Stainless　steel　exhibits　several　advantages　as　structural　material,　however　its　applications　are　limited　due　to　the　high　cost.　A　novel　stainless　steel,　S35657,　which　replaced　the　valuable　nickel　element　with　cheap　nitrogen,　was　designed　to　make　its　use　more　economical.　This　study　aims　to　clarify　the　potential　structural　application　of　the　novel　stainless　steel.　Tensile　tests　were　firstly　conducted　to　investigate　the　effect　of　steel　rolling　direction,　cold-forming　enhancement　and　welding　on　the　behaviour　of　grade　S35657,　with　comparisons　made　to　commonly　used　stainless　steel　S30408　and　mild　steel　Q355.　The　test　results　revealed　that　S35657　grade　exhibited　higher　strength　compared　to　stainless　steel　S30408,　attributed　to　the　added　nitrogen　element.　The　post-fire　behaviour　of　S35657　up　to　1200　°C　under　unloaded　conditions　was　tested,　alongside　its　post-cold-forming　behaviour.　This　thermo-mechanical　property　characterisation　indicated　no　significant　strength　deterioration　until　the　exposed　temperature　exceeded　800　°C,　although　the　benefits　of　cold-forming　diminished　above　500　°C.　Based　on　the　test　results,　the　existing　stress–strain　model　was　modified　to　accurately　represent　the　pre-　and　post-fire　stress–strain　response　for　grade　S35657.　Finally,　1269　test　data　of　S35657　stainless　steel　were　collected　and　statistically　analysed.　The　partial　resistance　factor　of　grade　S35657　was　determined　as　1.15　when　the　standard　value　of　nominal　yield　strength　was　selected　as　381.9　MPa.　©　2025　Elsevier　Ltd