JPS6361382B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing an aluminum alloy for cutting, and more particularly to a method for manufacturing an Al-Mg alloy for cutting, which is subjected to cutting processing and used for optical equipment parts, electrical equipment parts, automobile parts, etc. As an aluminum alloy with excellent machinability,
The AA2011 alloy, which has Cu as an essential component and small amounts of Pb and Bi added to it, 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 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-treated alloys with excellent surface treatment properties are used to improve corrosion resistance at the expense of machinability to some extent.
Al-Mg alloys such as AA5056 alloy are widely used. . However, this Al-Mg alloy
Due to the nature of the material, since it is a hardening alloy with excellent mechanical strength, it has the disadvantage that cutting resistance during cutting is large and cutting tools are subject to severe wear.
Particularly in recent years, when high-speed cutting is performed using automatic cutting machines, rapid tool wear is a serious hindrance to work. There is a growing desire for an aluminum alloy for aluminum alloys. 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 an Al-Mg alloy with the above-mentioned properties was found. In particular, the inventors discovered that the abrasion properties of cutting tools are greatly affected by the manufacturing conditions, and based on this knowledge, they completed the present invention. That is, this invention contains 2.0 to 8.0% Mg,
If necessary, an aluminum-based alloy containing 0.20% or less of at least one of Mn and Cr is used, and an ingot of the aluminum-based alloy is heated particularly at 500°C.
Provided is a method for producing an aluminum alloy for cutting, which comprises extruding after homogenizing at a temperature above, and then further drawing the extruded product at a processing rate of 10% or less. It is something to do. This will be explained in more detail below. First, to explain the reasons for limiting the alloy components mentioned above, Mg is an essential component to ensure the mechanical strength of the Al alloy and improve machinability, and if its content is less than 2%, the above effects will not be achieved. not enough,
If it exceeds 8%, problems such as decreased toughness, stress corrosion cracking, and decreased extrudability will arise. Therefore, a particularly preferable range is about 3 to 5%. Additionally, Mn and/or Cr, which should be added as necessary, are effective in preventing stress corrosion cracking and adjusting crystal grains, but if their content exceeds 0.20%, it impairs surface treatment properties. do. Next, regarding the homogenization process, the homogenization process itself is used in Al-Mg alloys for cutting.
This is a treatment that has been conventionally carried out in order to improve extrudability, toughness, corrosion resistance, etc. Therefore, in order to obtain the desired satisfaction with the above-mentioned properties, this treatment is generally performed using 530
It is carried out at a temperature of ~540°C. However, according to the findings of the inventors' experiments and research, the homogenization treatment performed under the above temperature conditions causes Mg-based crystallized substances in the alloy to enter the matrix. It has been found that processing at a temperature of less than 500°C is preferable from the viewpoint of tool life, as it increases the amount of solid solution in the cutting tool and as a result has a negative effect on the cutting tool. That is,
When homogenizing at temperatures below 500℃,
Since a large amount of Mg-based crystallized substances are generated, cutting wear can be reduced. However, in practice, in relation to the Mg content in the alloy and also in relation to various properties such as extrudability, toughness, and corrosion resistance that are expected by homogenization treatment, homogenization cannot be achieved at a temperature of about 530 to 540℃. There are also many requests for processing. Therefore, in such a case, the present invention solves the technical problem regarding tool wear by selecting the subsequent processing conditions, especially the drawing processing conditions usually performed after extrusion processing, within a specific range. The main theme is to improve these points. Therefore, in this invention, the limitation of the homogenization treatment conditions to 500°C or higher does not itself constitute the main feature of the invention, but the tool wear resistance can be improved by the specific conditions of the drawing process described below. Its limiting significance lies in the fact that it forms the premise for specifying the object to be measured. In practice, the homogenization treatment when applying this invention is performed at a temperature in the range of 500 to 550°C. Next, the drawing process will be explained. The drawing process is generally performed on an extruded product after extrusion processing for the purpose of correcting dimensional distortion, increasing mechanical strength, etc. However, in this drawing process, the processing rate also has a large effect on the wear of the cutting tool. That is, 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, from the point of view of tool life, it is most preferable not to perform this drawing process, and the scope of the present invention also includes the case where the processing rate is 0%, that is, the case where no drawing process is performed. However, in practice, even when performing drawing processing, if the homogenization treatment is performed at a temperature of 500℃ or higher as mentioned above, the maximum allowable range of the processing rate is
Limited to 10% or less. In other words, when drawing is performed at a processing rate of more than 10%, the homogenization process is performed at the above-mentioned temperature, which results in a significant increase in cutting force, and the wear resistance of the cutting tool becomes unsatisfactory. I can't get the results I want. Therefore, this invention reduces the processing rate to 10 when performing drawing processing.
% or less. Note that the extrusion process performed after the homogenization process and before the drawing process may cause Al-Mg depending on the process conditions.
It does not have a particularly large effect on the machinability of the alloy, the wear resistance of cutting tools, etc.
It is processed at an extrusion temperature of about 400 to 500°C. 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 compositions of various Al-Mg alloys that meet the range of alloy composition conditions of the present invention. After melting and casting each of these in accordance with conventional methods, the ingots were homogenized under the various conditions shown in Table 2, and then extruded at an extrusion temperature of 400°C to
It was made into a 20mm rod. This rod was then subjected to drawing processing at various processing rates shown in Table 2, and the properties of each were investigated.

【table】

[Table] Table 3 shows the mechanical properties, corrosion resistance,
The wear resistance of cutting tools is shown in comparison. Mechanical properties were measured using a JIS No. 4 test piece at a gauge distance of 50 mm, and corrosion resistance was measured by observing the surface corrosion after 500 hours of salt spray acceleration treatment according to JIS Z2371. . 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 0° Mounting angle 90° Using a high-speed hard cutting tool (SKH4) with the following specifications, each sample was cut using an automatic cutting machine under the following cutting conditions for 30 minutes, and then the wear width on the flank surface of the cutting tool was measured. be. (Cutting conditions) Cutting speed 300m/min Depth of cut 1mm Feed rate 0.2mm/rev Lubricant No lubrication In the results shown in Table 3, the examples of the present invention are compared with the comparative examples in terms of mechanical properties and corrosion resistance. are equivalent. On the other hand, with regard to the wear resistance of cutting tools, the embodiments of the present invention
The Al-Mg alloy clearly shows an improvement in tool life compared to a comparative example using an alloy with the same Mg content. Therefore, the aluminum alloy for cutting according to the present invention has properties superior to conventional products in terms of tool life, and is suitable for high-speed cutting with automatic cutting machines.

【table】

Claims (1)

[Claims] 1 Using an aluminum-based alloy containing 2.0 to 8.0% Mg (wt%, same hereinafter) and containing at least 0.20% or less of at least one of Mn and Cr as necessary, an ingot of the aluminum-based alloy, Especially 500
A method for producing an aluminum alloy for cutting, characterized in that the aluminum alloy is extruded after being homogenized at a temperature of ℃ or higher, and then the extruded product is further subjected to drawing processing at a processing rate of 10% or less.