JPS63486A - Method for improving wear resistance and seizure resistance for metallic member - Google Patents

Abstract

PURPOSE:To give excellent wear resistance and seizure resistance by sticking powdery aggregate or powdery forming body composing or carbide of the specific kind and quantity and the specific metallic phase, to surface of metallic member and then integrating them by fusing. CONSTITUTION:The powdery aggregate or powdery forming body is composed of 20-80mol% total of one kind or more of carbides of V, Ti, Zr, Nb, Ta, Hf and the remaining part of one kind or more of metals or alloy of Fe, Ni, Co or one kind or more of alloy as main component of Fe, Ni, Co and inevitable compounds. After sticking this powdery aggregate or powdery forming body to the surface of metallic member, the powdery aggregate or powdery forming body is fused by heat source having high energy density, to integrate the powdery aggregate or powdery forming body with the surface of metallic member by fusing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for improving the S wear resistance and seizure resistance of metal members.

(Prior Art) Metallic products having abrasive surfaces, such as cutting tools, plastic working tools, internal combustion engine cylinders, pistons, and bearings, are required to have not only wear resistance but also seizure resistance.

Endure J! It is well known that in order to improve wear resistance and seizure resistance, it is sufficient to improve the hardness of the metal surface. Methods for improving the hardness of metal surfaces include methods such as hardening and coating with alloy components that have wear resistance and seizure resistance.As for methods using hardening, conventional methods such as induction hardening In addition, there are surface hardening methods (hereinafter referred to as laser surface hardening) that use heat sources with high energy density such as lasers and electron beams, and these techniques are described in Japanese Patent Application Laid-open No. 54-112740 and No. 53-1.
37362. It is disclosed in Japanese Patent Application Laid-Open No. 55-2710.

In addition, there is a method to improve the wear resistance of the surface of cast iron products and the cutting edge of high-speed steel cutting tools by melting only the surface layer using a high-energy beam and then rapidly solidifying it (hereinafter referred to as laser glazing). is Japanese Patent Application Publication No. 5
No. 7-85926 and Japanese Patent Application Laid-Open No. 59-83718.

On the other hand, there is a method for coating one alloy component.

Methods include surface hardening treatments such as nitriding treatment, coating treatment, PVD treatment, CVD treatment, laser surface alloying, and laser cladding.

Among these, laser surface alloying involves creating a thin molten layer on the base metal by laser heating, adding alloying elements to this molten layer, and instantaneously diffusing the alloy components to form an alloy layer on the base metal surface. As a method of adding 0 alloying elements, which is a treatment method for adding alloying elements, there is a method in which an additive material containing the necessary alloying components is deposited on the surface of the base material in advance, and then melted into the base material by laser heating.

In addition, the method using laser cladding is a process very similar to laser alloying, and by setting the amount of additive material and laser irradiation conditions to W, the amount of melting of the base material is reduced, and the composition is close to that of the additive material. This is a technology to form a surface layer with

(Problems with conventional technology) In laser surface hardening, which is a type of hardening method,
Although it has the advantage that deformation caused by thermal strain and quenching is small, in terms of wear resistance, it is almost the same as conventional induction hardening. The product used has the disadvantage that even if surface hardening is performed again, there is little improvement effect. Another problem is that it cannot be applied to materials that cannot be hardened, such as austenitic stainless steel.

On the other hand, in the case of laser glazing, it is more effective than the surface hardening method for cast iron and high-speed steel, but the hardness is limited to about Hv900 to 1100. Also,
The disadvantage of laser glazing is that the steel types to which it can be applied are severely limited, and it is less effective for materials such as carbon steel and low-alloy steel, in which almost no undissolved second phase particles remain after normal quenching or solution treatment.

Further, there is a problem that the nitriding treatment and the fertilizing treatment do not have sufficient effects of improving wear resistance and seizure resistance. Also,
In surface hardening treatments such as PVD treatment and CVD treatment, Ti
Since a hard compound such as N or TiC is only mechanically bonded to the surface, the quality of the base material is likely to deteriorate, and furthermore, deformation due to thermal strain is likely to occur.

On the other hand, in surface alloying and cladding using laser, T
Metal carbides such as i C, W C, M o C and A20
3, a metal oxide such as T i 02 is added.

However, these hard compounds have very high melting points.

Further, (1) since hard compounds are very difficult to melt, if a large amount is added, unmelted compounds will remain in the alloyed layer. Since this unmelted compound usually exists in an aggregated state, it easily falls off and becomes a cause of defects such as bores and cracks.

(2) Since the hard compound has high viscosity, even if it is melted, it does not mix uniformly with the liquid phase of the base material, resulting in a partially uneven structure. Moreover, the bubbles cannot be completely removed from the surface and remain as defects in the alloy phase.

(3) Under conditions where the difference in specific gravity between the additive material and the base material is large, for example, when using AlI303 or SiC as the additive material and Fe, Ni, etc. as the base material, the unevenness shown in (2) may occur. The disadvantage is that it becomes more pronounced.

(Means for solving problems) The above problems include V, Ti, Zr, Nb, and Ta.

A total of 20 to 80 mo of one or more carbides of Hf
1%, with the remainder being a metal or alloy of one or more of Fe, Ni, and Co, or an alloy and inevitable compound whose main component is one or more of Fe, Ni, and Co. Or the powder molded body has wear resistance and/or
Alternatively, after adhering to the surface of a metal member whose seizure resistance is to be improved, the powder aggregate or the powder molded body is melted with a heat source having high energy density, and the powder aggregate or the powder molded body and the powder molded body are melted. The problem is solved by a method for improving the wear resistance and seizure resistance of a metal member, which is characterized by melting and integrating the surface of the metal member.

That is, in the present invention, a specific type and amount of carbide is used as a hard compound, and a powder aggregate or powder compact (hereinafter referred to as additive material) consisting of the carbide and a specific metal phase is temporarily attached to the surface of a metal member, By melting and integrating the carbonized material with the base using a laser or an electron beam, it is possible to improve the wear resistance and seizure resistance of the metal member without causing the problems of the laser alloying and cladding methods. This is what we discovered.

The present invention will be explained in detail below.

The additive material in the present invention is a powder aggregate or powder compact (consisting of carbide powder and metal or alloy powder). Therefore, the powder aggregate or powder compact is
When heated, the low melting point metal or alloy phase first melts;
Since each carbide particle is covered with the liquid phase of the metal or alloy, a liquid phase consisting of the carbide constituent elements and the metal or alloy component is almost instantaneously formed. Therefore, it is difficult for unmelted carbide to remain, and even if melt remains, the metal or alloy phase exists between the carbide particles, making it extremely difficult for these carbides to fall off. Moreover, since the viscosity of the obtained liquid phase is reduced, the base material liquid phase and the carbide are mixed uniformly, and defects such as bubbles are less likely to remain.

Now, the reason why the carbides are limited to carbides of V, Ti, Zr, Nb, Ta, and Hf will be explained. powder aggregate or
During alloying or cladding of a powder compact, a liquid phase containing a mixture of carbide and metal components is formed. When the liquid phase is cooled, the carbide is cooled while being partially dissolved in the metal phase of the matrix because the cooling rate is very fast, but most of the time it crystallizes finely again from the liquid phase. The compound that crystallizes from the liquid phase at this time is not necessarily the same as the compound that originally existed in the additive material; for example, when MoC or wc is melted together with Fe, Ni, Co, etc. M, C, etc., which are low hardness and brittle fJ carbides, crystallize from the phase. When such a weak phase crystallizes, the effect of improving wear resistance and the like is almost eliminated. On the other hand, V, Ti,
This is because the compounds of Zr, Nb, Ta, and Hf that crystallize from the liquid phase become very stable NaC-shaped carbides that do not exhibit brittle properties, which greatly improves wear resistance and seizure resistance.

The reason for containing one or more carbides of V, Ti, Zr, Nb, Ta, and Hf in a total amount of 20 to 80 mol% is that the amount of carbides in the powder aggregate or powder compact is 20 m
o If it is less than 1%, the effect of improving wear resistance and seizure resistance will not be sufficient, and if it exceeds 80 mol%, defects will easily occur during alloying or in the cladding phase, and the effect of wear resistance will not be sufficient. This is because it will no longer be.

In addition, carbides may be composed of metal elements of class 18 and C, such as VC, TiC, NbC, etc.
i) It may be composed of multiple metal elements such as C, (V, Nb)C, etc., or it may be a mixture of these elements, or it may contain other elements such as Fe, Ni, etc. However, there is no particular problem if the crystal structure is a carbide with an NaC pattern.

In the present invention, the metal powder of the powder aggregate or powder compact is composed of one or more metals of Fe, Ni, and Co, or an alloy phase containing these as main components. Other phases such as metals or alloys such as Fe, Ni 2 and Co have much lower melting points than carbides, melt before the carbides during surface alloying or cladding, and function to melt the carbides through a eutectic reaction. At this time, Fe, Ni, and C.

Or, if it is an alloy containing these as main components, after the carbide is melted, it will not change into other brittle compounds.

Note that it is desirable to use different metal components depending on the usage environment, and when wear resistance at relatively low temperatures is required, in addition to solid solution hardening and dispersion hardening, the metal phase is strengthened by martensitic transformation. It is desirable to use a Fe-based alloy phase that increases hardness at room temperature, and a Ni- or Co-based alloy phase when wear resistance at high temperatures is required.
i,G.

When a Fe-based alloy phase is used, the heat resistance and seizure resistance are also better than when a Fe-based alloy phase is used.

In addition, the additive material used in the present invention is most easily produced by mixing carbide powder and metal powder, but in this case, the metal powder can be Fe, Fe, Ni, Go gold alloy powder may be used; for example, carbon steel, stainless steel, high speed steel, etc. powder may be used instead of pure Fe powder.

As explained in the embodiments below, depending on the conditions, adding a specific alloying element to the metal phase may improve the wear resistance and seizure resistance. In some cases, the improvement effect is large.

Note that the above additive materials may include mixed particles manufactured by mixing carbide particles and powder particles made of a metal or alloy, or single powder particles made of a carbide and a metal or alloy component. In order to produce the latter additive material containing single particles, the carbide powder surface may be coated with a metal or alloy component by plating, vapor deposition, ion sputtering, etc.; 0-surface alloying, which involves coating the surface of alloy powder with carbide;
The latter additive material is superior in terms of the ease of melting of the carbide in the cladding, alloying, and quality of the cladding part, but special equipment is required to manufacture it, and the unit price of the additive material is high. Since they are expensive, they can be used depending on the purpose of use.

In addition, the additive material may be temporarily attached to the processed surface using an organic binder in powder form, and surface alloying or cladding may be performed, but since the additive material is scattered during laser or electron beam irradiation in the powder state, It is difficult to control the thickness because the tacking tends to shrink after surface alloying and tardging. After cutting to size, the ends are temporarily attached to the surface to be processed by spot welding or the like, and then they are melted and integrated with the base using a laser or an electron beam.

In the present invention, f! has a high energy density! % source to melt the powder aggregate or the powder compact.

The reason for using a material with high energy density as a heat source is as follows. In other words, in order to improve the wear resistance and seizure resistance of the alloying, clubbing phase, some of the carbides are forcibly dissolved in the matrix, and most of them are finely crystallized from the liquid phase.

It needs to be dispersed. To achieve this, the cooling rate must be increased, for example, 103w/cm for 8 sources.
A power density of 2 or more is required. When using a heat source with a low power density, the cooling rate is slow, which causes the aggregated and coarsened carbides, and the carbide constituent elements are no longer dissolved in the metal phase, resulting in sufficient wear resistance and seizure resistance of the metal parts. However, such heat sources with high energy density include, for example, lasers and electron beams.

[Description of Embodiments] (Second Item 1) In the present invention, Cr may be added to the metal phase in an amount of 2 to 30 mo 1% of the total composition other than carbides. It is effective for applications where special properties are required. The range of addition was 2 to 30%, which was 2 mol.
% or less, the crucible seizure effect is small, and 30 mol
This is because if it is added in excess of %, brittle carbides such as M, C, etc. are likely to crystallize, and in particular, brittle σ phase is likely to be formed even in the metal phase.

(Third claim) In addition, 0.5 to 20% of Mo or/and W is contained in the metal phase.
It may be added in a range of mol%.

In this case, it is effective for applications where wear resistance is particularly required. The reason why Mo and/or W are added is that they have the function of solid solution hardening or precipitation hardening of the metal phase. The reason for setting the addition amount to 0.5 to 20 mol% is that 0.5
If it is less than mol%, the effect of solid solution hardening or precipitation hardening of the metal phase is small, and if it exceeds 20mol%, it becomes brittle.
This is because it becomes difficult to crystallize carbides such as.

(4th claim) Also, the total amount of Cr, Mo, Wc7) added is 40 mol%
In this case, crystallization of brittle carbides can be prevented, and the wear resistance and seizure resistance of the metal member can be further improved.

(Claim 5) Any carbide can significantly harden the alloyed layer and the tarading layer, but among them, the effect of VC carbide is the greatest. Especially when wear resistance and seizure resistance are required, V
It is preferable to use an additive material containing C carbide of 10 mO% or more. VC carbide has relatively low stability (easily dissolves in solid solution) compared to other NaCA type cut carbides, so it is not recommended to use an additive material containing VC carbide. , the amount of carbide constituent elements (V, C) in solid solution in the metal phase after quenching from the liquid phase is large, and solid solution hardening in addition to dispersion hardening greatly contributes to the effect.

[Embodiments of the Invention] (First Example) After thoroughly mixing the types and amounts of hard compounds and metal powders shown in Table 1 with a V-mixer, about 20φ was mixed with a HIP.
A powder compact was produced. After that, the powder molded body was
It was processed into a size of mφ x 10 mm x 0.5 mm and used as an additive material. This additive material is 30 mm x 50 mm x
After temporary attachment by spot welding to the surface of a 5 mm metal base, the surface was alloyed by irradiating the surface with a laser, and its cross-sectional hardness and wear resistance were determined by Okoshi's abrasion test. Seizure resistance (severity of adhesive wear) was evaluated. HIP conditions, type of base material,
The laser irradiation conditions and evaluation test conditions are as follows.

I HIP conditions: 1050℃X roooatm
X 2 hours 2 Base material: 515C (Hv175) 3
Laser irradiation conditions: Output 3KW Speed 0.5m/min Spot diameter approx. 2mm 4 Evaluation test ■Hardness distribution: Micro hardness meter Load 300g ■Okoshi type a! Wear test 8: Phase f4t S U J 2 (HRCeO
) Friction pressure: j9400 m Load: 6.3 kgf Friction speed: 0.3 to 4.9 ta/sec 1) Cross section Macro structure and micro structure VC is selected as the carbide, and the cross section is the result of surface alloying using base material 315C. The macrostructure and microstructure are shown in Figure 2. From Figure 2, there are cracks and cracks in the alloyed layer.
There are no defects such as bores, and the thickness of the alloyed layer is about 0.5 to 0.6 mm, and the VC carbide in the same NaC pattern as the carbide present in the original additive material is fine. Exhibited on,
It is a dispersed organization.

2) Hardness of Alloyed Layer The hardness of the alloyed layer was measured for a material whose surface was alloyed with 515C selected as the substrate material and additive materials A to D shown in Table 1. Figure 1 shows the hardness distribution in the cross section.

The hardness decreases rapidly when the thickness of the alloyed layer exceeds about 0.5 mm, and becomes equal to the hardness of the base material at a distance of about 0.6 mm from one surface layer. Therefore, when comparing the hardness in the alloy layer, the main component of the carbide in the additive material is VC, and the amount is 2
Under conditions that vary from 0 to 80 mol%, the hardness of the alloyed layer tends to increase as the VC mol% increases.

In addition, the results of comparing the maximum hardness of the alloyed layer of the additive materials tested are shown in Figure 3.From Figure 3, the hardness of the alloyed layer is about 1100Hv or more, which is good hardness. There is. In particular, the hardness of H9I and J materials containing VC is higher than that of E, F, and G materials, which have the same components other than VC.
It can be seen that when 10 mol% or more of C is added, the hardness becomes even higher.

Using 5KD61, 5KH55, and pure titanium as the base material,
The results of hardness measurements using C and H as additive materials are shown in FIG. 4. From FIG. 4, it can be seen that hardness does not depend on the base material.

3) Wear test results The results of a wear test using 515C, KD61, 5KH55° pure titanium as the base material and the additives shown in Table 1 are shown in FIGS. 5 to 8.

Figure 5 shows the results of an experiment using the additive materials listed in Table 1 on the base material of 515C. Figure 6 shows the results of the experiment using the base material of 5KD61 with no treatment, PVD treatment, and treatment according to the present invention. Figure 7 shows the results of the wear resistance test for the material at 5KH.
55 shows the results of wear resistance experiments of untreated materials, PVD treatments, and materials treated according to the present invention.
FIG. 8 shows the results of a wear resistance experiment of a pure titanium base material treated according to the present invention. The wear amounts shown in FIGS. 5 to 8 were determined according to the formula below.

Amount of massaging Jt=Test load (Kgf) As the friction speed increases, untreated and PVD treated
E [7] Abrasion (a type of seizure) occurs, so the wear resistance is worse than at low speeds, but this tendency is small with alloyed products, and even if the base material changes, alloying will not occur. Layer F resistance! The wear resistance does not change much.

In addition, in the untreated materials and PVD treated materials of 315C and pure titanium, wear and seizure occurred rapidly under the test conditions, making it impossible to continue the test (Second Example) Additive Materials The influence of the metal components therein is shown below. Test pieces were manufactured using the additive materials shown in Table 2 under the same conditions as in Example 1, and were laser alloyed.

1) Effect of temperature on hardness of hardness alloyed layer! The results of the investigation are shown in Figure 9, and it can be seen that the hardness tends to decrease as the test temperature increases. The tendency of hardness is N as a metal component.
When using i or Go.

The hardness at room temperature is lower than that of Fe, but it becomes higher at high temperatures, and Ni or Co has excellent wear resistance at high temperatures.]
It represents 1 yen. In addition, those containing Mo are Mo
It can be seen that the hardness is higher in all humidity ranges than the one without.

2) It! Wear test The results of the wear experiment are shown in FIG. 10, and the experiment was conducted at a temperature of 400° C., at which wear progresses almost as solidification wear. From FIG. 10, it can be seen that when Ni or Co is used as the metal component, the wear due to coagulation is less than when Fe is used. Especially Mo
, and those containing W.

It can be seen that materials containing Cr have excellent adhesive wear resistance.

(Third Example) The additive material having the composition shown in the t51 table was not powder-molded,
Mix the powdered material with an acrylic binder to form a slurry, apply it to the base surface to a thickness of about 1 mm, and then apply the first
Laser alloying was performed under the same conditions as in the example. the result,
The thickness of the alloyed layer was about 0.25 mm, which was 1/4 of the original thickness, but the same results were obtained in terms of hardness and wear resistance.

(Fourth Example) Alloying treatment was performed using an electron beam using the -L powder-molded additive material shown in Table 2, but results similar to those obtained using a laser were obtained.

[Effects of the Invention] According to the present invention, it is possible to harden the surface layer without causing defects, improve wear resistance and seizure resistance, and improve the a! A great effect can be obtained by applying it to a metal member having a rubbing surface.

Furthermore, all the hard compounds used in the present invention are non-magnetic,
If a non-magnetic metal phase is used in the additive material, the surface layer of the non-magnetic material can be hardened without deteriorating its properties, and the surface layer can be selected according to the properties of the base metal.

Further, in the conventional method, laser cladding was impossible because only carbide was added, but in the present invention, since the added material itself is easily melted, cladding is also possible. Therefore, since the contamination of base metal components can be significantly reduced, it is possible to process even base materials that would be inconvenient if contamination occurs.

[Brief explanation of drawings]

Figure 1 is a graph of the hardness distribution from the surface, Figure 2 is a photograph of the macrostructure and microstructure of the surface alloyed layer, and Figure 3 is a graph of the hardness distribution from the surface.
The figure is a graph showing the influence of additive materials on hardness.
The figure shows the influence of the base material on hardness! Graph for finding 5th
The figure is a graph of the relationship between the amount of friction j1 and the friction speed using a base material of 515G.
A graph showing the relationship between the amount of wear and the friction speed. Figure 7 shows Pi! using 5KH55 as the base material. amount of wear and tear. Figure 8 is a graph that shows the relationship between the wear amount and friction speed using pure titanium as the base material. Figure 9 is a graph that shows the relationship between hardness and test temperature for guano. Figure 1θ is a graph showing the relationship between the type of additive material and the specific wear charge using 515G as the base material. Table 1 Table 2 Type of additive material 1 (2) Distance from surface (mm) 1. Type of additive material Type of additive material x 10-4 Base material SS 1
5 C friction speed (m/5ec) %10-' Base material M-S KD
61 Friction speed (m/5ec) ×10” MflHtNs S K
H55 Friction speed (m/5ec) Friction speed (m/sec) Figure 9 R, T 500 600 700 80
0 Test temperature (”O) × 10 Type of additive material

Claims (5)

[Claims] (1) A metal or alloy containing one or more carbides of V, Ti, Zr, Nb, Ta, and Hf in a total of 20 to 80 mol%, with the remainder being Fe, Ni, and Co, or Powder aggregates or powder compacts made of alloys and unavoidable compounds mainly composed of one or more of Fe, Ni, and Co can be used for metal members whose wear resistance and/or seizure resistance is to be improved. After adhering to the surface, the powder aggregate or the powder molded body is melted by a heat source having high energy density to melt and integrate the powder aggregate or the powder molded body and the surface of the metal member. A method for improving wear resistance and seizure resistance of metal members. (2) A method for improving wear resistance and seizure resistance of a metal member according to claim 1, which contains 2 to 30 mol% of Cr. (3) A method for improving wear resistance and seizure resistance of a metal member according to claim 1 or 2, which contains 0.50 to 20 mol% of Mo and/or W. (4) The method for improving wear resistance and seizure resistance of a metal member according to any one of claims 1 to 3, wherein the total amount of Cr, Mo, and W does not exceed 40 mol%. (5) Wear resistance and seizure resistance of the metal member according to any one of claims 1 to 4, which uses a powder aggregate or powder compact containing 10 mol% or more of V carbide as a part of the carbide. How to improve sex.