Ni-base alloy

Patent metadata

Field	Value
Publication number	US-9828656-B2
Application number	US-201314375581-A
Country	US
Kind code	B2
Filing date	Feb 6, 2013
Priority date	Feb 7, 2012
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

In a Ni-base alloy, an area-equivalent diameter D is calculated. D is defined by D=A 1/2 from an area A of a largest nitride in a field of view when an observation area S 0 is observed. This process is repeated in n fields of view for measurement, where n is the number of the fields of view for measurement, so as to acquire n pieces of data on D, and the pieces are arranged in ascending order D 1 , D 2 , . . . , D n to obtain a reduced variate y j . The obtained values are plotted on X-Y axis coordinates, where an X axis corresponds to D and a Y axis corresponds to y j . In a regression line y j =a×D+b, y j is obtained when a target cross-sectional area S is set to 100 mm 2 . When the obtained y j is substituted into the regression line, the estimated nitride maximum size is ≦25 μm in diameter.

First claim

The invention claimed is:

1. A cast and plastically-worked Ni-base alloy comprising:
13 mass % to 30 mass % of Cr;
0.01 mass % to 6 mass % of Ti;
8 mass % or less of Al; and
25 mass % or less of Fe, wherein
nitrides are present, and
an area-equivalent diameter D is calculated, and the area-equivalent diameter D is defined by D=A 1/2 from an area A of a largest nitride in a field of view when observation is performed at a magnification of 400 times to 3000 times for an observation area S 0 for measurement, this process is repeated in n fields of view for measurement, where n is the number of the fields of view for measurement, so as to acquire n pieces of data on the area-equivalent diameter D, and the pieces of data on the area-equivalent diameter D are arranged in ascending order of D 1 , D 2 , . . . , D n to obtain a reduced variate y j which is defined by the following Expression (1):
[Formula 1]
y j =−ln [−ln { j /( n+ 1)}]  (1)

(in the Expression (1), j is a rank number when the pieces of data on the area-equivalent diameter D are arranged in ascending order),
the obtained values are plotted on X-Y axis coordinates, where an X axis corresponds to the area-equivalent diameter D and a Y axis corresponds to the reduced variate y j , a regression line y j =a×D+b (a and b are constants) is obtained, and when a target cross-sectional area S for prediction is set to 100 mm 2 , y j is obtained through the following Expression (2):

[

Formula
⁢

⁢
2

]

y
j

=

-

ln
⁡

(

-
ln

⁢

S

S
0

+
S

)

,

(
2
)

 and
when the obtained value of y j is substituted into the regression line to calculate an estimated nitride maximum size, the estimated nitride maximum size is equal to or less than 25 μm in terms of area-equivalent diameter.

2. The cast and plastically-worked Ni-base alloy according to claim 1 , wherein the nitride is a titanium nitride.

Assignees

• Mitsubishi Materials Corp
• Hitachi Metals Mmc Superalloy Ltd

Inventors

• Itoh Masato
• Yaguchi Kenichi
• Fukuda Tadashi
• Matsui Takanori

Classifications

• C22C19/056 Primary

  with the maximum Cr content being at least 10% but less than 20% · CPC title

• F05C2201/0466

  Nickel · CPC title

• C22C19/055

  with the maximum Cr content being at least 20% but less than 30% · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title