JPS5874572A - Plasticity working tool for copper and copper alloy - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic working tool used for drawing, wire drawing, wire rolling, extrusion, or die casting of copper and copper-based alloys.

Conventionally, cemented carbide and die copper high speed steel have been used as plastic working tools for steel and copper alloys.

However, the manufacturing conditions for large fish products, such as wire drawing rolls, have become stricter year by year due to higher precision and economical requirements, and as a result, plastic working tools have also become more demanding in terms of heat resistance, abrasion resistance, and thermal shock resistance. Improvements such as these are required.

In order to satisfy these demands, new materials are being developed day and night in the fields of cemented carbide, die steel, and other materials, but no material that has the above-mentioned properties has yet been found.

Looking at the movement toward new plastic processing tool materials, there were only minor changes.

On the other hand, ceramics have recently attracted attention as a material for plastic working tools, but they also have excellent thermal shock resistance, impact resistance,
Because its properties such as brittleness are inferior to those of the materials mentioned above,
Among plastic working tools, it is only gradually beginning to be used in the field of guide rolls and the like, which have low stress, and at present, there is almost no idea of using it for rolling rolls.

The present inventors have arrived at this invention after many years of studying the possibility of using ceramic materials as plastic working tool materials.

That is, the present invention is a new plastic working tool made of a silicon nitride ceramic, in particular, having 596 or less pores and a sintered body obtained by pressureless sintering.

This brings about a revolutionary change that breaks the conventional concept of various plastic working tools.

Silicon nitride is a type of ceramic material, and although it has some weaknesses as a ceramic as mentioned above, on the other hand, it is superior to the metal materials in terms of wear resistance, especially at high temperatures. Wear resistance is 10 to 1 compared to Solera.
It reaches the value of 00 times the value. Therefore, among plastic working tools, its effects are particularly pronounced in the field of hot rolling rolls and the like that are used at high temperatures.

The general concept for conventional jigs and tools is that they reach the end of their service life after a short period of use, so processes and equipment have been designed accordingly.

However, the plastic working tool of this invention has a lifespan of 10 to 100 times longer than conventional tools, and these jigs and tools have come to be considered part of the equipment.
For example, it becomes possible to add this to regular maintenance items for the equipment itself, and there will be no unproductive situations such as equipment having to be shut down to replace jigs and tools during that time.

As a result, not only the operating rate of the equipment is improved, but also the amount of stock generated during the process is reduced, and there is no need to carry many jigs and tools on hand, which has a very large effect.

These plastic working "tools" vary depending on the metal to be plastic worked, but for example, when plastic working copper or copper alloy, if the tool is made of the previous material, the tool and copper or copper alloy, etc. A reaction occurs between the material and the workpiece, a welding phenomenon occurs, and the surface layer repeats the phenomenon of welding and separation, which increases the roughness or wear of the surface layer, and eventually reaches the end of its life.

In addition, particularly during hot working, cemented carbide and die steel high speed steel are subject to repeated welding and separation, which causes cracks to occur due to a peeling phenomenon called spalling and fatigue phenomena, which causes a shortened service life.

In view of the above points, the inventors of the present invention have conducted studies to solve the drawbacks of conventional plastic working tools for copper and copper alloys, and have arrived at the present invention.

This invention also provides a raw material composition for a plastic working tool for copper and copper alloys, in which 60% by weight or more of 5illN4 and one of oxides, carbides, borides, nitrides, or silicides of Group B of the Periodic Table of Elements are added. 1 to 25% by weight of a species or two or more species and A4A
Contains 1 to 25 weight% of any one of t20a, AAN, or further contains 1 to 5 weight% of TiO2 or 'l''iN and/or MyO, and has 5% vacancies.
It is characterized by being made of the following S i IN4 sintered body.

Hereinafter, Jin's invention will be explained in detail. First, it is important that the tool be made of a material that causes the welding phenomenon to be minimized.

However, ceramics have low weldability to metals.

Among them, the most common alumina type? Mick has low strength, high stress, and cannot withstand use in plastic processing where it is subjected to surgical damage due to reliability problems.

So, when I tried testing with various ceramic tools, S
It was discovered that a ceramic mainly composed of i8N4 exhibits superior performance as a plastic working tool for copper and copper alloys than the conventionally used cemented carbide and die steel.

S i JIN4 used as the main material in this invention
Two methods are known: a reactive sintering method in which a molded body of Si metal powder is nitrided, and a powder metallurgy method by mixing Si8N4 and additives. However, in the former method, more than 10% of pores remain, which is inappropriate for the purpose of the present invention.

It is also known that the latter production method uses additives, which greatly affect the properties.

However, basically, high strength and impact resistance are required, and for this purpose, it is necessary to use 60% by weight or more of Si8N4.

Next, as additives to be used for Si8N4 of 60% by weight or more, Ce0z, Ys+Oa of group 1B of the periodic system
, 1 to 25% by weight of one or more of oxides, carbides, borides, nitrides, or silicides such as YN, and A
1 to 25% by weight of any one of T, At20B, and A
is preferred. This is because if it is less than 1% by weight, sufficient strength cannot be obtained, and if it is more than 25% by weight, it becomes brittle.

A sintered body having such a composition is particularly excellent when used under conditions of 1100° C. or lower.

Therefore, it is effective for use in hot extrusion dies for buttons, rolling rolls, guide rolls, and other applications that can be used under the above conditions, as well as in the field of strong plastic working.

In addition to the above 5, the sintering aids include Ti0g, Ti
N.

By containing 1 to 5% by weight of - or MtO&, a denser sintered body can be obtained, and by using this sintered body, an excellent tool can be obtained.

In such a tool, if too many holes remain, the strength and reliability will decrease, so the weave density is preferably as high as possible. From this point of view, it is appropriate that the number of pores be 596 or less, but in areas where the manufacturing and usage conditions of the tool are not so severe, a porosity of 10% or less will not have much of an effect.

Additionally, metals such as B, Fe, Co, and Ni as additives can be effective if used in small amounts.

Regarding Si8N4, its crystal system can be used in either type 0 or type β without any difference in color effect.

The present invention will be explained in detail below with reference to Examples.

Example 1 Commercially available Si8N490% by weight and AzzOa 5% by weight,
After weighing Y20a520B and thoroughly mixing it in a ball mill, it was statically molded at a pressure of It/-, and then sintered at 1800°C under a nitrogen pressure of 1 atm to produce a 10th stage heat treatment for finishing copper wire. A roll for inter-rolling was produced. The temperature of the rolled material is 500℃, the area reduction rate is 25%, and the rolling speed is 12m/s.
It was ee.

The life of this hot rolling roll was due to roughness of the roll surface, and its use was stopped at approximately 1,550 tons.

Examples 2-4 Commercially available 5HIN480% by weight and Azgoa to% by weight
, Y20alO wt % were weighed and thoroughly mixed in a ball mill, and then a 1st θ stage hot rolling roll for finishing copper wire was produced under the same conditions as in Example 1.

Using this roll, rolling was performed at temperatures of 950°C, 700°C, and 500°C under the same conditions as in Example 1 except for the following conditions.

The amount of rolling required to reach the end of roll life and the cause of life are the first.
As shown in the table, it was observed that even at high temperatures, the roll life did not decrease, but rather tended to increase.

Table l Example 5 5 weight j! for Si8N480% by weight! 96 A220
A rolling roll was produced in the same manner as in Example 1 by adding g and 15% Y2O3. And Example 1
When rolling was performed under the same conditions as above, the roll life was reached at 2800 tons.

Examples 6 to 1O A rolling roll was produced in the same manner as in Example 1 by adding the sintering aid shown in Table 2 to 8ijlN4.

Using this roll, we rolled the rolling material until it reached its lifespan by changing the temperature of the rolling material, and the results shown in Table 2 were obtained, showing that the total rolling amount tends to decrease with low-temperature rolling. This was recognized.

Even with the addition of other additives such as 10WC and 15M0IC, the rolling amount of the rolls was equal to or higher than that.

1:::1.1 Example 11 Commercially available 5isN4% by weight, AtgOa 10% by weight, MtO 5% by weight, 5% by weight of MtO were mixed,
A guide roller for drawing copper wire was produced in the same manner as in Example 1.

The sintering temperature at this time was 1700°C.

The obtained guide roller of this example was made of commercially available cemented carbide,
A comparison test of the service life with a guide roller made of alumina ceramic was conducted, and the results shown in Table 3 were obtained, proving that the guide roller of this example is extremely superior.

The wire was moved at a speed of 15 m/sec and at a temperature of 500°C.

Table 3

Claims (2)

[Claims] (1) At least 60% by weight of Si 11N4 contains oxides, carbides, borides, and nitrides of group B of the periodic table), and 1 to 25% by weight of tsi or two or more of silicides. A plastic working tool for copper and copper alloys made of an Si8N4 sintered body containing 1 to 25% by weight of any one of Az, Az2os, and A/N and having 5% or less of pores. (2) TiO2 in 60% by weight or more of Si 8N4
The plastic working tool for copper and copper alloys according to claim 1, characterized in that it contains TiN and/or MtO in an amount of 1 to 5% by weight.