ELECTRIC RESISTANCE WELDED OIL COUNTRY TUBULAR GOODS AND MANUFACTURING METHOD OF ELECTRIC RESISTANCE WELDED OIL COUNTRY TUBULAR GOODS

• US 20130092280A1
• Filed: 02/03/2012
• Published: 04/18/2013
• Est. Priority Date: 04/19/2011
• Status: Active Grant

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel & Sumitomo Metal Corporation (Nippon Steel Corporation)
• Inventors: Asahi, Hitoshi, Sawamura, Mitsuru
• Granted Patent: US 9,126,283 B2
• Time in Patent Office: Days
• US Class Current: 138/177
• CPC Class Codes: B21C 37/08 Making tubes with welded or soldered seams with helically arranged seams B21C37/122
• CPC Class Codes: B23K 11/00 Resistance welding; Severing by resistance heating
• CPC Class Codes: B23K 11/002 specially adapted for particular articles or work
• CPC Class Codes: B23K 11/0073 Butt welding of long articles advanced axially
• CPC Class Codes: B23K 2101/06 Tubes
• CPC Class Codes: B23K 2101/10 Pipe-lines
• CPC Class Codes: B23K 2103/04 Steel or steel alloys
• CPC Class Codes: C21D 1/18 Hardening C21D1/02 takes precedence; Quenching with or without subsequent tempering quenching devices C21D1/62
• CPC Class Codes: C21D 1/25 Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
• CPC Class Codes: C21D 8/0226 Hot rolling
• CPC Class Codes: C21D 8/0263 following hot rolling
• CPC Class Codes: C21D 8/105 of ferrous alloys
• CPC Class Codes: C21D 9/08 for tubular bodies or pipes
• CPC Class Codes: C22C 38/001 containing N
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/12 containing tungsten, tantalum, molybdenum, vanadium, or niobium
• CPC Class Codes: C22C 38/14 containing titanium or zirconium
• CPC Class Codes: F16L 13/02 Welded joints
• CPC Class Codes: F16L 9/00 : Rigid pipes

Abstract

[Summary]

[Object] There are provided electric resistance welded oil country tubular goods having strength corresponding to API specification 5CT P110 without a heat treatment being performed on the whole steel pipe and further having excellent toughness, and a manufacturing method of an electric resistance welded oil country tubular goods.

[Solution] Electric resistance welded oil country tubular goods according to the present invention have a chemical composition that contains, in mass %, C: 0.05 to 0.12%, Si: 0.03 to 0.5%, Mn: 0.80 to 2.2%, P: 0.03% or less, S: 0.003% or less, Al: 0.08% or less, Nb: 0.01% to 0.10%, Ti: 0.005 to 0.03%, B: 0.0005 to 0.0030%, and N: 0.008% or less, and in which Ti>3.4 N is satisfied, its balance is composed of Fe and inevitable impurities, and, V_C90 is 15 to 40.

Claims

1. An electric resistance welded oil country tubular goods comprising:

a chemical composition that contains, in mass %,

C;

0.05 to 0.12%,

Si;

0.03 to 0.5%,

Mn;

0.80 to 2.2%,

P;

0.03% or less,

S;

0.003% or less,

Al;

0.08% or less,

Nb;

0.01% to 0.10%,

Ti;

0.005 to 0.03%,

B;

0.0005 to 0.0030%, and

N;

0.008% or less and in which Ti>

3.4 N is satisfied, its balance is composed of Fe and inevitable impurities, and V_C90 defined by Expression (1) below is 15 to 40, where a C content (%) is represented by [C], an Si content (%) is represented by [Si], an Mn content (%) is represented by [Mn], an Ni content (%) is represented by [Ni], a Cu content (%) is represented by [Cu], a Cr content (%) is represented by [Cr], and a Mo content (%) is represented by [Mo].

log V_C90=2.94−

0.75(2.7[C]+0.4[Si]+[Mn]+0.45[Ni]+0.45[Cu]+0.8[Cr]+2[Mo]) 

 

(1)

2. The electric resistance welded oil country tubular goods according to claim 1, further containing one type or two types or more selected from, in mass %,

Ni:

1% or less,

Cu;

1% or less,

Mo;

0.3% or less,

Cr;

0.8% or less,

V;

0.1% or less, and

Ca;

0.0060% or less.

3. The electric resistance welded oil country tubular goods according to claim 1, wherein

the electric resistance welded oil country tubular goods has a yield stress of 758 to 965 MPa and a tensile strength of 862 MPa or more.

4. The electric resistance welded oil country tubular goods according to claim 1, wherein

the electric resistance welded oil country tubular goods does not have yield point elongation in a test result of a tensile test.

5. The electric resistance welded oil country tubular goods according to claim 1, wherein

the electric resistance welded oil country tubular goods has a yield to tensile ratio of 85% to 95%.

6. The electric resistance welded oil country tubular goods according to claim 1, wherein

a structure of the electric resistance welded oil country tubular goods other than a structure of an electric resistance welded portion is made of a bainite uniform structure.

7. The electric resistance welded oil country tubular goods according to claim 2, wherein

the electric resistance welded oil country tubular goods has a yield stress of 758 to 965 MPa and a tensile strength of 862 MPa or more.

8. The electric resistance welded oil country tubular goods according to claim 2, wherein

the electric resistance welded oil country tubular goods does not have yield point elongation in a test result of a tensile test.

9. The electric resistance welded oil country tubular goods according to claim 2, wherein

the electric resistance welded oil country tubular goods has a yield to tensile ratio of 85% to 95%.

10. The electric resistance welded oil country tubular goods according to claim 2, wherein

a structure of the electric resistance welded oil country tubular goods other than a structure of an electric resistance welded portion is made of a bainite uniform structure.

11. An electric resistance welded oil country tubular goods manufactured by hot-rolling a steel slab and performing coiling at 300°

C. or lower to make a hot-rolled steel plate, and then forming the hot-rolled steel plate into a pipe shape and subjecting edge surfaces to electric resistance welding, the a steel slab having a chemical composition that contains, in mass %,

C;

0.05 to 0.12%,

Si;

0.03 to 0.5%,

Mn;

0.80 to 2.2%,

P;

0.03% or less,

S;

0.003% or less,

Al;

0.08% or less,

Nb;

0.01% to 0.10%,

Ti;

0.005 to 0.03%,

B;

0.0005 to 0.0030%, and

N;

0.008% or less and in which Ti>

3.4 N is satisfied, its balance is composed of Fe and inevitable impurities, and V_C90 defined by Expression (1) below is 15 to 40, where a C content (%) is represented by [C], an Si content (%) is represented by [Si], an Mn content (%) is represented by [Mn], an Ni content (%) is represented by [Ni], a Cu content (%) is represented by [Cu], a Cr content (%) is represented by [Cr], and a Mo content (%) is represented by [Mo].

log V_C90=2.94−

0.75(2.7[C]+0.4[Si]+[Mn]+0.45[Ni]+0.45[Cu]+0.8[Cr]+2[Mo]) 

 

(1)

12. The electric resistance welded oil country tubular goods according to claim 11, further containing one type or two types or more selected from, in mass %,

Ni:

1% or less,

Cu;

1% or less,

Mo;

0.3% or less,

Cr;

0.8% or less,

V;

0.1% or less, and

Ca;

0.0060% or less.

13. The electric resistance welded oil country tubular goods according to claim 11, wherein

the electric resistance welded oil country tubular goods is manufactured without performing a heat treatment with respect to a pipe body after the electric resistance welding.

14. The electric resistance welded oil country tubular goods according to claim 11, wherein

the electric resistance welded oil country tubular goods has a yield stress of 758 to 965 MPa and a tensile strength of 862 MPa or more.

15. The electric resistance welded oil country tubular goods according to claim 11, wherein

the electric resistance welded oil country tubular goods does not have yield point elongation in a test result of a tensile test.

16. The electric resistance welded oil country tubular goods according to claim 11, wherein

the electric resistance welded oil country tubular goods has a yield to tensile ratio of 85% to 95%.

17. The electric resistance welded oil country tubular goods according to claim 11, wherein

a structure of the electric resistance welded oil country tubular goods other than a structure of an electric resistance welded portion is made of a bainite uniform structure.

18. The electric resistance welded oil country tubular goods according to claim 12, wherein

the electric resistance welded oil country tubular goods is manufactured without performing a heat treatment with respect to a pipe body after the electric resistance welding.

19. The electric resistance welded oil country tubular goods according to claim 12, wherein

the electric resistance welded oil country tubular goods has a yield stress of 758 to 965 MPa and a tensile strength of 862 MPa or more.

20. The electric resistance welded oil country tubular goods according to claim 12, wherein

the electric resistance welded oil country tubular goods does not have yield point elongation in a test result of a tensile test.

21. The electric resistance welded oil country tubular goods according to claim 12, wherein

the electric resistance welded oil country tubular goods has a yield to tensile ratio of 85% to 95%.

22. The electric resistance welded oil country tubular goods according to claim 12, wherein

a structure of the electric resistance welded oil country tubular goods other than a structure of an electric resistance welded portion is made of a bainite uniform structure.

23. A manufacturing method of an electric resistance welded oil country tubular goods comprising:

hot-rolling a steel slab;

performing coiling at 300°

C. or lower to make a hot-rolled steel plate;

then forming the hot-rolled steel plate into a pipe shape; and

subjecting edge surfaces to electric resistance welding,

the steel slab having a chemical composition that contains, in mass %,

C;

0.05 to 0.12%,

Si;

0.03 to 0.5%,

Mn;

0.80 to 2.2%,

P;

0.03% or less,

S;

0.003% or less,

Al;

0.08% or less,

Nb;

0.01% to 0.10%,

Ti;

0.005 to 0.03%,

B;

0.0005 to 0.0030%, and

N;

0.008% or less and in which Ti>

3.4 N is satisfied, its balance is composed of Fe and inevitable impurities, and V_C90 defined by Expression (1) below is 15 to 40, where a C content (%) is represented by [C], an Si content (%) is represented by [Si], an Mn content (%) is represented by [Mn], an Ni content (%) is represented by [Ni], a Cu content (%) is represented by [Cu], a Cr content (%) is represented by [Cr], and a Mo content (%) is represented by [Mo].

log V_C90=2.94−

0.75(2.7[C]+0.4[Si]+[Mn]+0.45[Ni]+0.45[Cu]+0.8[Cr]+2[Mo]) 

 

(1)

24. The manufacturing method of the electric resistance welded oil country tubular goods according to claim 23, further containing one type or two types or more selected from, in mass %,

Ni:

1% or less,

Cu;

1% or less,

Mo;

0.3% or less,

Cr;

0.8% or less,

V;

0.1% or less, and

Ca;

0.0060% or less.

25. The manufacturing method of the electric resistance welded oil country tubular goods according to claim 23, wherein

a cooling rate in a range of 650 to 300°

C. is set to 15 to 50°

C./s.

26. The manufacturing method of the electric resistance welded oil country tubular goods according to claim 23, wherein

a heat treatment with respect to a pipe body is not performed after the electric resistance welding.

27. The manufacturing method of the electric resistance welded oil country tubular goods according to claim 24, wherein

a cooling rate in a range of 650 to 300°

C. is set to 15 to 50°

C./s.

28. The manufacturing method of the electric resistance welded oil country tubular goods according to claim 24, wherein

a heat treatment with respect to a pipe body is not performed after the electric resistance welding.