JPS6296646A - Alloy member for pump shaft sleeve and bearing - Google Patents

Abstract

PURPOSE:To obtain an alloy member for pump shaft sleeve and bearing excellent in corrosion resistance and wear resistance by limiting the grain size of hard phase and the kind and composition of binding phase in an alloy member. CONSTITUTION:An alloy is composed of a hard phase of tungsten carbide with 1-3mu grain size and a binding metal phase comprising 5-12wt% of the whole alloy, in which the binding metal phase consists of Ni, Co and Cr and the amounts of Ni and Cr are regulated to 50-90wt% and 1-10wt%, respectively, based on the total of the whole binding metals. Further, porosity of alloy and Rockwell hardness (scale A) at ordinary temp. are also regulated to <=1% and >=88, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is an alloy member for shaft sleeves and bearings of pumps for pumping up seawater, sewage, and rainwater, and is an application part of cemented carbide.

[Problems with conventional technology]

Conventionally, rubber or carbon-containing iron-based sintered alloys have been mainly used as materials for constructing pump bearings. However, with these materials, the contact surface between the sleeve attached to the pump shaft and the bearing is prone to wear, and the heat generated by contact can cause seizure, corrosion in seawater, and short pump life. there were. Furthermore, it was used with restrictions such as mixing sand and scale into the water.

[Problem that the invention seeks to solve]

There is a need for a pump shaft sleeve and bearing that solves these problems. The disadvantages of conventionally used materials are that they have poor wear resistance and lack corrosion resistance. Moreover, there are many conditions for these uses, and there is no one that can withstand the harsh conditions.

[Means for solving problems]

The present invention was developed to solve the above object, and its gist is that the present invention has a hard phase of tungsten carbide with a particle size of 1 to 3 μm and a binder metal phase of 5 to 12% by weight. The binding metal phase consists of Ni, Go and Cr, and N
i is 50% by weight or more and 9% by weight or less of the total bonded metal phase, and Cr is 1% by weight or more and 10% by weight or less of the total bonded metal phase, and the porosity is 5% or less Ronfuranil hardness at room temperature. (A scale) This is a pump shaft sleeve and a cemented carbide member for bearings, characterized by having an HRA of 88 or more.

This invention will be explained in more detail below.

The present inventors have conducted intensive studies on the particle size of cemented carbide and the type and composition of the binder metal phase in order to improve corrosion resistance and wear resistance, and as a result, they have arrived at the present invention.

In other words, the particle size of tungsten carbide, which is the hard phase, is 1μ.
If it is less than m, the hard phase will be poorly dispersed, resulting in a region with poor hardness distribution and low wear resistance. If it is 3 μm or more, the amount of tungsten carbide dispersed will be small, resulting in a decrease in hardness and poor wear resistance. If the total amount of bonded metal phase is less than 5% by weight, sinterability is poor, pores are generated, and wear resistance is poor.

If it exceeds 12% by weight, hardness decreases and wear resistance deteriorates. More preferably, the content is in the range of 5 to 10% by weight.

The reason why Ni is 50% by weight or more and 90% by weight or less of the total bound metal phase and Cr is limited to 1% by weight or more and 10% by weight or less is that if Ni is less than 50% by weight, it will be contained in water. Corrosion resistance against salt and the like deteriorates, and when it exceeds 90% by weight, hardness and strength decrease, and wear resistance decreases. Further C
If r is less than 1% by weight, it will not contribute to improving the corrosion resistance of the binder phase, and if it exceeds 10% by weight, the corrosion resistance will decrease, as well as the hardness and strength, and the wear resistance will deteriorate. More preferably, the range is from 3% by weight to 8% by weight.

By limiting the particle size of these hard phases and the type and composition of the binder phase, a cemented carbide having wear resistance and corrosion resistance can be produced. Furthermore, in addition to the above limitations, shaft sleeves and bearings can be used as pump shaft sleeves and bearing members by limiting the porosity of the cemented carbide to 1% or less and the hardness, that is, 88 or more on the A scale Ronfuranil hardness (HRA). The outline of the present invention is to dramatically improve the lifespan of.

As a method for producing the cemented carbide of the present invention, vacuum non-pressure sintering
) Cemented carbide that falls within the above limits for any method, from pressing, vacuum non-pressure sintering to HIP treatment, HIP sintering only,
Shows good long life as pump shaft sleeve and bearing.

The thus obtained cemented carbide is effective when applied to parts that slide in water, in addition to rotating shaft sleeves and bearings.

This will be explained below using examples.

Example 1 WC powder with an average particle size of 2 μm was mixed with Co, Ni, and Cr in the composition shown in Table 1, and subjected to wet mixing and pulverization.

This has an outer diameter of 100+ua and an inner diameter of 801. Height loOms
It was molded into a positive cylindrical shape, vacuum sintered at 1350°C to 1400°C, and then subjected to HIP treatment at 1380°C and 1000 ata+Ar.

Table 1 shows the relationship between alloy composition characteristics and performance.

Performance is achieved by using the above-mentioned shaft sleeve and ceramic for the bearing.
Salt 5 which is incorporated as a pump and adds sand of about 3smφ
% of seawater at a rotation speed of 200 rpa+, the possible rotation time was determined.

Table 1 Example 2 Shaft sleeves and bearings were made from the compositions of Example 1 (positive 2 and negative 2). Incorporating both into a pump, Example 1
We conducted a similar performance assessment.

As a result of comparing the lifespan of -2 and A2, it can be seen that A2 of the present invention has a long life even when used as a shaft sleeve bearing.

Table 2

Claims (1)

[Claims] In an alloy consisting of a hard phase of tungsten carbide with a particle size of 1 to 3 μm and a binder metal phase of 5 to 12% by weight of the entire alloy, the binder metal phase consists of Ni, Co and Cr, and N
i is 50% to 90% by weight of the total amount of all bonded metals, Cr is 1% to 10% by weight of the total amount of all bonded metals, the porosity of the alloy is 1% or less, and the Rockwell hardness at room temperature is An alloy member for a pump shaft sleeve and bearing, characterized in that the diameter (A scale) is 88 or more.