Flux-cored wire for welding ultrahigh tensile strength steel
View Patent ↗In a flux-cored wire for welding an ultrahigh tensile strength steel, one or more of CaF2, BaF2, SrF2, and MgF2 are included in the wire and, when a total amount thereof is defined as α, the α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire, one or more of Ti oxide, Si oxide, Mg oxide, and Al oxide are included in the wire and, when a total amount thereof is defined as β, the β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire, a ratio of an amount of the CaF2 with respect to the α is 0.50 or more, a ratio of the α with respect to the β is 2.0 to 800.0, and Ceq defined in the following expression is 0.60% to 1.20%, Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14.
1. A flux-cored wire for welding an ultrahigh tensile strength steel, which is a flux-cored wire for gas-shielded arc welding, the flux-cored wire comprising:
an outer steel sheath; and
a flux filled into the outer steel sheath,
wherein the flux comprises:
CaF 2 , alone or in combination with one or more selected from the group consisting of BaF 2 , SrF 2 , and MgF 2 , wherein a total amount thereof is defined as α, and α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire,
one or more selected from the group consisting of Ti oxide, Si oxide, Mg oxide, and Al oxide, wherein a total amount thereof is defined as β, and β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire,
one or more selected from the group consisting of CaCO 3 , BaCO 3 , SrCO 3 , and MgCO 3 , wherein a total amount thereof is 0% or more and less than 0.60% in terms of mass % with respect to the total mass of the wire, and
iron powder in an amount of 0% or more and less than 5.0% in terms of mass % with respect to the total mass of the wire,
wherein a ratio of an amount of the CaF 2 with respect to the α is 0.50 or more,
wherein a ratio of the α with respect to the β is 2.0 to 800.0,
wherein the flux-cored wire comprises C, Si, Mn, Al, Ni, V, P, S, Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, REM, and a remainder iron and impurities, and wherein a total amount of each of these components in an outer skin and the flux, in terms of mass % with respect to the total mass of the wire, is:
C: more than 0.080% and equal to or less than 0.200%,
Si: 0.05% to 1.50%,
Mn: 1.0% to 2.2%,
Al: 0.001% to 0.400%,
Ni: 1.0% to 9.0%,
V: more than 0.050% and equal to or less than 0.300%,
P: 0.020% or less,
S: 0.020% or less,
Cu: 0% to 0.800%,
Cr: 0% to 2.5%,
Mo: 0% to 2.0%,
Ti: 0% to 0.300%,
Nb: 0% to 0.05%,
B: 0% to 0.0100%,
Mg: 0% to 0.8%,
Ca: 0% to 0.5%, and
REM: 0% to 0.0100%, and
Ceq defined in following Expression (a) is 0.60% to 1.20%,
Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14 (a)
in which elements noted in brackets represent amounts of the respective elements in terms of mass %.
2. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 ,
wherein an amount of CaO in the wire is less than 0.15% in terms of mass % with respect to the total mass of the wire.
3. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 or 2 ,
wherein the ratio of the amount of CaF 2 with respect to the α is 0.90 or more.
4. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 ,
wherein in a tensile test of a deposited metal which is defined in Japanese Industrial Standards JIS Z 3111-2005 with respect to gas-shielded arc welding using the wire, tensile strength of the deposited metal is 950 MPa to 1500 MPa.
5. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 ,
wherein a slit-shaped gap does not exist in the outer steel sheath.
6. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 ,
wherein a perfluoropolyether oil is applied onto a surface of the wire.
7. A welding method using a flux-cored wire for gas-shielded arc welding, the method comprising gas-shielded arc welding a steel plate with a wire, wherein
the wire includes:
an outer steel sheath; and
a flux filled into the outer steel sheath, and wherein the flux comprises:
CaF 2 , alone or in combination with one or more selected from the group consisting of BaF 2 , SrF 2 , and MgF 2 , wherein a total amount thereof is defined as α, and α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire,
one or more selected from the group consisting of Ti oxide, Si oxide, Mg oxide, and Al oxide, wherein a total amount thereof is defined as β, and β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire,
one or more selected from the group consisting of CaCO 3 , BaCO 3 , SrCO 3 , and MgCO 3 , wherein a total amount thereof is 0% or more and less than 0.60% in terms of mass % with respect to the total mass of the wire, and
iron powder in an amount of 0% or more and less than 5.0% in terms of mass % with respect to the total mass of the wire,
wherein a ratio of an amount of the CaF 2 with respect to the α is 0.50 or more, wherein a ratio of the α with respect to the β is 2.0 to 800.0,
a total amount of an oxides of Na or K or fluorides of Na or K is 0.001% to 0.40% in terms of mass % with respect to the total mass of the wire,
wherein the flux-cored wire comprises C, Si, Mn, Al, Ni, V, P, S, Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, REM, and a remainder iron and impurities, and wherein a total amount of each of these components in an outer skin and the flux, in terms of mass % with respect to the total mass of the wire, is:
C: more than 0.080% and equal to or less than 0.200%,
Si: 0.05% to 1.50%,
Mn: 1.0% to 2.2%,
Al: 0.001% to 0.400%,
Ni: 1.0% to 9.0%,
V: more than 0.050% and equal to or less than 0.300%,
P: 0.020% or less,
S: 0.020% or less,
Cu: 0% to 0.800%,
Cr: 0% to 2.5%,
Mo: 0% to 2.0%,
Ti: 0% to 0.300%,
Nb: 0% to 0.05%,
B: 0% to 0.0100%,
Mg: 0% to 0.8%,
Ca: 0% to 0.5%, and
REM: 0% to 0.0100%, and
Ceq defined in following Expression a is 0.60% to 1.20%,
Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14 (a),
in which elements noted in brackets represent amounts of the respective elements in terms of mass %.
8. The welding method according to claim 7 ,
wherein an amount of CaO in the wire is less than 0.15% in terms of mass % with respect to the total mass of the wire.
9. The welding method according to claim 7 or 8 ,
wherein the ratio of the amount of CaF 2 with respect to the α is 0.90 or more.
10. The welding method according to claim 7 ,
wherein in a tensile test of a deposited metal which is defined in Japanese Industrial Standards JIS Z 3111-2005 with respect to gas-shielded arc welding using the wire, tensile strength of the deposited metal is 950 MPa to 1500 MPa.
11. The welding method according to claim 7 ,
wherein a slit-shaped gap does not exist in the outer steel sheath.
12. The welding method according to claim 7 ,
wherein a perfluoropolyether oil is applied onto a surface of the wire.
13. A manufacturing method for a weld joint,
wherein a tensile strength of the steel sheet is 950 MPa or more in the welding method according to claim 7 .
14. A weld joint manufactured by the manufacturing method for the weld joint according to claim 13 , the weld joint comprising:
the steel plate having the tensile strength of 950 MPa or more; and
a weld metal.
15. The weld joint according to claim 14 ,
wherein a tensile strength of the weld metal is 950 MPa or more.
16. The flux-cored wire for welding an ultrahigh tensile strength steel according to claim 1 , wherein an amount of CaO in the wire is 0.10% or less in terms of mass % with respect to the total mass of the wire.