JPS62278282A - Improvement of wear resistance and seizure resistance of metallic member - Google Patents

Abstract

PURPOSE:To provide superior wear resistance and seizure resistance, by temporarily attaching, as hard compounds, specific amounts of nitrides and carbides of specific kinds to the surface of a metallic member and by fusing the above by means of a heat source with high energy density to fuse the above into one body. CONSTITUTION:A powder aggregate or powder compact has a composition consisting of, by mole, 2-20% of 1 or >=2 kinds among the nitrides of V, Ti, Zr, and Nb, 20-80%, in combined total with the nitrides, of the carbides of V, Ti, Zr, Nb, Ta, and Hf, and the balance 1 or >=2 metals among Fe, Ni, and Co or alloys thereof or alloy composed principally of 1 or >=2 elements among Fe, Ni, and Co with inevitable impurities. The above material is allowed to adhere to the metallic-member surface and then the powder aggregate or powder compact is fused by means of a heat source having high energy density, so that said powder aggregate or powder compact and the surface of the metallic member can be fused into one body.

Description

[Detailed description of the invention] 3. Detailed description of the invention (industrial application field) Wood) AI improves the wear resistance and seizure resistance of metal members □
Regarding the method.

(Prior Art) Metal products that have wear 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.

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, coating with alloy components that have wear resistance and seizure resistance, etc. Methods using hardening include conventional methods such as induction hardening. In addition, there is a surface hardening method (hereinafter referred to as laser surface hardening) that uses a heat source with high energy density such as a laser or an electron beam.
No. 7362, disclosed in Japanese Patent Application Laid-Open No. 55-2710.

In addition, by melting and rapidly solidifying only the surface layer of the surface of pp iron products and the cutting edge of high-speed steel cutting tools using a high-energy beam (hereinafter referred to as laser glazing).
There are also methods for improving wear resistance, and these techniques are disclosed in JP-A-57-85926 and JP-A-59-83718.

On the other hand, methods for coating alloy components include surface hardening treatments such as nitriding treatment, fertilizing treatment, PVD treatment, and CVD treatment, and methods using 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 attached to 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 adjusting the amount of additive material and laser irradiation conditions, the amount of melting of the base material is reduced, and the Mi 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, laser glazing is more effective than surface hardening for cast iron and high-speed steel, but the hardness is limited to about Hv900 to 1100. Additionally, the types of steel that can be applied to laser glazing are significantly limited.
The disadvantage is that the effect is small 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, TiN
Since a hard compound such as or T i C 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 by laser, Ti is used to impart wear resistance to the base metal.
c, WC, MoC, etc., gold rA carbide and A pattern 203, T
Metal oxides such as iO2 are 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 y8, it easily falls off and becomes a cause of defects such as bores and cracks.

(2) Since hard compounds have high viscosity, even if they are melted, they do not mix uniformly with the liquid phase of the base material, resulting in a partially uneven structure. Moreover, the bubbles are not 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 Al2O3 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 Problem C) The above problem is that one or more nitrides of V, Ti, Zr, and Nb are contained in a total amount of 2 to 20 m o 1%.

V, Tf, Zr, Nb, Ta, Hfc7) One or more carbides in a total of 20 to 80 m of carbides and nitrides.
o Contains within a range of 1%, with the remainder being Fe, Ni, Go
one or more metals or alloys, or Fe,
A powder aggregate or powder molded body consisting of an alloy and inevitable compounds mainly composed of one or more of Ni and Co,
After adhering to the surface of a metal member whose wear resistance and/or seizure resistance is to be improved, the powder aggregate or powder compact is melted by a heat source with high energy density, and the powder aggregate or The problem is solved by a method for improving the wear resistance and seizure resistance of a metal member, which includes melting and integrating the powder molded body and the surface of the metal member.

That is, in the present invention, specific types and amounts of nitrides and carbides are used as hard compounds, and a powder aggregate or powder compact (hereinafter referred to as additive material) consisting of the carbides and a specific metal phase is temporarily applied to the surface of the metal member. By melting and integrating the additive material with the matrix using a laser or an electron beam, the wear resistance and seizure resistance of the metal member can be improved without causing the problems of the laser alloying and cladding methods. This is what I found out.

The present invention will be explained in detail below.

The additive material in the present invention is a powder aggregate or powder compact made of nitride and carbide powders and metal or alloy powders. Thus, when a powder aggregate or powder compact is heated, the low-melting metal or alloy phase first melts, and the individual royal compound (nitride and carbide) particles are covered by the liquid phase of the metal or alloy. As a result, a liquid phase consisting of the hard compound constituent elements and metal or alloy components is formed almost instantaneously. Therefore, unmelted hard compounds are unlikely to remain, and even if melt remains, metal or alloy phases exist between the hard compound particles, making it extremely difficult for these hard compounds to fall off. Furthermore, since the viscosity of the obtained liquid phase is reduced, the base material liquid phase and the hard compound are mixed uniformly, and defects such as bubbles are less likely to remain.

Cocote, hard compounds are V, T i, Z r
, one or more nitrides of N b and V , T
i.

It is one or more carbides of Zr, Nb, Ta, and Hf. The reason for using such a hard compound will be explained. During alloying or cladding of powder aggregates or powder compacts, a liquid phase is formed in which hard compound components and metal components are mixed. When the liquid phase is cooled, the hard compound is cooled while being partially dissolved in the metal phase of the matrix because the cooling rate is very fast, but most of the hard compound crystallizes finely from the liquid phase again. At this time, the compound crystallized from the liquid phase j) is not necessarily the same as the compound originally existing in the additive material; for example, MoC, WC, Fe, Ni, etc.

When it is melted together with Go, etc., M6C, which is a carbide with low hardness and brittleness, crystallizes from the liquid phase. When such a brittle phase crystallizes, the effect of improving wear resistance and the like is almost eliminated. On the other hand, V.

T i , Z r , N b , T a , H
The compound f that crystallizes from the liquid phase becomes a very stable NaC type carbide that does not exhibit brittle properties, and the effect of improving B wear resistance and seizure resistance is large.

The reason why the hard compound is contained in a total amount of 20 to 80 mol% is that if the amount of the hard compound in the powder aggregate or powder compact is less than 20 mol%, the effect of improving wear resistance and seizure resistance is insufficient. This is because if it exceeds 80 mol%, defects are likely to occur during alloying or in the cladding phase.

Note that the hard compound may be composed of one type of metal element and C, N, for example, 'VC, Tic, N
b One type of metal element and C, such as C, VN, TiN, etc.
It is composed of N, (V, Ti)C, (V
,Nb)C.

It may be composed of a plurality of metal elements such as (V, Ti)N, (V, Nb)N, etc., or it may be a mixture of these elements, or, for example, Fe.

Even if it contains other elements such as Ni, its crystal structure is Na
There is no particular problem as long as it is a C-cross type carbide.

Further, nitrides have a greater effect of improving wear resistance and seizure resistance than carbides, and are included in a total amount of 2 to 20 m o 1%. If the amount is less than 2mo 1%, sufficient effects cannot be obtained, and if it exceeds 20mo 1%, defects such as bores are likely to occur.

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. , the Co metal or alloy phase has a much lower melting point than the hard compound and melts before the hard compound during surface alloying or cladding;
It has the function of melting hard compounds through a eutectic reaction. At this time, Fe.

If it is Ni, Co or an alloy containing these as main components,
After the hard compound melts, it does 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. Fe-based alloy phase that increases hardness at room temperature, and Ni or C when wear resistance at high temperatures is required.

It is desirable to adopt a base alloy phase of Ni, C.

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.

Furthermore, the additive material used in the present invention is most easily produced by mixing a hard compound powder and a metal powder, but in this case, the metal powder may be Fe, even if pure metal powder is not used. , Ni, C.

Powders of alloys may be used, for example powders of carbon steel, stainless steel, high speed steel, etc. may be used instead of pure Fe powders.

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

Note that the above additive materials may include mixed particles manufactured by mixing hard compound particles and powder particles made of a metal or alloy, or the powder particles are composed of a hard compound and a metal or alloy component. To prepare the latter additive material containing a single particle, which may contain a single particle, a metal or alloy component is coated, evaporated, or
A coating method such as ion sputtering, or
On the other hand, from the viewpoints of surface alloying, ease of melting of hard compounds during cladding, alloying, quality of the cladding part, etc., the latter additive material is preferable. Although it is excellent, it requires a special bag opening to manufacture, and the unit cost of additive materials is high, so it can be used depending on the purpose of use.

Additionally, the additive material may be temporarily attached to the processed surface using an organic binder in powder form and subjected to one-surface alloying or clapboarding. The material doesn't stick well,
Furthermore, after surface alloying and clattering, the tacking shrinks over time, making it difficult to control the thickness. This problem is solved by first molding the powdered additive material by sintering, then cutting the molded material into appropriate sizes, temporarily attaching the ends to the workpiece surface using cedar welding, etc., and then laser or It can be melted and integrated with the base using an electron beam.

In the wood production method 1, the powder aggregate or the powder molded body is melted by a heat source having high energy density.

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 and cladding phase, part of the carbide is forcibly dissolved in the matrix, and most of it is finely crystallized and dispersed from the liquid phase. There is a need. For this purpose, the cooling rate must be increased (at least at the solidification temperature, it is estimated that 100° C./sec or higher is required), and for example, the heat source must have a power density of 10 3 w/cm 2 or higher. When using a heat source with a low power density, the cooling rate is slow, which causes the hard compound to aggregate and coarsen, and the constituent elements of the hard compound are no longer solidly dissolved in the metal phase. Examples of such heat sources with high energy density, such as lasers and electron beams, may be used.

[Description of embodiments] (Second claim) In the present invention, Cr may be added to the metal phase in an amount of 2 to 30 mol% of the total composition other than the hard compound.
In this case, it is effective for applications where seizure resistance is particularly required. The range of addition was 2 to 30% because 2 mo
If it is added less than 1%, the anti-seizure effect is small, and the
This is because if it is added in excess of ol%, brittle compounds such as M7C3 are likely to crystallize, and in particular, brittle σ phase is likely to be formed even in the metal phase.

(Third claim) Also, MO or/and W is contained in the metal phase in an amount of 0.5 to 20%.
It may be added in a range of 1% mO.

In this case, it is effective for applications where wear resistance is particularly required. The reason for adding Mo and/or W 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 m
This is because if it is less than ol%, the effect of solid solution hardening or precipitation hardening of the metal phase is small, and if it exceeds 20 mol%, brittle compounds such as M6C tend to crystallize.

(4th claim) Also, the total addition m(1) of Cr, Mo, and W is 40 mol%
In this case, it is possible to prevent #i weak compounds from crystallizing, and ITy# wear resistance and seizure resistance of the metal member are further improved.

(Claim 5) Any hard compound can significantly harden the alloyed layer and cladding layer, but among them, VC carbide has the greatest effect.When wear resistance and seizure resistance are required for PF, It is preferable to use an additive material containing 10 m o 1% or more of VC carbide.Since VC carbide has relatively low stability (easily forms a solid solution) compared to other NaC1 type carbides, 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) Hard compounds and metal powders of the type and amount shown in Table 1 were thoroughly mixed in a ■ mixer, and then heated to approximately 20φ by 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 temporarily attached to the surface of a metal base of 30 mm x 50 mm x 5 mm by spot welding, and then the surface is alloyed by irradiating the surface with a laser.
The cross-sectional hardness and the wear resistance and seizure resistance (severity of adhesive wear) were evaluated using the Okoshi type wear test. The HIP conditions, type of base material, laser irradiation conditions, and evaluation test conditions are as follows.

I HIP conditions: 1050℃X IQOOatm
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 = 2a small hardness tester Load 300g ■ Inukoshi type wear test: Compatible material S U J 2 (HRC60) Friction distance 400m Load 6.3 kgf Friction speed 4.9 m/sec It is known that wear resistance is proportional to the hardness of the material when the sliding conditions are the same. Therefore, we measured the hardness of the alloyed layer and estimated the effect of the additive on the wear resistance.

FIG. 1 shows the relationship between the hardness of the alloyed layer and the amount of added nitride. No defects such as cracks or bores were observed in the alloyed layer.
It has a healthy composition. The hardness of the alloyed layer was higher than that of the base metal material, and was 1100 Hv or more.

VC denitride = 20mo 1% and VC dedenitride -60m
When compared with ol%, VC + nitride = 60 mol% has higher hardness, the larger the amount of VC denitride, the better the wear resistance of the alloyed layer, the conditions of VC + Q oxide = &) mol% So, the hardness increases as the amount of added nitride increases, and when the amount of nitride is 5 mol%, it is about 1430 Hv, but when the amount of nitride is 15 mol%, it is about 1500 Hv, which is the shadow of nitride! indicates that the value is high.

Figure 2 shows the relationship between additive materials and specific wear amount.

The specific wear amount was determined using the formula shown below.

Amount of wear = Test load (Kgf) On the other hand, it can be seen that the additive materials shown in C-L, which are examples of the present invention, have a very small specific wear amount of about 0.8 or less. The specific wear amount is almost proportional to the hardness of the alloyed material, and the specific wear amount was about 0.25 for the F-added material, which has the highest hardness. Further, if the amount of hard compound in the additive material is the same, the specific wear amount is smaller for the material with a larger amount of nitride, indicating that the material has better wear resistance.

(Example 2) As shown in Table 2, an additive of TiN was used as the VC1 nitride as the carbide, and Ni, Co, and C were added to the metal material.
A test piece was manufactured using R, Fe, Mo, W, etc. under the same conditions as in Example 1, and the hardness and specific wear amount of the test piece were measured.

Figure 3 shows the results of measuring the hardness of the test pieces.

The hardness of the 0-alloyed layer was measured at room temperature and 500 to 800°C, and no defects such as cranks or bores were observed in the 0-alloyed layer, which had a healthy composition. The hardness was higher than that of 1,200 Hv at room temperature. When Ni or Co is used as the metal component, the hardness at room temperature is lower than when Fe is used, but it becomes higher at high temperatures, indicating that the hardness is excellent at high temperatures. Moreover, those containing Mo under any temperature conditions,
It shows high hardness and excellent wear resistance.

In Figure 4, the additive materials are VC50mol%, T i N1
0mδ1%, and the results of determining the specific wear amount using various base materials are shown, and the measurement temperature is room temperature.

There is no big difference in wear resistance when the base material is Fe, Ni, or Co, but when additives such as Cr, Mo, or W are added, the wear resistance improves, especially when the base material is made of Mo, W, or Fe. When this material is used, the specific wear amount is about 0.2, indicating that it has excellent wear resistance.

[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 friction surfaces of cutting tools, molds, internal combustion parts, etc. A great effect can be obtained by applying it to a metal member having.

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 not possible due to the addition of carbide alone, but in the present invention, since the additive material itself is easily melted, graphing is also possible.

Therefore, since the contamination of base metal components can be significantly reduced,
For example, it is possible to process even base materials that are inconvenient if contaminated.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the effect of nitride on hardness. FIG. 2 is a graph showing the relationship between specific wear amount and additive material when Fe is used as the base material. The third UA is a graph showing the relationship between hardness and test temperature when the additive materials are V C and T i N and the Mototamura materials are varied. Figure 4 shows the additive material as VC. It is a graph showing the relationship between the specific wear amount and the additive material when T i N is used and the base material is variously changed. Table 1 Table 2 Figure 1 Beer Curse Hardness (Load: 300 g) The O symbol indicates the type of additive material. Amount of nitride (mol%) Type of additive material RT 500600 700 800 Test temperature (℃)

Claims (5)

[Claims] (1) A total of 2 to 20 mol% of one or more nitrides of V, Ti, Zr, Nb, V, Ti, Zr, Nb, T
Contains one or more carbides of a, Hf in a range of 20 to 80 mol% in total of carbides and nitrides, and the remainder is a metal or alloy of one or more of Fe, Ni, Co, or Fe. , Ni, Co, Ni, Co, etc. The surface of a metal member whose wear resistance and/or seizure resistance is to be improved is a powder aggregate or a powder molded body made of an alloy and an unavoidable compound mainly composed of one or more of Ni and Co. After adhering to the metal member, the powder aggregate or the powder molded body is melted by a heat source having a high energy density, and the powder aggregate or the powder molded body is melted and integrated with 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 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.