JPS5850309B2 - Lead-containing sintered alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an iron-based sintered alloy made by press-forming and sintering metal powders consisting of iron, lead, and tin. The present invention relates to a lead-containing iron-based sintered alloy made of iron, lead, and tin, which prevents evaporation and is wear-resistant, or a molded product thereof.

Conventionally, lead-containing materials have been used as sintered oil-impregnated bearings or sliding parts because lead has the role of solid lubrication, and the JIS for sintered oil-impregnated bearings also lists them as iron-based type 2 oil-impregnated bearings (Fe -5% or less, Cu-3 to 10%, Pb-
3% or less), it can be used, for example, as a sintered alloy for oil-impregnated bearings.

Lead improves the smoothness of shafts and bearings, and also acts as a solid lubricant.

Oil-impregnated bearings are manufactured with low density due to oil impregnation, but in addition to oil-impregnated bearings, they are also used as slide blocks (sliding parts) made of iron containing lead as a high-density product.

Recently, lead-containing materials have been increasingly used as substitutes for copper-based bearings.

In the conventional lead-containing iron-based sintered materials as described above, lead evaporates during sintering, making it difficult to obtain a desired product quality and also causing a problem of fouling of the sintering furnace.

In the present invention, 5 to 15% by weight of lead powder and 0% of tin powder are used.
．． 5 to 3% by weight of residual iron powder is used as an essential component, but by adding and mixing 0.5 to 3% by weight of tin powder, a remarkable effect is shown in preventing evaporation of lead during sintering.

The lead removal rate after sintering due to the addition of tin (indicated by the weight loss rate before and after sintering), the strength properties (indicated by the crushing strength measurement according to JIS Z2507, that is, the crushing constant), and the hardness 0'Tsukukuru Hardness Tester H (shown on a scale)
- Shown in Figure 9.

That is, by adding 0.5 to 3% of tin, the lead removal rate is reduced and the strength and hardness are improved.

Although iron and lead do not form a solid solution, it is thought that iron and tin, and tin and lead exhibit their effects when they form a solid solution.

It is also possible to use an alloy powder of lead and tin instead of adding the inner pot.

The evaporation of lead can be suppressed by adding tin, but
In addition, the ability to lower the sintering temperature will further enhance the effect compared to a case in which tin is not included to obtain a certain strength property.

It should be noted that if the amount of tin exceeds 5%, evaporation tends to increase, causing variations.

When using this alloy for bearings, the wear resistance is improved by adding tin, but as the amount of tin increases, the coefficient of friction tends to increase, and noise generation becomes a problem, so the amount added is 3% or less. , preferably 2% or less.

The composition of this alloy consists of three elements: iron, lead, and tin, as well as copper and
Addition of zinc or the like does not impede the effect, and it is also effective to use lead and tin alloy powder, ie, solder powder, in place of the addition of lead and tin.

The above weight percentages are all numbers. As raw materials used in the present invention, it is preferable to use iron powder of about 80 mesh or less, and lead powder and tin powder of about 100 mesh or less.

The pressure applied when molding these raw materials is determined appropriately depending on the intended use of the molded product, but for example, for oil-impregnated bearings, the molding density is approximately 5.8 to 6.5 g/CC (theoretical density 70 to 80%), and in the case of making a high-density product, pressure may be applied so that the molding density is approximately 6.5 to 7 g/CC (80% or more of the theoretical density).

In the present invention, the raw material mixture or its pressure-molded product is
Generally, about 3
Sinter in 0-60 minutes.

Hereinafter, the present invention will be explained in more detail with reference to examples and the accompanying drawings.

In addition, in the examples, percentages are based on weight unless otherwise specified.

Examples 1 to 9 In these examples, various mixtures consisting of 5 to 15% atomized lead powder of 100 mesh or less, O to 3% of stamped tin powder of 100 mesh or less, and the remainder iron powder of 80 mesh or less were mixed into a powder with an inner diameter of 8 Pressure molded into a cylindrical shape with an outer diameter of 10 mm and a length of 12 mm to approximately 75% of the theoretical density, and sintered at a sintering temperature of 900° to 1130°C in butane converted gas for approximately 45 minutes. The results obtained by sintering are shown in FIGS. 1 to 9.

Incidentally, sintered products obtained by using less than 0.5% of tin are shown as comparative examples in FIGS. 1 to 9 together with examples of the present invention.

[Brief explanation of drawings]

Figures 1 to 3 show the relationship between sintering temperature and evaporation of hardness using the amount of tin added as a parameter when tin is added from 0 to 3% to iron-based sintered materials containing 15%, 10%, and 5% lead, respectively. Graphs of weight loss rate, FIGS. 4-6 are also graphs of sintering temperature versus compaction constant, and FIGS. 7-9 are graphs of sintering temperature versus hardness.

Claims (1)

[Claims] 1 5-15% by weight of lead powder and 0.5-3% by weight of tin powder,
A wear-resistant sintered alloy for bearings and sliding parts made of iron powder.