MARTENSITIC STAINLESS STEEL HAVING IMPROVED RESISTANCE TO SOFTENING AND MANUFACTURING METHOD THEREFOR

Disclosed in the present specification are a martensitic stainless steel and manufacturing method therefor, wherein the martensitic stainless steel is induced, through control over the alloy composition in terms of Cu, Nb, etc. and manufacturing method therefor, to form precipitates, such that the resistance thereof to softening is improved. According to an embodiment of the present invention, the martensitic stainless steel having an improved resistance to softening comprises, by weight %, 0.01-0.1% of C, 0.05-1.0% of Si, 0.05-1.0% of Mn, 11.0-14.0% of Cr, 0.05-1.0% of Ni, 0.5-2.0% of Cu, 0.03-0.08% of N, 0.02-0.5% of Nb, and the remainder of iron (Fe) and other unavoidable impurities, wherein Cu/Nb is 2-4, and the difference in hardness before and after a softening heat treatment may be greater than 0% and less than 10%. La présente invention concerne un acier inoxydable martensitique et son procédé de fabrication, l'acier inoxydable martensitique étant induit, par régulation de la composition d'alliage en termes de Cu, Nb, etc. et son procédé de fabrication, pour former des précipités, de telle sorte que sa résistance au ramollissement est améliorée. Selon un mode de réalisation de la présente invention, l'acier inoxydable martensitique ayant une résistance améliorée au ramollissement comprend, en % en poids, 0,01 à 0,1 % de C, 0,05 à 1,0 % de Si, 0,05 à 1,0 % de Mn, 11,0 à 14,0 % de Cr, 0,05 à 1,0 % de Ni, 0,5 à 2,0 % de Cu, 0,03 à 0,08 % de N, 0,02 à 0,5 % de Nb, et le reste de fer (Fe) et d'autres impuretés inévitables, où Cu/Nb va de 2 à 4, et la différence de dureté avant et après un traitement thermique de ramollissement peut être supérieure à 0 % et inférieure à 10 %. 본 명세서에서는, Cu 및 Nb 등의 합금조성과 제조방법 제어를 통해 석출물 형성을 유도하여 연화저항성을 향상시킨, 마르텐사이트계 스테인리스강 및 그 제조방법을 개시한다. 본 발명의 일 실시예에 따른 연화저항성이 향상된 마르텐사이트계 스테인리스강은, 중량%로, C: 0.01% 이상 0.1% 이하, Si: 0.05% 이상 1.0% 이하, Mn: 0.05% 이상 1.0% 이하, Cr: 11.0% 이상 14.0% 이하, Ni: 0.05% 이상 1.0% 이하, Cu: 0.5% 이상 2.0% 이하, N: 0.03% 이상 0.08% 이하, Nb: 0.02% 이상 0.5% 이하, Cu/Nb: 2 이상 4 이하, 잔부 Fe(철) 및 기타 불가피한 불순물을 포함하고, 연화열처리 전과 후의 경도 차이가 0% 초과 10% 미만일 수 있다.