JPS5916951A - 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 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 average particle size above 5mu occupies 10% or more, by surface ratio, of the entire boy of the carbides and that a density ratio above 92% is held. This sintered material is let optionally contain 0.1-2.0% one or more of Mo, W, Nb, Ti, V and Zr or further 0.1-10% one or more of Ni, Co, Cu and Mn. This sintered material when being 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 suitable for use in manufacturing structural members of construction machines and mining machines that are exposed to particularly severe wear conditions such as sand abrasion and mixed paper abrasion. The present invention relates to Fe-based sintered materials.

Traditionally, chrome cast iron or Qr was used to manufacture this type of structural part.
White pig iron cast irons such as -MO cast iron and KCr -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 significantly inferior, and as a result, it has a relatively short service life in practical use.
Furthermore, the castability is extremely poor, and the formation of cavities is significant, so there is a problem that stable mass production is lacking.

On the other hand, when manufacturing these structural parts, attempts have been made to braze chips made of highly wear-resistant tungsten carbide-based cemented carbide or titanium carbide-based cermet to the worn parts, but these materials are expensive and Not only is there
Currently, there are problems with impact resistance, etc., and there are also problems with the strength of the soldering material, making it difficult to achieve sufficient reliability.

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

0:1.5 to 5%, and optionally Mo,
One or more of W, Nbl, Ti, Vl and Zr: 0.1 to 20%, and Ni, C
One or more of o, Ou, and Mn:
Contains O, 1 to 10%, or both, with the remainder consisting of Fe and unavoidable impurities,
It has a structure in which carbides having a Vickers hardness of 1200 or more are dispersed in a matrix mainly composed of martensite, and the area ratio of the carbides to the whole carbide is 10 or more having an average particle size: When the Fe-based sintered material is composed of carbides having a diameter of 5 μm or more and a density ratio of 9z coefficient or more, excellent wear resistance is ensured by the carbides,
Furthermore, the martensitic matrix and density ratio ensure high strength and high toughness.
We have obtained the knowledge that when the Fe-based sintered material is used under the above-mentioned severe wear environment, it exhibits excellent performance over a long period of time.

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 (a) The O C component includes solid solution in the base material to 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 eI), and the amount of carbides with an average grain size of 5 μm or more is also less than 10 eI in terms of area ratio to the total carbide. The abrasion caused by dirt, sand, etc. was significant, 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. It is not possible to secure the desired strength and wear resistance, and on the other hand, if the content exceeds 5%, the paulownia wood becomes extremely brittle, making it difficult to secure the desired strength and toughness. Therefore, the content was determined to be 5 to 5%.

The (+)Or cr acid component is dissolved in the base material to strengthen it, and as described above, combines with C to form a highly hard Or carbide, and also contains Mo, W, Nb, Ti. , V
.

When Zr is contained, it forms a double carbide with Zr, which has the effect of improving the wear resistance of the material.
If the content is less than 4%, it will not be possible to disperse and precipitate the desired carbide in the desired amount, as in the case of the C component, while on the other hand, if the content exceeds 25%, as in the case of the C component, Since the material becomes brittle, its content 'ff
: 4 to 25 inches.

(c) Mo, Vlf, 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. Since there is, it may be included as necessary, but
If the content is less than 0.1%, the desired effect of improving wear resistance cannot be obtained, while if the content exceeds 20%, the paulownia wood will tend to become brittle.
It was set at ~20%.

(d) Ni, Co, Ou, 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 strength and toughness are particularly required. However, if the content is less than 01 parts, the desired effect of improving the above action cannot be obtained, and on the other hand, if the content exceeds 10 parts, no further improvement effect will be obtained. Therefore, considering economic efficiency, the total content was determined to be 0.1 to 10.

B. Density Specificity If the density ratio is less than 92 coefficients, not only will peeling wear caused by oversizing of pores occur, but it will also be difficult to secure the desired high strength, so the lower limit of the density ratio 92
%.

Next, a detailed explanation will be given using an example of the Fe-based sintered paulownia material of the present invention.

Examples of raw material powders include Fe powder with a particle size of -100 mesh, all of which have a particle size of -100 mesh f, and Cr contents of 5%, 13%, 25%, 35%, and 65%, respectively.
5 kinds of Fe-Cr alloy powders, same 100 mesh
carbon powder, all of which have an average particle size of 3 μm
o powder, Ni powder, W powder, and co powder, all with particle size -150 mesh Tic powder, VC powder, NbC
Powder, and W C powder, same 100 mesh cu
Powder, same 100 mesh Fe-Cr-Mo-
Nb alloy (Cr: 13%, Mo: 1%, Fe-Zr alloy (Zr:
6096 containing) powder, 100 mesb of Fe-Mn
Alloy (Mnn near S gold-containing powder.

and same 1. OOmesh Fe-Cr-Mn-
Mo-Ni alloy (Cr: 10%, Mn: 1%, Mo:
1%, Ni: 3%) powder is prepared, these raw material powders are blended into the composition shown in Table 1, mixed in a wet ball mill, dried, and then processed at 4 to 6 ton/ff.
The green compact is then sintered in a vacuum at a predetermined temperature within the temperature range of 1150 to 1350°C, and subsequently, after sintering, the compact is formed into a compact at a temperature of 850 to 1050°C. Oil quenching starts at a specified temperature within the
By performing a tempering treatment at a predetermined temperature within the temperature range, sintered alloys of the present invention] to 34 having substantially the same composition as the blended composition were manufactured.

Next, for the resulting sintered alloys 1 to 34 of the present invention, the density ratio, carbide area ratio, area ratio of carbide having an average particle size of 5 μm or more to the entire carbide, and Vickers hardness were measured, 1 grain size - 3Q in joint format
In muddy water containing 25 volumes of mesh earth and sand, load:
A wear test was conducted under the conditions of 4 Kg/crd, rotational speed: 180 r, p, m, and test time: 25 hours, and the wear depth was measured. The results of these measurements are shown in Table 1.

! , Table 2 shows the conventional Or cast iron (C: 3
．． 4%, Si: 2.1%, Mn: 0.7%, C
The results of the abrasion test under the same conditions are also shown.

From the results shown in Table 2, all of the sintered alloys 1 to 34 of the present invention have significantly superior wear resistance compared to conventional Cr cast iron, and have high strength, high hardness, and high toughness. It is clear that

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 It also exhibits excellent long-term performance even when used as structural parts for construction machinery and mining machinery that are exposed to severe abrasion environments such as soil abrasion and mixed paper abrasion.

Applicant: Mitsubishi Metals Corporation

Claims (4)

[Claims] (1) Cr: 4-25%, O: 1.5-5%
'i, and the remaining 9 is Fe and inevitable 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 10%
An Fe-based sintered material with excellent wear resistance characterized by being dominated by carbides having an average particle size of 5 μm or more and further having a density ratio of 92% or more. (2) Or: 4~. 25%, c: 1.5
~5%, and further contains Mo, W, Nb, Ti
, V, and Zr: 0
．． 1 to 20, with the remainder consisting of Fe and unavoidable impurities (weight range above), and carbide having a Vickers hardness of 1200 or more dispersed in an area ratio of 15% or more in a matrix mainly consisting of martensite. The carbide has a microstructure, and among the carbides, an area ratio of 10 or more to the whole carbide is occupied by carbides having an average particle size of 5 μm or more, and further has a density ratio of 92% or more. Fe-based sintered material with excellent wear resistance. (3) Or: 4-25%, O: 1.5-5
%f gold content, as well as Ni, C! o, C! Contains one or more of u and Mn: 01 to 10%, and has a composition C or more (weight range) with the remainder consisting of Fe and unavoidable impurities, and has a Vickers hardness on a substrate mainly made of martensite. has a structure in which carbides having a diameter of 1,200 or more are dispersed in an area ratio of 15% or more, and among the carbides, an area ratio of 10 or more to the entire carbide is occupied by carbides having an average particle size of 5 μm or more, Furthermore, Fe-based sintered 1i'l') with excellent wear resistance is characterized by having a density ratio of 92 inches or more. (4) Cr: 4-25%, O: 1.5-59
Contained in 1. Furthermore, one or more of Mo, W, Nb, Ti, V, and Zr: 0.1 to 20%;
Ni, Co, Ou. and one or more of Mn20.1-10
%, with the remainder consisting of Fe and unavoidable impurities (weight ratio), and a structure in which carbides having a Pinkers 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 10
An Fe-based sintered material having excellent wear resistance, characterized in that at least % is occupied by carbides having an average particle size of at least 57zm, and further has a density ratio of at least 9zm.