JPS63256275A - Sliding member with excellent seizure resistance and wear resistance - Google Patents

Abstract

PURPOSE:To obtain a sliding member with the excellent seizure resistance and wear resistance by forming the sliding surface of a build-up layer having the composite structure consisting of a heat resistant alloy matrix and a specific quantity of niobium particle carbide as the dispersed phase in the matrix. CONSTITUTION:The sliding surface of the sliding member is formed of the build-up layer having the composite structure consisting of the heat resistant alloy matrix and the 10-70wt.% niobium particle carbide as the dispersed phase in the matrix. A Fe base alloy, a Ni base alloy, a Co base alloy, etc., are cited as heat resistant alloy and these maintain the necessary strength and resistance to oxidation as a high-temperature member. Heat resistant alloy powder to be the matrix is mixed with the niobium powder carbide to be the dispersed phase at the fixed mixing rate (50% respectively) and a mixture is formed as material for build-up. This material for build-up is subjected to the build-up welding on the surface of base material by the plasma welding, etc. By this method, the sliding member is provided with the seizure resistance and the high wear resistance and its durability is improved and burden of maintenance can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sliding member that has excellent seizure resistance and wear resistance in a high temperature range.

[Conventional technology]

Sliding of rolling mill peripheral parts in hot rolling lines (e.g. side guide members on the entry side of the rolling mill), seamless pipe production line related parts (e.g. guide shoes that hold and guide steel billets and rough pipe materials in the drilling process), etc. The moving member needs to have excellent resistance to abrasion caused by a mating material that slides on its surface and seizure resistance to the mating material.

Conventionally, these sliding members were exclusively made of "Stellite".
Alloy (Cr: 30-32%, W: 4-12%, Fe: 0
．． 5-3%, C: 0.8-2%, balance Co), or high Cr, high Ni heat-resistant alloy steel (Cr: 2S-30%, Ni
:13-35%, C:O, l-1%, balance Fe) have been used. If the mating material of these sliding members is made of carbon steel or other material that has a thick oxide film on its surface, seizing may occur between the sliding member and the mating material, making stable operation difficult. will be held. This is because the thick oxide film formed on the surface of the mating material blocks direct metal-to-metal contact between the sliding member and the mating material.

[Problem that the invention seeks to solve]

However, if the mating material is different from the above-mentioned carbon steel and does not form a thick oxide film on its surface in a high temperature range, the mating material will migrate to the surface of the sliding member and the migration phenomenon will occur. As this progresses, seizure occurs at an early stage. In particular, 13Cr
When the mating material is stainless steel or higher Cr-containing stainless steel, the seizure phenomenon that occurs under sliding conditions involving high temperature, high surface pressure, and linear or rotational motion is remarkable. This is because this type of high Cr stainless steel is coated with a dense oxide film such as chromium oxide (CrzCh) at high temperatures, but because the oxide film is thin, it is subject to high sliding surface pressure and linear This is because the oxide film is destroyed by the application of sliding action such as motion or rotational motion, external force, etc., and the contact between the sliding member and the mating material becomes metal contact. Under high-speed sliding conditions, the destruction of the oxide film and the resulting seizure are promoted, and the wear of the sliding surface becomes significant. Also,
Surface damage such as seizure and abrasion that occurs on a sliding member causes deterioration of the surface quality of a subsequent mating member. For this reason, conventional sliding members have been forced to be replaced early and undergo frequent repair work.

In order to cope with the above-mentioned circumstances, the present invention strengthens the seizure resistance of the sliding member and increases the wear resistance.
This was done to ensure the durability of the sliding member, regardless of the material of the mating material, and to stabilize and improve the surface quality of the mating material.

[Means and effects for solving the problems] The sliding member of the present invention comprises a heat-resistant alloy M-IJ sock, and niobium carbide (Nbc) particles as a dispersed phase in the matrix.
It is characterized in that its sliding surface is formed of a build-up layer (hereinafter referred to as "composite build-up layer") having a composite structure in which 70% of the layers are mixed.

The composite overlay forming the sliding surface of the sliding member of the present invention is coated with a thick and strong oxide film, and the oxide film creates a gap between the sliding surface of the sliding member and the mating material. Metallic contact is blocked, and the oxide film acts as a lubricating film, thereby effectively preventing the mating material from adhering to the sliding surface, that is, from being seized. The formation of a strong and thick oxide film covering the sliding surface (the surface of the composite overlay layer) is closely related to the niobium carbide mixed in the composite structure.

In other words, when the build-up layer has a single-phase structure consisting only of a heat-resistant alloy, the oxide film that forms on the surface of the build-up layer has a thin film thickness.
, it is easily destroyed by sliding contact with the mating material, so it cannot be expected to have a stable function as a protective film that blocks metal contact between the sliding member and the mating material. However, according to the present invention, niobium carbide particles are added to the heat-resistant alloy When mixed, the niobium carbide particles act as a catalyst to promote the oxidation of the alloying elements on the surface of the heat-resistant alloy matrix, thereby producing a strong, dense, and thick oxide film. Moreover, the niobium carbide particles themselves do not change, and as carbide-based ceramic particles, they form a composite structure with the heat-resistant alloy as an extremely hard and chemically stable dispersed phase. Therefore, due to the dispersion-strengthening effect of the niobium carbide particles, the composite overlay layer can
It has both the strength required as a high-temperature member and the excellent wear resistance as a wear-resistant material.

There are various types of ceramics to be mixed as a dispersed phase in the metal matrix, such as oxide-based, nitride-based, and carbide-based ceramics, but in the present invention, niobium carbide is specifically specified as niobium carbide. The particles have a dispersion strengthening effect on the metal matrix (strength at high temperatures,
The present invention is based on the knowledge that it has a special function of not only enhancing wear resistance, etc., but also promoting surface oxidation of the metal matrix and forming a strong and stable protective film on the surface of the sliding member. , the lower limit of the amount of niobium carbide particles (mixing ratio) in the composite structure is 10% by weight. From the point of view of promoting the formation of an oxide film by niobium carbide particles, a smaller amount (for example, about 5% by weight) is sufficient, but since the dispersion strengthening effect is insufficient,
By setting the lower limit to 0% by weight, the dispersion strengthening effect was also ensured. On the other hand, set the upper limit to 7
The reason for specifying 0% by weight is that if it exceeds 70% by weight, the oxidation loss of the overlay bead becomes significant during the overlaying process in which the composite overlay layer is formed by welding overlay method etc.
This is because the quality of the overlay bead deteriorates and its suitability as a structural member is impaired. The particle size of the niobium carbide particles is not particularly limited, but from the viewpoint of both oxide film formation and dispersion strengthening effect, approximately 50 to 200 μm is appropriate.

The reason why the matrix metal of the composite overlay layer is made of a heat-resistant alloy is to ensure the strength, oxidation resistance, etc. necessary for a high-temperature member. The material is not particularly limited, but specific examples include MO1 in which C: 0.2% or less, Ni: 40% or less, Cr: 30% or less, and the balance is Fe or a part of Fe is 10% or less.
3% or less W, 3% or less Cu, 1% or less Ti, 1%
The following iron-based alloys substituted with one or more elements selected from the group of A13% or less Nb, 5% or less Co, C: 0.2% or less, Fe: 50% or less, C :10~2
5%, the remainder Ni, or a part of Ni is 10% or less W
, 20% or less Mo, 4% or less Nb, 3% or less Ti
Ni-based alloy substituted with one or more elements selected from the group of AJ of 52% or less, C: 0.5% or less, Cr: 5 to 30%, Fe: 50% or less, balance CO1 or Part of Go is less than 15% Ni
, a Co-based alloy substituted with one or two elements selected from the group consisting of 10% or less of W, and the like.

The sliding member of the present invention uses a mixture prepared by mixing heat-resistant alloy powder as a matrix and niobium carbide powder as a dispersed phase at a predetermined mixing ratio as a build-up material, and uses a separately prepared base material (carbon steel , alloy steel, etc.) by depositing one layer or multiple layers of heat-resistant alloy beads containing niobium carbide particles by a weld overlay method such as transferred arc plasma welding (PTA). Alternatively, instead of the welding method, a thermal spraying method may be used to spray the mixed powder onto the surface of the base material. Furthermore, as an alternative method, using a sintering method,
It is also possible to use a method of forming a built-up layer as a sintered body on the surface of the base material. The thickness of the composite overlay layer may be determined as appropriate depending on the usage conditions and required characteristics of the intended sliding member, but generally a thickness of 3 to 10++v+ is sufficient.

〔Example〕

(1) Formation of built-up layer A carbon steel disk (φ50×10L, mm) is used as a base material,
A composite build-up layer consisting of a heat-resistant alloy matrix and niobium carbide particles was formed on one side of the sample by PTA welding to obtain sample material A.

Its matrix metal composition is Co: 40%, Fe: 4
1%, Cr: 15%, Ni: 4%, and carbide particles (
The mixing ratio of the particles (average particle size: approximately 100 μm) was 50% by weight.

As a comparative example, a stellite alloy (Cr: 30%, W: 4%, Fe: 2%, C: 1
%, balance Co) to form a weld build-up layer consisting of
High Cr, high Ni heat-resistant cast steel (Cr: 30%, Ni
A sample C was obtained, which was made of a cast material of: 30%, W: 1%, C: 0.4%, and the balance was Fe.

All of the above sample materials A, B, and C were subjected to machining and polishing on the surface of the built-up layer. The build-up layer thickness is 5n+n+ in both cases.

(II) High-temperature sliding test and test results A high-temperature sliding test was conducted on each of the sample materials (A) to (C) using a sliding testing machine shown in FIG. In the figure, (1) is the column for mounting the test piece, (2) is the torque detector (load cell) attached to the bottom of the column (1), (3) is the rotating column for fixing the mating material, and (5) is It is a heating furnace. The test piece should be mounted on a post (
The sample material (A) (or B, C) is attached to the top of 1) with its overlay N (hatched portion) facing upward. At the bottom of the rotating column (2) for fixing the mating material, two pins (φ6 x 207!, ma+) (4, 4) are hung vertically as the mating material at symmetrical positions during its rotation. . The material of the mating material (pin) is 22Cr-6N+-3Mo-Fe duplex stainless steel.

As shown in the figure, the test piece is attached to the surface of the overlay layer (shaded area) of the specimen A (or B, C) attached to the support column (1), with the pins (4, 4) being the mating material. The end face is pressed and brought into sliding contact with the surface of the overlay layer of the test material with the axis of the support (3) as the center of rotation. However, the surface pressure of the pin against the surface of the overlay layer is 0.
6 kg/mm! , the sliding speed was 0.6 m/s, and the test temperatures were 600°C, 800°C, and 1000°C.
The presence or absence of seizure under each test condition was detected by a torque detector (2). FIG. 2 shows the relationship between the torque detected by the torque detector and the presence or absence of seizure. When seizure does not occur, the torque over time curve is flat and smooth as shown in curve 8m (a), but when seizure occurs, there is a sudden torque fluctuation as shown in curve (b). Therefore, the presence or absence of burn-in can be detected and measured with high accuracy.

Table 1 shows the results of the high temperature sliding test. In the table, "○" indicates no burn-in, and "x" indicates occurrence of burn-in.

Test material B (stellite alloy build-up layer) and test material C (high Cr, high Ni heat-resistant steel build-up layer), which are conventional materials, were tested at a test temperature of 6.
Seizure has already occurred at 00°C, whereas sample material A, which is an example of the invention, shows no seizure even at 1000°C, and has excellent antiseizure properties.

Table 1 Results of high temperature sliding test In addition, high temperature wear test conducted separately (temperature = 800°C, mating material: FCD50, surface pressure: 0.6 kg/mad”,
The amount of wear on the surface of the build-up layer measured at a sliding speed of 0.6 m/sec) was 758 n+g/m for sample B (stellite alloy build-up layer) and 758 n+g/m for sample C (high Cr, high Ni heat-resistant cast steel).
Test material A, which is an invention example,
Is that 76mg/n? It was confirmed that the material was extremely light, and its wear resistance far exceeded that of conventional materials.

〔Effect of the invention〕

The sliding member of the present invention can withstand conventional materials (such as stellite alloys and high Cr stainless steel), even against mating materials that are prone to seizure, such as high Cr stainless steel, under high surface pressure and high speed sliding contact conditions in a high temperature range. It exhibits superior seizure resistance that greatly exceeds that of Ni heat-resistant steel sliding members), and also has a high degree of wear resistance.

Therefore, the sliding member of the present invention is useful as a rolling mill peripheral member such as a side guide member in a hot rolling line, or a seamless pipe production line related member such as a guide shoe for piercing-rolled material, etc., which cannot be obtained with conventional materials. This improves durability, reduces maintenance costs, and stabilizes and improves the surface quality of the mating material.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of high-temperature sliding test procedures, and FIG. 2 is a graph showing a torque curve for determining the presence or absence of seizure occurrence. 1: Support for mounting the test piece, 2: Torque detector, 3: Rotating support for fixing the mating material, 4: Composite material, 5: Heating furnace.

Claims (1)

[Claims] (1) Heat-resistant alloy matrix and dispersed phase 10-7
A sliding member having excellent seizure resistance and wear resistance, the sliding surface of which is formed by a built-up layer having a composite structure consisting of 0% by weight of niobium carbide particles.