In the modern industrial field, stainless steel big diameter welded tube is widely used in many key industries such as petroleum, chemical industry, construction, energy, etc. due to its excellent performance, such as excellent corrosion resistance, high strength and good sealing performance. As the core link that determines the quality and performance of stainless steel big diameter welded tube, welding technology has always attracted much attention. At present, automatic welding technology occupies a dominant position in the production of stainless steel big diameter welded tube, among which submerged arc welding and plasma welding are the two most commonly used welding processes. Submerged arc welding is a welding method that uses granular flux accumulation to form protective conditions so that the arc burns under the flux layer. It has many significant advantages when welding stainless steel big diameter welded tube. On the one hand, due to the coverage of the flux, it can effectively isolate the air and reduce the risk of oxidation and nitridation of the weld metal, thereby improving the purity and quality stability of the weld. On the other hand, submerged arc welding has a high current density, fast welding speed, and extremely high production efficiency, which is especially suitable for welding long welds such as large-diameter welded pipes.
Plasma welding is a welding method that uses plasma arc as a heat source. Its arc energy is highly concentrated and has strong penetrating power. For stainless steel big diameter welded tube
, especially when the pipe wall is thick, plasma welding can achieve one-time penetration to ensure the penetration depth and strength of the weld. Moreover, the weld of plasma welding is beautiful, the heat-affected zone is small, and the performance of the parent material is less affected, which is of great significance for some application scenarios with strict requirements on material properties, such as the pipe connection of chemical reactors. During the welding process, the stability of the plasma arc is good, and the welding process can be accurately controlled to ensure the consistency of the weld quality. ​
Compared with other welding methods, automatic welding technology has unique advantages in the application of stainless steel big diameter welded tube. First of all, in terms of production efficiency, automatic welding equipment can operate continuously and stably, greatly shortening the welding cycle. Compared with manual welding, its speed is increased by several times or even dozens of times, greatly improving the production capacity of enterprises. Secondly, in terms of quality stability, automatic welding avoids individual differences and fatigue factors in manual operation, and can operate strictly according to the preset welding parameters, so that the quality of each weld can be reliably guaranteed, and the defective rate of the product is significantly reduced. Furthermore, from a cost perspective, although the initial investment in automatic welding equipment is large, in the long run, due to the improvement of production efficiency and the reduction of scrap rate, the production cost per unit product has decreased, bringing better economic benefits to the enterprise. ​
However, the welding technology of stainless steel big diameter welded tube also faces some challenges in practical applications. Due to the complex alloy composition of stainless steel, defects such as thermal cracks and pores are prone to occur during welding. For example, elements such as nickel and chromium in some stainless steel materials will react with other impurities at high temperatures to form low-melting eutectics, thereby increasing the possibility of thermal cracks. Moreover, the large-diameter welded pipe has a large size, and the thermal stress distribution during welding is uneven, which can easily cause the welded pipe to deform, affecting its installation and use. With the development of industry, the performance requirements for stainless steel big diameter welded tube are getting higher and higher, such as higher corrosion resistance, stronger strength, etc. This requires continuous improvement of welding process, research and development of new welding materials and technologies to meet the increasingly stringent application requirements. ​
In order to meet these challenges, the industry is also constantly exploring new development directions. On the one hand, by optimizing welding process parameters, such as adjusting welding current, voltage, welding speed, etc., to reduce the occurrence of welding defects. At the same time, develop new welding materials, such as special welding wires and fluxes, to better match them with stainless steel base materials and improve the performance of welds. On the other hand, introduce advanced welding control technology, such as using artificial intelligence and automation systems to monitor various parameters in the welding process in real time, and adjust the welding process in time according to feedback information to achieve intelligent welding.