JPS602382B2 - Manufacturing method of free-cutting nickel-chromium alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a nickel-chromium alloy having free machinability.

Nickel-chromium alloys containing silver are widely used in the dental, jewelry, and pharmaceutical industries, but the machinability of this type of alloy has not been considered much, and therefore sufficient machinability has not been obtained. I can't say that it is.

As a result of research on this point, the present inventor found that when silver is dissolved in an alloy, it has almost no effect on machinability, so it is necessary to intersperse the silver particles themselves in the alloy. It was found that machinability can be further improved if the material is made into a spherical shape of a predetermined size.

We also considered a manufacturing method for obtaining a nickel-chromium alloy containing such silver particles and having good machinability. In view of these points, the present invention provides a novel method for producing a nickel-chromium alloy that is endowed with free machinability.The present invention will be described below.

A first method for producing a free-machining nickel-chromium alloy according to the present invention is to produce a nickel-chromium alloy consisting of 0.1 to 5% by weight of silver, 5 to 25% by weight of chromium, and the remainder substantially nickel.
It is characterized in that the heat treatment is performed at a temperature of 00°C or more and less than 900°C.

That is, the long diameter 10 is suitable for improving machinability in the alloy.
Forming spherical silver particles with at least 7 peaks and 7 peaks in the short axis and a ratio of 3:2 or more, and making the silver particles occupy 0.5 to 30% of the cross-sectional area of the alloy. The objective is to obtain a nickel-chromium alloy with excellent machinability.

The nickel-chromium alloy manufactured by this manufacturing method is
It has excellent free cutting properties.

In other words, in this nickel-chromium alloy, the shape of the silver particles is spherical with a major axis of 10 degrees or more and a short axis of 7 degrees or more, with a ratio of 3:2 or more, which has the greatest effect on the machinability of the alloy. effect, and at the same time maintains the workability of the alloy at a reasonable level. By setting the proportion of silver particles having the specified particle shape to the cross-sectional area of the nickel-chromium alloy to be 0.5 to 30%, particularly preferably 6 to 20%, the alloy can be cut to the greatest extent possible. It can give gender,
Moreover, it is economically reasonable. Here, the silver percentage refers to a substantially distinguishable silver percentage in the matrix. These limitations are due to electron microscopy. The composition of the nickel-chromium alloy targeted by the production method of the present invention is 0.1 to 5% by weight of silver in order to effectively form spherical silver particles.
The basic composition is 5 to 25% by weight of chromium, and the remainder substantially nickel.

In addition, it is possible to add appropriate amounts of copper, iron, poppy, elemental, manganese, carbon, titanium, aluminum, etc. as necessary. Here, silver is essential for imparting machinability, and considering cost and dispersion of silver, about 5% is sufficient. Chromium is necessary for imparting corrosion resistance, and the proportion should be such that it does not adversely affect workability. In the manufacturing method of the present invention,
The heat treatment of the nickel-chromium alloy is performed at a temperature range of 700° C. or more and less than 900° C. at which the silver particles in the alloy are spheroidized.

When a nickel-chromium alloy is heat-treated under these conditions, the silver particles in the alloy are dispersed in the form of fibers at a temperature of 700 qo or less, but become spheroidal at temperatures above 700°C and below 90 qo, and become fine particles at temperatures above 900°C. It has been found through observation that the machinability of the alloy is improved by heating at 700°C.
It can be said that heat treatment within the temperature range of 900° C. or higher is effective. The silver particles in the nickel-chromium alloy are spheroidized and at the same time the silver particles are 0.5 in the cross-sectional area of the alloy.
This accounts for a proportion of ~30%, and the machinability of the alloy can also be improved in this respect.

A second method for producing a free-machining nickel-chromium alloy according to the present invention is to produce a nickel-chromium alloy consisting of 0.1 to 5% by weight of silver, 5 to 25% by weight of chromium, and the remainder substantially nickel.
After softening with phosphorus at a temperature of 0 to 1100, 70
It is characterized in that the heat treatment is performed at a temperature of 0° C. or more and less than 90 pi.

That is, initially 900 to 1
Phosphorous anchor treatment at 100°C removes internal strain from the alloy and improves drawing characteristics. In addition, heat treatment at 700°C or higher and lower than 900°C makes silver particles spheroidal to improve machinability. By doing so, it is possible to obtain a nickel-chromium alloy that eliminates internal strain and has both excellent drawing characteristics and excellent machinability.

In this way, the second manufacturing method combines two stages of heat treatment, and by performing the Akatsuki anchor treatment at a temperature of 900 to 1100°C, it is possible to effectively remove internal strain and improve drawing characteristics. If it is lower than that, the expected properties are not restricted, and if it is higher than that, the crystal grains will become coarse and the drawability will be inhibited, especially at 1000 to 1100°C.
It is preferable to carry out the reaction at a temperature of .

The heat treatment is performed after the anchor treatment, rapidly cooled to room temperature, and then heated to 700℃ again.
It may be heated to a temperature above 900° C. or may be heated continuously in the same furnace where the phosphor annealing was performed. The treatment holding time varies depending on the size of the material, but it requires at least 1 minute or more for Akatsuki hammer treatment, and 2 days or more for heat treatment. The relationship between the heating temperature of the processed material and the machinability in the experimental results obtained by the manufacturing method of the present invention will be described with reference to the diagram. Silver is used as a processed material. % by weight, 14% by weight of chromium
A nickel-chromium alloy consisting of 1.0% copper and the remainder substantially nickel was processed into a desired shape, and the processed material was heated at each temperature and drilled to measure machinability. The drilling conditions were as follows: 1.5 ribs of the drill, 35 disks of rotation, 2.0 k9 of drilling weight, and 6 sand drilling times. In the figure, below 700°C, where silver particles are fibrous, machinability is poor, and above 700°C, where silver particles are spherical, 900°C
It is clear that below qo, the machinability sharply increases around 80,000, and above 900:0, the machinability decreases again and becomes flat. In addition, in the figure, A is the heat treatment temperature range, and B is the competitive anchor temperature range. As explained above, the method for producing a free-cutting nickel-chromium alloy of the present invention obtains a nickel-chromium alloy having excellent machinability by interspersing silver particles having a spherical shape with a predetermined size in the alloy. be able to.

[Brief explanation of the drawing]

The figure is a diagram showing the relationship between heating temperature and machinability of a processed material.

Claims (1)

[Scope of Claims] 1. A nickel-chromium alloy consisting of 0.1 to 5% by weight of silver, 5 to 25% by weight of chromium, and the remainder substantially nickel,
A method for producing a free-cutting nickel-chromium alloy, which comprises performing heat treatment at a temperature of 0°C or more and less than 900°C. 2 A nickel-chromium alloy consisting of 0.1 to 5% by weight of silver, 5 to 25% by weight of chromium, and the remainder substantially nickel.
A method for producing a free-cutting nickel-chromium alloy, which comprises performing softening annealing at a temperature of ~1100°C and then heat treatment at a temperature of 700°C or more and less than 900°C.