JPS6227542A - Aluminum alloy for magnetic tape sliding parts - Google Patents

Abstract

PURPOSE:To obtain the titled aluminum alloy having superior machined surface and excellent in wear resistance to tapes by incorporating specific percentage of Cu, Fe, Si, Mg, Cr, Pb, Bi and Sn to Al. CONSTITUTION:The Al alloy consisting of, by weight, 0.5-5.0% Cu, 0.1-1.0% Fe, 6-10% Si, 0.05-2.0% Mg, 0.1-0.5% Cr, further 0.5-2.0%, in total, of one or more kinds among Pb, Bi and Sn and the balance Al with usual impurities and containing, if necessary, 0.5-2.0% Ni is prepared. Further, it is necessary to refine eutectic Si by the addition of trace amounts of Na, Sb, Sr, etc., at casting. In this way, the aluminum alloy for magnetic tape sliding parts having satisfactory surface hardness and wear resistance, capable of cold forging until considerably complicated shapes are reached and having superior machined surface can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a magnetic tape slider that has sufficient surface hardness and wear resistance, can be cold-forged into fairly complex shapes, and has a good cutting surface. This invention relates to aluminum alloys for moving parts.

[Conventional technology and its problems]

Conventionally, AC5 was mainly used for magnetic tape sliding parts.
Cast alloys such as A, ACaA and 2218 extruded rods and 2218 cast rods have been used. However, magnetic tape sliding parts made of these aluminum alloys all have some problems in manufacturing or product performance.

In other words, in the case of cast alloys such as AC5A and ACaA, surface defects caused by cavities and coarse crystallized substances occur on the machined surface that contacts the sliding surface of the magnetic tape, and magnetic powder often adheres when the tape runs. . Furthermore, in the case of 2218 extruded rods and 2218 cast rods, machinability is not very good and costs tend to be high.

Furthermore, due to recent advances in VTR equipment, in addition to conventional models, consideration is being given to transitioning to lightweight, compact, and high-performance models (such as the G-millimeter movie type). It is also necessary to increase the relative speed of moving parts, and the wear resistance of conventional alloys tends not to be sufficient.

[Means for solving problems]

In view of this, the present invention was developed as a result of various researches, and is a magnetic tape sliding component that has sufficient surface hardness and wear resistance, can be cold-forged into complex shapes, and has a good cutting surface. This is an aluminum alloy developed for Cuo, 5-5.
Owt% (% indicates wt% below) Fa0.1
~1.0%, 5i6-10%, Mg0.5-2.0,
Contains 0.1-0.5% Cr and further P, one or more of Bi%Sn, a total of 0.5-2.0mm, and if necessary Ni0.5-2.0mm. and the remainder M
and normal impurities.

[For production]

That is, in the present invention, the strength is increased by adding tu K S i and Mg, and at the same time, 81 is added in a considerably excessive amount than the amount of Sl required to make Mg and Si to form the eutectic S1.
In order to improve the wear resistance by forming Cu,
Further improve wear resistance by adding Fe and Cr.
On the other hand, in order to improve machinability and obtain a good cut surface, one or more of P6%Bi and Sn was added. Furthermore, in the case of high-performance magnetic tape sliding parts, there is a slight rise in temperature, so in that case, adding N1 is effective in obtaining stable wear resistance. However, in order to obtain good wear resistance and a good cut surface, Na and Sb are added during casting.
It is necessary to refine the eutectic Sl by adding trace amounts of , Sr, etc. Furthermore, the eutectic S1 refinement method is to maintain the molten metal temperature at 700-800°C at the end of melting, refine the eutectic Si by straining, adding trace amounts of Sb, Sr, etc., and then adding Mg. Akira S
It is characterized by promoting the miniaturization of i, and adding Bi or Sn immediately before the start of casting to prevent bonding with Mg and the like, and to disperse it uniformly and finely.

In the alloy of the present invention, the content of each additive element is limited as described above for the following reasons. That is, Cu
has the effect of increasing the strength of the base, and plays an auxiliary role in improving the wear resistance by eutectic Si. If it is less than 0.05%, no sufficient effect will be obtained, and if it exceeds 50%, cold forgeability will be degraded. Fe is an essential element for improving wear resistance, and if it is less than 0.1 inch, no effect is observed, and if it exceeds the LO coefficient, it reduces corrosion resistance. Sl is a main element that improves strength and wear resistance, and if it is less than 6%, the wear resistance will be equivalent to that of conventional alloys and is insufficient, and if it exceeds 10%, cold forgeability and cutting finish will deteriorate.

Furthermore, in order to improve cold forgeability, finished cutting surface, and wear resistance, it is essential to refine the eutectic Si by the method described above. Mg is an element that combines with Si to increase strength, and if it is less than 0.5 inches, the effect is insufficient, and if it exceeds 20 inches, cold forgeability is degraded. Cr is an essential element for improving wear resistance, and if it is less than 0.1%, its effect is insufficient, and if it exceeds 0.5%, it increases quenching sensitivity and reduces strength. P9. Bi and Sn
Both improve the cut surface and show similar effects when used alone or in combination, but if the total amount is less than 0.5%, the effect is small, and if it exceeds 2.0%, the strength and corrosion resistance are reduced. Ni is an element that can maintain wear resistance even when the temperature rises, and if it is less than 0.5%, its effect is insufficient, and if it exceeds 2.0%, the wear resistance effect is saturated. Therefore, Xl may be added depending on the degree of quality requirements.

One of the characteristics of the alloy of the present invention is that it can be easily cold-forged, and by cold forging, the dispersion of the υ precipitated particles becomes finer and more uniform, resulting in improved strength, wear resistance, and machinability. Then, solution treatment, quenching, and high-temperature aging are performed to obtain the desired strength. However, since the shape is almost close to the target product due to cold forging, there are no problems with dimensional accuracy or magnetic Cutting is performed only on the area that touches the tape sliding surface.

〔Example〕

Next, examples of the alloy of the present invention will be described. , the present invention alloys (Nα1-7) shown in Table 1, the comparative alloys (T4118)
~10) and conventional alloys (Nα11 to 13), test materials were prepared by the following method, and cold forgeability, cutting finish,
Abrasion resistance, tensile strength and corrosion resistance were investigated. The results are shown in Table 2.

Cold forgeability For the present invention alloys Nα1 to 7, comparative alloys No. 8 to 10, and conventional alloy Nα13, 50 cast rods with a diameter of 2.20 mm were used.
After soaking at a temperature of 0°C for 12 hours, the test material was extruded at a temperature of 1100°C into a round bar with a diameter of 65M. Also, for conventional alloy N11ll~12, the diameter is 6
Group 5's cast rods were used as test materials.

By cold forging using these test materials, magnetic tape Note 1 conventional alloy Nα11 is equivalent to AA221g.
Height I N (L12 is AA-Si-Cu alloy-r
Nα13 was processed into a shape similar to that of an AA-Si-p-3n alloy sliding part, and its forgeability was evaluated based on the occurrence of cracks and the like.

5 CO using test materials for which evaluation of cutting finish and other cold forgeability has been completed.
After being solution treated for 24 hours at 24° C., water quenching was performed, followed by high-temperature aging at 170° C. for 10 hours to obtain the test material [7]. For these test materials, the finished surface, 1st grade wear, tensile strength, and corrosion resistance were examined.

For the cut surface, the area that corresponds to the sliding surface of the magnetic tape is
- ~ 'Mon 1' A mirror finish was applied with a cutting blade, and the maximum surface roughness Rmax was measured. Abrasion resistance was measured by a tape running test using VTR magnetic tape using a mirror-finished test material)
1. Evaluation of wear resistance was carried out for 00 hours. However, there were two test temperatures: 20°C and 110°C. Corrosion resistance is 1 in a constant temperature and humidity atmosphere with a temperature of IIO℃ and a humidity of 100%.
It was kept for 2 days and evaluated based on the weight change during that time.

As can be seen from Table 2, the alloys Nα1 to 7 of the present invention exhibit cold forgeability equivalent to or better than the comparative alloys N (L8 to 10 and conventional alloys Nα11 and 13), and in terms of the cutting surface, the conventional alloy Nα111 A better cut surface can be obtained than 13.Also, in terms of wear resistance with tape, conventional alloy N(1
Nos. 11 to 13 show much better abrasion resistance. In terms of tensile strength and corrosion resistance, the alloy of the present invention has properties equivalent to or better than those of conventional alloys. On the other hand, comparative alloys NIL g and 9, which are outside the composition range of the alloy of the present invention,
Cr is not added or p[+, Bi, S
If none of n is added, the surface roughness of the cut surface will be insufficient; on the other hand, comparative alloy N [L 8
When Or 2 is not added and the amount of Fe 2 added is small, as in No. 10 and 10, the abrasion resistance with the tape is insufficient.

〔Effect of the invention〕

As described above, according to the alloy of the present invention, magnetic tape sliding parts can be obtained that have sufficient surface hardness and wear resistance, can be cold-forged into fairly complex shapes, and have a good cutting surface. Among these, it is particularly characterized by a good cutting surface and good abrasion resistance with the tape.

Claims (1)

[Claims] 1) Cu0.5-5.0wt%, Fe0.1-1.0w
t%, Si6-10wt%, Mg0.5-2.0wt%
, 0.1 to 0.5 wt% of Cr, and a total of 0.5 to 2.0 wt% of one or more of Pb, Bi, and Sn.
%, optionally 0.5 to 2.0 wt % Ni, and the remainder Al and normal impurities.