"Stainless steel never rusts":Incorrect.Stainless steel can rust (e.g., through pitting corrosion, stress corrosion cracking, intergranular corrosion) in highly corrosive environments, with poor maintenance, when its surface is contaminated (e.g., by carbon steel dust or salt), or if the passive film is damaged and cannot self-repair in the specific environment.

Nickel alloys play an irreplaceable role in extreme environments (high temperature, corrosion, high stress) due to their exceptional properties. Different grades of nickel alloys are suited for various industrial applications, and selecting the appropriate alloy requires careful consideration of temperature, corrosive media, and mechanical requirements. With advancements in materials science, new nickel alloys (e.g., those optimized for additive manufacturing) continue to emerge, offering even greater possibilities for industrial progress.

There is no definitive answer as to which type of stainless steel pipe is superior—welded or seamless—as the optimal choice depends entirely on the specific application and operating conditions. Historically, seamless pipes were the only option for stainless steel piping. However, advancements in metallurgy and welding technology have significantly improved the quality of welded pipes, making them nearly comparable to seamless pipes in many scenarios.