JPS5845364A - Manufacture of aluminum alloy for cutting - Google Patents

Abstract

PURPOSE:To obtain an Al alloy for cutting providing a long life to a tool by extruding an Al-Mg alloy ingot after homogenizing at a specified temp. CONSTITUTION:An Al alloy ingot contg. 2.0-8.0wt% Mg or further contg. <=0.20wt% at least one of Mn and Cr is homogenized especially at <=500 deg.C and extruded. The homogenizing temp. is made as low as possible only to elongate the life of a tool, yet it is practically restricted to <=500 deg.C from the relation among the elongation of the life, the improvement of the extrusibility and other characteristics to be provided such as toughness and corrosion resistance. The conditions during the extrusion do not exert particularly serious influence on the wear of the cutting tool, and the extrusion is carried out at about 400-500 deg.C extrusion temp. of a conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aluminum alloy for cutting, and more specifically, a method for producing an aluminum alloy for cutting, which is processed by cutting to be used for optical equipment parts, electrical equipment parts, automobile parts, etc. Regarding the manufacturing method.

An aluminum alloy with excellent machinability is Aa20, which has Cu as an essential component and a small amount of PbXB1 added to it.
11 alloy is well known. This alloy has excellent machinability, but on the other hand, it is a heat-treatable alloy and requires solution treatment and quenching processes during manufacturing, making it expensive to manufacture and inherently having extremely poor corrosion resistance. There are some drawbacks.

For this reason, for applications that require particularly high surface treatment properties, such as optical equipment and communication equipment, non-heat treatment alloys with excellent surface treatment properties are used to improve corrosion resistance at the expense of machinability to some extent. Al-Mg such as AA5056 alloy
alloys are widely used. However, this Al-Mg alloy
Due to the nature of the material, it is a hardening alloy with excellent mechanical strength, so it has high cutting resistance during cutting.
The disadvantage is that the cutting tools are subject to severe wear. Especially these days,
In the current situation where high-speed cutting is performed using automatic cutting machines, rapid tool wear is a serious hindrance to work, and in recent years, tools with improved tool life and excellent cutting performance have been increasingly improved in this regard. The appearance of aluminum 2m alloy has come to be desired.

In view of the above circumstances, the present inventors conducted various studies on the composition of aluminum alloy and its manufacturing conditions with the intention of improving tool life, and found that A1, which has the above-mentioned properties, was developed.
- It was discovered that the abrasiveness of cutting tools is greatly affected by the manufacturing conditions of Mg-based alloys, and based on this knowledge, the present invention was completed.

That is, the present invention contains 20 to 8.0% Mg, and if necessary, at least one of Mn and Or is 0.
The method is characterized in that an aluminum-based alloy containing 20 or less aluminum is used, and an ingot of the aluminum-based alloy is homogenized at a temperature of 500° C. or less, and then extruded. The present invention provides a method for producing an aluminum alloy for cutting, which is characterized in that when drawing is performed, the drawing process is carried out at a processing rate of 60 inches or less. .

First, the reasons for limiting the alloy components mentioned above are as follows: Mg
It is an essential component for ensuring the mechanical strength of FiA1 alloy and improving its machinability. If the content is less than 2 tres, the above effects will not be sufficient, and if it exceeds 8 ts, the toughness will decrease and stress will occur. Problems such as corrosion cracking and decreased extrudability arise.

Therefore, a particularly preferable range is about 3 to 5 inches. Furthermore, Mn and/or Cr, which should be added as necessary, is effective in preventing stress corrosion cracking and adjusting crystal grains, but if the content exceeds 0.20%, surface treatment properties are inhibited. .

Next, regarding the homogenization treatment, the homogenization treatment itself is a treatment that has been conventionally commonly performed in order to improve extrudability, toughness, corrosion resistance, etc. in Al-Mg alloys for cutting. It is. However, the conventional processing conditions are generally at a high temperature of about 530 to 540°C. However, according to the results of experiments and research conducted by the present inventors, when homogenization treatment is performed at the above-mentioned temperature,
It has been found that this increases the amount of Mg-based crystallized substances in the alloy dissolved into the matrix, which has an extremely adverse effect on cutting tools. Based on these findings, further research revealed that when homogenization treatment is performed at a temperature below 500°C, a large amount of Mg-based products are generated, which significantly reduces the wear of cutting tools. It's worth it. Therefore, in this invention, the homogenization treatment conditions before extrusion are limited to a temperature of 500° C. or less. However, from the point of view of increasing tool life, it is preferable that the temperature conditions for the homogenization treatment be as low as possible, and it is most preferable not to perform the homogenization treatment. In this sense, the lower limit of the homogenization treatment temperature in this invention is not particularly limited, but in practice, when considered in relation to other features such as improved extrudability and desired characteristics, 200 ° C.
It is preferable to process at a temperature higher than 400℃, especially 400℃~
A temperature range of 500°C is excellent not only in terms of extrudability but also in terms of toughness, corrosion resistance, etc. Although the treatment time varies depending on the correlation with temperature, it can be carried out in about 2 to 12 hours, and preferably about 4 to 7 hours.

The extrusion processing performed after the homogenization treatment does not have a particularly large effect on the machinability of the Al-Mg alloy, the wear resistance of cutting tools, etc., depending on the processing conditions, and the extrusion processing performed by the conventional conventional method is about 400°C to 500°C. It is sufficient to process at an extrusion temperature of .

After extrusion, the extruded product is usually subjected to drawing for the purpose of correcting dimensional distortion, increasing mechanical strength, etc. However, even with this drawing process, the processing rate still has a large effect on the wear of the cutting tool. According to the knowledge that the present inventors have been able to elucidate, generally speaking, the lower the drawing rate, the more favorable results can be obtained in terms of tool life. Therefore, like the homogenization treatment described above, it is most preferable not to perform this drawing process only from the point of view of tool life.
Assuming that the present invention is carried out at the following temperatures, the actual drawing rate conditions do not have a particularly significant effect on tool life. However, the permissible range is at least 60% or less, and when drawing is performed at a processing rate exceeding 60 inches, regardless of the homogenization processing conditions, the cutting force increases significantly, causing the wear of the cutting tool. It is not possible to obtain satisfactory results in this respect. Even when the homogenization temperature is set at 500° C. or lower, the drawing rate is practically preferably set at 30 inches or lower.

When considering the application of this invention to the industrial production of aluminum alloys for cutting, it is important to consider not only the tool life but also the relationship with mechanical properties such as machinability and mechanical strength, as well as extrudability, corrosion resistance,
In terms of toughness, etc., the homogenization treatment conditions are 400°C to 500°C for about 4 to 7 hours, and on this premise, it is preferable to perform the drawing process at a processing rate of about 10 to 30%. be. .

Next, examples of the present invention will be shown in comparison with comparative examples, and the performance of the obtained cutting aluminum alloys will be compared.

Examples Table 1 shows the chemical components of various Al-Mg alloys that meet the range of alloy composition conditions of the present invention. After each of these was melted and cast according to a conventional method, the ingots were homogenized under various temperature conditions shown in Table 2, and then extruded at an extrusion temperature of 400°C to a diameter of 20 mm. It was made into a stick. Then, the properties of each rod were investigated using samples of this rod as it was or those that had been further subjected to drawing processing at various processing rates shown in Table 2.

Table 1 Table 2 Table 3 shows a comparison of the mechanical properties, corrosion resistance, and wear resistance of cutting tools of the various samples mentioned above. Mechanical properties were measured using a JIS No. 4 test piece with a gage distance of 50 mm, and corrosion resistance was measured by observing the corrosion status of the surface after salt water spray x 500 hours of corrosion acceleration treatment using J Engineering 5 = Z2371. ◎ marks are good, and ○ marks are slightly inferior but good. In addition, the wear resistance of cutting tools is as follows: Front rake angle 0° Side rake angle 20' Front relief angle 7° Side relief angle 7° Front cutting edge angle 8° Side cutting angle 0° Nose radius Oo Mounting angle 90° The wear width of the tiller surface was measured using an automatic cutting machine under the following cutting conditions using a high-speed hard pie (SKH4) having specifications for 30 minutes.

(Cutting conditions) Cutting speed 200 rn/n Depth of cut 1 mm Comb speed 0.2 mm/rev Lubricant No lubrication In the results shown in Table 3, the mechanical properties and corrosion resistance of the examples of the present invention were Regarding this, it is almost the same as the comparative example.

On the other hand, regarding the wear resistance of the cutting tool, the cutting tool A! -Mg-based alloys clearly have the effect of improving tool life compared to comparative examples using alloys with the same Mg content. Therefore, the aluminum alloy for cutting according to the present invention has better properties than conventional products in terms of tool life, and is suitable for high-speed cutting with automatic cutting machines.

Table-3 -! L

Claims (1)

[Claims] (1) Using an aluminum-based alloy containing 2.0 to 80% Mg (wt%, the same applies hereinafter) and optionally containing 0.20% or less of at least one of Mn and Cr, the aluminum-based alloy 1. A method for producing an aluminum alloy for cutting, which comprises homogenizing an ingot at a temperature of 500° C. or lower and then extruding it. (Use an aluminum-based alloy containing 2.0 to 8.0% Mg and, if necessary, 0.20 or less of at least one of Mn and Cr, and heat the ingot of the aluminum-based alloy to a temperature below 500°C. 1. A method for producing an aluminum alloy for cutting, which comprises homogenizing the aluminum alloy at a temperature of 100 mm, extruding it, and then further drawing it at a processing rate of 60 inches or less.