CN113957356A

CN113957356A - Iron-based alloy for corrosion-resistant coating and application

Info

Publication number: CN113957356A
Application number: CN202111255702.0A
Authority: CN
Inventors: 郜俊震; 董世新; 刘林林; 王祥; 王贵宗; 陈佳鹏
Original assignee: Jiangsu Zhiren Jingxing New Material Research Institute Co ltd
Current assignee: Jiangsu Zhiren Jingxing New Material Research Institute Co ltd
Priority date: 2021-10-27
Filing date: 2021-10-27
Publication date: 2022-01-21

Abstract

The invention discloses an iron-based alloy for a corrosion-resistant coating and application thereof, wherein the iron-based alloy comprises the following components in percentage by mass: 33.0 to 40.0 percent of Cr, 0.5 to 8.0 percent of Mo, 1.0 to 8.0 percent of Si, 0.1 to 5.0 percent of Al and the balance of Fe. The iron-based alloy for the corrosion-resistant coating provided by the invention can form a protective coating with enough corrosion resistance and enough adhesion to a substrate. The coating may be performed using existing processes such as laser cladding, plasma overlay PTA, HVOF, HVAF, plasma spraying, and the like.

Description

Iron-based alloy for corrosion-resistant coating and application

Technical Field

The invention belongs to the field of corrosion-resistant iron-based alloy, and particularly relates to corrosion-resistant iron-based alloy for a surface coating process and application thereof.

Background

Iron-based alloys require components with high corrosion resistance, such as high temperature, atmospheric, water vapor, water and oxidizing acid corrosion resistance, under certain environmental conditions. In order to improve the corrosion resistance of the surface of the workpiece, a surface coating process, such as laser cladding, plasma transferred arc overlaying, thermal spraying, and the like, is usually adopted to coat the surface of the workpiece with a corrosion-resistant material. Martensitic stainless steels, such as 431 alloy, are often used as coating materials. However, the existing materials cannot meet the corrosion resistance requirement under special environments, particularly the corrosion resistance under severe environments such as high temperature (more than or equal to 1000 ℃) and sulfur-containing environment, or the existing materials cannot meet the requirements on surface coating technology or the bonding property of a matrix.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a corrosion-resistant iron-based alloy for a surface coating process and application thereof.

In order to realize the purpose, the following technical scheme is adopted: an iron-based alloy for a corrosion-resistant coating comprises the following components in percentage by mass: 33.0 to 40.0 percent of Cr, 0.50 to 8.0 percent of Mo, 1.0 to 8.0 percent of Si, 0.1 to 5.0 percent of Al and the balance of Fe.

Further, the composition also comprises the following components in percentage by mass: less than 1.0 percent of Mn, less than 4.0 percent of Nb, less than 4.0 percent of W or less than 4.0 percent of V, and the weight is 0.1 to 4.0 percent of the total weight of the alloy.

The application of the iron-based alloy in the aspect of corrosion-resistant coatings is characterized in that the iron-based alloy is in a powder form, and a coating is formed on the surface of a substrate by adopting a plasma surfacing and laser cladding mode.

The granularity range of the alloy powder is-100 to +300 meshes, and further the granularity range of the alloy powder is-100 to +250 meshes.

The alloying elements will now be described in terms of their role and preferred amounts:

chromium (Cr)

The chromium (Cr) content is 33.0-40.0 wt.% of the alloy. Chromium provides sufficient corrosion resistance and hardness to the resulting coating. The lower limit of Cr is 33.0 wt.%, and the upper limit is 40 wt.%, and these upper and lower limits can be freely combined. While it is common for the Cr content in solid solution to exceed 12% to give the alloy sufficient corrosion resistance, ferritic stainless steels typically have a Cr content of 15% to 30%. Without wishing to be bound by theory, in certain harsh environments, where higher corrosion resistance is required for the alloy, the Cr content is set to be higher than 30 wt.%, and it has been found that when the Cr content is within the above range, the requirements regarding corrosion resistance can be achieved.

Molybdenum (Mo)

The addition of Mo enhances the pitting corrosion resistance, namely PRE index, of the alloy, and the addition of Mo also has the effect of refining the grains of the cladding structure.

In the present invention, the content of Mo is 0.5 to 8.0 wt.%. The lower limit is 0.50 wt.% or more, preferably 5.0 wt.% or more. The upper limit is 8.0 wt.% or less, preferably 7.0 wt.% or less, and more preferably 6.5 wt.% or less.

Silicon (Si)

The addition of Si mainly improves the high-temperature corrosion resistance of the alloy, and simultaneously avoids or reduces the formation of oxides of Fe or other alloy elements in the coating process, because Si has high affinity to oxygen, the formed silicate slag floats to the surface of a molten pool to form protection, and the formation of FeO is reduced. Si also increases the fluidity of the bath metal, making the liquid metal easily wettable on the substrate surface.

In the present invention, the content of Si is 1.0 to 8.0 wt.%. The lower limit is 1.0 wt.% or more, preferably 4.5 wt.% or more. The upper limit is 8.0 wt.% or less, preferably 6.5 wt.% or less.

Aluminum (Al)

The addition of Al can further improve the corrosion resistance of the alloy.

In the present invention, the content of Al is 0.1 to 5.0 wt.%. The lower limit is 0.1 wt.% or more, preferably 2.0 wt.% or more. The upper limit is 5.0 wt.% or less, preferably 4.0 wt.% or less.

Optional Components

The alloy may also comprise one or more of the following optional components:

1.1.00 wt.% or less Mn;

2.4.00 wt.% or less Nb;

3.4.00 wt.% or less of W;

4.4.00 wt.% or less of V;

the addition of these components, which may include one, two, three or all four of them, in a total amount of 0.10 to 4.00 wt.% of the alloy, may improve the processing properties of the coating as well as the hardness and corrosion resistance properties of the final coating.

In order to be suitable for forming coatings by methods such as plasma deposition, laser cladding, etc., the alloy needs to be present in powder form. The method of preparing the powder is not particularly limited, and suitable methods are well known to those skilled in the art. Such methods are preferably atomization, for example water atomization or gas atomization.

The iron-based alloy for the corrosion-resistant coating provided by the invention can form a protective coating with enough corrosion resistance and enough adhesion to a matrix, and can resist high-temperature oxidation. The coating may be performed using existing processes such as laser cladding, plasma overlay PTA, HVOF, HVAF, plasma spraying, and the like.

Drawings

FIG. 1 is an electron micrograph of a corrosion resistant iron-based alloy powder according to example 1.

Fig. 2 is a particle size distribution diagram of the corrosion-resistant iron-based alloy powder of example 1.

Detailed Description

In order to make the technical solutions of the present application better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to specific embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "comprises" and "comprising," and any variations thereof, in the description and claims of this application, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

A corrosion-resistant iron-based alloy powder for a surface coating process is shown in figure 1, wherein the particle size distribution of the alloy powder is 53-200 mu m, as shown in figure 2.

The contents of the elements in percentage by mass of the alloy powder are shown in Table 1.

TABLE 1

Fe	Cr	Mo	Si	Al	Mn
						Balance of	40％	6.5％	5％	3.5％	0.2％

The alloy powder was coated on a steel column of 150mm diameter using plasma overlay welding, and the coating was in a salt spray chamber for 6000 hours with no corrosion found.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. An iron-based alloy for a corrosion-resistant coating is characterized by comprising the following components in percentage by mass: 33.00 to 40.00 percent of Cr, 0.50 to 8.00 percent of Mo, 1.00 to 8.00 percent of Si, 0.10 to 5.00 percent of Al and the balance of Fe.

2. The iron-based alloy for a corrosion-resistant coating according to claim 1, wherein: the paint also comprises the following components in percentage by mass: less than 1.00 percent of Mn, less than 4.00 percent of Nb, less than 4.00 percent of W or less than 4.00 percent of V, or a mixture of more than two of Mn, Nb, W and V, and the weight is 0.1 to 4.0 percent of the total weight of the alloy.

3. Use of an iron-based alloy according to claim 1 or 2 for corrosion-resistant coatings, characterized in that: the iron-based alloy is in a powder form, and a coating is formed on the surface of a substrate by adopting a plasma surfacing and laser cladding mode.

4. Use according to claim 3, characterized in that: the grain size range of the alloy powder is-100 to +300 meshes.