Weld metal and welded structure

Patent metadata

Field	Value
Publication number	US-9879335-B2
Application number	US-201414655412-A
Country	US
Kind code	B2
Filing date	Feb 3, 2014
Priority date	Feb 4, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

This welded structure comprises a weld metal which contains C, Si, Mn, Cr, Mo, V, Nb, N and O in prescribed amounts respectively with the balance being Fe and unavoidable impurities and which exhibits an A value of 200 or more and a Z value of 0.05 or more. The A value is calculated from the element contents of the weld metal according to the formula: A value=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×10 4 . The Z value is calculated according to the formula: Z value=N×[insol. V] [wherein N (particles/μm) is the number density of carbide particles present in a prior austenite grain boundary per unit grain boundary in the stress-relief annealed weld metal, and [insol. V] is the concentration of compound-type V as determined by analyzing an extraction residue of the stress-relief annealed weld metal].

First claim

The invention claimed is:

1. A weld metal, comprising:
C: 0.05 to 0.15 mass %;
Si: 0.10 to 0.50 mass %;
Mn: 0.60 to 1.30 mass %;
Cr: 1.80 to 3.00 mass %;
Mo: 0.80 to 1.20 mass %;
V: 0.25 to 0.50 mass %;
Nb: 0.010 to 0.050 mass %;
N: greater than 0 up to 0.025 mass %; and
O: 0.020 to 0.060 mass %,
one or both of Cu: greater than 0 up to 1.00 mass % and Ni: greater than 0 up to 1.00 mass %,
Fe and inevitable impurities,
wherein an A value satisfies 200 or more, the A value being obtained by a composition of the weld metal according to a formula
A value=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×10 4

and
wherein a Z value is 0.05 or more, the Z value being obtained according to a formula
Z value=N×[insol. V],

where N is number density (particles/μm) of carbide particles per unit grain boundary, the carbide particles existing in a prior austenite grain boundary of a stress-relief annealed weld metal, and [insol. V] is concentration of compound-type V determined by an extraction residue of the stress-relief annealed weld metal.

2. The weld metal according to claim 1 , further comprising other elements including at least one of the groups (b) and (c):
(b) B: 0.0050 mass % or less (not including 0 mass %); and
(c) one or more of W: 0.50 mass % or less (not including 0 mass %), Al: 0.030 mass % or less (not including 0 mass %), and Ti: 0.020 mass % or less (not including 0 mass %).

3. A welded structure, comprising the weld metal according to claim 1 .

4. The weld material according to claim 1 , comprising
C: 0.07 to 0.13 mass %;
Si: 0.15 to 0.40 mass %;
Mn: 0.70 to 1.20 mass %;
Cr: 1.90 to 2.80 mass %;
Mo: 0.90 to 1.15 mass %;
V: 0.27 to 0.45 mass %;
Nb: 0.012 to 0.040 mass %;
N: more than 0 to 0.020 mass %; and
O: 0.025 to 0.050 mass %.

5. The weld material according to claim 4 , comprising Mn: 0.75 to 1.15 mass %.

6. The weld material according to claim 4 , comprising Cr: 2.00 to 2.60 mass %.

7. The weld material according to claim 4 , comprising Mo: 0.90 to 1.10 mass %.

8. The weld material according to claim 4 , comprising V: 0.30 to 0.40 mass %.

9. The weld material according to claim 4 , comprising Nb: 0.012 to 0.035 mass %.

10. The weld material according to claim 1 , wherein the inevitable impurities are P: 0.020 mass % or less, Sn: 0.010 mass % or less, and As: 0.010 mass % or less.

11. The weld material according to claim 1 , wherein the A value is from 202 to 270.

12. The weld material according to claim 1 , wherein the A value is from 205 to 250.

13. The weld material according to claim 1 , wherein the Z value is from 0.07 to 0.20.

14. The weld material according to claim 1 , comprising Cu and Ni in a total amount of 0.05 to 1.50 mass %.

15. The weld material according to claim 1 , comprising B in amount of greater than 0 and not more than 0.0050 mass %.

16. The weld material according to claim 1 , comprising W in an amount of greater than 0 and not more than 0.50 mass %.

17. The weld material according to claim 1 , comprising Al in an amount of greater than 0 and not more than 0.030 mass %.

18. The weld material according to claim 1 , comprising Ti in an amount of greater than 0 and not more than 0.020 mass %.

Assignees

• Kobe Steel Ltd

Inventors

• Nako Hidenori
• Yamashita Ken
• Otsu Minoru
• Sakata Mikihiro
• Taniguchi Genichi

Classifications

• C22C38/32

  with boron · CPC title

• C22C38/20

  with copper · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title

• C22C38/04

  containing manganese · CPC title

• C22C38/42

  with copper · CPC title