Stainless steel product containing B and method for production thereof
View Patent ↗A stainless steel slab containing B, wherein a protecting material is joined onto at least two faces across the bloom from each other in a stainless steel bloom containing B of 0.3–2.5 mass %, being integrated into one-piece by forming a weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by following formulas (1)–(4), and a method to produce a steel product by rolling said slab. Further, it is preferable to interpose an insert material between above stainless steel bloom and above protecting material in bonding process. 15≦Cr eq≦30 , (1) 4≦Cr eq −Ni eq ≦17, (2) Cr eq =Cr+1.5 Si+Mo−5 B, (3) Ni eq =Ni+30 (C+N)+0.5 Mn (4) Herein, each symbol of a chemical element designates the content (mass %) of relevant chemical element contained in steel. Accordingly, it makes it possible to subject a stainless steel slab containing B to hot working without generating edge cracking, so as to be used as a source material of a neutron shielding container and a separator of a fuel cell.
1. A stainless steel slab containing B, wherein a protecting material made of a stainless steel containing B of 0.3 mass % or less is joined onto at least two faces across the bloom from each other, excluding a working plane, in a stainless steel bloom containing B of 0.3–2.5 mass %, being integrated into one-piece by forming a weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by formulas (1)–(4) as below;
15≦Cr eq≦ 30 (1)
4≦Cr eq −Ni eq≦ 17 (2)
where,
Cr eq =Cr+1.5×Si+Mo−5×B (3)
Ni eq =Ni+30×(C+N)+0.5×Mn (4)
Herein, each symbol of a chemical element designates the content (mass %) of relevant chemical element contained in steel.
2. A stainless steel slab containing B according to claim 1 , wherein an insert material containing B of 0.4–2.5 mass % is interposed between above stainless steel bloom and above protecting material.
3. A stainless steel slab containing B according to claim 1 , wherein the thickness of above protecting material is 10 mm or more.
4. A stainless steel slab containing B according to claim 2 , wherein the thickness of above protecting material is 10 mm or more.
5. A method for production of a stainless steel product containing B, wherein a protecting material made of a stainless steel containing B of 0.3 mass % or less is joined onto at least two faces across the bloom from each other, excluding a working plane, in a stainless steel bloom containing B of 0.3–2.5 mass %, being integrated into one-piece by applying electron beam welding method to form an intervening weld metal comprising a stainless steel with chemical composition that satisfies the relationship expressed by formulas (1)–(4) as below, and subsequently subjected to heating followed by processing;
15≦Cr eq≦ 30 (1)
4≦Cr eq −Ni eq≦ 17 (2)
where,
Cr eq =Cr+1.5×Si+Mo−5×B (3)
Ni eq =Ni+30×(C+N)+0.5×Mn (4)
Herein, each symbol of a chemical element designates the content (mass %) of relevant chemical element contained in steel.
6. A method for production of a stainless steel product containing B according to claim 5 , wherein an insert material containing B of 0.4–2.5 mass % is interposed between above stainless steel bloom and above protecting material.
7. A method for production of a stainless steel product containing B according to claim 5 , wherein the thickness of above protecting material is 10 mm or more.
8. A method for production of a stainless steel product containing B according to claim 6 , wherein the thickness of above protecting material is 10 mm or more.
9. A neutron shielding container made by using a stainless steel product containing B that is produced by a method according to claim 5 .
10. A neutron shielding container made by using a stainless steel product containing B that is produced by a method according to claim 6 .
11. A separator of a fuel cell made by using a stainless steel product containing B that is produced by a method according to claim 5 .
12. A separator of a fuel cell made by using a stainless steel product containing B that is produced by a method according to claim 6 .