JP-2026075070-A - Process equipment and welding process for weaving submerged arc welding of saddle-shaped welds using small diameter wire in a 3G position.

Abstract

[Problem] To provide a process equipment and welding process for weaving submerged arc welding of saddle-shaped welds using a small diameter wire in a 3G position, belonging to the field of high-temperature gas furnace manufacturing technology. [Solution] By utilizing the design of welding robots and welding processes, and while meeting standards and design specifications, and with the premise of significantly improving welding efficiency, the conventional submerged arc welding method has the problem of not being able to form the weld area, and a weaving submerged arc welding process using a small diameter wire can be adopted to improve welding efficiency. [Selection Diagram] Figure 6

Inventors

• 何 ▲氷▼
• 王 育忠
• 劉 慶
• 江 国▲イェン▼
• 王 ▲衛▼東
• 劉 遠彬
• 戴 光明
• ▲デン▼ 道勇
• 李 恩
• 楊 小杰
• 楊 其成

Assignees

• 東方電気（広州）重型機器有限公司

Dates

Publication Date

20260507

Application Date

20251015

Priority Date

20241021

Claims (4)

1. A welding process used for welding saddle-shaped welds of high-temperature gas ducts and cylinder assemblies, A process equipment for weaving submerged arc welding of saddle-shaped welds using a small diameter wire in a 3G position, It includes a steam generator, a welding robot, an operating platform, a lifting device, an external support device, an internal support device, and a heating assembly, the steam generator including a high-temperature gas duct and a cylinder assembly, The external support device fixes the high-temperature gas duct and the cylinder assembly, The operating platform is provided above the welding area of the high-temperature gas duct and the cylinder assembly. The welding robot and lifting device are provided on one side of the high-temperature gas duct and the cylinder assembly. The internal support device is provided within the high-temperature gas duct and the cylinder assembly, and contacts the inner wall surface of the high-temperature gas duct and the cylinder assembly. The heating assembly is connected to the internal support device, the heating assembly has a heating end, the heating end contacts the high-temperature gas duct and the inner wall surface of the cylinder assembly, The welding robot includes a robot support stand, a robot base, a multi-axis movable mechanism, a multi-axis welding arm, and a welding gun, wherein the robot base is provided on the robot support stand, the multi-axis movable mechanism is provided on the robot base, the multi-axis welding arm is connected to the Z-axis movable end of the multi-axis movable mechanism, and the welding gun is connected to the Z-axis movable end of the multi-axis welding arm. The heating assembly includes an electric heating device and a plurality of heating plates, the electric heating device being electrically connected to the heating plates, the heating plates forming the heating end of the heating assembly, the heating plates being connected to the internal support device, and the heating plates being provided with saddle-shaped end faces that contact the high-temperature gas duct and the inner wall surface of the cylinder assembly, the process equipment includes Step S1 involves fixing the high-temperature gas duct and the cylinder assembly to the external support device, installing the welding robot and lifting device on the external support device side, and installing the internal support device and the heating assembly inside the high-temperature gas duct and the cylinder assembly. Step S2 is a step of turning on the heating assembly to preheat the high-temperature gas duct and the cylinder assembly, wherein the preheating temperature range is 175 to 250°C and the preheating time is 2 hours or more. Step S3 is to weld the weld groove between the high-temperature gas duct and the cylinder assembly, Step s31 involves first performing backing welding on the aforementioned weld groove, then filling welding, and finally performing coating welding to form a coating weld bead. The step s32 includes performing temper welding on the coated weld bead to form a temper weld bead, In step S3, during the welding process, the temperature between the weld beads of the high-temperature gas duct and the cylinder assembly is monitored to ensure it does not exceed 250°C. If the temperature of the workpiece rises due to the heat input during welding, the temperature of the welding area is allowed to cool naturally in the air to between 150°C and 250°C before continuing welding. The recommended temperature difference is 50°C or less. When performing shielded welding, the heating assembly ensures that the temperature of the welding area is between 210°C and 250°C. The aforementioned weld groove is a saddle-shaped narrow groove with a locking groove, the groove width at the bottom is 22 mm, the groove surface angle is 2°, and the minimum thickness of the backing plate in the locking groove is 6 mm. The backing and filling welds of the aforementioned weld grooves are multi-layer multi-pass welds. The welding direction is changed after each layer of welding, and the change in groove width is monitored in real time. For areas with low cumulative thickness, single-stage thickness repair welding is performed for each area. The number of repair layers is determined based on actual measurement results. After repair welding, it is necessary to reduce the difference in groove width in each area, with a target difference of 3 mm or less. After completion, the remaining grooves are filled. In step s31, the weld groove is filled with fill welding, and the weld area is limited to be flush with the edge of the groove or up to 2 mm lower than the surface of the groove, and then the cover weld bead and tempered weld bead are welded. In steps s31 and s32, the number of weld beads in the covered weld bead is two or more, the number of weld beads in the tempered weld bead is one or more, one end of the covered weld bead covers the surface of the base material, the weld bead of the tempered weld bead overlaps with the covered weld bead and is located at 1/3 of the width of the covered weld bead. Furthermore, step S4 is a step of performing post-heating on the high-temperature gas duct and the cylinder assembly, wherein post-heating should be performed on the welded area after welding has been interrupted or completed, the post-heating temperature is limited to 250 to 400°C, and the post-heating time is 4 hours or more. Step S5 involves performing heat treatment on the high-temperature gas duct and the cylinder assembly, Step S6 involves removing the high-temperature gas duct and the internal support device within the cylinder assembly, The step includes performing a non-destructive test on the high-temperature gas duct and the cylinder assembly, A welding process characterized by the following:
2. In step S1, the welding surface of the weld groove between the high-temperature gas duct and the cylinder assembly and the area within a minimum range of 50 mm nearby are cleaned to ensure that the groove surface meets the cleanliness requirements. A welding process used for welding a saddle-shaped welded joint of a high-temperature gas duct and cylinder assembly as described in feature 1.
3. In step S3, before welding, verification coordinate points are set, and the number of welding coordinate points is 32 or more. Advance welding and reverse welding can share welding coordinate points in the intermediate region, but independent welding coordinate points must be set in the arc start region and arc end region. A welding process used for welding a saddle-shaped welded joint of a high-temperature gas duct and cylinder assembly as described in feature 1.
4. In step S7, the non-destructive testing items include visual inspection of the weld surface, dimensional inspection of the weld, magnetic particle inspection of the weld surface, ultrasonic inspection of the weld, and radiographic inspection of the weld. A welding process used for welding a saddle-shaped welded joint of a high-temperature gas duct and cylinder assembly as described in feature 1.

Description

This invention belongs to the field of high-temperature gas furnace manufacturing technology, and specifically relates to process equipment and welding process for weaving submerged arc welding using a small-diameter wire with a continuously variable angle narrow gap in a 3G position for extra-large saddle-shaped welds of high-temperature gas ducts and cylinder assemblies of steam generators in high-temperature gas furnaces. A high-temperature gas-cooled reactor (HRC) is a reactor technology that possesses high-temperature characteristics and uses gas for core cooling. It uses graphite as a moderator and helium as a coolant, generating electricity through the conversion of atomic energy, thermal energy, mechanical energy, and electrical energy. As an advanced fourth-generation nuclear power reactor technology, the HRC boasts extremely high safety, so much so that it's sometimes called a "foolish reactor." Even in the event of a serious accident and the loss of all cooling capacity, the reactor can remain safe without any external intervention, and a core meltdown will not occur. Due to the special design of its fuel elements, it can withstand high temperatures and has low residual heat, allowing it to remove core heat through natural heat dissipation alone. HRCs have high thermal efficiency because the gaseous working fluid stores more heat and converts it more efficiently into electrical energy. They can meet different power demands by adjusting the reactor output to respond more quickly to changes in load. Because of its high outlet temperature, HRCs can meet the demand for most heat sources in fields such as ethanol refining, petrochemicals, and hydrogen production. In the main equipment and pressure vessels of nuclear power plants, the welds connecting cylinders and branch pipes have a saddle-like shape and are therefore called "saddle-type" welds. There are mainly two structural designs for saddle-type welds in conventional Chinese and overseas nuclear power plants and ordinary pressure vessels. One is a "pseudo-saddle" structure, where the groove bottom is flat, the welding position is 1G, and the structure itself has no slope, so gravity has little effect on the shaping of the weld, making welding easy. However, it requires a large dimensional margin during procurement and later removal by machining, resulting in higher procurement costs, and the subsequent machining process wastes a lot of resources. This problem becomes more pronounced as the saddle size increases. Another structural form is the "true saddle" weld, where the groove bottom is a saddle surface with a certain incline. While this offers little margin for machining, the saddle dimension typically does not exceed 40 mm, and the maximum allowable incline for upward and downward welding does not exceed 10°, remaining within the downward position range. Although gravity affects the metal in the molten pool during the welding process, it can still meet the requirements, albeit with differences in form and performance. In the "true saddle" structure, as the saddle dimension increases (the incline increases), the influence of gravity on the metal flow in the molten pool increases during welding. Beyond a certain point (when the incline exceeds 15°), the welding position changes from downward to vertical. The molten iron in the molten pool is then excessively affected by gravity, exceeding the surface tension of the molten pool itself. This causes the molten iron to escape, resulting in poor weld formation and affecting the weld quality. In the structure of the high-temperature gas furnace product, it is necessary to weld the nozzle flange of the high-temperature gas duct (branch pipe) of the SG to the upper cylinder. The wall thickness of the SG cylinder is 205 mm, the groove bottom is a continuous saddle shape (see Figure 4 for a schematic diagram of the welding trajectory), the welding trajectory is 3G (downward) → 1G → 3G (upward) → 1G → 3G (downward) → 1G → 3G (upward) → 1G, the projection of the eight different trajectory segments on the circumference is eight unevenly divided circumferential regions, the spatial position and inclination of the welding gun change in real time, the maximum inclination difference is approximately 36° (the maximum angle for 3G upward is 18°, and the maximum angle for 3G downward is -18°), and the height difference (saddle dimension) is a maximum of approximately 380 mm. The saddle welds on the nozzle flanges of the high-temperature gas ducts of the upper cylinders are thick, with a groove depth of 260 mm in the circumferential direction of the cylinder. Approximately 1500 kg of welding rods are consumed to weld the nozzle flanges of the high-temperature gas ducts of one steam generator (SG). While the dimensions of the branch pipes in the high-temperature gas reactor RPV are the same as those of the SG branch pipes, the outer diameter and thickness of the cylinders are larger (6180 mm and 240 mm, respectivel