JPS6210238A - Manufacture of wear resistant sintered iron alloy for sliding current collector - Google Patents

Abstract

PURPOSE:To manufacture a wear resistant sintered iron alloy for a sliding current collector such as a sliding plate for a pantograph by subjecting a powdery material consisting of granular or powdery chrome, metallic sulfide, phosphorus and iron powder in a specified weight ratio to mixing, compression molding and sintering to form a sintered alloy matrix and by impregnating the specified amount of lead or a lead alloy into the alloy matrix. CONSTITUTION:A powdery material is composed of 2-14wt.% granular or powdery chrome, 2-7wt.% metallic sulfide, <1wt.% phosphorus and the balance iron powder. The powdery material is mixed, compression-molded and sintered to form a sintered alloy matrix. This alloy matrix and lead or a lead alloy are placed in a vacuum furnace, where 2-8% lead or lead alloy is impregnated into the alloy matrix.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to an iron-based sintered alloy with excellent dust resistance that is used in current collector sliding parts without using lubricating oil, especially at a speed of 260 km.
The present invention relates to a method for manufacturing an iron-based wear-resistant sintered alloy for current collector sliding plates suitable for use as pantograph sliding plates for high-speed electric cars running at speeds of 270 km/h to 270 km/h.

[Conventional technology]

The iron-based layer-resistant sintered alloy currently used for Shinkansen railings is mainly composed of iron powder and lacks lubricity, so we created an iron-based sintered alloy matrix with the desired porosity.

The sintered alloy matrix is impregnated with 17 to 27% lead. However, when a large amount of lead is impregnated in this way, since lead is a metal with a low melting point, the surface of the sliding plate is melted by the spark discharge when the overhead wire and the sliding plate are separated, and the lead is eluted and the sliding plate is damaged. There is a risk of roughening the surface of the bearing, and there is still room for improvement as sliding wear is relatively high due to these reasons.

In order to improve the above-mentioned problems, one of the inventors of the present invention, etc., mixed metal sulfides such as molybdenum disulfide and tungsten disulfide into iron powder to exhibit lubricating performance by the gold-sulfide. In addition, a method for manufacturing an iron-based layer-resistant sintered alloy that firmly incorporates 80 to 150 meshes of granular chromium in the iron-based alloy and has dust resistance due to the granular chromium and lubrication performance due to the metal sulfide is provided. Invented first (Patent No. 10)
09420, Japanese Patent Publication No. 54-42332).

According to the present invention, it is possible to exhibit good dust resistance and lubrication performance without lead impregnation at a speed of about 2201w/H, but if the speed is further increased to 2201w/H, good dust resistance and lubrication performance can be achieved without lead impregnation.
When the speed is increased to 60km/H-270km/H, the dust resistance and lubrication performance are insufficient.

[Problem that the invention seeks to solve]

In view of the problems of the prior art as described above, the present invention provides
It is an object of the present invention to provide an iron-based abrasive and sintered alloy for current collector sliding, which exhibits excellent dust resistance even at speeds of 60km/H to 270km/H, and which can also improve the durability of sliding plates and overhead wires. be.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention uses metal sulfides such as 2 to 14% by weight of granular chromium, molybdenum disulfide, tungsten disulfide, iron sulfide, copper sulfide, etc.
~7% phosphorus, 1% or less phosphorus, and the balance iron powder is mixed, compression molded at 6 to 8 T/d, and then sintered to form approximately
The method is characterized in that a sintered alloy matrix having a porosity of about 10% is prepared, and 2 to 8% of lead or lead alloy is impregnated into the sintered alloy matrix.

[Effect]

As mentioned above, the present invention is made mainly of iron powder, and in order to improve dust resistance at high speeds, a larger amount of chromium is mixed therein than in the previous invention, and this is firmly incorporated into the sintered alloy matrix. Molybdenum disulfide.

Metal sulfides such as tungsten disulfide, iron sulfide, and copper sulfide are blended to create a sintered alloy matrix that has lubricating properties itself and has poor wettability when impregnated with lead, and the sintered alloy matrix is made of a lead-free lead alloy. Since the lead is impregnated, the amount of lead to be impregnated is 2~
The dust resistance of granular chromium is suppressed to a low 8%, and the lubrication performance of the metal sulfide uniformly distributed in the sintered alloy matrix and the lubrication performance of the impregnated lead or lead alloy combine together. In addition to exhibiting extremely excellent dust resistance.

The durability of not only the sliding plate but also the overhead wire can be significantly improved.

More specifically, the metal sulfides used in the present invention, such as molybdenum disulfide, tungsten disulfide, iron sulfide, and copper sulfide, are extremely fine, and are uniformly mixed between the iron powder to form a powder of 80 to 150 mesh. The particles of chromium are evenly distributed in the iron-based sintered alloy. And, as is clear from the test results described below,
The dust resistance of granular chromium, the metal sulfide contained in the sintered alloy matrix, and the lubrication performance of lead or lead alloy impregnated after sintering combine to provide extremely excellent performance at high speeds of 260 to 270 km/h. Demonstrates excellent dust resistance and lubrication performance.

In the mixing ratio of chromium and iron powder as described above, the appropriate amount of metal sulfide is 2 to 7%, and 2%
If it is less than 7%, the effect will be small, and if it is more than 7%, the mechanical strength of the alloy will decrease.

When sintering the molded body made of the mixed powder of iron, chromium, and metal sulfide, phosphorus purifies the iron with its strong deoxidizing action, and also removes Fe formed on the surface of the powder in the early stage of sintering.
By increasing the amount of liquid phase in the 5P-Fe eutectic composition, the chromium mixed for the purpose of dust resistance and the metal sulfide mixed for the purpose of increasing lubricity are firmly incorporated into the sintered body. It shrinks in the state and promotes densification. If the amount of phosphorus added is 1% or more, it becomes brittle. Furthermore, if the reducing atmosphere in the sintering furnace is nearly perfect and the raw materials are clean, the above effects can be achieved even if the amount of phosphorus added is reduced.

The granular chromium powder used has a mesh size of 80-150, and is present in the iron-based sintered alloy densified as described above in a state of being strongly entrapped as a single chromium solid. Unique rust resistance.

Demonstrates dust resistance. If the content is less than 2%, it is insufficient to improve dust resistance, and if it is 14% or more, the mechanical strength of the entire sintered alloy decreases.

Furthermore, in the present invention, as described above, the sintered alloy matrix is impregnated with lead or a lead alloy, but at this time, the sintered alloy matrix has already been mixed with metal sulfide, which is a lubricant. Therefore, during lead impregnation, the temperature resistance is poor and impregnation of lead is hindered to some extent, and the molding pressure of the mixed powder is reduced to 6 to 8 T.
/cnT, the lead impregnation rate can be made 2 to 8%. Note that during lead impregnation, the sintered alloy matrix may be re-pressurized if necessary. If the amount of lead impregnated is less than 2%, the lubricity effect is insufficient, and if it is 8% or more, it is unnecessary.

In addition, the above Fe-Cr-P-MoS2 (WS, , FeS
.

CIJS)'s sintered alloys include a small amount of iron, molybdenum, tungsten, nickel, cobalt, and titanium.

Even if it is replaced with copper, carbon, chromium, etc., or one or more of these compounds, the layer resistance of the sliding board and overhead wire will not be significantly affected. Therefore, it is also included in the present invention to replace a small amount of iron with the above-mentioned metals or compounds thereof. Further, in the following examples, an example was shown in which lead was impregnated, but a lead alloy may be impregnated instead of lead, and this case is also naturally included in the present invention.

〔Example〕

Hereinafter, specific examples of the present invention will be described for each embodiment.

Example 1 In terms of weight ratio, 80 to 150 mesh of granular chromium (
(hereinafter simply referred to as chromium) 5%, phosphorus 0.5%, molybdenum 2%, nickel 0.7%, copper 2%, tungsten carbide 1%, carbon 0.3%, molybdenum disulfide 4%, balance iron powder. The raw materials were mixed uniformly using a mixer, and then compression molded at 7 T/d.
Sintering was performed at 150°C for 30 minutes. The obtained sintered alloy matrix was placed in a vacuum furnace together with a solid lead element at a temperature of 680°C.
1,2 (A product impregnated with 4.5% lead in 1 minute was obtained.

Example 2 By weight: 6% chromium, 0.3% phosphorus, 1% copper, Fe
Each raw material was blended in the proportions of 3% W, 0.2% carbon, 5% molybdenum disulfide, and the balance iron powder, and after uniformly mixing this with a mixer, compression molding was performed at 6.5 T/cd in a reducing atmosphere. Sintering was performed at 1150°C for 30 minutes. The obtained sintered alloy matrix was placed in a vacuum furnace together with a solid lead element at a temperature of 680°C.
- A product impregnated with 4.8% lead was obtained in 120 minutes.

Example 3 By weight: 8% chromium, 3% tungsten disulfide,
The raw materials were mixed at a ratio of 1.5% copper sulfide, 0.4% phosphorus, and the balance was iron powder, and after uniformly mixing this with a mixer, 6T/
It was compression molded using CD and sintered at 1150°C for 30 minutes in a reducing atmosphere. The obtained sintered alloy matrix was placed in a vacuum furnace together with a solid lead element, and at a temperature of 680°C for 120 minutes, the lead was reduced to 5.
% impregnated product was obtained.

Example 4 Raw materials were mixed in a weight ratio of 9% chromium, 0.2% phosphorus, 3% molybdenum disulfide, 2% tungsten disulfide, and the balance was iron powder, and the mixture was uniformly mixed using a mixer. After that, it was compression molded at 8T/d and heated at 1150℃-30 in a reducing atmosphere.
Sintered in minutes. The resulting sintered alloy matrix was placed in a vacuum furnace together with a solid lead element.

A product in which the button was impregnated by 4.0% was obtained at a temperature of 680° C. for 120 minutes.

Example 5 In terms of weight ratio, chromium 12%, molybdenum disulfide 3%,
Each raw material was blended at a ratio of 1.5% iron sulfide and the balance was iron powder, mixed uniformly using a mixer, compression molded at 7.5T/CJ, and sintered at 1150℃ for 30 minutes in a reducing atmosphere. did. The obtained sintered alloy matrix was placed in a vacuum furnace together with a solid lead element, and at a temperature of 680° C. for 120 minutes, a product in which the button was impregnated by 4.3% was obtained.

Table 1 shows the physical properties of the sintered alloys obtained in each of the above examples.

Table 1 also shows the test pieces obtained from the sintered alloys obtained in each of the above-mentioned Examples 5 to 5, and the current
A test piece 10 x 25 x 901 m made of the iron-based sintered alloy sliding plate used in / H) was attached to a rotary sliding test machine, with a pressing cuff kg, current AC 150 A, and a sliding speed of 75 km/h for 160 minutes. Each test piece was slid on a trolley wire with lubrication, and the specific wear rate of each test piece, the wear thickness of the other trolley wire, and the temperature rise of the test piece were measured. The results are shown in Table 2.

As is clear from Table 1 above, the sintered alloys of Examples 1 to 5 obtained according to the present invention have physical properties necessary for pantograph sliding plates of high-speed electric cars, In addition, as is clear from Table 2, the current speed is 220 kn+/I (compared to the sliding plates used before and after), and the wear resistance is significantly improved.

It has been proven that it does not damage the other party's overhead lines.

Furthermore, as is clear from Tables 1 and 2 of each example, 2 to 14% of chromium, 2 to 7% of metal sulfide, 1 to 1% of phosphorus
% or less, the balance is iron powder, even if a small amount of iron is replaced with molybdenum, tungsten, nickel, cobalt, titanium, copper, carbon, chromium, or their compounds, the combination of metal sulfide as a lubricant If the button is impregnated with the sintered alloy in an amount within the above range from 2 to 8%, the wear resistance will hardly change.

〔Effect of the invention〕

As described above, according to the present invention, the abrasion resistance of the sliding plate is significantly improved, and the sliding surface is smooth and glossy with a blackish brown color, and the temperature rise of the sliding plate is low. It has the effect of significantly reducing surface damage and abrasion, and is extremely useful as a pantograph sliding plate for high-speed electric cars of 260 kn+/H to 270 km/H.

Claims (1)

[Claims] By weight, granular chromium 2-14%, metal sulfide 2
~7% phosphorus, 1% or less phosphorus, and the balance iron powder is mixed, compression molded, and sintered to create a sintered alloy matrix, and the sintered alloy matrix is impregnated with 2 to 8% lead or lead alloy. A method for producing a ferrous and wear-resistant sintered alloy for current collector sliding.