FLUX-CORED WIRE, MANUFACTURING METHOD OF WELDED JOINT, AND WELDED JOINT

• US 20190329347A1
• Filed: 11/08/2016
• Published: 10/31/2019
• Est. Priority Date: 11/08/2016
• Status: Active Grant

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel Corporation
• Inventors: FUJIMOTO, Hiroki, WATANABE, Kotaro, TOTSUKA, Yasuhito
• Granted Patent: US 11,400,539 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2101/18 Sheet panels
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• CPC Class Codes: B23K 35/0266 flux-cored
• CPC Class Codes: B23K 35/3073 with Mn as next major constituent
• CPC Class Codes: B23K 35/36 Selection of non-metallic compositions, e.g. coatings, fluxes B23K35/34 takes precedence; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest selection of soldering or welding materials proper B23K35/24
• CPC Class Codes: B23K 35/3602 Carbonates, basic oxides or hydroxides
• CPC Class Codes: B23K 35/3605 Fluorides
• CPC Class Codes: B23K 35/362 Selection of compositions of fluxes B23K35/365, B23K35/368 take precedence
• CPC Class Codes: B23K 9/025 for rectilinear seams
• CPC Class Codes: B23K 9/164 making use of a moving fluid
• CPC Class Codes: B23K 9/167 and of a non-consumable electrode
• CPC Class Codes: B23K 9/173 and of a consumable electrode
• CPC Class Codes: B23K 9/1735 making use of several electrodes
• CPC Class Codes: B23K 9/23 taking account of the properties of the materials to be welded
• CPC Class Codes: B23K 9/24 Features related to electrodes form or composition of electrodes B23K35/00
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/005 containing rare earths, i.e. Sc, Y, Lanthanides
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/42 with copper
• CPC Class Codes: C22C 38/44 : with molybdenum or tungsten
• CPC Class Codes: C22C 38/46 : with vanadium
• CPC Class Codes: C22C 38/48 : with niobium or tantalum
• CPC Class Codes: C22C 38/50 : with titanium or zirconium
• CPC Class Codes: C22C 38/54 : with boron
• CPC Class Codes: C22C 38/58 : with more than 1.5% by weight of manganese

Abstract

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO₂ equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF₂ is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

Claims

1. A flux-cored wire comprising:

a steel sheath; and

a flux filling the inside of the steel sheath,

wherein the flux contains

a fluoride including 0.11% or more in total of one or two or more selected from the group consisting of CaF₂, MgF₂, LiF, NaF, K₂ZrF₆, BaF₂, K₂SiF₆, and Na₃AlF₆ in terms of F-equivalent value with respect to a total mass of the flux-cored wire,

4.30% to 7.50% of a Ti oxide in terms of TiO₂-equivalent value with respect to the total mass of the flux-cored wire,

0.30% to 2.40% in total of an oxide including one or two or more selected from the group consisting of a Fe oxide, a Ba oxide, a Na oxide, a Si oxide, a Zr oxide, a Mg oxide, an Al oxide, a Mn oxide, and a K oxide in terms of equivalent value of each of FeO, BaO, Na₂O, SiO₂, ZrO₂, MgO, Al₂O₃, MnO₂, and K₂O with respect to the total mass of the flux-cored wire, excluding the Ti oxide and a Ca oxide, and

0% to 0.60% in total of a carbonate including one or two or more selected from the group consisting of MgCO₃, Na₂CO₃, LiCO₃, CaCO₃, K₂CO₃, BaCO₃, FeCO₃, and MnCO₃ in terms of mass % with respect to the total mass of the flux-cored wire,

an amount of the Ca oxide in terms of CaO equivalent is 0% or more and less than 0.20% in terms of mass % with respect to the total mass of the flux-cored wire,

an amount of the CaF₂ is 0% or more and less than 0.50% in terms of mass % with respect to the total mass of the flux-cored wire,

a chemical composition of the flux-cored wire excluding the fluoride, the oxide, the Ti oxide, the Ca oxide, and the carbonate includes, in terms of mass % with respect to the total mass of the flux-cored wire,

C;

0.003% to 0.120%,

Si;

0.45% to 1.00%,

Mn;

1.00% to 3.50%,

P;

0.030% or less,

S;

0.020% or less,

Al;

0.08% to 0.70%,

Cu;

0% to 0.50%,

Ni;

0% to 0.60%,

Cr;

0% to 1.00%,

Mo;

0% to 1.00%,

Nb;

0% to 0.20%,

V;

0% to 0.200%,

Ti;

0% to 0.10%,

B;

0% to 0.020%,

Bi;

0% to 0.030%,

Mg;

0% to 0.90%,

Ca;

0% to 0.50%,

REM;

0% to 0.0100%, and

a remainder consisting of Fe and impurities,

a Z value calculated by Formula 1 is 2.00% or less,

a V value calculated by Formula 2 is 5.0 to 27.0, and

Ceq calculated by Formula 3 is 0.30% to 1.00% or less,

Z=0.7×

([Na₃AlF₆]+[NaF]+[MgF₂])+0.8×

([K₂SiF₆]+[K₂ZrF₆])+0.9×

([LiF]+[BaF₂])+3.5×

([CaF₂]);

 

 

Formula 1

V=([TiO₂]+1.2×

[SiO₂]+1.4×

[Al₂O₃]+1.5×

[ZrO₂])/(F)^1/2;

 

 

Formula 2

Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14;

 

 

Formula 3

where each chemical formula enclosed by square brackets in Formula 1 indicate an amount of a compound corresponding to the chemical formula in terms of mass % with respect to the total mass of the flux-cored wire, each chemical formula enclosed by square brackets in Formula 2 indicates an amount of a compound corresponding to the chemical formula in terms of equivalent values of the compounds with respect to the total mass of the flux-cored wire, F in Formula 2 indicates a total amount of the fluoride in terms of F-equivalent value, and each element symbol enclosed by square brackets in Formula 3 indicates an amount of an element corresponding to the element symbol contained in the chemical composition of the flux-cored wire excluding the fluoride, the oxide, the Ti oxide, the Ca oxide, and the carbonate in terms of mass % with respect to the total mass of the flux-cored wire.

2. The flux-cored wire according to claim 1,

wherein the total amount of the fluoride in terms of the F-equivalent value with respect to the total mass of the flux-cored wire is 0.50% or more.

3. The flux-cored wire according to claim 1,

wherein the Z value is 1.80% or less.

4. The flux-cored wire according to claim 1,

wherein a total amount of the Na₃AlF₆, the NaF, and the MgF₂ in terms of mass % with respect to the total mass of the flux-cored wire to a total amount of the fluoride in terms of mass % with respect to the total mass of the flux-cored wire is 0.50% or more.

5. The flux-cored wire according to claim 1,

wherein the steel sheath has a seamless shape.

6. The flux-cored wire according to claim 1,

wherein the steel sheath has a slit-like gap.

7. The flux-cored wire according to claim 1, further comprising:

a perfluoropolyether oil applied to a surface of the flux-cored wire.

8. The flux-cored wire according to claim 1,

wherein an amount of hydrogen in the flux-cored wire is 12 ppm or less with respect to the total mass of the flux-cored wire.

9. The flux-cored wire according to claim 1,

wherein the amount of the CaF₂ in terms of mass % with respect to the total mass of the flux-cored wire is less than 0.20%.

10. A manufacturing method of a welded joint comprising:

performing gas shielded arc welding on a steel using the flux-cored wire according to claim 1.

11. The manufacturing method of a welded joint according to claim 10,

wherein the steel is one selected from the group consisting of

a steel plate having a plate thickness of 12 mm or less and a Pcm of 0.36% or less,

a steel plate having a plate thickness of more than 12 mm and 25 mm or less and a Pcm of 0.33% or less,

a steel plate having a plate thickness of more than 25 mm and 40 mm or less and a Pcm of 0.31% or less, and

a steel plate having a plate thickness of more than 40 mm and 100 mm or less and a Pcm of 0.29% or less, and

when the gas shielded arc welding is performed on the steel, in a case where a temperature of the steel is lower than 5°

C., the steel is preheated to cause the temperature of the steel to be 5°

C. or higher, and in a case where the temperature of the steel is 5°

C. or higher, the gas shielded arc welding is performed without preheating the steel,

where Pcm is calculated by Formula 4,

Pcm=[C]+[Si]/30+[Mn]/20+[Cu]/20+[Ni]/60+[Cr]/20+[Mo]/15+[V]/10+5×

[B];

 

 

Formula 4

provided that each element symbol to which square brackets are added indicates an amount of an element corresponding to the element symbol contained in the steel in terms of unit mass %.

12. A welded joint obtained by the manufacturing method of a welded joint according to claim 10.

13. A flux-cored wire comprising:

a steel sheath; and

a flux filling the inside of the steel sheath,

wherein an amount of diffusible hydrogen in a weld metal obtained by performing DC gas shielded arc welding using the flux-cored wire under a condition specified in JIS Z 3118 is 1.0 ml/100 g or less, and

a weight of spatter generated per welding time when DC gas shielded arc welding is performed using the flux-cored wire under a condition that a wire side is positive, a welding position is downhand, a current value is 270 A, a voltage value is 30 V, a welding rate is 30 cm/min, a kind of a shielding gas is 100% CO₂ gas, and a flow rate of the shielding gas is 25 L/min is 3.5 g/min or less.

14. A flux-cored wire comprising:

a steel sheath; and

a flux filling the inside of the steel sheath,

wherein the flux-cored wire contains, in terms of mass % with respect to a total mass of the flux-cored wire, Al;

0.08% to 0.70%, Ni;

0% to 0.60%, a Ti oxide in terms of TiO₂ equivalent;

4.30% to 7.50%,

an amount of diffusible hydrogen in a weld metal obtained by performing DC gas shielded arc welding using the flux-cored wire under a condition specified in JIS Z 3118 is 1.0 ml/100 g or less, and

a weight of spatter generated per welding time when DC gas shielded arc welding is performed using the flux-cored wire under a condition that a wire side is positive, a welding position is downhand, a current value is 270 A, a voltage value is 30 V, a welding rate is 30 cm/min, a kind of a shielding gas is 100% CO₂ gas, and a flow rate of the shielding gas is 25 L/min is 3.5 g/min or less.