Cast product having alumina barrier layer

Patent metadata

Field	Value
Publication number	US-11072847-B2
Application number	US-201816227970-A
Country	US
Kind code	B2
Filing date	Dec 20, 2018
Priority date	Mar 23, 2012
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

To provide a cast product having an alumina barrier layer and method for producing the same. A cast product having an alumina barrier layer of the present invention is a cast product in which an alumina barrier layer containing Al 2 O 3 is formed on the surface of a cast body, and the cast body contains C: 0.3 mass % to 0.7 mass %, Si: 0.1 mass % to 1.5 mass %, Mn: 0.1 mass % to 3 mass %, Cr: 15 mass % to 40 mass %, Ni: 20 mass % to 55 mass %, Al: 2 mass % to 4 mass %, rare earth element: 0.005 mass % to 0.4 mass %, W: 0.5 mass % to 5 mass % and/or Mo: 0.1 mass % to 3 mass %, and 25 mass % or more of Fe in the remainder and an inevitable impurity, and 80 mass % or more of the rare earth element is La.

First claim

What is claimed is:

1. A method for producing a cast product having an alumina barrier layer, for use in a high temperature atmosphere, comprising:
a step of conducting a treatment by an acid solution containing a polyhydric alcohol liquid on a surface of a cast body made of a heat resistant alloy containing 15 mass % or more of Cr and 20 mass % or more of Ni, and 2 mass % to 4 mass % of Al; and
a heat treatment step for forming an alumina barrier layer containing Al 2 O 3 on a surface by conducting a heat treatment on the cast body having subjected to the acid treatment.

2. The method for producing a cast product according to claim 1 , wherein the acid treatment is conducted by a glyceregia liquid containing nitric acid, hydrochloric acid and glycerol, or by a glycol liquid containing glycol.

3. The method for producing a cast product according to claim 1 , wherein the polyhydric alcohol liquid contained in the glyceregia liquid or the glycol liquid is more than 10 mass % and 40 mass % or less.

4. The method for producing a cast product according to claim 1 , wherein the cast body is a tube body having a bent part, and subjected to a bending process prior to the acid treatment.

5. The method for producing a cast product according to claim 1 , wherein an alumina barrier layer containing Al 2 O 3 having a thickness of 0.05 μm or more is formed on the surface of the cast product by a heat treatment.

6. The method for producing a cast product according to claim 1 , wherein the cast body contains C: 0.3 mass % to 0.7 mass %, Si: 0.1 mass % to 1.5 mass % or less, Mn: 0.1 mass % to less than 3.0 mass %, Cr: 15 mass % to 40 mass %, Ni: 20 mass % to 55 mass %, Al: 2 mass % to 4 mass %, rare earth element: 0.005 mass % to 0.4 mass %, W: 0.5 mass % to 5 mass % and/or Mo: 0.1 mass % to 3 mass %, and the remainder of Fe and an inevitable impurity.

7. The method for producing a cast product according to claim 6 , wherein the cast body contains at least one kind of Ti: 0.01 mass % to 0.6 mass %, Zr: 0.01 mass % to 0.6 mass % and Nb: 0.1 mass % to 3.0 mass %.

8. The method for producing a cast product according to claim 6 , wherein the cast body contains more than 0.01 mass % and 0.1 mass % or less of B.

9. The method for producing a cast product according to claim 7 , wherein the cast body contains more than 0.01 mass % and 0.1 mass % or less of B.

10. The method for producing a cast product according to claim 1 , wherein the alumina barrier layer containing Al 2 O 3 is composed of Al 2 O 3 in 80 area % or more of a surface of the alumina barrier layer.

11. The method for producing a cast product according to claim 5 , wherein the alumina barrier layer containing Al 2 O 3 is composed of Al 2 O 3 in 80 area % or more of a surface of the alumina barrier layer.

Assignees

• Kubota Kk

Inventors

• Enjo Youhei
• Hineno Makoto
• Uramaru Shinichi
• Hashimoto Kunihide

Classifications

• B22D21/00

  Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor {(non-ferrous ingots B22D7/005)} · CPC title

• C22C19/052

  with the maximum Cr content being at least 40% · CPC title

• C23C8/18

  Oxidising of ferrous surfaces · CPC title

• B22D29/00

  Removing castings from moulds, not restricted to casting processes covered by a single main group; Removing cores; Handling ingots {(B22D13/10, B22D11/124, B22D17/00 take precedence)} · CPC title

• B23K2103/06

  Cast-iron alloys · CPC title