Joining structure and method for manufacturing joining structure
AssigneeKabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
InventorsKyohei MAEDA, Tetsu IWASE
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Abstract
A joint structure including a first member, a second member superposed on the first member, a steel insertion member, and a welded part formed on an insertion tip of the insertion member. Each of the first member and the second member includes a high tensile strength steel. The steel insertion member is held by the second member in a state of having been inserted toward a superposition surface between the first member and the second member from a surface of the second member opposite the superposition surface. A carbon equivalent Ceq of the insertion member is lower than a carbon equivalent Ceq of the second member, where Ceq=C+Si/30+Mn/20+2P+4S.
Claims20
A joint structure comprising:
- a first member comprising a high tensile strength steel;
- a second member comprising a high tensile strength steel and superposed on the first member:
- a steel insertion member held by the second member in a state of having been inserted toward a superposition surface between the first member and the second member from a surface of the second member opposite the superposition surface;
- and
- a welded part formed on an insertion tip of the insertion member by melting the insertion member and the first member,
- wherein a carbon equivalent Ceq of the insertion member is lower than a carbon equivalent Ceq of the second member, wherein the carbon equivalent Ceq is a value defined by formula (1):
- Ceq=C+Si/30+Mn/20+2P+4S (1)
- wherein C, Si, Mn, P and S each represent a content, in mass %, of each element, and when the element is not contained, the content thereof is 0.
A joint structure comprising:
- a first member comprising a high tensile strength steel;
- a second member comprising a high tensile strength steel and superposed on the first member;
- a pair of steel insertion members held by the first member and the second member, respectively, in a state of having been inserted toward a superposition surface between the first member and the second member from each surface of the first member and the second member opposite the superposition surface, and
- a welded part formed on insertion tips of the pair of the insertion members by melting the insertion members each other,
- wherein a carbon equivalent Ceq (M1) of the first member, a carbon equivalent Ceq (M2) of the second member, a carbon equivalent Ceq (N1) of the insertion member inserted in the second member and a carbon content Ceq (N2) of the insertion member inserted in the first member satisfy relationships (1) and (2):
- Ceq=C+Si/30+Mn/20+2P+4S (1)
- wherein C, Si, Mn, P and S each represent a content, in mass %, of each element, and when the element is not contained, the content thereof is 0;
- and
- Ceq(M1)+Ceq(M2)≥Ceq(N1)+Ceq(N2) (2).
A method for manufacturing a joint structure by joining a first member comprising a high tensile strength steel and a second member comprising a high tensile strength steel, the method comprising:
- inserting a steel insertion member into the second member and holding it;
- and
- superposing the second member on the first member and forming a welded part of the insertion member and the first member in an insertion tip of the insertion member,
- wherein a carbon equivalent Ceq of the insertion member is lower than a carbon equivalent Ceq of the second member, wherein the carbon equivalent Ceq is a value defined by formula (1):
- Ceq=C+Si/30+Mn/20+2P+4S (1)
- wherein C, Si, Mn, P and S each represent a content, in mass %, of each element, and when the element is not contained, the content thereof is 0.
A method for manufacturing a joint structure by joining a first member comprising a high tensile strength steel and a second member comprising a high tensile strength steel, the method comprising:
- inserting steel insertion members into the first member and the second member, respectively, and holding them;
- and
- superposing the second member on the first member so that the insertion members face each other, and forming a welded part from these insertion members in insertion tips of the insertion members,
- wherein a carbon equivalent Ceq (M1) of first member, a carbon equivalent Ceq (M2) of the second member, a carbon equivalent Ceq (N1) of the insertion member inserted in the second member and a carbon content Ceq (N2) of the insertion member inserted in the first member satisfy relationships (1) and (2):
- Ceq=C+Si/30+Mn/20+2P+4S (1)
- wherein C, Si, Mn, P and S each represent a content, in mass %, of each element, and when the element is not contained, the content thereof is 0;
- and
- Ceq(M1)+Ceq(M2)≥Ceq(N1)+Ceq(N2) (2).
Dependencies are inferred from the claim text.