Stainless steel sheet for welded structural components and method for making the same

A stainless steel sheet comprising:

• less than abut 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• about 2.0 mass percent or less of Mo;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (5), (6), and (7) are satisfied:
• (C)+(N)≦0.015 (3)(Cr)+1.2×(Ni)+1.5×(Mo)≧15.0 (5)(Ni)+0.5×((Mn)+(Mo))+30×(C)≦3.0 (6)(Cr)+0.8×(Mo)−(Mn)−1.7×(Ni)−27×(C)−100×(N)≧9.0 (7)
• where (Cr), (Mo), (Ni), (Mn), (C), and (N) represent Cr, Mo, Ni, Mn, C, and N contents on a mass percent basis, respectively.

A stainless steel sheet comprising:

• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to about 15 mass percent of Cr;
• more than abpit 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• at least one of about 2 mass percent or less of Cu and about 2 mass percent or less of Co;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (8), (9), and (10) are satisfied:
• (C)+(N)≦0.015 (3)(Cr)+1.2×(Ni)+0.5×(Cu)+0.3×(Co)≧15.0 (8)(Ni)+0.5×((Mn)+(Cu))+30×(C)≦3.0 (9)(Cr)−(Mn)−1.7×(Ni)−27×(C)−100×(N)−0.3×(Cu)≧9.0 (10)
• where (Cr), (Ni), (Mn), (Cu), (Co), (C), and (N) represent Cr, Ni, Mn, Cu, Co, C, and N contents on a mass percent basis, respectively.

A stainless steel sheet comprising:

• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to about 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• about 2.0 mass percent or less of Mo;
• at least one of about 2 mass percent or less of Cu and about 2 mass percent or less of Co;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (11), (12), and (13) are satisfied:
• (C)+(N)≦0.015 (3)(Cr)+1.2×(Ni)+1.5×(Mo)+0.5×(Cu)+0.3×(Co)≧15.0 (11)(Ni)+0.5×((Mn)+(Mo)+(Cu))+30×(C)≦3.0 (12)(Cr)+0.8×(Mo)−(Mn)−1.7×(Ni)−27×(C)−100×(N)−0.3×(Cu)≧9.0 (13)
• where (Cr), (Mo), (Ni), (Mn), (Cu), (Co), (C), and (N) represent Cr, Mo, Ni, Mn, Cu, Co, C, and N contents on a mass percent basis, respectively.

A method for making a hot-rolled stainless steel sheet, comprising the steps of:

• hot-rolling a steel slab;
• annealing the hot-rolled sheet;
• and
• optionally, pickling the hot-rolled sheet,
• wherein the steel slab comprises:
• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to bout 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (1) to (4) are satisfied:
• (Cr)+1.2×(Ni)≧15.0 (1)(Ni)+0.5×(Mn)+30×(C)≦3.0 (2)(C)+(N)≦0.015 (3)(Cr)−(Mn)−1.7×(Ni)−27×(C)−100×(N)≧9.0 (4)
• where (Cr), (Ni), (Mn), (C), and (N) represent Cr, Ni, Mn, C, and N contents on a mass percent basis, respectively.

A method for making a hot-rolled stainless steel sheet, comprising the steps of:

• hot-rolling a steel slab;
• annealing the hot-rolled sheet;
• and
• optionally, pickling the hot-rolled sheet,
• wherein the steel slab comprises:
• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to about 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• about 2.0 mass percent or less of Mo;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (5), (6), and (7) are satisfied:
• (C)+(N)≦0.015 (3)(Cr)+1.2×(Ni)+1.5×(Mo)≧15.0 (5)(Ni)+0.5×((Mn)+(Mo))+30×(C)≦3.0 (6)(Cr)+0.8×(Mo)−(Mn)−1.7×(Ni)−27×(C)−100×(N)≧9.0 (7)
• where (Cr), (Mo), (Ni), (Mn), (C), and (N) represent Cr, Mo, Ni, Mn, C, and N contents on a mass percent basis, respectively.

A method for making a hot-rolled stainless steel sheet, comprising the steps of:

• hot-rolling a steel slab;
• annealing the hot-rolled sheet, and
• optionally, pickling the hot-rolled sheet,
• wherein the steel slab comprises:
• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to about 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• at least one of about 2 mass percent or less of Cu and about 2 mass percent or less of Co;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (8), (9), and (10) are satisfied:
• (C)+(N)<0.015 (3)(Cr)+1.2×(Ni)+0.5×(Cu)+0.3×(Co)≧15.0 (8)(Ni)+0.5×((Mn)+(Cu))+30×(C)≦3.0 (9)(Cr)−(Mn)−1.7×(Ni)−27×(C)−100×(N)−0.3×(Cu)≧9.0 (10)
• where (Cr), (Ni), (Mn), (Cu), (Co), (C), and (N) represent Cr, Ni, Mn, Cu, Co, C, and N contents on a mass percent basis, respectively.

A method for making a hot-rolled stainless steel sheet, comprising the steps of:

• hot-rolling a steel slab;
• annealing the hot-rolled sheet;
• and
• optionally, pickling the hot-rolled sheet,
• wherein the steel slab comprises:
• less than about 0.008 mass percent of C;
• about 1.0 mass percent or less of Si;
• about 1.5 mass percent or less of Mn;
• about 11 to about 15 mass percent of Cr;
• more than about 1.0 mass percent and about 2.5 mass percent or less of Ni;
• less than about 0.10 mass percent of Al;
• about 0.009 mass percent or less of N;
• about 0.04 mass percent or less of P;
• about 0.01 mass percent or less of S;
• about 2.0 mass percent or less of Mo;
• at least one of about 2 mass percent or less of Cu and about 2 mass percent or less of Co;
• and
• the balance being Fe and incidental impurities,
• wherein expressions (3), (11), (12), and (13) are satisfied:
• (C)+(N)≦0.015 (3)(Cr)+1.2×(Ni)+1.5×(Mo)+0.5×(Cu)+0.3×(Co)≧15.0 (11)(Ni)+0.5×((Mn)+(Mo)+(Cu))+30×(C)≦3.0 (12)(Cr)+0.8×(Mo)−(Mn)−1.7×(Ni)−27×(C)−100×(N)−0.3×(Cu)≧9.0 (13)
• where (Cr), (Mo), (Ni), (Mn), (Cu), (Co), (C), and (N) represent Cr, Mo, Ni, Mn, Cu, Co, C, and N contents on a mass percent basis, respectively.