a vertical state.

[0044] Therefore, the present invention provides a welding device for local repair of the dummy bar ingot head, such as Figure 1-5 As shown, the welding device is used to support the dummy bar head 3 in a vertical state, so as to facilitate welding and repairing the traction part of the end of the head 31 of the head. The welding device is manufactured according to the specifications of the dummy bar head 3 to be supported, and includes a base frame 1, which includes a rectangular bottom plate 11 and side plates 12 respectively fixedly arranged on the edges of the upper surface of the bottom plate 11. The bottom plate 11 is preferably made of a 25mm thick steel plate through cutting and machining, and the side plates 12 are preferably made of 100mm channel steel and welded at the edges of the bottom plate 11 to form a rectangular frame. The spacing between the front and rear side plates 12 is not less than the length of the flat connecting portion 32, which is convenient for placing the dummy bar head 3.

[0045] In this embodiment, two front support rods 21 whose tops are adapted to the bottom plane 37 are welded at intervals on the front side of the bottom plate 11 of the base frame 1, which are used to support the front side of the bottom plane 37. The distance between the two front support rods 21 is between the thickness of the flat connecting portion 32 and the distance between the outermost ends of the two bottom planes 37, preferably slightly larger than the thickness of the flat connecting portion 32, and the height is adapted to the distance between the bottom plane 37 and the bottom of the flat connecting portion 32; two rear support rods 22 whose tops are adapted to the second inclined surface 36 are welded at intervals on the rear side of the bottom plate 11 of the base frame 1, which correspond to the two front support rods 21, respectively, and are used to support the two second inclined surfaces 36, the two rear support rods 22, respectively. The spacing is between the thickness of the flat connecting part 32 and the spacing between the outermost ends of the two second inclined surfaces 36, preferably slightly larger than the thickness of the flat connecting part 32; the left and right sides of the bottom plate 11 of the base frame 1 are respectively welded with a first side support rod 23 and a second side support rod 24, whose tops are respectively adapted to the two first inclined surfaces 35; each support rod is preferably cut and processed from 80 square steel, and the first side support rod 23, the second side support rod 24, the two rear support rods 22 and the two front support rods 21 respectively support the front sides of the two first inclined surfaces 35, the two second inclined surfaces 36 and the two bottom planes 37, so that the ingot guide rod head 3 can be in a vertical state, which is convenient for welding repair.

[0046] As a preferred embodiment, the front support rod 21 and the rear support rod 22 are respectively vertically arranged on the base frame 1, and the first side support rod 23 and / or the second side support rod 24 are obliquely arranged on the base frame 1. Preferably, the first side support rod 23 or the second side support rod 24 is vertically arranged, and the other support rod is obliquely arranged to facilitate the support and welding requirements of the ingot rod head 3.

[0047] When in use, first make a base frame 1 according to the specifications of the dummy rod head 3, and place the base frame 1 horizontally, lift the dummy rod head 3 and place it vertically on the bottom plate 11 of the base frame 1, then weld the first side support rods 23, the second side support rods 24, the rear support rods 22 and the front support rods 21 in sequence to support and keep the dummy rod head 3 vertically placed, then perform welding repair on the traction deformation position of the dummy rod head 3, and after the repair is completed and the dummy rod head 3 is lifted and moved away, the welding device can provide support for welding repair of other dummy rod heads 3 of the same specification.

[0048] As a preferred embodiment, the tops of the two rear support rods 22 may be respectively provided with top stops 221 for limiting support when the dummy rod ingot head 3 is hoisted and placed.

[0049] Embodiment 2:

[0050] The present invention provides a dummy bar head repair process, wherein the dummy bar head 3 is formed by an ingot head head 31 and a flat connecting portion 32 in one piece, and the front, rear and bottom of the lower parts of both sides of the ingot head head 31 are symmetrically provided with a first inclined surface 35, a second inclined surface 36 and a bottom plane 37, respectively, and the center of the end portion is an ingot head traction position and is provided with a traction position notch 34, and the steps are as follows:

[0051] S1, manufacturing of welding device and setting of dummy bar head 3;

[0052] 1.1. According to the specifications of the dummy bar head 3 to be repaired, a base frame 1 of the welding device in Example 1 is manufactured, and the base frame 1 is placed horizontally;

[0053] 1.2. Place the dummy bar head 3 vertically on the base frame 1, with the head 31 and the flat connecting portion 32 facing upward and downward respectively. According to the positional relationship between the first inclined surface 35, the second inclined surface 36 and the bottom plane 37 of the head 31 and the base frame 1, and the specifications of the flat connecting portion 32, determine the sizes of the front support rod 21, the rear support rod 22, the first side support rod 23 and the second side support rod 24 and manufacture them respectively;

[0054] 1.3. Weld and fix the front support rods 21, the rear support rods 22, the first side support rods 23 and the second side support rods 24 on the base frame 1, so that the tops of the front support rods 21, the rear support rods 22, the first side support rods 23 and the second side support rods 24 support the bottom plane 37, the second inclined surface 36 and the first inclined surface 35 respectively;

[0055] 1.4. Cut and grind the deformed position of the notch 34 at the traction position of the spindle head 31;

[0056] 1.5. According to the size of the notch 34 at the traction location, a hat-shaped traction structure 4 for traction is machined through alloy steel plate. The hat-shaped traction structure 4 is machined through cutting of an 80 mm alloy steel plate. The material is 42CrMo high-strength steel or equivalent material. The front side and the bottom are open. A welding groove 41 is respectively provided at the welding position between the top of the hat-shaped traction structure 4 and the notch 34 at the traction location;

[0057] S2. Preparation before welding:

[0058] 2.1. Welding equipment: Panasonic YD-350FR2 manual carbon dioxide gas shielded welding machine; welding materials: ER120S-G welding wire, gas shielded welding wire φ1.2mm;

[0059] 2.2. Heating device: ZWK-180KW heat treatment temperature control box (5-stage setting of time and temperature for heating, constant temperature and cooling, 0-1000℃ temperature control, 180KW, can carry 9 10KW heaters at the same time) crawler heating plate;

[0060] 2.3. Welding material: 42CrMo high-strength steel;

[0061] 2.4. Welding position: horizontal fixed welding 1G;

[0062] 2.5. Auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, sample, thermometer, magnifying glass, thermal insulation cotton;

[0063] 2.6. Requirements before welding: The welding position area and welding materials must be free of oil, oxide layer and moisture, etc., and the metallic luster must be exposed; use oxyacetylene flame to remove moisture and grease, and then use emery cloth or grinding wheel machine to grind and remove rust;

[0064] 2.7. Welding technical requirements: single-sided welding and double-sided forming, the weld cladding layer fuses the parent material, the weld has no welding defects and meets the design dimensions;

[0065] 2.8. Welding process parameters: Welding parameters are determined according to welding equipment, welding materials and welding requirements;

[0066] Welding process parameters

[0067] Weldlayers Weldmethod Filler material filler metal Φ (mm) Amps Current (A) Volts Voltage (V) Polarity Travelspeed welding speed (mm / s) Weldingspeed wire feeding speed (mm / s) Heat input (kJ / mm) Bottom Layer MAG ER120S-G Φ1.2 160-180 22-24 DCEP 4.3-6.6 -- 0.6-0.91 Filling layer MAG ER120S-G Φ1.2 240-260 26-32 DCEP 5.0-7.0 -- 1.0-1.1 Covering layer MAG ER120S-G Φ1.2 240-260 26-32 DCEP 5.0-7.0 -- 0.9-1.1

[0068] S3, welding implementation;

[0069] Welding process route: assemble the partially replaced cap-shaped traction structure 4--clean on both sides of the welding groove 41--preheat the crawler heating plate to 250~300℃--ER120S-G welding wire--bottom layer welding straight wire feeding method--filling layer and cover layer adopt crescent wire feeding method--maintain interlayer temperature--hammer to eliminate local welding stress--clean each layer without welding defects--weld seam tracking tempering 300℃--cool to room temperature for UT flaw detection--delivery and use. Specific:

[0070] 3.1. A hat-shaped traction structure 4 is arranged at the notch 34 of the traction part, and the areas on both sides of each welding groove 41 are cleaned. The notch 34 of the traction part and the hat-shaped traction structure 4 are preheated to a temperature range of 250-300°C by means of a crawler-type heating plate of a heat treatment temperature control box; in order to better reduce the local temperature difference stress, improve the internal structure, and prevent the weld metal from solidifying and crystallizing with a large crystallization temperature zone, which is prone to segregation and high-carbon martensite with high hardness and brittleness, leading to severe embrittlement, a temperature measuring gun is used to verify the temperature on both sides of the weld during heating;

[0071] 3.2. After the preheating temperature is reached, each welding groove 41 is welded with a manual carbon dioxide gas shielded welding machine and a φ1.2mm ER120S-G welding wire. The horizontal angle between the welding gun and the weldment is 85-95°. The straight line wire method is used. The bottom layer is welded on one side and formed on both sides. After welding, the weld surface is cleaned and confirmed to be free of any welding defects. The weld is flat to facilitate the welding of the filling layer.

[0072] 3.3. Keep the interlayer temperature not lower than the preheating temperature range. Use a manual carbon dioxide gas shielded welding machine and φ1.2mm ER120S-G welding wire to weld the filling layer and the cover layer. Use the crescent-shaped wire method to clean the weld surface layer by layer. When the weld layer reaches 10mm, it is necessary to further eliminate the local welding stress by hammering. After ensuring that there are no welding defects, proceed to the next layer of welding. The cover layer must be higher than the parent material, but not higher than 3mm. Both sides of the weld should maintain a smooth transition with the parent material.

[0073] 3.4. After all welding is completed, continue to use the track-type heating plate of the heat treatment temperature control box to track and heat the weld area to 300℃ and keep it horizontal for 10 hours, then wrap it with insulation cotton and slowly cool it to room temperature. After passing the UT flaw detection and fully meeting the requirements, it can be delivered for use.

Claims

1. A welding device for partially repairing a dummy bar ingot head, wherein the dummy bar ingot head (3) is formed by an ingot head head (31) and a flat connecting portion (32) being integrally formed, and the front, rear and bottom portions of the lower portions of both sides of the ingot head head (31) are respectively provided with a first inclined surface (35), a second inclined surface (36) and a bottom plane (37), characterized in that: The welding device is used to support the dummy bar head (3), and comprises a base frame (1), the front side of the base frame (1) being provided with two front support rods (21) whose tops are matched with the bottom plane (37) at intervals, the rear side of the base frame (1) being provided with two rear support rods (22) whose tops are matched with the second inclined planes (36) at intervals, and the left and right sides of the base frame being provided with a first side support rod (23) and a second side support rod (24) whose tops are matched with the two first inclined planes (35) respectively; wherein: the tops of the first side support rod (23) and the second side support rod (24) are respectively used to support the two first inclined planes (35), the tops of the two rear support rods (22) are respectively used to support the two second inclined planes (36), and the tops of the two front support rods (21) are respectively used to support the front sides of the two bottom planes (37), and together, the dummy bar head (3) is placed in a vertical state.

2. A welding device for repairing a dummy bar head according to claim 1, characterized in that: The tops of the rear support rods (22) are respectively provided with top stops (221).

3. A welding device for repairing a dummy bar head according to claim 1, characterized in that: The base frame (1) comprises a rectangular bottom plate (11) and side plates (12) respectively fixedly arranged on the edges of the upper surface of the bottom plate (11), wherein the distance between the front and rear side plates (12) is not less than the length of the flat connecting portion (32), and the front support rod (21), the rear support rod (22), the first side support rod (23) and the second side support rod (24) are respectively fixedly arranged on the bottom plate (11).

4. A welding device for repairing a dummy bar head according to claim 1, characterized in that: The front support rod (21) and the rear support rod (22) are respectively arranged vertically on the base frame (1), and the first side support rod (23) and / or the second side support rod (24) are arranged obliquely on the base frame (1).

5. The welding device for repairing a dummy bar head according to claim 1, characterized in that: The base frame (1) is formed by welding steel plates and channel steels, and the front support rod (21), the rear support rod (22), the first side support rod (23) and the second side support rod (24) are formed by machining square steel.

6. A process for repairing a dummy bar ingot head, wherein the dummy bar ingot head (3) is formed by an ingot head head (31) and a flat connecting portion (32) being integrally formed, the front, rear and bottom of the lower parts of both sides of the ingot head head (31) are respectively provided with a first inclined surface (35), a second inclined surface (36) and a bottom plane (37), the center of the end portion is an ingot head traction position and is provided with a traction position notch (34), characterized in that: Here are the steps: S1, manufacturing of welding device and setting of dummy bar head (3); 1.1) According to the specifications of the dummy bar head (3) to be repaired, a base frame (1) of the welding device according to any one of claims 1 to 5 is manufactured, and the base frame (1) is placed horizontally; 1.2) vertically placing the dummy rod ingot head (3) on the base frame (1), with the ingot head head (31) and the flat connecting portion (32) facing upward and downward respectively, and determining the sizes of the front support rod (21), the rear support rod (22), the first side support rod (23) and the second side support rod (24) and manufacturing them according to the positional relationship between the first inclined surface (35), the second inclined surface (36) and the bottom plane (37) of the ingot head head (31) and the base frame (1), and the specifications of the flat connecting portion (32); 1.3) Welding and fixing each front support rod (21), the rear support rod (22), the first side support rod (23) and the second side support rod (24) on the base frame (1), so that the top of each front support rod (21), the rear support rod (22), the first side support rod (23) and the second side support rod (24) respectively supports the bottom plane (37), the second inclined surface (36) and the first inclined surface (35); 1.4) Cutting and grinding the deformed position of the notch (34) at the traction position of the ingot head (31); 1.5) According to the size of the traction slot (34), a hat-shaped traction structure (4) for traction that can be arranged inside the traction slot (34) is machined by alloy steel plate, and welding grooves (41) are respectively provided at the top of the hat-shaped traction structure (4) and the welding position of the traction slot (34); S2. Preparation before welding: 2.1) Welding equipment: manual carbon dioxide gas shielded welding machine; welding materials: ER120S-G welding wire, gas shielded welding wire φ1.2mm; 2.2) Heating device: heat treatment temperature control box, crawler type heating plate; 2.3) Welding material: 42CrMo high-strength steel; 2.4) Welding position: horizontal fixed welding 1G; 2.5) Auxiliary facilities: angle grinder, file, hammer, flat shovel, mask, sample, thermometer, magnifying glass, thermal insulation cotton; 2.6) Requirements before welding: The welding area and welding materials must be free of oil, oxide layer and moisture, and the metallic luster must be exposed; 2.7) Welding technical requirements: single-sided welding and double-sided forming, the weld cladding layer fuses the parent material, the weld has no welding defects and meets the design dimensions; 2.8) Welding process parameters: Welding parameters are determined according to welding equipment, welding materials and welding requirements; S3, welding implementation; 3.1) The hat-shaped traction structure (4) is arranged in pairs at the notch (34) at the traction position, and the areas on both sides of each welding groove (41) are cleaned, and the notch (34) at the traction position and the hat-shaped traction structure (4) are preheated to a temperature range of 250-300° C. by means of a crawler-type heating plate of a heat treatment temperature control box; 3.2) After the preheating temperature is reached, each welding groove (41) is welded with the manual carbon dioxide gas shielded welding machine and the 1.2 mm ER120S-G welding wire. The horizontal angle between the welding gun and the weldment is 85-95°. The straight line wire feeding method is used. The bottom layer is welded on one side and formed on both sides. After welding, the weld surface is cleaned and confirmed to be free of any welding defects and the weld is flat. 3.3) Keep the interlayer temperature not lower than the preheating temperature range, use the manual carbon dioxide gas shielded welding machine and φ1.2mm ER120S-G welding wire to weld the filling layer and the cover layer, use the crescent-shaped wire feeding method, clean the weld surface layer by layer, and when the weld layer reaches 10mm, further eliminate the local welding stress by hammering to ensure that there are no welding defects before welding the next layer. Ensure that the cover layer is higher than the base material, and the two sides of the weld maintain a smooth transition with the base material; 3.4) After all welding is completed, continue to use the heat treatment temperature control box crawler heating plate to track and heat the weld area to 300℃ and keep it horizontal for 10 hours, then wrap it with insulation cotton and slowly cool it to room temperature. After passing UT flaw detection and fully meeting the requirements, it can be delivered for use.

7. The repair process according to claim 6, characterized in that: The welding equipment is a Panasonic YD-350FR2 manual carbon dioxide gas shielded welding machine, and the heat treatment temperature control box is a ZWK-180KW heat treatment temperature control box.

8. The repair process according to claim 6, characterized in that: When welding the base layer, the welding current is 160-180A, the arc voltage is 22-24V, the welding speed is 4.3-6.6mm / s, and the heat input is 0.6-0.9kJ / mm; when welding the filling layer, the welding current is 240-260A, the arc voltage is 26-32V, the welding speed is 5.0-7.0mm / s, and the heat input is 1.0-1.1kJ / mm; when welding the cover layer, the welding current is 240-260A, the arc voltage is 26-32V, the welding speed is 5.0-7.0mm / s, and the heat input is 0.9-1.1kJ / mm.

9. The repair process according to claim 6, characterized in that: When welding the cover layer, the cover layer shall not be higher than the base material by 3mm.

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