The mainstream welding and processing techniques for stainless steel plates are three types: Tungsten Inert Gas (TIG) welding, Shielded Metal Arc Welding (SMAW), and Gas Metal Arc Welding (GMAW) with inert shielding gas. Each has its own strengths and weaknesses, and in practical stainless steel plate welding operations, a flexible choice should be made based on the material used and the welding requirements.
Tungsten Inert Gas welding uses pure argon as a protective gas. During welding, it neither reacts chemically with the stainless steel plate nor dissolves in the molten metal, effectively preventing the burning of metal elements in the weld and other potential welding defects that may arise from this. Also, due to the higher density of this protective gas, it is less likely to float and dissipate during protection, offering good protection. This welding method is advantageous because the heat source and filler wire are independently controlled, making heat adjustment more convenient and allowing for easier control of the welding line energy input into the weld. Therefore, it is suitable for welding in various positions and easy to achieve single-sided welding with double-sided formation. However, the main disadvantage of TIG welding is its shallow penetration, slow deposition rate, and relatively low processing efficiency, which can lead to relatively greater deformation of the stainless steel plate during welding.
In comparison, SMAW offers higher flexibility and convenience in operation. The welding equipment is relatively simple and easy to move, and the equipment cost is cheaper than other arc welding methods, leading to its widespread application. However, compared to other welding methods such as GMAW and submerged arc welding, SMAW has a slower deposition rate and lower deposition factor. After each pass is welded, it is necessary to clean the slag thoroughly, and cleaning the slag inside the groove is more troublesome.
Gas Metal Arc Welding with inert shielding gas, commonly known as MIG welding, uses argon gas or a small amount of oxygen mixed with argon as a protective gas. This results in a stable arc, fine droplets, and stable transition, with minimal spatter. The welding method has a high current density and deep penetration of the base material, resulting in a high melting speed of the wire and a high welding speed of the weld, and high welding production efficiency, especially suitable for welding of medium and thick structures. However, the corresponding welding equipment is more complex and the equipment cost is higher.
When welding thin-walled pressure vessels made of stainless steel plates, due to their particularity and the requirements of relevant standards, the quality requirements for the back of the root pass of the weld are particularly high. For the root pass, TIG welding is superior to SMAW and GMAW with inert shielding gas, mainly because the heat source and filler wire are controlled separately, making heat adjustment convenient; and this welding method does not have high requirements for the operator's skill and the quality of the joint assembly. Therefore, for single-sided welding with double-sided formation, TIG welding is used for the root pass. Finally, it should be understood that when welding stainless steel plates, protective gas must be filled on the back to prevent oxidation reactions on the back of the weld.
1. Tungsten Inert Gas Welding
Tungsten Inert Gas welding uses pure argon as a protective gas. During welding, it neither reacts chemically with the stainless steel plate nor dissolves in the molten metal, effectively preventing the burning of metal elements in the weld and other potential welding defects that may arise from this. Also, due to the higher density of this protective gas, it is less likely to float and dissipate during protection, offering good protection. This welding method is advantageous because the heat source and filler wire are independently controlled, making heat adjustment more convenient and allowing for easier control of the welding line energy input into the weld. Therefore, it is suitable for welding in various positions and easy to achieve single-sided welding with double-sided formation. However, the main disadvantage of TIG welding is its shallow penetration, slow deposition rate, and relatively low processing efficiency, which can lead to relatively greater deformation of the stainless steel plate during welding.
2. Shielded Metal Arc Welding
In comparison, SMAW offers higher flexibility and convenience in operation. The welding equipment is relatively simple and easy to move, and the equipment cost is cheaper than other arc welding methods, leading to its widespread application. However, compared to other welding methods such as GMAW and submerged arc welding, SMAW has a slower deposition rate and lower deposition factor. After each pass is welded, it is necessary to clean the slag thoroughly, and cleaning the slag inside the groove is more troublesome.
3. Gas Metal Arc Welding with Inert Shielding Gas
Gas Metal Arc Welding with inert shielding gas, commonly known as MIG welding, uses argon gas or a small amount of oxygen mixed with argon as a protective gas. This results in a stable arc, fine droplets, and stable transition, with minimal spatter. The welding method has a high current density and deep penetration of the base material, resulting in a high melting speed of the wire and a high welding speed of the weld, and high welding production efficiency, especially suitable for welding of medium and thick structures. However, the corresponding welding equipment is more complex and the equipment cost is higher.When welding thin-walled pressure vessels made of stainless steel plates, due to their particularity and the requirements of relevant standards, the quality requirements for the back of the root pass of the weld are particularly high. For the root pass, TIG welding is superior to SMAW and GMAW with inert shielding gas, mainly because the heat source and filler wire are controlled separately, making heat adjustment convenient; and this welding method does not have high requirements for the operator's skill and the quality of the joint assembly. Therefore, for single-sided welding with double-sided formation, TIG welding is used for the root pass. Finally, it should be understood that when welding stainless steel plates, protective gas must be filled on the back to prevent oxidation reactions on the back of the weld.
