Abstract: Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm2 if hot-formed or hot-rolled; and measuring 800 mm2 if cold-rolled, does not contain non-metallic inclusions of diameter >10 ?m, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 ?m over 100 mm2, the observation being performed by image analysis over a polished surface measuring 650 mm2.

Abstract: Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm2 if hot-formed or hot-rolled; and measuring 800 mm2 if cold-rolled, does not contain non-metallic inclusions of diameter>10 ?m, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 ?m over 100 mm2, the observation being performed by image analysis over a polished surface measuring 650 mm2.

Abstract: Disclosed is a steel whose composition includes specified wt % of: Ni, Mo, Co, Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Y+Ta+Cr+C+Al+B+Ti+N, Ni+Co+Mo, Al, Ti, N, Si, Mn, C, S, P, B, H, O, Cr, Cu, W, Zr, Ca, Mg, Nb, V, Ta, Y, the remainder being iron and impurities resulting from production. The inclusion population, observed by image analysis on a polished surface of 650 mm2 if the steel is in the form of a hot-formed part or a hot-rolled sheet and 800 mm2 if the steel is in the form of a cold-rolled sheet, does not include non-metal inclusions of an equivalent diameter greater than 10 ?m. Also disclosed are a product created from the steel, and a manufacturing method.

Abstract: Disclosed is a steel whose composition includes specified wt % of: Ni, Mo, Co, Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Y+Ta+Cr+C+Al+B+Ti+N, Ni+Co+Mo, Al, Ti, N, Si, Mn, C, S, P, B, H, O, Cr, Cu, W, Zr, Ca, Mg, Nb, V, Ta, Y, the remainder being iron and impurities resulting from production. The inclusion population, observed by image analysis on a polished surface of 650 mm2 if the steel is in the form of a hot-formed part or a hot-rolled sheet and 800 mm2 if the steel is in the form of a cold-rolled sheet, does not include non-metal inclusions of an equivalent diameter greater than 10 ?m. Also disclosed are a product created from the steel, and a manufacturing method.

Abstract: Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm2 if hot-formed or hot-rolled; and measuring 800 mm2 if cold-rolled, does not contain non-metallic inclusions of diameter >10 ?m, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 ?m over 100 mm2, the observation being performed by image analysis over a polished surface measuring 650 mm2.