US20070154342A1

US20070154342A1 - Multi metal base hardfacing alloy

Info

Publication number: US20070154342A1
Application number: US11/600,818
Authority: US
Inventors: Chin-Pang Tu; Likey Chen; Wei-Jen Wang; Hung-Cheng Chen; Chun-Hui Lai; Shing-Hwa Chen; Jien-Wei Yeh
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2005-12-30
Filing date: 2006-11-17
Publication date: 2007-07-05
Also published as: TWI298661B; TW200724283A

Abstract

A multi metal base hardfacing alloy is provided. The atom percent of each element in the alloy is smaller than 35%. When the alloy is used as a welding material, it has advantages such as low operating temperature, better physical strength hardiness, acid resistance, basic resistance, anti-oxidation, and interface obturation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 094147567 filed in Taiwan, R.O.C. on Dec. 30, 2005, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE PRESENT INVENTION

1. Field of Invention
The present invention relates to a metal material, and more particularly to a multi metal base hardfacing alloy.
2. Related Art
Along with the progress of research and development of metal materials, metal materials have come to have characteristics such as high strength, high tenacity, high processibility, and low price. Therefore, metal materials are widely used in machinery manufacturing, mould processing, construction, shipbuilding, the automobile industry, and the like, and a large amount of metal materials are consumed. Thus, worldwide demand for metal materials is continuously increasing and metal materials have become one of the structural materials that are largely consumed and widely used. However, due to the improvement of the cleanliness and the lowered roughness of the surface of metal materials, better welding efficiency is required for joining them.
Most machine and equipment errors are not caused by destruction, but result from abrasion between individual parts, so it has been an important subject how to effectively solve the problem of abrasion between components. Moreover, as for the operating environment at present, many machines such as the die caster, forging machine, copper wire rolling device, extrusion device, and cold rolling mill must operate under the high temperature. Therefore, machines must withstand the high temperature and the abrasion. However, the hardness of metal materials is significantly reduced, the tensile strength is weakened, and softening is aggravated under the high temperature. Thus, it is very important to adopt a hardfacing material.
The hardfacing technical process is one effective method to solve the problem about defect of metal materials under the high temperature and to increase the anti-wear physical property of the surface. Generally, processes such as welding, thermal j spray welding, and the like can effectively reduce the loss caused by abrasion, rustiness, and so on.
The hardfacing technical process promotes the development and perfection of the hardfacing technique according to the application of materials. According to properties, the hardfacing materials can be divided into iron base alloy, nickel base alloy, cobalt base alloy, ceramic material, self fluxing alloy, tungsten carbide material, special alloy material, composite material, and the like. And according to the products made of the hardfacing materials, the materials can be divided into alloy wire, alloy powder and composite powder, ceramic powder, cermet powder, nanometer powder, strip, bar, bare welding rod, electric welding rod, tube welding rod, tube wire, soft wire, and so on.
U.S. Pat. No. 4,728,493 discloses a formulation of atoms in respective percents as Cr 45-60%, Ni 25-44%, Mo 6.5-12%, Cb 2.0-4.5%, C 1.5-2.8%, and S 0.4-1.2%, wherein the major component is chromium base alloy, and can be adapted to a vapor corrosion environment, so it can be used as a hardfacing construction material for oil rigs. The hardfacing property thereof mainly comes from the C element and heavy metal elements added in the formulation. The hardfacing strength is enhanced by carbide precipitation. And the major mechanism of rust-resistance thereof comes from adding plenty of Cr.
Furthermore, in order to meet demands for hardness of the contact surface, some patents adopt an iron base alloy as the major component of the formulation, for example, U.S. Pat. No. 5,431,136 and U.S. Pat. No. 4,810,464. U.S. Pat. No. 5,431,136 emphasizes that it is adapted to hardfacing for the oil drill of the oil rig without adding Al or B. In the formulation, the atoms, besides Fe, and the percents thereof are C 1.3-2%, Cr 19-23%, Mo 8-11%, Ni 17-21%, Mn 6-13%, Si <0.5%, O <0.06%, and the hardfacing strength is also enhanced by carbide precipitation. U.S. Pat. No. 4,810,464 emphasizes a formulation of iron base alloy, which can provide the same hardness without adding Co. In the formulation, besides Fe, the other atoms and the respective percents thereof are B 3-5%, Ni 27-43%, Si 0.1-5%, C 0.2-1.5%, Mn 0.1-2%, and Cr about 10%, and the hardfacing strength is enhanced by boride and carbide precipitation. However, during fabrication of the hardfacing rod, the alloy powder must be processed by plasma in a vacuum, so mass production of the hardfacing rod is complicated and cannot be widely applied effectively.
U.S. Pat. No. 6,793,878 adopts a cobalt base alloy as the major component and has characteristics such as stability under high temperature, anti-wear, and anti-oxidation. U.S. Pat. No. 4,331,741 adopts a nickel base alloy as the major component, and has characteristics such as stability under high temperature and anti-wear. Besides Ni, the other atoms and the respective percents thereof are Cr 27-30%, Mo 7-9.5%, W 4-6%, Mn 0.75-1.3%, Ti 0.05-0.5%, Cb 0.2-0.75%, C 1.2-1.8%, Si 1-1.75%, and Fe <5%, and the hardfacing strength is enhanced by carbide precipitation and the forming of tungsten carbide. However, during fabrication of the welding rod, alloy powders of a specific size are required and the fabricating must be performed by plasma in a vacuum. Therefore, it is inconvenient to fabricate the welding rod, and is difficult to be widely used in commerce.
Moreover, Taiwan Patent TW567230 for example discloses a concept of high-entropy and multi-element alloy materials, but does not claim the application of hardfacing.
The components of the hardfacing material can stand against harsh environments, i.e., the components are prepared directed to specific environments, such that effects of rust resistance, anti-oxidation, and the like can be achieved.
As such, the improper selection of welding materials for hardfacing may result in disadvantages such as poor quality of welding and poor binding property between the welding layer and the base material.

SUMMARY OF THE PRESENT INVENTION

In view of the above, the main object of the present invention is to provide a multi metal base hardfacing alloy, to solve the problems of poor welding quality and poor binding between the welding layer and the base material.
Another object of the present invention is to provide a multi metal base hardfacing alloy, wherein a concept of a multi metal base is adopted to prepare the formulation of the hardfacing material, thus achieving extensive use under the various environments.
The present invention provides a multi metal base hardfacing alloy, which includes Fe, Ni, Cr, and Mn or Mo. Either Mn or Mo is selected. The atom percent of Fe is a % (5%≦a %≦35%), that of Ni is b % (5%≦b %≦35%), that of Cr is c % (5%≦c %≦35%), and that of Mn or Mo is d % (5%≦d %≦35%) in the alloy, wherein a %+b %+c %+d %≦100%.
According to the multi metal base hardfacing alloy illustrated by an embodiments of the present invention, Al may be added with an atom percent of e % in the alloy, wherein 2%≦e %≦12%, and a %+b %+c %+d %+e %≦100%. According to the present invention, Co can also be added as required, and the atom percent of Co is f % in the alloy, wherein 17%≦f %≦21%, and a %+b %+c %+d %+f %≦100%.
The present invention further provides a multi metal base hardfacing alloy, which includes Fe, Ni, Cr, Mn and Mo. The atom percent of Fe is a % (5%≦a %≦35%), that of Ni is b % (5%≦b %≦35%), that of Cr is c % (5%≦c %≦35%), that of Mn is d % (5%≦d %≦35%), and that of Mo is e % (5%≦e %≦35%) in the alloy, wherein a %+b %+c %+d %+e %≦100%.
According to the multi metal base hardfacing alloy illustrated by embodiments of the present invention, Al may be added with an atom percent of f % in the alloy, wherein 2%≦f %≦12%, and a %+b %+c %+d %+e %+f %≦100%. According to the present invention, Co can also be added as required, and the atom percent of Co is g % in the total alloy, wherein 17%≦g %≦21%, and a %+b %+c %+d %+e %+g %≦100%.
The present invention provides a multi metal base hardfacing alloy, which is completely different from the conventional design architecture of hardfacing alloy formulation having one major element. According to the formulation of the multi metal base hardfacing alloy, the atom percent of each major element is smaller than 35%, for achieving extensive use under the various environments.
Furthermore, according to the multi metal base hardfacing alloy provided by the present invention, when it is used as a welding material, the preheating temperature thereof is lower than that of the conventional formulation. Therefore, it has the characteristic of low preheating temperature. Generally, the conventional hardfacing alloy must be preheated to above 400° C. when used as a welding material, but the alloy of the present invention need only be preheated to 200° C., which greatly reduces the cost of the welding process.
The present invention adopts the multi metal base alloy as the hardfacing material. The fabricating process of the welding rod of the alloy can be performed by smelting directly in an atmospheric environment. The principle and mechanism for enhancing the hardfacing strength is based on the principle of the high entropy of multi-element materials. Different from the principle of the ordinary formulation of hardfacing alloy based on the carbide or boride precipitation, the problem that the hardfacing material is fragile due to the carbide or boride contained therein can be avoided in the present invention.
The features and practice of the preferred embodiments of the present invention will be illustrated in detail below with the accompanying drawings. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below for illustration only, and which thus is not limitative of the present invention, and wherein:
FIG. 1 shows data about hardness according to the formulation of the multi metal base hardfacing alloy of the preferred embodiments of the present invention; and
FIG. 2 shows data about hardness according to the formulation of the multi metal base hardfacing alloy without Co of the preferred embodiments of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The content of the present invention is illustrated in detail in the following part by embodiments making reference to the drawings. The symbols mentioned in the specification refer to the symbols in the drawings.
The present invention provides a multi metal base hardfacing alloy, which includes Fe, Ni, Cr, and Mn or Mo, wherein either Mn or Mo is selected. The atom percent of Fe is a % (5%≦a %≦35%), that of Ni is b % (5%≦b %≦35%), that of Cr is c % (5%≦c %≦35%), and that of Mn or Mo is d % (5%≦d %≦35%) in the alloy, wherein a %+b %+c %+d %≦100%.
Al (aluminum) is added into the above-mentioned multi metal base hardfacing alloy with an atom percent of e % in the alloy, wherein 2%≦e %≦12%, and a %+b %+c %+d %+e %≦100%. Co (cobalt) may also be added as required with an atom percent of f % in the alloy, wherein 17%≦f %≦21%, and a %+b %+c %+d %+f %≦100%. Moreover, the multi metal base hardfacing alloy of the present invention does not contain the specific elements such as B or C.
The present invention further provides a multi metal base hardfacing alloy, which includes Fe, Ni, Cr, Mn, and Mo. The atom percent of Fe is a % (5%≦a %≦35%), that of Ni is b % (5%≦b %≦35%), that of Cr is c % (5%≦c %≦35%), that of Mn is d % (5%≦d %≦35%), and that of Mo is e % (5%≦e %≦35%) in the alloy, wherein a %+b %+c %+d %+e %≦100%.
Al is added into the aforementioned multi metal base hardfacing alloy with an atom percent of f % in the alloy, wherein 2%≦f %≦12%, and a %+b %+c %+d %+e %+f %≦100%. Co may also be added as required with an atom percent of g % in the alloy, wherein 17%≦g %≦21%, and a %+b %+c %+d %+e %+g %≦100%. Moreover, the multi metal base hardfacing alloy of the present invention does not contain the specific elements such as B or C.
The multi metal base hardfacing alloy of the present invention can be applied in the hardfacing welding technique. Various heating sources and methods are used to heat the materials having desired functions in the form of powder or welding rod into fusing, melting, or alloying states, and then the materials are deposited on the surface of the workpiece to form good bonded coating, thus providing the following outstanding features.
(1) As coating material, almost all metal (alloy), non-metal (ceramic, cermet), and various composite materials are included.
(2) As for coating preparation, techniques such as flame, arc, gas protection, isoionic method, laser method, and the like can be applied, and the process can be performed in the factory or maintenance and wrought steel can be carried out on the spot, so it is flexible and convenient.
(3) As for base material, the base materials of superalloy (or base materials of poor weldability) can be replaced by low alloy or carbon steel, and thus the consumption of noble metal is reduced and the function of the hardfacing technique is improved.
(4) Thermal spray, spray welding, and overlay welding can be used in combination, thereby achieving a perfect technical effect;
(5) A workpiece can be reused many times after being mended and repaired, thus further prolonging the service life thereof.
The multi metal base hardfacing alloy of the present invention can be applied to a standard operation of the ordinary hardfacing welding, and the operation can be started when the preheating temperature reaches 200° C. instead of the above 400° C. as the conventional hardfacing alloy requires. Various experiments and experimental values are listed in detail in the following part, in order to illustrate the function of the present invention. However, the claims of the present invention are not to be restricted by the experiments.
According to the formulation of Experiment 1, the atoms and the weight percents thereof are Fe 28-29%, Mn 18-19%, Ni 30-31%, Cr 17-18%, and A14-5%. After processing the surface of one test plate by hardfacing welding one to four layers of the multi metal base hardfacing alloy of the present invention, the hardness of the surface of the test plate is measured and compared, to demonstrate the hardfacing effect. As seen in the experimental data, the hardness is raised to 31 HRC (Rockwell hardness) after welding the first layer, to 32 HRC after welding the second layer, to 42 HRC after welding the third layer, and remains 42 HRC after welding the fourth layer. Under the same concept, some modifications can be made to the formulation of the multi metal base hardfacing alloy of the present invention, and similar effects of hardfacing processing can also be achieved.
FIG. 1 shows the data about the hardness according to the formulation of the multi metal base hardfacing alloy of the preferred embodiments of the present invention. As shown in FIG. 1, the weight percent range of Experiment 1 of the present invention is changed to be Fe 14-29%, Mn 18-32%, Ni 16-31%, Cr 14-31%, A12-8% in Experiments 1A-1D, and the hardness of the hard face falls in a range of 40-51 HRC. Therefore, it can be widely used under the different atmospheric environments.
Likewise, some modifications can be made to the formulation of the multi metal base hardfacing alloy, and the similar effect of hardfacing processing can also be achieved. As shown in Experiment 2 of the present invention, the weight percents are Fe (24-26%), Co (17-18%), Ni (16-18%), Cr (14-16%), Mo (13-15%), and Al (8-9%). Further, as shown in Experiment 3, the weight percents are Fe (17-20%), Co (18-21%), Ni (18-20%), Cr (17-18%), Al (4-5%), and Mn (18-19%). As shown in Experiment 4, the weight percents are Fe (23-26%), Co (19-21%), Ni (19-21%), Cr (15-17%), Al (5-6%), and Mo (10-12%). All of the foregoing experiments can achieve the purpose of effectively enhancing the hardfacing property to above 40 HRC.
Finally, according to the concept of the present invention, in Experiments 5A-5G, the hardfacing technique is applied with the multi metal base hardfacing alloy of the present invention in the application without Co. FIG. 2 shows the hardness data according to the formulation of the multi metal base hardfacing alloy without Co in the preferred embodiments of the present invention. As shown in FIG. 2, the atoms and weight percents thereof in Experiments 5A-5G are Al (6-12%), Cr (12-22%), Mn (13-23%), Fe (9-29%), Ni (8-30%), and Mo (13-30%), wherein the hardness of the hard face falls in a range of 45-65 HRC, and it can also be widely used in the various environments. The above-mentioned experiments demonstrate that the formulation of the multi metal base hardfacing alloy is applicable to improving the hardfacing effect and achieving extensive use in the various environments at the same time.
The present invention adopts the concept of multi metal base to prepare the formulation of hardfacing material. The fabricating process of the welding rod of the alloy formulation can be performed by smelting directly in an atmospheric environment. The principle and mechanism for enhancing the hardfacing strength is based on the principle of the high entropy of multi-element alloy materials. Different from the principle of the ordinary formulation of hardfacing alloy based on carbide or boride precipitation, the problem that the hardfacing material is fragile due to carbide or boride contained therein can be avoided.
Moreover, as the multi metal base of the present invention are in accordance with the high-entropy and high-stability principle of the second law of thermodynamics, the present invention has the characteristics such as anti-oxidation and anti-corrosion. Therefore, it can be widely and fully used under the various environments, and further become the total solution for formulation of hardfacing material, which is novel and has special features different from existing, foregoing patents.
To prepare a hardfacing alloy formulation with extensive use in the various environments, the present invention provides a multi metal base hardfacing alloy, which is completely different from the conventional design architecture of a hardfacing alloy with one major element. The atom percent of each major element of the multi metal base hardfacing alloy formulation is smaller than 35% in the alloy, thus achieving extensive use in the various environments. Moreover, the operating temperature of the hardfacing alloy formulation provided by the present invention is lower than that of the conventional one. In general, the hardfacing alloy of the conventional formulation must be preheated to above 400° C., but the alloy of the present invention need only be preheated to 200° C. to perform welding. Therefore, it is more convenient and easier to operate.
Some multi metal base alloys of the present invention adopt Fe, Ni, Cr, Mo, and Mn, wherein the atom percent of each element in the alloy is smaller than 35%. Through the practical tests, it is demonstrated that the multi metal base hardfacing alloy formulation has good hardfacing property under the different environments. The multi metal base alloy of the present invention is more flexible in the design of the hardfacing alloy, and the proportions of the components can be slightly adjusted and changed according to the various desired properties. The present invention provides a multi metal base hardfacing alloy, which is applicable to the various environments based on the concept of the multi metal base design.
The multi metal base hardfacing alloy of the present invention adopts the multi metal base concept. The atom percent of each element of the alloy is smaller than 35%. The formulation of the hardfacing alloy is prepared according to the concept of multi metal base, for achieving extensive use in the various environments. As the basic ingredient of the welding material, the welding material has advantages such as low operating temperature, better physical strength hardiness, acid resistance, basic resistance, anti-oxidation, and interface obturation, so it is progressive and practical.
The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A multi metal base hardfacing alloy, comprising:

Fe, with an atom percent a % in the alloy, 5%≦a %≦35%;

Ni, with the atom percent b % in the alloy, 5%≦b %≦35%;

Cr, with the atom percent c % in the alloy, 5%≦c %≦35%; and

Mn, with the atom percent d % in the alloy, 5%≦d %≦35%,

wherein, a %+b %+c %+d %≦100%.

2. The multi metal base hardfacing alloy according to claim 1, wherein Al is included by an atom percent of e % in the alloy, 2%≦e %≦12%, and a %+b %+c %+d %+e %≦100%.

3. The multi metal base hardfacing alloy according to claim 1, wherein Co is further included by an atom percent of f % in the alloy, 17%≦f %≦21%, and a %+b %+c %+d %+f %≦100%.

4. A multi metal base hardfacing alloy, comprising:

Fe, with an atom percent a % in the alloy is, 5%≦a %≦35%;

Ni, with the atom percent b % in the alloy, 5%≦b %≦35%;

Cr, with the atom percent c % in the alloy, 5%≦c %≦35%; and

Mo, with the atom percent d % in the alloy, 5%≦d %≦35%,

wherein, a %+b %+c %+d %≦100%.

5. The multi metal base hardfacing alloy according to claim 4, wherein Al is included by an atom percent of e % in the alloy, 2%≦e %≦12%, and a %+b %+c %+d %+e %≦=100%.

6. The multi metal base hardfacing alloy according to claim 4, wherein Co is further included by an atom percent of f % in the alloy, 17%≦f %≦21%, and a %+b %+c %+d %+f %≦100%.

7. A multi metal base hardfacing alloy, comprising:

Fe, with an atom percent a % in the alloy, 5%≦a %≦35%;

Ni, with the atom percent b % in the alloy, 5%≦b %≦35%;

Cr, with the atom percent c % in the alloy, 5%≦c %≦35%;

Mn, with the atom percent d % in the alloy, 5%≦d %≦35%; and

Mo, with the atom percent e % in the alloy, 5%-e %≦35%;

wherein, a %+b %+c %+d %+e %≦100%.

8. The multi metal base hardfacing alloy according to claim 7, wherein Al is included by an atom percent of f % in the alloy, 2%≦f %≦12%, and a %+b %+c %+d %+e %+f %≦100%.

9. The multi metal base hardfacing alloy according to claim 7, wherein Co is further included by an atom percent of g % in the alloy, 17%≦g %≦21%, and a %+b %+c %+d %+e %+g %≦100%.