JPH10193174A - Oxide dispersion strengthened alloy welding filler metal - Google Patents

Abstract

[PROBLEMS] To provide practically sufficient strength and ductility when welded between oxide dispersion strengthened alloys or between an oxide dispersion strengthened alloy and a heat-resistant alloy at relatively low temperature or relatively low stress. To provide a welding filler metal capable of providing the joint material with the welding filler metal. SOLUTION: The filler material composition is expressed by weight%, C: 0.001 to 0.001%.
0.15%, Si: ≦ 1.0%, Mn: ≦ 3.5%, C
r: 18.0 to 50%, Mo: ≤ 10.0%, Fe: ≤
3.0%, Ti: ≦ 0.8%, Al: ≦ 1.50%, N
b: ≦ 3.0%, Co: ≦ 15.0%, balance substantially N
i.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filler metal for welding a member that needs to be joined in a high-temperature use application such as a radiant tube, a reformer tube, a high-temperature heating furnace part, etc. Also, the present invention relates to a filler metal used for welding an oxide dispersion strengthened alloy and a heat-resistant alloy.

[0002]

2. Description of the Related Art
Ni-based heat-resistant alloys are often used as heat-resistant materials for jet engines and gas turbines. In the case of a Ni-based alloy, an intermetallic compound structure (γ ′ phase) having a high temperature strength and a high composition based on Ni ₃ Al can be generated, which acts to enhance the heat resistance of the alloy by performing a precipitation hardening action. This γ '
The phase has a maximum strength of about 700 to 800 ° C., and in the case of a Ni-based alloy having the γ ′ phase as a precipitation hardening phase,
It can be used under the temperature condition of 00 ° C or less. However, when the temperature is higher than that, the γ 'phase is melted and cannot work as a strengthening factor.

On the other hand, Y ₂ O _{3 is} contained in a metal matrix.
An oxide dispersion strengthened alloy obtained by dispersing and strengthening fine oxide particles has attracted attention as having higher heat resistance. In this oxide dispersion strengthened alloy, since the oxide particles do not react with the metal matrix even at a high temperature, the strength can be maintained even at a high temperature of 1000 ° C. or more, and high heat resistance of high temperature heating furnace parts and the like is required. The application to the member which is done is studied.

[0004] For example, the following materials have been developed to the point of practical use. MA956 (Fe-20Cr-4.5Al- 0.5Ti-0.5Y 2 O 3) MA754 (Ni-20Cr-0.3Al-0.5Ti-0.05C-1.0Fe-0.6Y 2 O
₃ ) MA6000 (Ni-15Cr-2.0Mo-4.0W-4.5Al-2.5Ti-2.0Ta-
_{0.01B-0.15Zr-0.05C-1.1Y 2} O 3) Among MA754 is solid-solution strengthened Ni-based alloy, also MA6000 exhibit high temperature strength in γ'-strengthened Ni-based alloy.

By the way, when such an oxide dispersion strengthened alloy is used as a component requiring joining in a high temperature use application,
The joining method becomes a problem. Bonding methods for this kind of oxide dispersion strengthened alloy include brazing, solid phase diffusion bonding,
Liquid phase diffusion bonding is generally used, but these bonding methods are time-consuming and costly.

Therefore, as a joining method, specifically, when joining at a relatively low temperature or a relatively low stress site, it is desirable that welding, which is the most common joining method, can be used. In the case of (1), there is a problem that the agglomeration and coarsening of the oxide occur, and the strength and ductility are remarkably reduced, and the original characteristics of the oxide dispersion strengthened alloy are sacrificed. was difficult.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has a strength sufficient for practical use when used for joining relatively low temperature or relatively low stress parts.
It is an object of the present invention to provide a filler metal having excellent ductility and excellent weldability. Thus, the filler material of claim 1 of the present application is
And C: 0.001 to 0.15%, Si: ≦ 1.0%,
Mn: ≦ 3.5%, Cr: 18.0-50%, Mo: ≦
10.0%, Fe: ≦ 3.0%, Ti: ≦ 0.8%, A
l: ≦ 1.50%, Nb: ≦ 3.0%, Co: ≦ 15.
0% balance is substantially made of Ni.

According to a second aspect of the present invention, in the first aspect, the respective components of P, S, and Cu are expressed in weight% and P: ≦ 0.0
3%, S: ≤ 0.015%, Cu: ≤ 0.50%.

[0009]

The filler metal of the present invention is based on Ni for securing heat resistance, corrosion resistance and toughness, and is added with a large amount of Cr for securing oxidation resistance. When the oxide dispersion strengthened alloy is welded using the filler metal of the present invention, the strength of the weld at a relatively low temperature or relatively low stress is sufficiently high for practical use. ， Can be given ductility.

[0010] The filler material of the present invention is particularly suitable for MIG welding, TI
Suitable for G welding and plasma welding.

The filler of the present invention is, for example,
Oxide dispersion strengthened alloys or
Particularly suitable for welding with heat-resistant alloys. Oxide dispersion strengthened alloy Ni-20Cr-0.3Al-0.5Ti-0.05C-1.0Fe-0.6Y_TwoO_Three  Ni-30Cr-0.3Al-0.5Ti-0.05C-1.0Fe-0.6Y_TwoO_Three  Ni-15Cr-4.5Al-4W-2.5Ti-2Mo-2Ta-1.1Y_TwoO_Three  Fe-20Cr-4.5Al-0.5Ti-0.5Y_TwoO_Three Heat-resistant alloy Ni-32Cr-15W-0.3C-0.3Fe Fe-25Cr-20Ni-0.4C Fe-26Cr-35Ni-0.6C Fe-34Cr-30Ni-5W-0.3Ti

Next, the reasons for limiting each chemical component in the present invention will be described in detail. C: 0.001 to 0.15% C contributes to securing high-temperature strength by forming carbides and stabilizing austenite. However, for that purpose, it is necessary to contain 0.001% or more. On the other hand, if it is contained in excess of 0.15%, a decrease in high-temperature strength, a decrease in toughness, and a decrease in corrosion resistance are caused. Therefore, in the present invention, the upper limit is 0.15%.

Si: ≦ 1.0% Si acts as a deoxidizing agent and contributes to improving oxidation resistance and improving the flowability of the weld metal. However, if the content exceeds 1.0%, the high-temperature strength and the toughness are reduced, so the upper limit is set to 1.0%. Note that a desirable lower limit is 0.01%.

Mn: ≦ 3.5% Mn works as a deoxidizing and desulfurizing agent and contributes to stabilization of austenite. However, if it is contained in excess of 3.5%, the toughness and the corrosion resistance are reduced.
% Or less. Note that a desirable lower limit is 0.01%.

Cr: 18.0 to 50% Cr is an essential component for improving oxidation resistance, and 18.0%
It is necessary to contain the above. However, if added in excess of 50%, austenite becomes unstable, embrittlement phases such as σ phase and α phase are precipitated, and the toughness is reduced, so the upper limit is set to 50%.

Mo: ≦ 10.0% Mo is an element contributing to solid solution strengthening and improvement of corrosion resistance. However, if it is contained in excess of 10.0%, the toughness due to the precipitation of an embrittlement phase like Cr is obtained. 10. To reduce the
0% or less.

Fe: ≦ 3.0% Fe contributes to cost reduction. However, when the content is more than 3.0%, the strength at high temperatures is reduced, and the toughness is reduced due to the instability of austenite.

Ti: ≦ 0.8% Ti contributes to ensuring high-temperature strength by forming carbides. However, if the content exceeds 0.8%, the toughness decreases due to precipitation of the embrittlement phase, so the upper limit is set to 0.8%.

Al: ≤ 1.50% Al acts as a deoxidizing agent and contributes to the prevention of welding cracks. However, if the content is more than 1.50%, the arc at the time of welding becomes unstable. Therefore, in the present invention, the content is set to 1.50% or less.

Nb: ≦ 3.0% Nb contributes to solid-solution strengthening and ensuring high-temperature strength by forming carbides. However, if the content exceeds 3.0%, the toughness decreases due to precipitation of the embrittlement phase, so the upper limit is set to 3.0%.

Co: ≦ 15.0% Co contributes to solid solution strengthening and stabilization of austenite.
However, if the content is more than 15.0%, the cost increases, so the upper limit is set to 15.0%.

P: ≦ 0.03% Since P causes intergranular corrosion and impairs hot workability at the time of production, the content is restricted to 0.03% or less.

S: ≦ 0.015% S affects the quality of the bead shape. The excessive addition impairs the hot workability at the time of production, so the content is made 0.015% or less.

Cu: ≤0.50% If the content of Cu exceeds 0.50%, the hot workability at the time of production is impaired. Therefore, the upper limit is set to 0.50%.

[0025]

Next, embodiments of the present invention will be described in detail. For the oxide dispersion strengthened alloy A and the heat-resistant alloy B having the following chemical compositions, welding tests were performed using filler metals having various chemical compositions shown in Table 1. A: Ni-20Cr-0.4Ti- 0.3Al-0.2Fe-0.6Y 2 O 3 B: Ni-32Cr-15W-0.3C-0.3Fe

[0026]

[Table 1]

In the welding test, a 4 mm-thick plate was abutted to perform TIG welding, and a tensile test piece having a parallel portion of 2 mm (thickness) × 10 mm (width) × 50 mm (length) was collected from the welded portion. A tensile test was performed. The results are shown in Table 2. In Table 2, A / A represents welding between A and A, and A / B represents welding between A and B, respectively.

[0028]

[Table 2]

From the results shown in Table 2, the filler metal of the present invention has a tensile strength of 75 MPa or more and an elongation of 4.0% or more, and the bead shapes are all good. It can be seen that it is sufficiently practical as a filler metal for welding of the oxide dispersion strengthened type alloy at the site of extremely low stress.

Although the embodiment of the present invention has been described in detail, this is merely an example, and the present invention can be implemented in various modified forms without departing from the gist thereof.

[0031]

The filler material according to the present invention is based on Ni for securing heat resistance, corrosion resistance and toughness, and also contains a large amount of Cr for securing oxidation resistance. In the case of securing the strength by addition, when welding the oxide dispersion strengthened alloy using the filler material of the present invention,
Practically sufficient strength and ductility can be given as the strength of the welded portion at a relatively low temperature or a relatively low stress.

Claims (2)

[Claims] C: 0.001 to 0.15% in weight% Si: ≤ 1.0% Mn: ≤ 3.5% Cr: 18.0 to 50% Mo: ≤ 10.0% Fe: ≤ 3.0% Ti: ≤ 0.8% Al: ≤ 1.50% Nb: ≤ 3.0% Co: ≤ 15.0% The filler metal for oxide dispersion strengthened alloys consisting essentially of Ni with the balance being Ni. . 2. The method according to claim 1, wherein each component of P, S, and Cu is P: ≦ 0.03% S: ≦ 0.015% Cu: ≦ 0.50% by weight%. Filler metal for welding oxide dispersion strengthened alloys.