JPS5916952A - Fe-based sintered material excellent in wear resistance - Google Patents

Abstract

PURPOSE:To obtain the Fe-based sintered material useful as a structural element provided with excellent wear resistance, high strength and high toughness, by specifying the contents of Cr and C as main components, and the surface ratio, particle size and density ratio of carbides. CONSTITUTION:The Fe-based sintered material comprising 4-25wt% Cr, 1.5- 5% C, 0.05-2% one or more of P, B and Si, and the balance Fe and inevitable impurities. It has the structure that carbides having Vickers hardness above 1,200 are dispersed in the martensite-based matrix at a surface ratio above 15%. Said carbides are controlled so that a part having an averge particle size above 5mu occupies 10% or more, by surface ratio, of the entire body of the carbides and that a density ratio above 92% is held. This sintered material is let optionally contain 0.1-20% one or more of Mo, W, Nb, Ti and V or further 0.1-10% one or more of Ni, Co, Cu and Mn. This sintered material when used as the structural element of a construction or mining machinery exhibits excellent properties.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has excellent wear resistance and is particularly suitable for use in manufacturing construction machines and mining machines that are exposed to severe wear conditions such as dirt wear and mixed paper wear. This invention relates to Fe-based sintered materials.

Traditionally, chrome cast iron and Or
White pig iron cast irons such as -Mo cast iron and Or-MO-V cast iron are used, but these white pig iron cast irons all have hard and brittle carbides in the form of needles or plates.

Or, because it has a network-like precipitated structure,
Although it has high hardness, its strength and toughness are extremely poor, and as a result, it has a relatively short service life in practical use, and its castability is also extremely poor and the formation of cavities is significant, making it difficult to achieve stable mass production. There is a problem that it is missing.

On the other hand, when manufacturing these structural parts, attempts have been made to braze the entire chip to wear parts using materials such as tungsten carbide-based cemented carbide or titanium carbide-based cermet, which have excellent wear resistance, but these paulownia materials are expensive. Not an idiot who is
There are problems such as impact resistance, and brazing also has problems with strength, so it is currently not possible to obtain sufficient reliability.

Therefore, from the above-mentioned viewpoint, the present inventors developed paulownia wood, which has excellent abrasion resistance and is particularly suitable for manufacturing structural members that are exposed to severe abrasion conditions such as sand abrasion and paper mixed abrasion. As a result of conducting research to obtain low-cost materials using powder metallurgy that allows for stable mass production, we have found that sintered materials can be made by weight,
Cr: 4 to 25 inches.

C: 15-5LI), P, B, and one or more of Si: 005-2, and if necessary, one of Mo, W, Nb, Ti, V, and Zr. One or more types of: 01-20 staff,
111゜One or two of CO, Cu, and Mn
It has a composition containing either or both of 201% to 10% of 20% to 10%, with the remainder consisting of Fe and unavoidable impurities, and has a carbide having a Vickers hardness of 1200 or more on a substrate mainly consisting of martensite in terms of area ratio. 15'l
It has a structure in which f or more is dispersed, and among the carbides, an area ratio of 101 or more to the whole carbide has an average particle size of 5μ
When the Fe-based sintered material is composed of carbides having a density of m or more and a density ratio of 92% or more, the carbide ensures excellent wear resistance, and the martensitic matrix and The density ratio ensures high strength and high toughness, and therefore, when this Fe-based sintered material is used under severe wear environments such as those mentioned above, it exhibits excellent long-term performance. I have gained knowledge that this will happen.

This invention has been made based on the above findings, and the reason why the component composition, the area ratio of carbides, and the density ratio are limited to the above-mentioned values will be explained below.

A. Ingredient composition -) C In the C component, as well as solid solution in the base material and strengthen it,
Or, and Mo contained as needed.

It combines with W, Nb, Ti, V, and Zr to form a hard carbide with a Vickers hardness of 1200 or more and improves the wear resistance of the material, but its content is less than 1.5%. In this case, the amount of carbides dispersed and precipitated in the matrix is so small that the total area ratio is less than 15%, and the amount of carbides with an average particle size of 5 μm or more is also less than 10% in area ratio to the total carbide. The material became brittle and suffered significant abrasion due to dirt and sand, making it impossible to secure the desired excellent abrasion resistance, and furthermore, the proportion of martensite that made up the base material was less than 70% of the total area. Desired strength and wear resistance cannot be secured, while if the content exceeds 5%, the material becomes extremely brittle, making it difficult to secure desired strength and toughness. Therefore, the content was determined to be 15 to 5.

(b) The crOr acid component is dissolved in the base material to strengthen it, and as described above, combines with C to form an Or carbide having high hardness, and contains Mo, W, Nb, Ti, V.

When it contains Zr and Zr, it forms a double carbide with this, which has the effect of improving the wear resistance of the phase material, but if the content is less than 4%, the same effect as in the case of the C component occurs. Unable to disperse and precipitate a specified amount of carbide,
On the other hand, if the content exceeds 25%, the material becomes brittle as in the case of C component, so the content should be reduced to 4%.
It was determined to be ~25qb.

(C) P, B, and Si These components have the effect of significantly improving sinterability, densifying the material, and solidly dissolving in the base material, thereby improving strength. If the content is less than 0.05, the desired improvement effect on the above action cannot be obtained, while if the content exceeds 2, the amount of liquid phase during sintering becomes too large, causing shape deformation and decreasing toughness. On the contrary, the content was determined to be 0.05 to 2.

(d) Mo, W, Nb, Ti, V,
and Zr These components not only solidly dissolve in the base material and strengthen it, but also combine with C to form extremely hard carbides and double carbides, thereby further improving the wear resistance of paulownia wood. Therefore, it is included as necessary, but if the content is less than 0.1%, the desired effect of improving wear resistance cannot be obtained, while if it is included in excess of 20atj, the phase material tends to become brittle. Therefore, the total content was determined to be 0.1 to 20 inches.

(cL) Ni, Co, Cu, and Mn These components have the effect of forming a solid solution in the base material, further strengthening it, and significantly improving the toughness of the material, so they are suitable for materials with particular requirements for strength and toughness. However, if the content is less than 0.1%, the desired effect of improving the above action cannot be obtained, but on the other hand, if the content exceeds 10%, further improvement may be obtained. Since no effect appears,
Taking economic efficiency into consideration, the content 'i 0.1-10%
It was determined that

B. Density Ratio If the density ratio is less than 92%, not only will exfoliation wear caused by overfilling of pores occur, but it will also be difficult to secure the desired high strength, so the lower limit of the density ratio 'ff
: Set as 92%.

Next, the present invention will be specifically explained using an example of the Fe-based sintered paulownia wood material.

Examples of raw material powders include Fe powder with a particle size of -100 mesh, and five types of Fe-Or, all of which have a particle size of -100 mesh, and have Cr contents of 5, 13, 25, 35, and 65, respectively. Alloy powder, carbon powder of the same 100 mesh, both MO with average particle size: 3 μm
C powder Ni powder, W powder, and COC powder all have a particle size of -150 mesh TIC powder, VC powder, N1
) C powder, WC powder, same 100 mesh Cu
powder.

Fe-OrFe-0r-alloy (C
! r: 13%.

Mo: 1%, Nb nia% content) powder, same 100meS
h Fe-Zr alloy (Zr: 60% content) powder, same 1
00 mesh Fe-Mn alloy (containing 5% Mn nia) powder and the same 100 mesh Fe-Cr-Mn
-Mo-Ni alloy (Or: 10%.

(containing Mn: 1%, Mo: 1%, Ni: 3%) powder, and also Fe of the same 100 mesh
-P alloy (P: 27 content) powder, Fe-B alloy (B:
(17% content) powder, Ni-P alloy (P:12% content)
Powder and Fe-81 alloy (Si: 42% content) powder were prepared, and these raw material powders were blended into the composition shown in Table 1, mixed in a wet ball mill, dried, and then 4 to 6 tons The green compact is formed into a compact at a pressure of 1,030°C to 1,200°C in a vacuum, and then sintered at a predetermined temperature within a temperature range of 850°C to 1,200°C after sintering.
By oil quenching from a predetermined temperature within the temperature range of 1030°C and finally tempering at a predetermined temperature within the temperature range of 150 to 250°C, a book with substantially the same composition as the blended composition is produced. Invention sintered alloys 1 to 49 were produced, respectively.

Next, regarding the resulting sintered alloys 1 to 49 of the present invention, the density ratio, carbide area ratio, and average grain size: 5/l
In addition to measuring the area ratio and Vickers hardness of carbides having a particle size of 1.0 m or more to the whole carbide, in muddy water containing 30 volumetric volumes of earth and sand with a grain size of -30 mesh,
Load: 5 Kg/cnl, rotation speed = 200
A wear test was conducted under the conditions of r-T'1 m, +test time: 20 hours, and the wear depth was measured. The results of these measurements are shown in Table 2. Table 2 also shows conventional Or cast iron (C: 3.3%, Si: 1.7tI) for comparison purposes.

The wear test results under the same conditions for Mn:Q, 9%, Or: 1.5% are also shown.

From the results shown in Table 2, all of the sintered alloys 1 to 49 of the present invention have significantly superior wear resistance compared to conventional Or cast iron, and also have high strength, high hardness, and high toughness. That is clear.

As mentioned above, the sintered paulownia material of the present invention has excellent wear resistance, high strength, and high toughness, so it can of course be used in fields that require these properties, and especially Even when used in the structural parts of construction machinery and mining machinery, which are exposed to severe abrasion environments such as soil abrasion and mixed paper abrasion, it exhibits excellent performance over an extremely long period of time.

Applicant - Mitsubishi Metals Corporation

Claims (3)

[Claims] (1) Or: 4-25%, O: 1.5-
5%, P, B. and one or more of Sl: 0.05-2
Composition C containing Fe and the remainder consisting of Fe and unavoidable impurities
% by weight or more), and has a structure in which carbides having a Vickers hardness of 1200 or more are dispersed in an area ratio of 15 or more in a matrix mainly consisting of martensite, and among the carbides, the area ratio to the whole carbide is An Fe-based sintered material having excellent wear resistance, characterized in that a ratio of 10 or more is occupied by carbide having an average grain size of 5 μm or more, and further has a density ratio of 92 or more. (2) Or: 4-25%, C: 1.5-5%
, P, B. and one or more of Sl: 0.05~
2eI)? : Contains gold, further contains Mo, W, Nb,
A base material containing 1 to 20% of one or more of Ti, V, and Zr, with the remainder consisting of Fe and unavoidable impurities (weight percent), and mainly consisting of martensite. Vickers hardness is 12
It has a structure in which carbides having 00 or more are dispersed in an area ratio of 15% or more, and among the carbides, 10% or more in area ratio of the entire carbide is occupied by carbides having an average particle size of 5 μm or more, and [ Fθ-based sintered paulownia material with excellent wear resistance, characterized by having a density ratio of 92% or more (3) Cr: 4-25%, C: 1.5-5%, P
,B. and one or more of Si 20, 05-2
further contains Ni, Co, Cu, and Mn
One or more of the following: o, 1 to 10%, with the remainder consisting of Fe and unavoidable impurities (more than 1% by weight)
), and has a structure in which carbides having a Vickers hardness of 1200 or more are dispersed in a matrix mainly consisting of martensite with an area ratio of 15 or more, and among the carbides, the area ratio to the whole carbide is 10 or more is occupied by carbides having an average particle size of 5 μm or more, and 9
Fe-based sintered paulownia material with excellent wear resistance characterized by having a density ratio of 2 or more (/l) Or: 4 to 25%, C: L 5 to 5%, P
,B. and one or more types of Sl: 0.05 to 2
%, and further contains Mo, W, Nb, Ti,
One or more of V and Zr: o1
~2o and *Ni-, Co, Cu, and M] One or more of 1; 01 to 10%;
The remaining 9 consists of Fe and unavoidable impurities (this is the weight)
In addition, it has a structure in which carbides having a Vickers hardness of 1200 or more are dispersed in an area ratio of 15 or more in a matrix mainly consisting of martensite, and among the carbides, an average area ratio of 101 or more to the whole carbide is Particle size: dominated by carbides with a particle size of 5 μm or more, and VC9
A Fe-based sintered paulownia material with excellent wear resistance characterized by having a density ratio of 2% or more.