304N Stainless Steel Plate

When strength meets corrosion resistance in demanding applications like nuclear reactors or cryogenic tanks, ASTM A240 Grade 304N (S30451) stainless steel plate provides a nitrogen-enhanced austenitic solution. We also call it A240 Gr 304N in technical circles (Gr for Grade), A240 SS 304N (SS for stainless steel), A240 TP 304N (TP for tubing plate, frequent in piping specs), or the classic AISI 304N plate (from the American Iron and Steel Institute). Whatever term you searched, you’re likely after a material that boosts the yield strength of standard 304 through 0.10-0.16% nitrogen addition, while keeping low carbon for weldability and a PREN of 20-22 for mild corrosives.

  ASTM A240 Grade 304N (UNS S30451) is a nitrogen-strengthened, low-carbon austenitic stainless steel under ASTM A240 for chromium-nickel plates, sheets, and strips in pressure vessels and general service. It modifies standard 304 by adding 0.10-0.16% nitrogen for solid-solution hardening, increasing yield strength by 20-30% while maintaining excellent ductility and weldability—ideal for high-stress applications where phase stability is crucial, like nuclear fuel elements or cryogenic vessels. Low carbon (≤0.08%) curbs sensitization in the 425-870°C HAZ, passing ASTM A262 Practice E without annealing in many cases. Born from needs for stronger 304 in the 1970s nuclear boom, 304N uses N to interstitially strengthen without carbides or exotics.