(1) manual arc welding
Manual arc welding is a welding method by manually operating arc covered electrode. In manual arc welding, the covered electrode and the workpiece are locally heated to a molten state by the arc generated between the covered electrode and the workpiece, and the droplets at the end of the covered electrode fuse with the molten base metal to form a molten pool. As the arc moves forward, the liquid metal in the molten pool gradually cools and crystallizes to form a weld. Manual arc welding of stainless steel is the most widely used, which can be used to weld all kinds of stainless steel. It is characterized by small heat affected zone, easy quality assurance, simple equipment and flexible operation, and is suitable for various welding positions and different plate thicknesses. Now stainless steel covered electrode can basically meet the welding requirements of various stainless steels, and there is almost no restriction on the choice of covered electrode.
The disadvantage is low production efficiency; Poor working conditions; The requirements for welders are high, and on many occasions, welders must have considerable qualifications; The welding deposited metal of some materials can not meet the use requirements, such as ultra-high purity stainless steel; Generally, thin plates with workpiece thickness below 1mm are not suitable for manual arc welding.
(2) Automatic submerged arc welding is to cover the welding arc with a layer of granular meltable flux. A welding method without exposing arc light. At present, it is mainly used for welding austenitic stainless steel plates, which is characterized by large welding current, large penetration depth and small workpiece groove. High welding speed and high production efficiency; The solidification of weld metal is slow, and the metallurgical reaction between liquid metal and molten flux takes more time, which reduces the possibility of porosity in weld. The weld seam is beautiful, the working environment is good, the operation is easy, and the requirements for welders are relatively simple.
The disadvantages are large welding heat input, wide heat affected zone and coarse weld structure; Special consideration should be given to the cooperation between welding wire and flux when selecting materials; The welding position can only be the flat welding position; The relative position between the arc and the groove cannot be observed directly, and there must be an automatic tracking device.
(3) tungsten inert gas shielded welding
TIG welding can be divided into manual welding, semi-automatic welding and automatic welding. argon tungsten-arc welding
It is widely used in stainless steel. Suitable for all-position welding, generally no splash, beautiful weld. It is especially suitable for the welding of thin parts. GIG is often used as a gasket when welding the grooves of many thick parts, thus avoiding manual electrification.
Arc welding is prone to cracks and difficult to remove slag. Inert gas can effectively isolate air, is insoluble in metal and does not react with metal, and can ensure the chemical composition requirements of stainless steel.
The disadvantages are deep melting, slow deposition speed, low production efficiency and high production cost.
(4) Metal electrode gas shielded welding
GMAW uses the arc between the fusible welding wire and the workpiece to be welded as a heat source to melt the welding wire and the base metal, and sends shielding gas to the welding area to form the arc, the molten welding wire and the molten pool.
Near the parent metal should avoid contact with ambient air. The continuously supplied welding wire metal is continuously melted and transferred to the molten pool, and fused with the molten base metal to form welding metal, thereby connecting the workpieces. Melting electrode gas
Protective welding can be automatic welding or semi-automatic welding.
Metal electrode gas shielded welding can be divided into metal inert gas shielded welding (MIG), metal electrode oxidation gas shielded welding (MAG), CO2 gas shielded welding and flux-cored wire gas shielded welding.
Metal inert gas (MIG) is widely used in stainless steel welding. Argon, helium or their mixture are usually used as shielding gas in the welding zone. Because there is no coating on the surface of welding wire.
The layer and current can be greatly improved, so the base metal has a large penetration depth, the welding wire has a fast melting speed and a high deposition rate. Compared with TIG welding, it can greatly improve the production efficiency. It is especially suitable for welding medium and heavy plates.
(5) plasma arc welding
Plasma arc is a kind of compressed arc. Because the arc segment is slightly compressed, the energy is concentrated, the temperature is high and the flame flow speed is fast. Therefore, plasma arc welding can be fully penetrated within a certain range of parent metal thickness, especially for stainless steel pipes.
Longitudinal seam welding. Compared with TIG welding, plasma arc welding has the advantages of faster welding speed, better arc flatness and greater thermal influence, and can weld very thin workpieces, the thinnest of which can reach 0.025 mm
Hope to adopt, thank you.