Development of a Novel Single-Column Tube-Plate Automatic Submerged Arc Welding Machine
Abstract
Submerged arc welding (SAW) is widely used in the welding of heavy steel structures due to its advantages such as high power utilization, strong weld formation and penetration, low spatter, and low risk of deformation. The SAW process is a relatively mature welding process and very convenient in operation. However, traditional SAW machines are relatively large and are suitable for mass production in large sites. In view of this situation, a novel single-column tube-plate automatic submerged arc welding machine has been developed herein. The machine was designed to reduce the size and cost, and provide the feasibility of numerical control operation and make welding parameters adjustable. The novel machine is fully automatic and equipped with a mechanical arm for automatic welding and a PLC system for programming and controlling the motion trajectory and welding conditions. This machine was used to weld steel nozzle pipes with a thickness of 10 mm and pipes with a length of 400 mm, and the relevant weld history was recorded. The results indicated that both penetration and width were of good quality and that the weld stability and appearance were excellent.
Keywords: Submerged arc welding (SAW), Automatic submerged arc welding, Single-Column tube-plate automatic welding
1. Introduction
Submerged arc welding (SAW) is widely used in the welding of heavy steel structures due to its advantages such as high power utilization, strong weld formation and penetration, low spatter, and low risk of deformation [1–3]. The SAW process is a relatively mature welding process as it is simple to operate and utilizes a relatively simple equipment structure. The traditional SAW machines are relatively large and are suitable for mass production in large sites. However, the development of light-weight portable SAW machines is ultimately gaining much attention in recent years. It has been found that the reduction of welding component dimensions and the optimization of welding operation process can reduce the material consumption and cost of welding. Furthermore, the operation process can be adjusted according to the actual needs of different materials and structure components.
In view of this situation, a novel single-column tube-plate automatic submerged arc welding machine has been developed herein. The novel machine is fully automatic and equipped with a mechanical arm for automatic welding and a PLC system for programming and controlling the motion trajectory and welding conditions. Its design concepts and welding performance are presented herein.
2. Design and components
The schematic diagram of the proposed machine is shown in Figure 1. This machine is located on a single column, with a rotating mechanism connected to the welding torch at the right side and a welding gun connected to the welding torch at the other side. The welding gun is designed to adjust the welding current, otherwise, the mechanical arm will move along the two sides of the axle to carry out the welding task. In order to achieve the desired welding location, x-y displacement and z-axis mechanism are provided in the column. The z-axis mechanism is intended to adjust the position of welding torch and is equipped with a sensing device for fall detection.
Figure 1. Schematic diagram of the proposed single-column tube-plate automatic submerged arc welding machine
The machine is equipped with a PLC system to control the motion trajectory and welding conditions, realize automatic welding and keep a record of the weld history for traceability purposes. In addition, the control system includes a touch screen for manual input and display of welding parameters and welding progress.
The machine is also provided with a water cooling system which is connected to the welding gun and the welding torch. In addition, multiple sensors are provided in order to detect the pressure, temperature, and current of the welding system in order to avoid any welding failure.
3. Performance of the version machine
The novel machine was used to weld steel nozzle pipes with a thickness of 10 mm and pipes with a length of 400 mm. The welding process was fully automatic and the relevant weld history was recorded. During the welding process, the welding current was monitored and adjusted accordingly, and water cooling was used to ensure the optimal temperature of the welding element. The welding speed was maintained at 25 mm/s and the welding time was 25 s.
The welds were then inspected, and the results indicated that the penetration and width were of good quality and the weld stability and appearance were excellent. (see figure 2).
Figure 2. Cross-sectional view of the welded nozzle pipe showing excellent weld quality
4. Conclusion
In conclusion, a novel single-column tube-plate automatic submerged arc welding machine was developed. The proposed machine is capable of welding different shapes and sizes of steel structures with a thickness of 10 mm and a length of 400 mm with excellent quality. The machine is equipped with a PLC system for programming and controlling the motion trajectory and welding conditions, as well as a touch screen for manual input and display of welding parameters and welding progress. The results indicated that the welding quality was excellent and that the novel machine could offer a cost-effective solution for the welding of light-weight steel structures.
