The reasons are as follows: 6.
1. Stable austenitic structure: Austenitic stainless steel maintains its austenitic crystal structure during the welding process. Unlike other stainless steels that may undergo phase transformation during welding, this stabilized austenitic structure minimizes the risk of welding-induced brittleness and cracking.
2. Low thermal conductivity: Compared with some other metals, the thermal conductivity of austenitic stainless steel is relatively low. This feature helps concentrate heat in the welding area, allowing for better control of the welding process. Slower cooling rates are associated with lower thermal conductivity, which helps reduce susceptibility to cracking.
3. High nickel content: The high nickel content in austenitic stainless steel contributes to its stability and ductility during welding. Because nickel helps prevent the formation of brittle phases and enhances the material's ability to absorb thermal expansion stresses without cracking.
4. Low Carbon Content: Low carbon versions of austenitic stainless steels are often used in welding applications. The low carbon content minimizes the formation of chromium carbides at grain boundaries, thereby reducing susceptibility to intergranular corrosion during welding.
5. Corrosion resistance: Austenitic stainless steel is known for its excellent corrosion resistance, and this corrosion resistance can still be maintained in the heat-affected zone during the welding process. This corrosion resistance ensures that the welded joint retains its protective passivation layer, preventing corrosion-related problems.
6. Ductility and toughness: Austenitic stainless steel has high ductility and toughness, allowing it to deform and absorb stress during the welding process. This ductility helps prevent the occurrence and expansion of cracks.
Due to their high chromium content (16-30%), austenitic stainless steels have good corrosion resistance at both low and high temperatures.
Generally speaking, austenitic stainless steel is non-magnetic and may become slightly magnetic after cold working. See this article for the specific reasons.
Regarding the magnetism of austenitic stainless steels, I would add that the magnetic properties of austenitic stainless steel weld metals will actually vary from non-magnetic (like fully austenitic stainless steels 310, 320 and 330) to significantly magnetic (like fully austenitic stainless steels 310, 320 and 330). Such as 312 stainless steel), in which the ferrite content is the phase that causes magnetism.
The most common austenitic stainless steels, such as 308(L), 309(L), 316(L), and 347, are slightly magnetic due to the presence of some ferrite. Although fully annealed austenitic stainless steels are non-magnetic, cold working of lower alloy grades such as 304 may produce some degree of magnetism.