JPH0136543B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an aluminum alloy for magnetic tape contact parts that has excellent machinability and frictional properties. The present invention relates to an aluminum alloy for magnetic tape contact parts, which has characteristics suitable for upper and lower cylinders and tape guide parts, has excellent machinability, and has excellent friction characteristics. [Prior Art] The heart of a VTR consists of a rotating magnetic head for magnetically recording and reproducing video signals on a magnetic tape, and a tape guide drum for stably running the magnetic tape. These parts are used every time you record or play back video.
It comes into contact with the magnetic surface of the tape that has magnetic particles attached to it, causing repeated friction. Therefore, in order to run the magnetic tape stably without damaging it, improve the precision of the reproduced video, and obtain high-quality images, that is, images with no color unevenness and high clarity, efforts are being made to improve and improve magnetic tapes. There is a strong need for improved materials for magnetic tape contact components. Therefore, the following properties are required for materials for magnetic tape contact parts. (1) Excellent tape abrasion resistance. (2) The coefficient of friction with the tape is small. (3) Excellent mechanical properties. (4) Excellent machinability (tool life, cutting finish). (5) Excellent deformability (cold forgeability). (6) Low coefficient of thermal expansion. In order to improve the accuracy of reconstructed images, among the above properties, (1) excellent tape friction resistance, and (2) a small coefficient of friction with the tape are the most important properties. has been done. Since various magnetic tape contact parts having these properties have been proposed in the past,
Hereinafter, conventional materials for magnetic tape contact parts will be explained. Copper alloy with Cr hard plating on the surface, austenitic type, for VTR tape contact parts.
There are SUS materials, ceramic coatings, aluminum casting materials with alumite coating, etc., but there are difficulties in improving quality and productivity. Traditionally, alloys that focused on friction resistance were
Al-Si-Cu-Mg alloy material equivalent to A4032 is well known. In addition, aluminum alloy is lightweight,
The Al-Si-Cu-Mg alloy mentioned above has excellent wear resistance and mechanical properties, so it is generally suitable as a material for tape contact parts because it has excellent processability and is non-magnetic. By providing excellent machinability for this type of alloy without sacrificing strength, good results have been obtained as a material for VTR tape contact parts, but the hard primary Si particles peel off. There is a problem of damaging the magnetic tape. Further, there is also the problem that the life of the cutting blade during cutting, the surface roughness of the machined surface, and the finished dimensional accuracy are not sufficient. [Problems to be solved by the invention] The present invention solves the conventional problems as explained above.
In view of the various problems with materials for magnetic tape contact parts of VTRs, the present inventor has completed intensive research, and that is, the material has the properties required as a material for magnetic tape contact parts as explained above. In particular, it has excellent machinability (tool wear), excellent tape wear resistance, and a low coefficient of friction with the tape, making it suitable for parts such as VTR upper and lower cylinders and magnetic tape guide parts. Excellent machinability with
The present invention also provides an aluminum alloy for magnetic tape contact parts that has excellent frictional properties. [Means for solving the problems] The aluminum alloy for magnetic tape contact parts having excellent machinability and friction properties according to the present invention has: (1) Zn0.4-1.5wt%, Si6.1- 12.0wt%, Cu2.0~
5.0 wt%, Mg 0.2 to 1.5 wt%, and the remainder substantially consists of Al, which is an aluminum alloy for magnetic tape contact parts that has excellent machinability and friction characteristics. (2) Zn0.4~1.5wt%, Si6.1~12.0wt%, Cu2.0~
5.wt%, Mg0.2~1.5wt%, and contains one or both of Fe0.7wt% or less, Mn0.7wt% or less, and Ti0.2wt% or less, Zr0.2wt A second invention provides an aluminum alloy for magnetic tape contact parts, which has excellent machinability and friction characteristics, and is characterized by containing one or two of the following % or less, and the remainder being substantially Al. This invention consists of two inventions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The aluminum alloy for magnetic tape contact parts having excellent machinability and frictional properties according to the present invention will be described in detail below. First, the components and component ratios of the aluminum alloy for magnetic tape contact parts having excellent machinability and friction characteristics according to the present invention will be explained. Zn is an important element that improves tape wear resistance and lowers the coefficient of friction. Zn is thought to exert a lubricating effect by solid solution in the aluminum base, and its content is 0.4wt%. Below 1.5wt, this effect is not sufficient;
If the content exceeds %, processability and strength will be impaired. Therefore, the Zn content is set to 0.4 to 1.5 wt%. Si is an important element for improving tape friction resistance and lowering the friction coefficient.
If it is less than 6.1wt%, the effect of improving tape abrasion resistance and reducing the coefficient of friction is small, and
If the content exceeds 12.0 wt%, these effects will improve, but the machinability will decrease. Therefore, the Si content is set to 6.1 to 12.0 wt%. Cu is an element that increases strength and improves machinability by forming Al-Cu-Mg-based precipitates.If the content is less than 2.0wt%, this effect is not sufficient; If the content exceeds wt%, the tape wear resistance will decrease and the processability (deformability) will decrease.
also deteriorates. Therefore, the Cu content is 2.0~5.0wt%
shall be. Mg is an element that reduces the coefficient of friction, and when the content is less than 0.2wt%, this effect is small, and
If the content exceeds 1.5 wt%, the tape wear resistance will be poor and the deformation resistance will be increased, resulting in a decrease in workability.
Therefore, the Mg content is set to 0.2 to 1.5 wt%. Fe and Mn are elements that reduce the wear coefficient.
By containing one or both of Fe and Mn, the frictional properties with the magnetic tape are improved, and during solidification, a compound of Al ₆ (MnFe) is crystallized, which improves the frictional properties. Yes, the content is
If both Fe and Mn are contained in excess of 0.7wt%, workability will be impaired and corrosion resistance will also be adversely affected. Then,
The Fe content is 0.7wt% or less, and the Mn content is 0.7wt% or less. Ti refines the casting structure, Zn refines the recrystallized structure, improves the strength and workability of the alloy, and Ti,
Even if the Zr content exceeds 0.2 Wt%, the effect is not so great, and on the contrary, giant intermetallic compounds are crystallized, which adversely affects workability and cutting properties. Therefore, the Ti content should be 0.2wt% or less, and the Zr content should be 0.2wt% or less. Next, the effects of Si and Zn contained in the aluminum alloy for magnetic tape contact parts having excellent machinability and friction properties according to the present invention will be explained in more detail. In general, the higher the Si content, the better the wear resistance, but on the other hand, it is also known to shorten tool life during cutting, so if machinability is important, wear resistance may be sacrificed to some extent. must be
For example, VTR cylinders are no exception. However, in the past, not much research has been done on the influence of material factors on the friction properties of aluminum alloys as magnetic tape contact materials, and the present inventor investigated the characteristics of various commercially available magnetic tapes. We selected a magnetic tape and studied the components and component ratios that affect the frictional properties between the magnetic tape and aluminum alloy. According to the research conducted by the present inventor, it is extremely effective to include Si in order to improve tape wear resistance and reduce the coefficient of friction.
It has been found that the effect is even more significant when these are simultaneously included. In Al-4Cu-1Mg alloys with different Si contents, the results of Si content against tape wear resistance and friction coefficient are marked with ○. The results of aluminum alloys for magnetic tape contact parts with excellent properties are shown in [Figures 1a and 2a] with ● marks. Furthermore, to explain the effect of Zn, the results of the dependence of Zn content on tape wear resistance and friction coefficient in Al-8Si-4Cu-1Mg alloys with different Zn contents [Fig. 1b, As shown in Figure 2b], it was found that the inclusion of Zn improved the tape abrasion resistance and reduced the coefficient of friction. This is thought to be due to the fact that Zn brings about a lubricating effect by forming a solid solution in the Al base. In addition to this Zn, low melting point metals such as Pb and Sn also have a similar effect, but Pb and Sn have a lubricating effect. It cannot be used as a substitute for Zn because it hardly dissolves in solid solution and impairs corrosion resistance. And even if the Si content is relatively low, Zn
The above effects can be obtained by containing Si, which can suppress the Si content, which is problematic for tool life, and as a result, tool life can be extended,
In addition, it has excellent tape abrasion resistance and a small coefficient of friction, making it ideal as an aluminum alloy for magnetic tape contact parts. Furthermore, when explaining Si content, machinability, and tape abrasion resistance in Fig. 3, the higher the Si content, the better the tape abrasion resistance, while the machinability tends to be inferior. ), the alloy of the present invention (marked with ▲) shows that excellent tape abrasion resistance can be obtained with a low Si content. For example, it can be seen that alloy No. 2 of the present invention, which has tape wear resistance equal to or higher than conventional alloy No. 10, has superior machinability. [Example] An example of an aluminum alloy for magnetic tape contact parts having excellent machinability and friction characteristics according to the present invention will be described. Example Aluminum alloys having the components and content ratios shown in Table 1 were melted by a conventional method (in this case, a refiner such as Na or Sr may be used). Next, it was made into a billet of 150φ and heated to 480℃.
After soaking for ×8 hours, the extrusion temperature was 420°C.
A 63φ rod was prepared at an extrusion speed of 5 m/min and used as a test material. The various test results are shown in Table 1. Friction properties, cutting tests, and tensile strength were tested using T6 heat treated test pieces, and deformability was tested using O heat treated test pieces. T6 heat treatment Solution treatment; 510℃×1Hr→Water cooling Aging treatment：170℃×10Hr O heat treatment 380℃×2Hr→Slow cooling ≪Test method≫ (1) Tape abrasion resistance Cylindrical test on commercially available VTR magnetic tape The pieces were rotated in contact and the amount of wear was measured. In addition, adjustment was made using a tape feeding device so that the tape magnetic powder on the contact surface did not peel off. Tape wear resistance: WS Average roughness of test piece before test: Ra ₀ (μ) Average roughness of test piece after test: Ra ₁ (μ) WS=Ra ₀ −Ra ₁ (2) Coefficient of dynamic friction Cylindrical test piece A commercially available VTR magnetic tape was run with a winding angle of 90°C under a reverse tension of 70g, the applied load was measured, and the coefficient of dynamic friction was measured. Incidentally, the coefficient of friction is the ratio of the magnitude of the frictional force F acting on the contact surfaces of two objects to the magnitude R of the force (vertical load) that presses the two surfaces perpendicularly = F/P
It is expressed as Note that it is an anonymous number. (3) Deformability A cylindrical specimen with a constant diameter and a constant height was deformed using the drop hammer method, and the machining rate at which cracking occurred was defined as the critical machining rate. (4) Tool wear A 63φ T6 heat-treated rod was continuously machined externally, and the partition deterioration of the cutting surface due to tool wear was observed and the degree of deterioration was evaluated into three levels. Yu←‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
--→Poor A B C Cutting conditions Cutting speed 100 m/min Feed 0.03 mm/rev Depth of cut 0.5 mm No cutting oil Tool SKH type 4 single-edged bit (rake angle 0°, nip angle 7°)

【table】

〔Effect of the invention〕

As explained above, since the aluminum alloy for magnetic tape contact parts having excellent machinability and friction characteristics according to the present invention has the above-mentioned structure, it has excellent tape abrasion resistance, It has the excellent effects of having a small coefficient of friction, excellent machinability, and being able to obtain high-quality images.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the relationship between tape abrasion resistance, friction coefficient, and Si and Zn, and Figure 3 is a diagram showing the relationship between tape wear resistance, friction coefficient, and Si and Zn.
FIG. 3 is a diagram showing the relationship between content, machinability, and tape wear resistance.

Claims (1)

[Claims] 1 Zn0.4~1.5wt%, Si6.1~12.0wt%, Cu2.0~
An aluminum alloy for magnetic tape contact parts having excellent machinability and friction characteristics, the aluminum alloy containing 5.0 wt%, Mg 0.2 to 1.5 wt%, and the remainder substantially consisting of Al. 2 Zn0.4~1.5wt%, Si6.1~12.0wt%, Cu2.0~
5.0wt%, Mg0.2~1.5wt%, and contains one or both of Fe0.7wt% or less and Mn0.7wt% or less, and Ti0.2wt% or less and Zr0.2wt%. An aluminum alloy for magnetic tape contact parts having excellent machinability and frictional properties, characterized by containing one or two of the following, and the remainder being substantially Al.