Weld metal with excellent creep characteristics

Patent metadata

Field	Value
Publication number	US-9289859-B2
Application number	US-201213982763-A
Country	US
Kind code	B2
Filing date	Feb 9, 2012
Priority date	Feb 9, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

This weld metal has excellent creep characteristics and has a given chemical composition. In the weld metal, the value A defined by equation (1) is 200 or greater, and carbide particles each having an equivalent-circle diameter of 0.40 μm or more have an average equivalent-circle diameter less than 0.85 μm. In the segments that connect the centers of three or more carbide particles which are present on a 6-μm straight line and which each has an equivalent-circle diameter of 0.40 μm or more, the sum of the lengths of the portions where the segments intersect the carbide particles is 25% or more of the overall length of the segments.

Value A =([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×10 4   (1)

In the equation, [V], [Nb], [Cr], and [Mo] respectively indicate the contents (mass %) of V, Nb, Cr, and Mo in the weld metal.

First claim

What is claimed is:

1. A weld metal, consisting essentially of:
C in a content by mass of from 0.05 to 0.20%,
Si in a content by mass of from 0.10 to 0.50%,
Mn in a content by mass of from 0.60 to 1.3%,
Cr in a content by mass of from 1.8 to 3.0%,
Mo in a content by mass of from 0.8 to 1.5%,
V in a content by mass of from 0.25 to 0.50%,
Nb in a content by mass of from 0.010 to 0.050%,
N in a content by mass of greater than 0% and no more than 0.025%,
O in a content by mass of from 0.020 to 0.060%,
iron, and
inevitable impurities,
wherein a value A defined by formula (I) is 200 or greater, the formula expressed as follow:
Value A =([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×10 4   (1),

wherein [V], [Nb], [Cr], and [Mo] respectively indicate contents of V, Nb, Cr, and Mo by mass % in the weld metal,
carbide particles each having an equivalent-circle diameter of 0.40 μm or more contained in the weld metal have an average equivalent-circle diameter of less than 0.85 μm, and
in segments connecting centers of three or more carbide particles which are present on a 6-μm straight line and each of which has an equivalent-circle diameter of 0.4 μm or more, a sum of lengths of portions where the segments intersect the carbide particles is 25% or more of an overall length of the segments.

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

3. The weld metal according to claim 1 , wherein the value A is 250 or less.

4. The weld metal according to claim 1 , wherein the carbide particles each having the equivalent-circle diameter of 0.40 μm or more contained in the weld metal have an average equivalent-circle diameter of less than 0.7 μm.

5. The weld metal according to claim 1 , wherein in segments connecting centers of three or more carbide particles which are present on the 6-μm straight line and each of which has the equivalent-circle diameter of 0.4 μm or more, a sum of lengths of portions where the segments intersect the carbide particles is 40% or more of the overall length of the segments.

Assignees

• Nako Hidenori
• Yamashita Ken
• Otsu Minoru
• Sakata Mikihiro
• Taniguchi Genichi
• Kobe Steel Ltd

Inventors

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

Classifications

• B23K9/16

  making use of shielding gas · CPC title

• B23K9/025

  for rectilinear seams · CPC title

• B23K9/23

  taking account of the properties of the materials to be welded · CPC title

• C22C38/24

  with vanadium · CPC title

• B23K35/308 Primary

  with Cr as next major constituent · CPC title